From 4bfbc2691de8c869339090e851703209b17ba378 Mon Sep 17 00:00:00 2001 From: Thorsten Blum Date: Tue, 10 Jun 2025 12:40:59 +0200 Subject: [PATCH 01/22] mux: Convert mux_control_ops to a flex array member in mux_chip Convert mux_control_ops to a flexible array member at the end of the mux_chip struct and add the __counted_by() compiler attribute to improve access bounds-checking via CONFIG_UBSAN_BOUNDS and CONFIG_FORTIFY_SOURCE. Use struct_size() to calculate the number of bytes to allocate for a new mux chip and to remove the following Coccinelle/coccicheck warning: WARNING: Use struct_size Use size_add() to safely add any extra bytes. No functional changes intended. Link: https://github.com/KSPP/linux/issues/83 Signed-off-by: Thorsten Blum Link: https://lore.kernel.org/r/20250610104106.1948-2-thorsten.blum@linux.dev Signed-off-by: Kees Cook --- drivers/mux/core.c | 7 +++---- include/linux/mux/driver.h | 4 ++-- 2 files changed, 5 insertions(+), 6 deletions(-) diff --git a/drivers/mux/core.c b/drivers/mux/core.c index 02be4ba37257..a3840fe0995f 100644 --- a/drivers/mux/core.c +++ b/drivers/mux/core.c @@ -98,13 +98,12 @@ struct mux_chip *mux_chip_alloc(struct device *dev, if (WARN_ON(!dev || !controllers)) return ERR_PTR(-EINVAL); - mux_chip = kzalloc(sizeof(*mux_chip) + - controllers * sizeof(*mux_chip->mux) + - sizeof_priv, GFP_KERNEL); + mux_chip = kzalloc(size_add(struct_size(mux_chip, mux, controllers), + sizeof_priv), + GFP_KERNEL); if (!mux_chip) return ERR_PTR(-ENOMEM); - mux_chip->mux = (struct mux_control *)(mux_chip + 1); mux_chip->dev.class = &mux_class; mux_chip->dev.type = &mux_type; mux_chip->dev.parent = dev; diff --git a/include/linux/mux/driver.h b/include/linux/mux/driver.h index 18824064f8c0..e58e59354e23 100644 --- a/include/linux/mux/driver.h +++ b/include/linux/mux/driver.h @@ -56,18 +56,18 @@ struct mux_control { /** * struct mux_chip - Represents a chip holding mux controllers. * @controllers: Number of mux controllers handled by the chip. - * @mux: Array of mux controllers that are handled. * @dev: Device structure. * @id: Used to identify the device internally. * @ops: Mux controller operations. + * @mux: Array of mux controllers that are handled. */ struct mux_chip { unsigned int controllers; - struct mux_control *mux; struct device dev; int id; const struct mux_control_ops *ops; + struct mux_control mux[] __counted_by(controllers); }; #define to_mux_chip(x) container_of((x), struct mux_chip, dev) From 29bb79e9dbf1ba100125e39deb7147acd490903f Mon Sep 17 00:00:00 2001 From: "Gustavo A. R. Silva" Date: Tue, 17 Jun 2025 13:05:36 -0600 Subject: [PATCH 02/22] stddef: Introduce TRAILING_OVERLAP() helper macro Add new TRAILING_OVERLAP() helper macro to create a union between a flexible-array member (FAM) and a set of members that would otherwise follow it. This overlays the trailing members onto the FAM while preserving the original memory layout. Co-developed-by: Kees Cook Signed-off-by: Gustavo A. R. Silva Link: https://lore.kernel.org/r/aFG8gEwKXAWWIvX0@kspp Signed-off-by: Kees Cook --- include/linux/stddef.h | 20 ++++++++++++++++++++ 1 file changed, 20 insertions(+) diff --git a/include/linux/stddef.h b/include/linux/stddef.h index 929d67710cc5..dab49e2ec8c0 100644 --- a/include/linux/stddef.h +++ b/include/linux/stddef.h @@ -93,4 +93,24 @@ enum { #define DECLARE_FLEX_ARRAY(TYPE, NAME) \ __DECLARE_FLEX_ARRAY(TYPE, NAME) +/** + * TRAILING_OVERLAP() - Overlap a flexible-array member with trailing members. + * + * Creates a union between a flexible-array member (FAM) in a struct and a set + * of additional members that would otherwise follow it. + * + * @TYPE: Flexible structure type name, including "struct" keyword. + * @NAME: Name for a variable to define. + * @FAM: The flexible-array member within @TYPE + * @MEMBERS: Trailing overlapping members. + */ +#define TRAILING_OVERLAP(TYPE, NAME, FAM, MEMBERS) \ + union { \ + TYPE NAME; \ + struct { \ + unsigned char __offset_to_##FAM[offsetof(TYPE, FAM)]; \ + MEMBERS \ + }; \ + } + #endif From 5e54510a9389caa922360218a83a58cd30fec686 Mon Sep 17 00:00:00 2001 From: "Gustavo A. R. Silva" Date: Fri, 27 Jun 2025 12:55:19 -0600 Subject: [PATCH 03/22] acpi: nfit: intel: avoid multiple -Wflex-array-member-not-at-end warnings -Wflex-array-member-not-at-end was introduced in GCC-14, and we are getting ready to enable it, globally. Use the new TRAILING_OVERLAP() helper to fix a dozen instances of the following type of warning: drivers/acpi/nfit/intel.c:692:35: warning: structure containing a flexible array member is not at the end of another structure [-Wflex-array-member-not-at-end] Acked-by: Dan Williams Tested-by: Dan Williams Signed-off-by: Gustavo A. R. Silva Link: https://lore.kernel.org/r/aF7pF4kej8VQapyR@kspp Signed-off-by: Kees Cook --- drivers/acpi/nfit/intel.c | 119 +++++++++++++++++--------------------- 1 file changed, 52 insertions(+), 67 deletions(-) diff --git a/drivers/acpi/nfit/intel.c b/drivers/acpi/nfit/intel.c index 3902759abcba..bce6f6a18426 100644 --- a/drivers/acpi/nfit/intel.c +++ b/drivers/acpi/nfit/intel.c @@ -55,10 +55,9 @@ static unsigned long intel_security_flags(struct nvdimm *nvdimm, { struct nfit_mem *nfit_mem = nvdimm_provider_data(nvdimm); unsigned long security_flags = 0; - struct { - struct nd_cmd_pkg pkg; + TRAILING_OVERLAP(struct nd_cmd_pkg, pkg, nd_payload, struct nd_intel_get_security_state cmd; - } nd_cmd = { + ) nd_cmd = { .pkg = { .nd_command = NVDIMM_INTEL_GET_SECURITY_STATE, .nd_family = NVDIMM_FAMILY_INTEL, @@ -120,10 +119,9 @@ static unsigned long intel_security_flags(struct nvdimm *nvdimm, static int intel_security_freeze(struct nvdimm *nvdimm) { struct nfit_mem *nfit_mem = nvdimm_provider_data(nvdimm); - struct { - struct nd_cmd_pkg pkg; + TRAILING_OVERLAP(struct nd_cmd_pkg, pkg, nd_payload, struct nd_intel_freeze_lock cmd; - } nd_cmd = { + ) nd_cmd = { .pkg = { .nd_command = NVDIMM_INTEL_FREEZE_LOCK, .nd_family = NVDIMM_FAMILY_INTEL, @@ -153,10 +151,9 @@ static int intel_security_change_key(struct nvdimm *nvdimm, unsigned int cmd = ptype == NVDIMM_MASTER ? NVDIMM_INTEL_SET_MASTER_PASSPHRASE : NVDIMM_INTEL_SET_PASSPHRASE; - struct { - struct nd_cmd_pkg pkg; + TRAILING_OVERLAP(struct nd_cmd_pkg, pkg, nd_payload, struct nd_intel_set_passphrase cmd; - } nd_cmd = { + ) nd_cmd = { .pkg = { .nd_family = NVDIMM_FAMILY_INTEL, .nd_size_in = ND_INTEL_PASSPHRASE_SIZE * 2, @@ -195,10 +192,9 @@ static int __maybe_unused intel_security_unlock(struct nvdimm *nvdimm, const struct nvdimm_key_data *key_data) { struct nfit_mem *nfit_mem = nvdimm_provider_data(nvdimm); - struct { - struct nd_cmd_pkg pkg; + TRAILING_OVERLAP(struct nd_cmd_pkg, pkg, nd_payload, struct nd_intel_unlock_unit cmd; - } nd_cmd = { + ) nd_cmd = { .pkg = { .nd_command = NVDIMM_INTEL_UNLOCK_UNIT, .nd_family = NVDIMM_FAMILY_INTEL, @@ -234,10 +230,9 @@ static int intel_security_disable(struct nvdimm *nvdimm, { int rc; struct nfit_mem *nfit_mem = nvdimm_provider_data(nvdimm); - struct { - struct nd_cmd_pkg pkg; + TRAILING_OVERLAP(struct nd_cmd_pkg, pkg, nd_payload, struct nd_intel_disable_passphrase cmd; - } nd_cmd = { + ) nd_cmd = { .pkg = { .nd_command = NVDIMM_INTEL_DISABLE_PASSPHRASE, .nd_family = NVDIMM_FAMILY_INTEL, @@ -277,10 +272,9 @@ static int __maybe_unused intel_security_erase(struct nvdimm *nvdimm, struct nfit_mem *nfit_mem = nvdimm_provider_data(nvdimm); unsigned int cmd = ptype == NVDIMM_MASTER ? NVDIMM_INTEL_MASTER_SECURE_ERASE : NVDIMM_INTEL_SECURE_ERASE; - struct { - struct nd_cmd_pkg pkg; + TRAILING_OVERLAP(struct nd_cmd_pkg, pkg, nd_payload, struct nd_intel_secure_erase cmd; - } nd_cmd = { + ) nd_cmd = { .pkg = { .nd_family = NVDIMM_FAMILY_INTEL, .nd_size_in = ND_INTEL_PASSPHRASE_SIZE, @@ -318,10 +312,9 @@ static int __maybe_unused intel_security_query_overwrite(struct nvdimm *nvdimm) { int rc; struct nfit_mem *nfit_mem = nvdimm_provider_data(nvdimm); - struct { - struct nd_cmd_pkg pkg; + TRAILING_OVERLAP(struct nd_cmd_pkg, pkg, nd_payload, struct nd_intel_query_overwrite cmd; - } nd_cmd = { + ) nd_cmd = { .pkg = { .nd_command = NVDIMM_INTEL_QUERY_OVERWRITE, .nd_family = NVDIMM_FAMILY_INTEL, @@ -354,10 +347,9 @@ static int __maybe_unused intel_security_overwrite(struct nvdimm *nvdimm, { int rc; struct nfit_mem *nfit_mem = nvdimm_provider_data(nvdimm); - struct { - struct nd_cmd_pkg pkg; + TRAILING_OVERLAP(struct nd_cmd_pkg, pkg, nd_payload, struct nd_intel_overwrite cmd; - } nd_cmd = { + ) nd_cmd = { .pkg = { .nd_command = NVDIMM_INTEL_OVERWRITE, .nd_family = NVDIMM_FAMILY_INTEL, @@ -407,10 +399,9 @@ const struct nvdimm_security_ops *intel_security_ops = &__intel_security_ops; static int intel_bus_fwa_businfo(struct nvdimm_bus_descriptor *nd_desc, struct nd_intel_bus_fw_activate_businfo *info) { - struct { - struct nd_cmd_pkg pkg; + TRAILING_OVERLAP(struct nd_cmd_pkg, pkg, nd_payload, struct nd_intel_bus_fw_activate_businfo cmd; - } nd_cmd = { + ) nd_cmd = { .pkg = { .nd_command = NVDIMM_BUS_INTEL_FW_ACTIVATE_BUSINFO, .nd_family = NVDIMM_BUS_FAMILY_INTEL, @@ -518,33 +509,31 @@ static enum nvdimm_fwa_capability intel_bus_fwa_capability( static int intel_bus_fwa_activate(struct nvdimm_bus_descriptor *nd_desc) { struct acpi_nfit_desc *acpi_desc = to_acpi_desc(nd_desc); - struct { - struct nd_cmd_pkg pkg; + TRAILING_OVERLAP(struct nd_cmd_pkg, pkg, nd_payload, struct nd_intel_bus_fw_activate cmd; - } nd_cmd = { - .pkg = { - .nd_command = NVDIMM_BUS_INTEL_FW_ACTIVATE, - .nd_family = NVDIMM_BUS_FAMILY_INTEL, - .nd_size_in = sizeof(nd_cmd.cmd.iodev_state), - .nd_size_out = - sizeof(struct nd_intel_bus_fw_activate), - .nd_fw_size = - sizeof(struct nd_intel_bus_fw_activate), - }, + ) nd_cmd; + int rc; + + nd_cmd.pkg = (struct nd_cmd_pkg) { + .nd_command = NVDIMM_BUS_INTEL_FW_ACTIVATE, + .nd_family = NVDIMM_BUS_FAMILY_INTEL, + .nd_size_in = sizeof(nd_cmd.cmd.iodev_state), + .nd_size_out = + sizeof(struct nd_intel_bus_fw_activate), + .nd_fw_size = + sizeof(struct nd_intel_bus_fw_activate), + }; + nd_cmd.cmd = (struct nd_intel_bus_fw_activate) { /* * Even though activate is run from a suspended context, * for safety, still ask platform firmware to force * quiesce devices by default. Let a module * parameter override that policy. */ - .cmd = { - .iodev_state = acpi_desc->fwa_noidle - ? ND_INTEL_BUS_FWA_IODEV_OS_IDLE - : ND_INTEL_BUS_FWA_IODEV_FORCE_IDLE, - }, + .iodev_state = acpi_desc->fwa_noidle + ? ND_INTEL_BUS_FWA_IODEV_OS_IDLE + : ND_INTEL_BUS_FWA_IODEV_FORCE_IDLE, }; - int rc; - switch (intel_bus_fwa_state(nd_desc)) { case NVDIMM_FWA_ARMED: case NVDIMM_FWA_ARM_OVERFLOW: @@ -582,10 +571,9 @@ const struct nvdimm_bus_fw_ops *intel_bus_fw_ops = &__intel_bus_fw_ops; static int intel_fwa_dimminfo(struct nvdimm *nvdimm, struct nd_intel_fw_activate_dimminfo *info) { - struct { - struct nd_cmd_pkg pkg; + TRAILING_OVERLAP(struct nd_cmd_pkg, pkg, nd_payload, struct nd_intel_fw_activate_dimminfo cmd; - } nd_cmd = { + ) nd_cmd = { .pkg = { .nd_command = NVDIMM_INTEL_FW_ACTIVATE_DIMMINFO, .nd_family = NVDIMM_FAMILY_INTEL, @@ -688,27 +676,24 @@ static int intel_fwa_arm(struct nvdimm *nvdimm, enum nvdimm_fwa_trigger arm) { struct nfit_mem *nfit_mem = nvdimm_provider_data(nvdimm); struct acpi_nfit_desc *acpi_desc = nfit_mem->acpi_desc; - struct { - struct nd_cmd_pkg pkg; + TRAILING_OVERLAP(struct nd_cmd_pkg, pkg, nd_payload, struct nd_intel_fw_activate_arm cmd; - } nd_cmd = { - .pkg = { - .nd_command = NVDIMM_INTEL_FW_ACTIVATE_ARM, - .nd_family = NVDIMM_FAMILY_INTEL, - .nd_size_in = sizeof(nd_cmd.cmd.activate_arm), - .nd_size_out = - sizeof(struct nd_intel_fw_activate_arm), - .nd_fw_size = - sizeof(struct nd_intel_fw_activate_arm), - }, - .cmd = { - .activate_arm = arm == NVDIMM_FWA_ARM - ? ND_INTEL_DIMM_FWA_ARM - : ND_INTEL_DIMM_FWA_DISARM, - }, - }; + ) nd_cmd; int rc; + nd_cmd.pkg = (struct nd_cmd_pkg) { + .nd_command = NVDIMM_INTEL_FW_ACTIVATE_ARM, + .nd_family = NVDIMM_FAMILY_INTEL, + .nd_size_in = sizeof(nd_cmd.cmd.activate_arm), + .nd_size_out = sizeof(struct nd_intel_fw_activate_arm), + .nd_fw_size = sizeof(struct nd_intel_fw_activate_arm), + }; + nd_cmd.cmd = (struct nd_intel_fw_activate_arm) { + .activate_arm = arm == NVDIMM_FWA_ARM ? + ND_INTEL_DIMM_FWA_ARM : + ND_INTEL_DIMM_FWA_DISARM, + }; + switch (intel_fwa_state(nvdimm)) { case NVDIMM_FWA_INVALID: return -ENXIO; From 10299c07c94aa0997fa43523b53301e713a6415d Mon Sep 17 00:00:00 2001 From: Kees Cook Date: Sat, 28 Jun 2025 16:40:38 -0700 Subject: [PATCH 04/22] kunit/fortify: Add back "volatile" for sizeof() constants MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit It seems the Clang can see through OPTIMIZER_HIDE_VAR when the constant is coming from sizeof. Adding "volatile" back to these variables solves this false positive without reintroducing the issues that originally led to switching to OPTIMIZER_HIDE_VAR in the first place[1]. Reported-by: Nathan Chancellor Closes: https://github.com/ClangBuiltLinux/linux/issues/2075 [1] Cc: Jannik Glückert Suggested-by: Nathan Chancellor Fixes: 6ee149f61bcc ("kunit/fortify: Replace "volatile" with OPTIMIZER_HIDE_VAR()") Reviewed-by: Nathan Chancellor Link: https://lore.kernel.org/r/20250628234034.work.800-kees@kernel.org Signed-off-by: Kees Cook --- lib/tests/fortify_kunit.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/lib/tests/fortify_kunit.c b/lib/tests/fortify_kunit.c index 29ffc62a71e3..fc9c76f026d6 100644 --- a/lib/tests/fortify_kunit.c +++ b/lib/tests/fortify_kunit.c @@ -1003,8 +1003,8 @@ static void fortify_test_memcmp(struct kunit *test) { char one[] = "My mind is going ..."; char two[] = "My mind is going ... I can feel it."; - size_t one_len = sizeof(one) - 1; - size_t two_len = sizeof(two) - 1; + volatile size_t one_len = sizeof(one) - 1; + volatile size_t two_len = sizeof(two) - 1; OPTIMIZER_HIDE_VAR(one_len); OPTIMIZER_HIDE_VAR(two_len); From 2d8ae9a4f1bc04a118e3d438ac50dd49281b34fd Mon Sep 17 00:00:00 2001 From: Andy Shevchenko Date: Fri, 11 Jul 2025 11:55:14 +0300 Subject: [PATCH 05/22] string: Group str_has_prefix() and strstarts() The two str_has_prefix() and strstarts() are about the same with a slight difference on what they return. Group them in the header. Signed-off-by: Andy Shevchenko Link: https://lore.kernel.org/r/20250711085514.1294428-1-andriy.shevchenko@linux.intel.com Signed-off-by: Kees Cook --- include/linux/string.h | 20 ++++++++++---------- 1 file changed, 10 insertions(+), 10 deletions(-) diff --git a/include/linux/string.h b/include/linux/string.h index 01621ad0f598..fdd3442c6bcb 100644 --- a/include/linux/string.h +++ b/include/linux/string.h @@ -345,16 +345,6 @@ extern ssize_t memory_read_from_buffer(void *to, size_t count, loff_t *ppos, int ptr_to_hashval(const void *ptr, unsigned long *hashval_out); -/** - * strstarts - does @str start with @prefix? - * @str: string to examine - * @prefix: prefix to look for. - */ -static inline bool strstarts(const char *str, const char *prefix) -{ - return strncmp(str, prefix, strlen(prefix)) == 0; -} - size_t memweight(const void *ptr, size_t bytes); /** @@ -562,4 +552,14 @@ static __always_inline size_t str_has_prefix(const char *str, const char *prefix return strncmp(str, prefix, len) == 0 ? len : 0; } +/** + * strstarts - does @str start with @prefix? + * @str: string to examine + * @prefix: prefix to look for. + */ +static inline bool strstarts(const char *str, const char *prefix) +{ + return strncmp(str, prefix, strlen(prefix)) == 0; +} + #endif /* _LINUX_STRING_H_ */ From fc07839203f3b98fa9afac370aaba283afc10433 Mon Sep 17 00:00:00 2001 From: Kees Cook Date: Thu, 17 Jul 2025 01:52:12 -0700 Subject: [PATCH 06/22] seq_buf: Introduce KUnit tests Add KUnit tests for the seq_buf API to ensure its correctness and prevent future regressions, covering the following functions: - seq_buf_init() - DECLARE_SEQ_BUF() - seq_buf_clear() - seq_buf_puts() - seq_buf_putc() - seq_buf_printf() - seq_buf_get_buf() - seq_buf_commit() $ tools/testing/kunit/kunit.py run seq_buf =================== seq_buf (9 subtests) =================== [PASSED] seq_buf_init_test [PASSED] seq_buf_declare_test [PASSED] seq_buf_clear_test [PASSED] seq_buf_puts_test [PASSED] seq_buf_puts_overflow_test [PASSED] seq_buf_putc_test [PASSED] seq_buf_printf_test [PASSED] seq_buf_printf_overflow_test [PASSED] seq_buf_get_buf_commit_test ===================== [PASSED] seq_buf ===================== Link: https://lore.kernel.org/r/20250717085156.work.363-kees@kernel.org Reviewed-by: David Gow Signed-off-by: Kees Cook --- lib/Kconfig.debug | 9 ++ lib/tests/Makefile | 1 + lib/tests/seq_buf_kunit.c | 208 ++++++++++++++++++++++++++++++++++++++ 3 files changed, 218 insertions(+) create mode 100644 lib/tests/seq_buf_kunit.c diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug index ebe33181b6e6..087beae1e8fb 100644 --- a/lib/Kconfig.debug +++ b/lib/Kconfig.debug @@ -2460,6 +2460,15 @@ config SCANF_KUNIT_TEST If unsure, say N. +config SEQ_BUF_KUNIT_TEST + tristate "KUnit test for seq_buf" if !KUNIT_ALL_TESTS + depends on KUNIT + default KUNIT_ALL_TESTS + help + This builds unit tests for the seq_buf library. + + If unsure, say N. + config STRING_KUNIT_TEST tristate "KUnit test string functions at runtime" if !KUNIT_ALL_TESTS depends on KUNIT diff --git a/lib/tests/Makefile b/lib/tests/Makefile index 56d645014482..8294abbe21f1 100644 --- a/lib/tests/Makefile +++ b/lib/tests/Makefile @@ -37,6 +37,7 @@ obj-$(CONFIG_OVERFLOW_KUNIT_TEST) += overflow_kunit.o obj-$(CONFIG_PRINTF_KUNIT_TEST) += printf_kunit.o obj-$(CONFIG_RANDSTRUCT_KUNIT_TEST) += randstruct_kunit.o obj-$(CONFIG_SCANF_KUNIT_TEST) += scanf_kunit.o +obj-$(CONFIG_SEQ_BUF_KUNIT_TEST) += seq_buf_kunit.o obj-$(CONFIG_SIPHASH_KUNIT_TEST) += siphash_kunit.o obj-$(CONFIG_SLUB_KUNIT_TEST) += slub_kunit.o obj-$(CONFIG_TEST_SORT) += test_sort.o diff --git a/lib/tests/seq_buf_kunit.c b/lib/tests/seq_buf_kunit.c new file mode 100644 index 000000000000..8a01579a978e --- /dev/null +++ b/lib/tests/seq_buf_kunit.c @@ -0,0 +1,208 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * KUnit tests for the seq_buf API + * + * Copyright (C) 2025, Google LLC. + */ + +#include +#include + +static void seq_buf_init_test(struct kunit *test) +{ + char buf[32]; + struct seq_buf s; + + seq_buf_init(&s, buf, sizeof(buf)); + + KUNIT_EXPECT_EQ(test, s.size, 32); + KUNIT_EXPECT_EQ(test, s.len, 0); + KUNIT_EXPECT_FALSE(test, seq_buf_has_overflowed(&s)); + KUNIT_EXPECT_EQ(test, seq_buf_buffer_left(&s), 32); + KUNIT_EXPECT_EQ(test, seq_buf_used(&s), 0); + KUNIT_EXPECT_STREQ(test, seq_buf_str(&s), ""); +} + +static void seq_buf_declare_test(struct kunit *test) +{ + DECLARE_SEQ_BUF(s, 24); + + KUNIT_EXPECT_EQ(test, s.size, 24); + KUNIT_EXPECT_EQ(test, s.len, 0); + KUNIT_EXPECT_FALSE(test, seq_buf_has_overflowed(&s)); + KUNIT_EXPECT_EQ(test, seq_buf_buffer_left(&s), 24); + KUNIT_EXPECT_EQ(test, seq_buf_used(&s), 0); + KUNIT_EXPECT_STREQ(test, seq_buf_str(&s), ""); +} + +static void seq_buf_clear_test(struct kunit *test) +{ + DECLARE_SEQ_BUF(s, 128); + + seq_buf_puts(&s, "hello"); + KUNIT_EXPECT_EQ(test, s.len, 5); + KUNIT_EXPECT_FALSE(test, seq_buf_has_overflowed(&s)); + KUNIT_EXPECT_STREQ(test, seq_buf_str(&s), "hello"); + + seq_buf_clear(&s); + + KUNIT_EXPECT_EQ(test, s.len, 0); + KUNIT_EXPECT_FALSE(test, seq_buf_has_overflowed(&s)); + KUNIT_EXPECT_STREQ(test, seq_buf_str(&s), ""); +} + +static void seq_buf_puts_test(struct kunit *test) +{ + DECLARE_SEQ_BUF(s, 16); + + seq_buf_puts(&s, "hello"); + KUNIT_EXPECT_EQ(test, seq_buf_used(&s), 5); + KUNIT_EXPECT_FALSE(test, seq_buf_has_overflowed(&s)); + KUNIT_EXPECT_STREQ(test, seq_buf_str(&s), "hello"); + + seq_buf_puts(&s, " world"); + KUNIT_EXPECT_EQ(test, seq_buf_used(&s), 11); + KUNIT_EXPECT_FALSE(test, seq_buf_has_overflowed(&s)); + KUNIT_EXPECT_STREQ(test, seq_buf_str(&s), "hello world"); +} + +static void seq_buf_puts_overflow_test(struct kunit *test) +{ + DECLARE_SEQ_BUF(s, 10); + + seq_buf_puts(&s, "123456789"); + KUNIT_EXPECT_FALSE(test, seq_buf_has_overflowed(&s)); + KUNIT_EXPECT_EQ(test, seq_buf_used(&s), 9); + + seq_buf_puts(&s, "0"); + KUNIT_EXPECT_TRUE(test, seq_buf_has_overflowed(&s)); + KUNIT_EXPECT_EQ(test, seq_buf_used(&s), 10); + KUNIT_EXPECT_STREQ(test, seq_buf_str(&s), "123456789"); + + seq_buf_clear(&s); + KUNIT_EXPECT_EQ(test, s.len, 0); + KUNIT_EXPECT_FALSE(test, seq_buf_has_overflowed(&s)); + KUNIT_EXPECT_STREQ(test, seq_buf_str(&s), ""); +} + +static void seq_buf_putc_test(struct kunit *test) +{ + DECLARE_SEQ_BUF(s, 4); + + seq_buf_putc(&s, 'a'); + seq_buf_putc(&s, 'b'); + seq_buf_putc(&s, 'c'); + + KUNIT_EXPECT_EQ(test, seq_buf_used(&s), 3); + KUNIT_EXPECT_FALSE(test, seq_buf_has_overflowed(&s)); + KUNIT_EXPECT_STREQ(test, seq_buf_str(&s), "abc"); + + seq_buf_putc(&s, 'd'); + KUNIT_EXPECT_EQ(test, seq_buf_used(&s), 4); + KUNIT_EXPECT_FALSE(test, seq_buf_has_overflowed(&s)); + KUNIT_EXPECT_STREQ(test, seq_buf_str(&s), "abc"); + + seq_buf_putc(&s, 'e'); + KUNIT_EXPECT_EQ(test, seq_buf_used(&s), 4); + KUNIT_EXPECT_TRUE(test, seq_buf_has_overflowed(&s)); + KUNIT_EXPECT_STREQ(test, seq_buf_str(&s), "abc"); + + seq_buf_clear(&s); + KUNIT_EXPECT_EQ(test, s.len, 0); + KUNIT_EXPECT_FALSE(test, seq_buf_has_overflowed(&s)); + KUNIT_EXPECT_STREQ(test, seq_buf_str(&s), ""); +} + +static void seq_buf_printf_test(struct kunit *test) +{ + DECLARE_SEQ_BUF(s, 32); + + seq_buf_printf(&s, "hello %s", "world"); + KUNIT_EXPECT_EQ(test, seq_buf_used(&s), 11); + KUNIT_EXPECT_FALSE(test, seq_buf_has_overflowed(&s)); + KUNIT_EXPECT_STREQ(test, seq_buf_str(&s), "hello world"); + + seq_buf_printf(&s, " %d", 123); + KUNIT_EXPECT_EQ(test, seq_buf_used(&s), 15); + KUNIT_EXPECT_FALSE(test, seq_buf_has_overflowed(&s)); + KUNIT_EXPECT_STREQ(test, seq_buf_str(&s), "hello world 123"); +} + +static void seq_buf_printf_overflow_test(struct kunit *test) +{ + DECLARE_SEQ_BUF(s, 16); + + seq_buf_printf(&s, "%lu", 1234567890UL); + KUNIT_EXPECT_FALSE(test, seq_buf_has_overflowed(&s)); + KUNIT_EXPECT_EQ(test, seq_buf_used(&s), 10); + KUNIT_EXPECT_STREQ(test, seq_buf_str(&s), "1234567890"); + + seq_buf_printf(&s, "%s", "abcdefghij"); + KUNIT_EXPECT_TRUE(test, seq_buf_has_overflowed(&s)); + KUNIT_EXPECT_EQ(test, seq_buf_used(&s), 16); + KUNIT_EXPECT_STREQ(test, seq_buf_str(&s), "1234567890abcde"); + + seq_buf_clear(&s); + KUNIT_EXPECT_EQ(test, s.len, 0); + KUNIT_EXPECT_FALSE(test, seq_buf_has_overflowed(&s)); + KUNIT_EXPECT_STREQ(test, seq_buf_str(&s), ""); +} + +static void seq_buf_get_buf_commit_test(struct kunit *test) +{ + DECLARE_SEQ_BUF(s, 16); + char *buf; + size_t len; + + len = seq_buf_get_buf(&s, &buf); + KUNIT_EXPECT_EQ(test, len, 16); + KUNIT_EXPECT_PTR_NE(test, buf, NULL); + + memcpy(buf, "hello", 5); + seq_buf_commit(&s, 5); + + KUNIT_EXPECT_EQ(test, seq_buf_used(&s), 5); + KUNIT_EXPECT_FALSE(test, seq_buf_has_overflowed(&s)); + KUNIT_EXPECT_STREQ(test, seq_buf_str(&s), "hello"); + + len = seq_buf_get_buf(&s, &buf); + KUNIT_EXPECT_EQ(test, len, 11); + KUNIT_EXPECT_PTR_NE(test, buf, NULL); + + memcpy(buf, " worlds!", 8); + seq_buf_commit(&s, 6); + + KUNIT_EXPECT_EQ(test, seq_buf_used(&s), 11); + KUNIT_EXPECT_FALSE(test, seq_buf_has_overflowed(&s)); + KUNIT_EXPECT_STREQ(test, seq_buf_str(&s), "hello world"); + + len = seq_buf_get_buf(&s, &buf); + KUNIT_EXPECT_EQ(test, len, 5); + KUNIT_EXPECT_PTR_NE(test, buf, NULL); + + seq_buf_commit(&s, -1); + KUNIT_EXPECT_TRUE(test, seq_buf_has_overflowed(&s)); +} + +static struct kunit_case seq_buf_test_cases[] = { + KUNIT_CASE(seq_buf_init_test), + KUNIT_CASE(seq_buf_declare_test), + KUNIT_CASE(seq_buf_clear_test), + KUNIT_CASE(seq_buf_puts_test), + KUNIT_CASE(seq_buf_puts_overflow_test), + KUNIT_CASE(seq_buf_putc_test), + KUNIT_CASE(seq_buf_printf_test), + KUNIT_CASE(seq_buf_printf_overflow_test), + KUNIT_CASE(seq_buf_get_buf_commit_test), + {} +}; + +static struct kunit_suite seq_buf_test_suite = { + .name = "seq_buf", + .test_cases = seq_buf_test_cases, +}; + +kunit_test_suite(seq_buf_test_suite); + +MODULE_DESCRIPTION("Runtime test cases for seq_buf string API"); +MODULE_LICENSE("GPL"); From 57fbad15c2eee77276a541c616589b32976d2b8e Mon Sep 17 00:00:00 2001 From: Kees Cook Date: Thu, 17 Jul 2025 16:25:06 -0700 Subject: [PATCH 07/22] stackleak: Rename STACKLEAK to KSTACK_ERASE In preparation for adding Clang sanitizer coverage stack depth tracking that can support stack depth callbacks: - Add the new top-level CONFIG_KSTACK_ERASE option which will be implemented either with the stackleak GCC plugin, or with the Clang stack depth callback support. - Rename CONFIG_GCC_PLUGIN_STACKLEAK as needed to CONFIG_KSTACK_ERASE, but keep it for anything specific to the GCC plugin itself. - Rename all exposed "STACKLEAK" names and files to "KSTACK_ERASE" (named for what it does rather than what it protects against), but leave as many of the internals alone as possible to avoid even more churn. While here, also split "prev_lowest_stack" into CONFIG_KSTACK_ERASE_METRICS, since that's the only place it is referenced from. Suggested-by: Ingo Molnar Link: https://lore.kernel.org/r/20250717232519.2984886-1-kees@kernel.org Signed-off-by: Kees Cook --- Documentation/admin-guide/sysctl/kernel.rst | 4 +-- Documentation/arch/x86/x86_64/mm.rst | 2 +- Documentation/security/self-protection.rst | 2 +- .../zh_CN/security/self-protection.rst | 2 +- MAINTAINERS | 4 +-- arch/Kconfig | 4 +-- arch/arm/Kconfig | 2 +- arch/arm/boot/compressed/Makefile | 2 +- arch/arm/kernel/entry-common.S | 2 +- arch/arm64/Kconfig | 2 +- arch/arm64/kernel/entry.S | 2 +- arch/arm64/kernel/pi/Makefile | 2 +- arch/arm64/kvm/hyp/nvhe/Makefile | 2 +- arch/loongarch/Kconfig | 2 +- arch/riscv/Kconfig | 2 +- arch/riscv/kernel/entry.S | 2 +- arch/riscv/kernel/pi/Makefile | 2 +- arch/riscv/purgatory/Makefile | 2 +- arch/s390/Kconfig | 2 +- arch/s390/kernel/entry.S | 2 +- arch/x86/Kconfig | 2 +- arch/x86/entry/calling.h | 4 +-- arch/x86/purgatory/Makefile | 2 +- drivers/firmware/efi/libstub/Makefile | 8 ++--- drivers/misc/lkdtm/Makefile | 2 +- .../lkdtm/{stackleak.c => kstack_erase.c} | 26 +++++++------- fs/proc/base.c | 6 ++-- include/linux/{stackleak.h => kstack_erase.h} | 18 +++++----- include/linux/sched.h | 4 ++- kernel/Makefile | 10 +++--- kernel/fork.c | 2 +- kernel/{stackleak.c => kstack_erase.c} | 18 +++++----- lib/Makefile | 2 +- scripts/Makefile.gcc-plugins | 6 ++-- security/Kconfig.hardening | 36 ++++++++++--------- tools/objtool/check.c | 2 +- tools/testing/selftests/lkdtm/config | 2 +- 37 files changed, 101 insertions(+), 95 deletions(-) rename drivers/misc/lkdtm/{stackleak.c => kstack_erase.c} (89%) rename include/linux/{stackleak.h => kstack_erase.h} (85%) rename kernel/{stackleak.c => kstack_erase.c} (90%) diff --git a/Documentation/admin-guide/sysctl/kernel.rst b/Documentation/admin-guide/sysctl/kernel.rst index dd49a89a62d3..19224eeac1c2 100644 --- a/Documentation/admin-guide/sysctl/kernel.rst +++ b/Documentation/admin-guide/sysctl/kernel.rst @@ -1465,7 +1465,7 @@ stack_erasing ============= This parameter can be used to control kernel stack erasing at the end -of syscalls for kernels built with ``CONFIG_GCC_PLUGIN_STACKLEAK``. +of syscalls for kernels built with ``CONFIG_KSTACK_ERASE``. That erasing reduces the information which kernel stack leak bugs can reveal and blocks some uninitialized stack variable attacks. @@ -1473,7 +1473,7 @@ The tradeoff is the performance impact: on a single CPU system kernel compilation sees a 1% slowdown, other systems and workloads may vary. = ==================================================================== -0 Kernel stack erasing is disabled, STACKLEAK_METRICS are not updated. +0 Kernel stack erasing is disabled, KSTACK_ERASE_METRICS are not updated. 1 Kernel stack erasing is enabled (default), it is performed before returning to the userspace at the end of syscalls. = ==================================================================== diff --git a/Documentation/arch/x86/x86_64/mm.rst b/Documentation/arch/x86/x86_64/mm.rst index f2db178b353f..a6cf05d51bd8 100644 --- a/Documentation/arch/x86/x86_64/mm.rst +++ b/Documentation/arch/x86/x86_64/mm.rst @@ -176,5 +176,5 @@ Be very careful vs. KASLR when changing anything here. The KASLR address range must not overlap with anything except the KASAN shadow area, which is correct as KASAN disables KASLR. -For both 4- and 5-level layouts, the STACKLEAK_POISON value in the last 2MB +For both 4- and 5-level layouts, the KSTACK_ERASE_POISON value in the last 2MB hole: ffffffffffff4111 diff --git a/Documentation/security/self-protection.rst b/Documentation/security/self-protection.rst index 910668e665cb..a32ca23c21b0 100644 --- a/Documentation/security/self-protection.rst +++ b/Documentation/security/self-protection.rst @@ -303,7 +303,7 @@ Memory poisoning When releasing memory, it is best to poison the contents, to avoid reuse attacks that rely on the old contents of memory. E.g., clear stack on a -syscall return (``CONFIG_GCC_PLUGIN_STACKLEAK``), wipe heap memory on a +syscall return (``CONFIG_KSTACK_ERASE``), wipe heap memory on a free. This frustrates many uninitialized variable attacks, stack content exposures, heap content exposures, and use-after-free attacks. diff --git a/Documentation/translations/zh_CN/security/self-protection.rst b/Documentation/translations/zh_CN/security/self-protection.rst index 3c8a68b1e1be..93de9cee5c1a 100644 --- a/Documentation/translations/zh_CN/security/self-protection.rst +++ b/Documentation/translations/zh_CN/security/self-protection.rst @@ -259,7 +259,7 @@ KALLSYSM，则会直接打印原始地址。 -------- 在释放内存时，最好对内存内容进行清除处理，以防止攻击者重用内存中以前 -的内容。例如，在系统调用返回时清除堆栈（CONFIG_GCC_PLUGIN_STACKLEAK）, +的内容。例如，在系统调用返回时清除堆栈（CONFIG_KSTACK_ERASE）, 在释放堆内容是清除其内容。这有助于防止许多未初始化变量攻击、堆栈内容 泄露、堆内容泄露以及使用后释放攻击（user-after-free）。 diff --git a/MAINTAINERS b/MAINTAINERS index 0c1d245bf7b8..470d159d8fea 100644 --- a/MAINTAINERS +++ b/MAINTAINERS @@ -9992,8 +9992,6 @@ L: linux-hardening@vger.kernel.org S: Maintained T: git git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux.git for-next/hardening F: Documentation/kbuild/gcc-plugins.rst -F: include/linux/stackleak.h -F: kernel/stackleak.c F: scripts/Makefile.gcc-plugins F: scripts/gcc-plugins/ @@ -13087,10 +13085,12 @@ T: git git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux.git for-next/har F: Documentation/ABI/testing/sysfs-kernel-oops_count F: Documentation/ABI/testing/sysfs-kernel-warn_count F: arch/*/configs/hardening.config +F: include/linux/kstack_erase.h F: include/linux/overflow.h F: include/linux/randomize_kstack.h F: include/linux/ucopysize.h F: kernel/configs/hardening.config +F: kernel/kstack_erase.c F: lib/tests/randstruct_kunit.c F: lib/tests/usercopy_kunit.c F: mm/usercopy.c diff --git a/arch/Kconfig b/arch/Kconfig index a3308a220f86..4d1908f6f084 100644 --- a/arch/Kconfig +++ b/arch/Kconfig @@ -630,11 +630,11 @@ config SECCOMP_CACHE_DEBUG If unsure, say N. -config HAVE_ARCH_STACKLEAK +config HAVE_ARCH_KSTACK_ERASE bool help An architecture should select this if it has the code which - fills the used part of the kernel stack with the STACKLEAK_POISON + fills the used part of the kernel stack with the KSTACK_ERASE_POISON value before returning from system calls. config HAVE_STACKPROTECTOR diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig index 3072731fe09c..cb0b2e2211ca 100644 --- a/arch/arm/Kconfig +++ b/arch/arm/Kconfig @@ -87,11 +87,11 @@ config ARM select HAVE_ARCH_KGDB if !CPU_ENDIAN_BE32 && MMU select HAVE_ARCH_KASAN if MMU && !XIP_KERNEL select HAVE_ARCH_KASAN_VMALLOC if HAVE_ARCH_KASAN + select HAVE_ARCH_KSTACK_ERASE select HAVE_ARCH_MMAP_RND_BITS if MMU select HAVE_ARCH_PFN_VALID select HAVE_ARCH_SECCOMP select HAVE_ARCH_SECCOMP_FILTER if AEABI && !OABI_COMPAT - select HAVE_ARCH_STACKLEAK select HAVE_ARCH_THREAD_STRUCT_WHITELIST select HAVE_ARCH_TRACEHOOK select HAVE_ARCH_TRANSPARENT_HUGEPAGE if ARM_LPAE diff --git a/arch/arm/boot/compressed/Makefile b/arch/arm/boot/compressed/Makefile index d61369b1eabe..f9075edfd773 100644 --- a/arch/arm/boot/compressed/Makefile +++ b/arch/arm/boot/compressed/Makefile @@ -9,7 +9,7 @@ OBJS = HEAD = head.o OBJS += misc.o decompress.o -CFLAGS_decompress.o += $(DISABLE_STACKLEAK_PLUGIN) +CFLAGS_decompress.o += $(DISABLE_KSTACK_ERASE) ifeq ($(CONFIG_DEBUG_UNCOMPRESS),y) OBJS += debug.o AFLAGS_head.o += -DDEBUG diff --git a/arch/arm/kernel/entry-common.S b/arch/arm/kernel/entry-common.S index f379c852dcb7..88336a1292bb 100644 --- a/arch/arm/kernel/entry-common.S +++ b/arch/arm/kernel/entry-common.S @@ -119,7 +119,7 @@ no_work_pending: ct_user_enter save = 0 -#ifdef CONFIG_GCC_PLUGIN_STACKLEAK +#ifdef CONFIG_KSTACK_ERASE bl stackleak_erase_on_task_stack #endif restore_user_regs fast = 0, offset = 0 diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig index 55fc331af337..e2a9e013b6a9 100644 --- a/arch/arm64/Kconfig +++ b/arch/arm64/Kconfig @@ -187,12 +187,12 @@ config ARM64 select HAVE_ARCH_KCSAN if EXPERT select HAVE_ARCH_KFENCE select HAVE_ARCH_KGDB + select HAVE_ARCH_KSTACK_ERASE select HAVE_ARCH_MMAP_RND_BITS select HAVE_ARCH_MMAP_RND_COMPAT_BITS if COMPAT select HAVE_ARCH_PREL32_RELOCATIONS select HAVE_ARCH_RANDOMIZE_KSTACK_OFFSET select HAVE_ARCH_SECCOMP_FILTER - select HAVE_ARCH_STACKLEAK select HAVE_ARCH_THREAD_STRUCT_WHITELIST select HAVE_ARCH_TRACEHOOK select HAVE_ARCH_TRANSPARENT_HUGEPAGE diff --git a/arch/arm64/kernel/entry.S b/arch/arm64/kernel/entry.S index 5ae2a34b50bd..67331437b2aa 100644 --- a/arch/arm64/kernel/entry.S +++ b/arch/arm64/kernel/entry.S @@ -614,7 +614,7 @@ SYM_CODE_END(ret_to_kernel) SYM_CODE_START_LOCAL(ret_to_user) ldr x19, [tsk, #TSK_TI_FLAGS] // re-check for single-step enable_step_tsk x19, x2 -#ifdef CONFIG_GCC_PLUGIN_STACKLEAK +#ifdef CONFIG_KSTACK_ERASE bl stackleak_erase_on_task_stack #endif kernel_exit 0 diff --git a/arch/arm64/kernel/pi/Makefile b/arch/arm64/kernel/pi/Makefile index 4d11a8c29181..f440bf57b1a5 100644 --- a/arch/arm64/kernel/pi/Makefile +++ b/arch/arm64/kernel/pi/Makefile @@ -2,7 +2,7 @@ # Copyright 2022 Google LLC KBUILD_CFLAGS := $(subst $(CC_FLAGS_FTRACE),,$(KBUILD_CFLAGS)) -fpie \ - -Os -DDISABLE_BRANCH_PROFILING $(DISABLE_STACKLEAK_PLUGIN) \ + -Os -DDISABLE_BRANCH_PROFILING $(DISABLE_KSTACK_ERASE) \ $(DISABLE_LATENT_ENTROPY_PLUGIN) \ $(call cc-option,-mbranch-protection=none) \ -I$(srctree)/scripts/dtc/libfdt -fno-stack-protector \ diff --git a/arch/arm64/kvm/hyp/nvhe/Makefile b/arch/arm64/kvm/hyp/nvhe/Makefile index a76522d63c3e..0b0a68b663d4 100644 --- a/arch/arm64/kvm/hyp/nvhe/Makefile +++ b/arch/arm64/kvm/hyp/nvhe/Makefile @@ -12,7 +12,7 @@ asflags-y := -D__KVM_NVHE_HYPERVISOR__ -D__DISABLE_EXPORTS ccflags-y := -D__KVM_NVHE_HYPERVISOR__ -D__DISABLE_EXPORTS -D__DISABLE_TRACE_MMIO__ ccflags-y += -fno-stack-protector \ -DDISABLE_BRANCH_PROFILING \ - $(DISABLE_STACKLEAK_PLUGIN) + $(DISABLE_KSTACK_ERASE) hostprogs := gen-hyprel HOST_EXTRACFLAGS += -I$(objtree)/include diff --git a/arch/loongarch/Kconfig b/arch/loongarch/Kconfig index 4b19f93379a1..1514789bea4a 100644 --- a/arch/loongarch/Kconfig +++ b/arch/loongarch/Kconfig @@ -120,11 +120,11 @@ config LOONGARCH select HAVE_ARCH_KASAN select HAVE_ARCH_KFENCE select HAVE_ARCH_KGDB if PERF_EVENTS + select HAVE_ARCH_KSTACK_ERASE select HAVE_ARCH_MMAP_RND_BITS if MMU select HAVE_ARCH_RANDOMIZE_KSTACK_OFFSET select HAVE_ARCH_SECCOMP select HAVE_ARCH_SECCOMP_FILTER - select HAVE_ARCH_STACKLEAK select HAVE_ARCH_TRACEHOOK select HAVE_ARCH_TRANSPARENT_HUGEPAGE select HAVE_ARCH_USERFAULTFD_MINOR if USERFAULTFD diff --git a/arch/riscv/Kconfig b/arch/riscv/Kconfig index 36061f4732b7..cfc084fc9e6f 100644 --- a/arch/riscv/Kconfig +++ b/arch/riscv/Kconfig @@ -135,13 +135,13 @@ config RISCV select HAVE_ARCH_KASAN if MMU && 64BIT select HAVE_ARCH_KASAN_VMALLOC if MMU && 64BIT select HAVE_ARCH_KFENCE if MMU && 64BIT + select HAVE_ARCH_KSTACK_ERASE select HAVE_ARCH_KGDB if !XIP_KERNEL select HAVE_ARCH_KGDB_QXFER_PKT select HAVE_ARCH_MMAP_RND_BITS if MMU select HAVE_ARCH_MMAP_RND_COMPAT_BITS if COMPAT select HAVE_ARCH_RANDOMIZE_KSTACK_OFFSET select HAVE_ARCH_SECCOMP_FILTER - select HAVE_ARCH_STACKLEAK select HAVE_ARCH_THREAD_STRUCT_WHITELIST select HAVE_ARCH_TRACEHOOK select HAVE_ARCH_TRANSPARENT_HUGEPAGE if 64BIT && MMU diff --git a/arch/riscv/kernel/entry.S b/arch/riscv/kernel/entry.S index 75656afa2d6b..3a0ec6fd5956 100644 --- a/arch/riscv/kernel/entry.S +++ b/arch/riscv/kernel/entry.S @@ -220,7 +220,7 @@ SYM_CODE_START_NOALIGN(ret_from_exception) #endif bnez s0, 1f -#ifdef CONFIG_GCC_PLUGIN_STACKLEAK +#ifdef CONFIG_KSTACK_ERASE call stackleak_erase_on_task_stack #endif diff --git a/arch/riscv/kernel/pi/Makefile b/arch/riscv/kernel/pi/Makefile index 81d69d45c06c..7dd15be69c90 100644 --- a/arch/riscv/kernel/pi/Makefile +++ b/arch/riscv/kernel/pi/Makefile @@ -2,7 +2,7 @@ # This file was copied from arm64/kernel/pi/Makefile. KBUILD_CFLAGS := $(subst $(CC_FLAGS_FTRACE),,$(KBUILD_CFLAGS)) -fpie \ - -Os -DDISABLE_BRANCH_PROFILING $(DISABLE_STACKLEAK_PLUGIN) \ + -Os -DDISABLE_BRANCH_PROFILING $(DISABLE_KSTACK_ERASE) \ $(call cc-option,-mbranch-protection=none) \ -I$(srctree)/scripts/dtc/libfdt -fno-stack-protector \ -include $(srctree)/include/linux/hidden.h \ diff --git a/arch/riscv/purgatory/Makefile b/arch/riscv/purgatory/Makefile index fb9c917c9b45..240592e3f5c2 100644 --- a/arch/riscv/purgatory/Makefile +++ b/arch/riscv/purgatory/Makefile @@ -53,7 +53,7 @@ targets += purgatory.ro purgatory.chk PURGATORY_CFLAGS_REMOVE := -mcmodel=kernel PURGATORY_CFLAGS := -mcmodel=medany -ffreestanding -fno-zero-initialized-in-bss -PURGATORY_CFLAGS += $(DISABLE_STACKLEAK_PLUGIN) -DDISABLE_BRANCH_PROFILING +PURGATORY_CFLAGS += $(DISABLE_KSTACK_ERASE) -DDISABLE_BRANCH_PROFILING PURGATORY_CFLAGS += -fno-stack-protector -g0 # Default KBUILD_CFLAGS can have -pg option set when FTRACE is enabled. That diff --git a/arch/s390/Kconfig b/arch/s390/Kconfig index 0c16dc443e2f..a8e74ed8e3cc 100644 --- a/arch/s390/Kconfig +++ b/arch/s390/Kconfig @@ -176,10 +176,10 @@ config S390 select HAVE_ARCH_KCSAN select HAVE_ARCH_KMSAN select HAVE_ARCH_KFENCE + select HAVE_ARCH_KSTACK_ERASE select HAVE_ARCH_RANDOMIZE_KSTACK_OFFSET select HAVE_ARCH_SECCOMP_FILTER select HAVE_ARCH_SOFT_DIRTY - select HAVE_ARCH_STACKLEAK select HAVE_ARCH_TRACEHOOK select HAVE_ARCH_TRANSPARENT_HUGEPAGE select HAVE_ARCH_VMAP_STACK diff --git a/arch/s390/kernel/entry.S b/arch/s390/kernel/entry.S index 0f00f4b06d51..75b0fbb236d0 100644 --- a/arch/s390/kernel/entry.S +++ b/arch/s390/kernel/entry.S @@ -124,7 +124,7 @@ _LPP_OFFSET = __LC_LPP #endif .macro STACKLEAK_ERASE -#ifdef CONFIG_GCC_PLUGIN_STACKLEAK +#ifdef CONFIG_KSTACK_ERASE brasl %r14,stackleak_erase_on_task_stack #endif .endm diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig index 340e5468980e..bc3708cad46b 100644 --- a/arch/x86/Kconfig +++ b/arch/x86/Kconfig @@ -204,13 +204,13 @@ config X86 select HAVE_ARCH_KFENCE select HAVE_ARCH_KMSAN if X86_64 select HAVE_ARCH_KGDB + select HAVE_ARCH_KSTACK_ERASE select HAVE_ARCH_MMAP_RND_BITS if MMU select HAVE_ARCH_MMAP_RND_COMPAT_BITS if MMU && COMPAT select HAVE_ARCH_COMPAT_MMAP_BASES if MMU && COMPAT select HAVE_ARCH_PREL32_RELOCATIONS select HAVE_ARCH_SECCOMP_FILTER select HAVE_ARCH_THREAD_STRUCT_WHITELIST - select HAVE_ARCH_STACKLEAK select HAVE_ARCH_TRACEHOOK select HAVE_ARCH_TRANSPARENT_HUGEPAGE select HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD if X86_64 diff --git a/arch/x86/entry/calling.h b/arch/x86/entry/calling.h index d83236b96f22..94519688b007 100644 --- a/arch/x86/entry/calling.h +++ b/arch/x86/entry/calling.h @@ -369,7 +369,7 @@ For 32-bit we have the following conventions - kernel is built with .endm .macro STACKLEAK_ERASE_NOCLOBBER -#ifdef CONFIG_GCC_PLUGIN_STACKLEAK +#ifdef CONFIG_KSTACK_ERASE PUSH_AND_CLEAR_REGS call stackleak_erase POP_REGS @@ -388,7 +388,7 @@ For 32-bit we have the following conventions - kernel is built with #endif /* !CONFIG_X86_64 */ .macro STACKLEAK_ERASE -#ifdef CONFIG_GCC_PLUGIN_STACKLEAK +#ifdef CONFIG_KSTACK_ERASE call stackleak_erase #endif .endm diff --git a/arch/x86/purgatory/Makefile b/arch/x86/purgatory/Makefile index ebdfd7b84feb..e0a607a14e7e 100644 --- a/arch/x86/purgatory/Makefile +++ b/arch/x86/purgatory/Makefile @@ -35,7 +35,7 @@ targets += purgatory.ro purgatory.chk PURGATORY_CFLAGS_REMOVE := -mcmodel=kernel PURGATORY_CFLAGS := -mcmodel=small -ffreestanding -fno-zero-initialized-in-bss -g0 PURGATORY_CFLAGS += -fpic -fvisibility=hidden -PURGATORY_CFLAGS += $(DISABLE_STACKLEAK_PLUGIN) -DDISABLE_BRANCH_PROFILING +PURGATORY_CFLAGS += $(DISABLE_KSTACK_ERASE) -DDISABLE_BRANCH_PROFILING PURGATORY_CFLAGS += -fno-stack-protector # Default KBUILD_CFLAGS can have -pg option set when FTRACE is enabled. That diff --git a/drivers/firmware/efi/libstub/Makefile b/drivers/firmware/efi/libstub/Makefile index 939a4955e00b..94b05e4451dd 100644 --- a/drivers/firmware/efi/libstub/Makefile +++ b/drivers/firmware/efi/libstub/Makefile @@ -22,16 +22,16 @@ cflags-$(CONFIG_X86) += -m$(BITS) -D__KERNEL__ -std=gnu11 \ # arm64 uses the full KBUILD_CFLAGS so it's necessary to explicitly # disable the stackleak plugin -cflags-$(CONFIG_ARM64) += -fpie $(DISABLE_STACKLEAK_PLUGIN) \ +cflags-$(CONFIG_ARM64) += -fpie $(DISABLE_KSTACK_ERASE) \ -fno-unwind-tables -fno-asynchronous-unwind-tables cflags-$(CONFIG_ARM) += -DEFI_HAVE_STRLEN -DEFI_HAVE_STRNLEN \ -DEFI_HAVE_MEMCHR -DEFI_HAVE_STRRCHR \ -DEFI_HAVE_STRCMP -fno-builtin -fpic \ $(call cc-option,-mno-single-pic-base) \ - $(DISABLE_STACKLEAK_PLUGIN) + $(DISABLE_KSTACK_ERASE) cflags-$(CONFIG_RISCV) += -fpic -DNO_ALTERNATIVE -mno-relax \ - $(DISABLE_STACKLEAK_PLUGIN) -cflags-$(CONFIG_LOONGARCH) += -fpie $(DISABLE_STACKLEAK_PLUGIN) + $(DISABLE_KSTACK_ERASE) +cflags-$(CONFIG_LOONGARCH) += -fpie $(DISABLE_KSTACK_ERASE) cflags-$(CONFIG_EFI_PARAMS_FROM_FDT) += -I$(srctree)/scripts/dtc/libfdt diff --git a/drivers/misc/lkdtm/Makefile b/drivers/misc/lkdtm/Makefile index 39468bd27b85..03ebe33185f9 100644 --- a/drivers/misc/lkdtm/Makefile +++ b/drivers/misc/lkdtm/Makefile @@ -8,7 +8,7 @@ lkdtm-$(CONFIG_LKDTM) += perms.o lkdtm-$(CONFIG_LKDTM) += refcount.o lkdtm-$(CONFIG_LKDTM) += rodata_objcopy.o lkdtm-$(CONFIG_LKDTM) += usercopy.o -lkdtm-$(CONFIG_LKDTM) += stackleak.o +lkdtm-$(CONFIG_LKDTM) += kstack_erase.o lkdtm-$(CONFIG_LKDTM) += cfi.o lkdtm-$(CONFIG_LKDTM) += fortify.o lkdtm-$(CONFIG_PPC_64S_HASH_MMU) += powerpc.o diff --git a/drivers/misc/lkdtm/stackleak.c b/drivers/misc/lkdtm/kstack_erase.c similarity index 89% rename from drivers/misc/lkdtm/stackleak.c rename to drivers/misc/lkdtm/kstack_erase.c index f1d022160913..4fd9b0bfb874 100644 --- a/drivers/misc/lkdtm/stackleak.c +++ b/drivers/misc/lkdtm/kstack_erase.c @@ -1,7 +1,7 @@ // SPDX-License-Identifier: GPL-2.0 /* * This code tests that the current task stack is properly erased (filled - * with STACKLEAK_POISON). + * with KSTACK_ERASE_POISON). * * Authors: * Alexander Popov @@ -9,9 +9,9 @@ */ #include "lkdtm.h" -#include +#include -#if defined(CONFIG_GCC_PLUGIN_STACKLEAK) +#if defined(CONFIG_KSTACK_ERASE) /* * Check that stackleak tracks the lowest stack pointer and erases the stack * below this as expected. @@ -85,7 +85,7 @@ static void noinstr check_stackleak_irqoff(void) while (poison_low > task_stack_low) { poison_low -= sizeof(unsigned long); - if (*(unsigned long *)poison_low == STACKLEAK_POISON) + if (*(unsigned long *)poison_low == KSTACK_ERASE_POISON) continue; instrumentation_begin(); @@ -96,7 +96,7 @@ static void noinstr check_stackleak_irqoff(void) } instrumentation_begin(); - pr_info("stackleak stack usage:\n" + pr_info("kstack erase stack usage:\n" " high offset: %lu bytes\n" " current: %lu bytes\n" " lowest: %lu bytes\n" @@ -121,7 +121,7 @@ out: instrumentation_end(); } -static void lkdtm_STACKLEAK_ERASING(void) +static void lkdtm_KSTACK_ERASE(void) { unsigned long flags; @@ -129,19 +129,19 @@ static void lkdtm_STACKLEAK_ERASING(void) check_stackleak_irqoff(); local_irq_restore(flags); } -#else /* defined(CONFIG_GCC_PLUGIN_STACKLEAK) */ -static void lkdtm_STACKLEAK_ERASING(void) +#else /* defined(CONFIG_KSTACK_ERASE) */ +static void lkdtm_KSTACK_ERASE(void) { - if (IS_ENABLED(CONFIG_HAVE_ARCH_STACKLEAK)) { - pr_err("XFAIL: stackleak is not enabled (CONFIG_GCC_PLUGIN_STACKLEAK=n)\n"); + if (IS_ENABLED(CONFIG_HAVE_ARCH_KSTACK_ERASE)) { + pr_err("XFAIL: stackleak is not enabled (CONFIG_KSTACK_ERASE=n)\n"); } else { - pr_err("XFAIL: stackleak is not supported on this arch (HAVE_ARCH_STACKLEAK=n)\n"); + pr_err("XFAIL: stackleak is not supported on this arch (HAVE_ARCH_KSTACK_ERASE=n)\n"); } } -#endif /* defined(CONFIG_GCC_PLUGIN_STACKLEAK) */ +#endif /* defined(CONFIG_KSTACK_ERASE) */ static struct crashtype crashtypes[] = { - CRASHTYPE(STACKLEAK_ERASING), + CRASHTYPE(KSTACK_ERASE), }; struct crashtype_category stackleak_crashtypes = { diff --git a/fs/proc/base.c b/fs/proc/base.c index c667702dc69b..be34612af8b6 100644 --- a/fs/proc/base.c +++ b/fs/proc/base.c @@ -3291,7 +3291,7 @@ static int proc_pid_ksm_stat(struct seq_file *m, struct pid_namespace *ns, } #endif /* CONFIG_KSM */ -#ifdef CONFIG_STACKLEAK_METRICS +#ifdef CONFIG_KSTACK_ERASE_METRICS static int proc_stack_depth(struct seq_file *m, struct pid_namespace *ns, struct pid *pid, struct task_struct *task) { @@ -3304,7 +3304,7 @@ static int proc_stack_depth(struct seq_file *m, struct pid_namespace *ns, prev_depth, depth); return 0; } -#endif /* CONFIG_STACKLEAK_METRICS */ +#endif /* CONFIG_KSTACK_ERASE_METRICS */ /* * Thread groups @@ -3411,7 +3411,7 @@ static const struct pid_entry tgid_base_stuff[] = { #ifdef CONFIG_LIVEPATCH ONE("patch_state", S_IRUSR, proc_pid_patch_state), #endif -#ifdef CONFIG_STACKLEAK_METRICS +#ifdef CONFIG_KSTACK_ERASE_METRICS ONE("stack_depth", S_IRUGO, proc_stack_depth), #endif #ifdef CONFIG_PROC_PID_ARCH_STATUS diff --git a/include/linux/stackleak.h b/include/linux/kstack_erase.h similarity index 85% rename from include/linux/stackleak.h rename to include/linux/kstack_erase.h index 3be2cb564710..4e432eefa4d0 100644 --- a/include/linux/stackleak.h +++ b/include/linux/kstack_erase.h @@ -1,6 +1,6 @@ /* SPDX-License-Identifier: GPL-2.0 */ -#ifndef _LINUX_STACKLEAK_H -#define _LINUX_STACKLEAK_H +#ifndef _LINUX_KSTACK_ERASE_H +#define _LINUX_KSTACK_ERASE_H #include #include @@ -9,10 +9,10 @@ * Check that the poison value points to the unused hole in the * virtual memory map for your platform. */ -#define STACKLEAK_POISON -0xBEEF -#define STACKLEAK_SEARCH_DEPTH 128 +#define KSTACK_ERASE_POISON -0xBEEF +#define KSTACK_ERASE_SEARCH_DEPTH 128 -#ifdef CONFIG_GCC_PLUGIN_STACKLEAK +#ifdef CONFIG_KSTACK_ERASE #include #include @@ -50,7 +50,7 @@ stackleak_task_high_bound(const struct task_struct *tsk) static __always_inline unsigned long stackleak_find_top_of_poison(const unsigned long low, const unsigned long high) { - const unsigned int depth = STACKLEAK_SEARCH_DEPTH / sizeof(unsigned long); + const unsigned int depth = KSTACK_ERASE_SEARCH_DEPTH / sizeof(unsigned long); unsigned int poison_count = 0; unsigned long poison_high = high; unsigned long sp = high; @@ -58,7 +58,7 @@ stackleak_find_top_of_poison(const unsigned long low, const unsigned long high) while (sp > low && poison_count < depth) { sp -= sizeof(unsigned long); - if (*(unsigned long *)sp == STACKLEAK_POISON) { + if (*(unsigned long *)sp == KSTACK_ERASE_POISON) { poison_count++; } else { poison_count = 0; @@ -72,7 +72,7 @@ stackleak_find_top_of_poison(const unsigned long low, const unsigned long high) static inline void stackleak_task_init(struct task_struct *t) { t->lowest_stack = stackleak_task_low_bound(t); -# ifdef CONFIG_STACKLEAK_METRICS +# ifdef CONFIG_KSTACK_ERASE_METRICS t->prev_lowest_stack = t->lowest_stack; # endif } @@ -82,7 +82,7 @@ asmlinkage void noinstr stackleak_erase_on_task_stack(void); asmlinkage void noinstr stackleak_erase_off_task_stack(void); void __no_caller_saved_registers noinstr stackleak_track_stack(void); -#else /* !CONFIG_GCC_PLUGIN_STACKLEAK */ +#else /* !CONFIG_KSTACK_ERASE */ static inline void stackleak_task_init(struct task_struct *t) { } #endif diff --git a/include/linux/sched.h b/include/linux/sched.h index 4f78a64beb52..b7d2f2fd4cd4 100644 --- a/include/linux/sched.h +++ b/include/linux/sched.h @@ -1607,8 +1607,10 @@ struct task_struct { /* Used by BPF for per-TASK xdp storage */ struct bpf_net_context *bpf_net_context; -#ifdef CONFIG_GCC_PLUGIN_STACKLEAK +#ifdef CONFIG_KSTACK_ERASE unsigned long lowest_stack; +#endif +#ifdef CONFIG_KSTACK_ERASE_METRICS unsigned long prev_lowest_stack; #endif diff --git a/kernel/Makefile b/kernel/Makefile index 32e80dd626af..e4f01f1d4d0c 100644 --- a/kernel/Makefile +++ b/kernel/Makefile @@ -139,11 +139,11 @@ obj-$(CONFIG_WATCH_QUEUE) += watch_queue.o obj-$(CONFIG_RESOURCE_KUNIT_TEST) += resource_kunit.o obj-$(CONFIG_SYSCTL_KUNIT_TEST) += sysctl-test.o -CFLAGS_stackleak.o += $(DISABLE_STACKLEAK_PLUGIN) -obj-$(CONFIG_GCC_PLUGIN_STACKLEAK) += stackleak.o -KASAN_SANITIZE_stackleak.o := n -KCSAN_SANITIZE_stackleak.o := n -KCOV_INSTRUMENT_stackleak.o := n +CFLAGS_kstack_erase.o += $(DISABLE_KSTACK_ERASE) +obj-$(CONFIG_KSTACK_ERASE) += kstack_erase.o +KASAN_SANITIZE_kstack_erase.o := n +KCSAN_SANITIZE_kstack_erase.o := n +KCOV_INSTRUMENT_kstack_erase.o := n obj-$(CONFIG_SCF_TORTURE_TEST) += scftorture.o diff --git a/kernel/fork.c b/kernel/fork.c index 1ee8eb11f38b..1ec66911f6f6 100644 --- a/kernel/fork.c +++ b/kernel/fork.c @@ -93,7 +93,7 @@ #include #include #include -#include +#include #include #include #include diff --git a/kernel/stackleak.c b/kernel/kstack_erase.c similarity index 90% rename from kernel/stackleak.c rename to kernel/kstack_erase.c index bb65321761b4..201b846f8345 100644 --- a/kernel/stackleak.c +++ b/kernel/kstack_erase.c @@ -6,14 +6,14 @@ * * Author: Alexander Popov * - * STACKLEAK reduces the information which kernel stack leak bugs can + * KSTACK_ERASE reduces the information which kernel stack leak bugs can * reveal and blocks some uninitialized stack variable attacks. */ -#include +#include #include -#ifdef CONFIG_STACKLEAK_RUNTIME_DISABLE +#ifdef CONFIG_KSTACK_ERASE_RUNTIME_DISABLE #include #include #include @@ -68,7 +68,7 @@ late_initcall(stackleak_sysctls_init); #define skip_erasing() static_branch_unlikely(&stack_erasing_bypass) #else #define skip_erasing() false -#endif /* CONFIG_STACKLEAK_RUNTIME_DISABLE */ +#endif /* CONFIG_KSTACK_ERASE_RUNTIME_DISABLE */ #ifndef __stackleak_poison static __always_inline void __stackleak_poison(unsigned long erase_low, @@ -91,7 +91,7 @@ static __always_inline void __stackleak_erase(bool on_task_stack) erase_low = stackleak_find_top_of_poison(task_stack_low, current->lowest_stack); -#ifdef CONFIG_STACKLEAK_METRICS +#ifdef CONFIG_KSTACK_ERASE_METRICS current->prev_lowest_stack = erase_low; #endif @@ -113,7 +113,7 @@ static __always_inline void __stackleak_erase(bool on_task_stack) else erase_high = task_stack_high; - __stackleak_poison(erase_low, erase_high, STACKLEAK_POISON); + __stackleak_poison(erase_low, erase_high, KSTACK_ERASE_POISON); /* Reset the 'lowest_stack' value for the next syscall */ current->lowest_stack = task_stack_high; @@ -161,11 +161,11 @@ void __used __no_caller_saved_registers noinstr stackleak_track_stack(void) unsigned long sp = current_stack_pointer; /* - * Having CONFIG_STACKLEAK_TRACK_MIN_SIZE larger than - * STACKLEAK_SEARCH_DEPTH makes the poison search in + * Having CONFIG_KSTACK_ERASE_TRACK_MIN_SIZE larger than + * KSTACK_ERASE_SEARCH_DEPTH makes the poison search in * stackleak_erase() unreliable. Let's prevent that. */ - BUILD_BUG_ON(CONFIG_STACKLEAK_TRACK_MIN_SIZE > STACKLEAK_SEARCH_DEPTH); + BUILD_BUG_ON(CONFIG_KSTACK_ERASE_TRACK_MIN_SIZE > KSTACK_ERASE_SEARCH_DEPTH); /* 'lowest_stack' should be aligned on the register width boundary */ sp = ALIGN(sp, sizeof(unsigned long)); diff --git a/lib/Makefile b/lib/Makefile index c38582f187dd..632e69d25feb 100644 --- a/lib/Makefile +++ b/lib/Makefile @@ -337,7 +337,7 @@ obj-$(CONFIG_UBSAN) += ubsan.o UBSAN_SANITIZE_ubsan.o := n KASAN_SANITIZE_ubsan.o := n KCSAN_SANITIZE_ubsan.o := n -CFLAGS_ubsan.o := -fno-stack-protector $(DISABLE_STACKLEAK_PLUGIN) +CFLAGS_ubsan.o := -fno-stack-protector $(DISABLE_KSTACK_ERASE) obj-$(CONFIG_SBITMAP) += sbitmap.o diff --git a/scripts/Makefile.gcc-plugins b/scripts/Makefile.gcc-plugins index 435ab3f0ec44..28b8867c4e84 100644 --- a/scripts/Makefile.gcc-plugins +++ b/scripts/Makefile.gcc-plugins @@ -12,15 +12,15 @@ gcc-plugin-$(CONFIG_GCC_PLUGIN_STACKLEAK) += stackleak_plugin.so gcc-plugin-cflags-$(CONFIG_GCC_PLUGIN_STACKLEAK) \ += -DSTACKLEAK_PLUGIN gcc-plugin-cflags-$(CONFIG_GCC_PLUGIN_STACKLEAK) \ - += -fplugin-arg-stackleak_plugin-track-min-size=$(CONFIG_STACKLEAK_TRACK_MIN_SIZE) + += -fplugin-arg-stackleak_plugin-track-min-size=$(CONFIG_KSTACK_ERASE_TRACK_MIN_SIZE) gcc-plugin-cflags-$(CONFIG_GCC_PLUGIN_STACKLEAK) \ += -fplugin-arg-stackleak_plugin-arch=$(SRCARCH) gcc-plugin-cflags-$(CONFIG_GCC_PLUGIN_STACKLEAK_VERBOSE) \ += -fplugin-arg-stackleak_plugin-verbose ifdef CONFIG_GCC_PLUGIN_STACKLEAK - DISABLE_STACKLEAK_PLUGIN += -fplugin-arg-stackleak_plugin-disable + DISABLE_KSTACK_ERASE += -fplugin-arg-stackleak_plugin-disable endif -export DISABLE_STACKLEAK_PLUGIN +export DISABLE_KSTACK_ERASE # All the plugin CFLAGS are collected here in case a build target needs to # filter them out of the KBUILD_CFLAGS. diff --git a/security/Kconfig.hardening b/security/Kconfig.hardening index fd1238753cad..125b35e2ef0f 100644 --- a/security/Kconfig.hardening +++ b/security/Kconfig.hardening @@ -82,10 +82,10 @@ choice endchoice -config GCC_PLUGIN_STACKLEAK +config KSTACK_ERASE bool "Poison kernel stack before returning from syscalls" + depends on HAVE_ARCH_KSTACK_ERASE depends on GCC_PLUGINS - depends on HAVE_ARCH_STACKLEAK help This option makes the kernel erase the kernel stack before returning from system calls. This has the effect of leaving @@ -103,6 +103,10 @@ config GCC_PLUGIN_STACKLEAK are advised to test this feature on your expected workload before deploying it. +config GCC_PLUGIN_STACKLEAK + def_bool KSTACK_ERASE + depends on GCC_PLUGINS + help This plugin was ported from grsecurity/PaX. More information at: * https://grsecurity.net/ * https://pax.grsecurity.net/ @@ -117,37 +121,37 @@ config GCC_PLUGIN_STACKLEAK_VERBOSE instrumented. This is useful for comparing coverage between builds. -config STACKLEAK_TRACK_MIN_SIZE - int "Minimum stack frame size of functions tracked by STACKLEAK" +config KSTACK_ERASE_TRACK_MIN_SIZE + int "Minimum stack frame size of functions tracked by KSTACK_ERASE" default 100 range 0 4096 - depends on GCC_PLUGIN_STACKLEAK + depends on KSTACK_ERASE help - The STACKLEAK gcc plugin instruments the kernel code for tracking + The KSTACK_ERASE option instruments the kernel code for tracking the lowest border of the kernel stack (and for some other purposes). It inserts the stackleak_track_stack() call for the functions with a stack frame size greater than or equal to this parameter. If unsure, leave the default value 100. -config STACKLEAK_METRICS - bool "Show STACKLEAK metrics in the /proc file system" - depends on GCC_PLUGIN_STACKLEAK +config KSTACK_ERASE_METRICS + bool "Show KSTACK_ERASE metrics in the /proc file system" + depends on KSTACK_ERASE depends on PROC_FS help - If this is set, STACKLEAK metrics for every task are available in - the /proc file system. In particular, /proc//stack_depth + If this is set, KSTACK_ERASE metrics for every task are available + in the /proc file system. In particular, /proc//stack_depth shows the maximum kernel stack consumption for the current and previous syscalls. Although this information is not precise, it - can be useful for estimating the STACKLEAK performance impact for - your workloads. + can be useful for estimating the KSTACK_ERASE performance impact + for your workloads. -config STACKLEAK_RUNTIME_DISABLE +config KSTACK_ERASE_RUNTIME_DISABLE bool "Allow runtime disabling of kernel stack erasing" - depends on GCC_PLUGIN_STACKLEAK + depends on KSTACK_ERASE help This option provides 'stack_erasing' sysctl, which can be used in runtime to control kernel stack erasing for kernels built with - CONFIG_GCC_PLUGIN_STACKLEAK. + CONFIG_KSTACK_ERASE. config INIT_ON_ALLOC_DEFAULT_ON bool "Enable heap memory zeroing on allocation by default" diff --git a/tools/objtool/check.c b/tools/objtool/check.c index f23bdda737aa..5451bdbcf84a 100644 --- a/tools/objtool/check.c +++ b/tools/objtool/check.c @@ -1192,7 +1192,7 @@ static const char *uaccess_safe_builtin[] = { "__ubsan_handle_type_mismatch_v1", "__ubsan_handle_shift_out_of_bounds", "__ubsan_handle_load_invalid_value", - /* STACKLEAK */ + /* KSTACK_ERASE */ "stackleak_track_stack", /* TRACE_BRANCH_PROFILING */ "ftrace_likely_update", diff --git a/tools/testing/selftests/lkdtm/config b/tools/testing/selftests/lkdtm/config index 7afe05e8c4d7..bd09fdaf53e0 100644 --- a/tools/testing/selftests/lkdtm/config +++ b/tools/testing/selftests/lkdtm/config @@ -2,7 +2,7 @@ CONFIG_LKDTM=y CONFIG_DEBUG_LIST=y CONFIG_SLAB_FREELIST_HARDENED=y CONFIG_FORTIFY_SOURCE=y -CONFIG_GCC_PLUGIN_STACKLEAK=y +CONFIG_KSTACK_ERASE=y CONFIG_HARDENED_USERCOPY=y CONFIG_RANDOMIZE_KSTACK_OFFSET_DEFAULT=y CONFIG_INIT_ON_FREE_DEFAULT_ON=y From 9ea1e8d28add49ab3c1ecfa43f08d92ee23f3e33 Mon Sep 17 00:00:00 2001 From: Kees Cook Date: Thu, 17 Jul 2025 16:25:07 -0700 Subject: [PATCH 08/22] stackleak: Rename stackleak_track_stack to __sanitizer_cov_stack_depth The Clang stack depth tracking implementation has a fixed name for the stack depth tracking callback, "__sanitizer_cov_stack_depth", so rename the GCC plugin function to match since the plugin has no external dependencies on naming. Link: https://lore.kernel.org/r/20250717232519.2984886-2-kees@kernel.org Signed-off-by: Kees Cook --- include/linux/kstack_erase.h | 2 +- kernel/kstack_erase.c | 4 +- scripts/gcc-plugins/stackleak_plugin.c | 52 +++++++++++++------------- security/Kconfig.hardening | 4 +- tools/objtool/check.c | 2 +- 5 files changed, 32 insertions(+), 32 deletions(-) diff --git a/include/linux/kstack_erase.h b/include/linux/kstack_erase.h index 4e432eefa4d0..bf3bf1905557 100644 --- a/include/linux/kstack_erase.h +++ b/include/linux/kstack_erase.h @@ -80,7 +80,7 @@ static inline void stackleak_task_init(struct task_struct *t) asmlinkage void noinstr stackleak_erase(void); asmlinkage void noinstr stackleak_erase_on_task_stack(void); asmlinkage void noinstr stackleak_erase_off_task_stack(void); -void __no_caller_saved_registers noinstr stackleak_track_stack(void); +void __no_caller_saved_registers noinstr __sanitizer_cov_stack_depth(void); #else /* !CONFIG_KSTACK_ERASE */ static inline void stackleak_task_init(struct task_struct *t) { } diff --git a/kernel/kstack_erase.c b/kernel/kstack_erase.c index 201b846f8345..e49bb88b4f0a 100644 --- a/kernel/kstack_erase.c +++ b/kernel/kstack_erase.c @@ -156,7 +156,7 @@ asmlinkage void noinstr stackleak_erase_off_task_stack(void) __stackleak_erase(false); } -void __used __no_caller_saved_registers noinstr stackleak_track_stack(void) +void __used __no_caller_saved_registers noinstr __sanitizer_cov_stack_depth(void) { unsigned long sp = current_stack_pointer; @@ -174,4 +174,4 @@ void __used __no_caller_saved_registers noinstr stackleak_track_stack(void) current->lowest_stack = sp; } } -EXPORT_SYMBOL(stackleak_track_stack); +EXPORT_SYMBOL(__sanitizer_cov_stack_depth); diff --git a/scripts/gcc-plugins/stackleak_plugin.c b/scripts/gcc-plugins/stackleak_plugin.c index d20c47d21ad8..e486488c867d 100644 --- a/scripts/gcc-plugins/stackleak_plugin.c +++ b/scripts/gcc-plugins/stackleak_plugin.c @@ -9,7 +9,7 @@ * any of the gcc libraries * * This gcc plugin is needed for tracking the lowest border of the kernel stack. - * It instruments the kernel code inserting stackleak_track_stack() calls: + * It instruments the kernel code inserting __sanitizer_cov_stack_depth() calls: * - after alloca(); * - for the functions with a stack frame size greater than or equal * to the "track-min-size" plugin parameter. @@ -33,7 +33,7 @@ __visible int plugin_is_GPL_compatible; static int track_frame_size = -1; static bool build_for_x86 = false; -static const char track_function[] = "stackleak_track_stack"; +static const char track_function[] = "__sanitizer_cov_stack_depth"; static bool disable = false; static bool verbose = false; @@ -58,7 +58,7 @@ static void add_stack_tracking_gcall(gimple_stmt_iterator *gsi, bool after) cgraph_node_ptr node; basic_block bb; - /* Insert calling stackleak_track_stack() */ + /* Insert calling __sanitizer_cov_stack_depth() */ stmt = gimple_build_call(track_function_decl, 0); gimple_call = as_a_gcall(stmt); if (after) @@ -120,12 +120,12 @@ static void add_stack_tracking_gasm(gimple_stmt_iterator *gsi, bool after) gcc_assert(build_for_x86); /* - * Insert calling stackleak_track_stack() in asm: - * asm volatile("call stackleak_track_stack" + * Insert calling __sanitizer_cov_stack_depth() in asm: + * asm volatile("call __sanitizer_cov_stack_depth" * :: "r" (current_stack_pointer)) * Use ASM_CALL_CONSTRAINT trick from arch/x86/include/asm/asm.h. * This constraint is taken into account during gcc shrink-wrapping - * optimization. It is needed to be sure that stackleak_track_stack() + * optimization. It is needed to be sure that __sanitizer_cov_stack_depth() * call is inserted after the prologue of the containing function, * when the stack frame is prepared. */ @@ -137,7 +137,7 @@ static void add_stack_tracking_gasm(gimple_stmt_iterator *gsi, bool after) input = build_tree_list(NULL_TREE, build_const_char_string(2, "r")); input = chainon(NULL_TREE, build_tree_list(input, sp_decl)); vec_safe_push(inputs, input); - asm_call = gimple_build_asm_vec("call stackleak_track_stack", + asm_call = gimple_build_asm_vec("call __sanitizer_cov_stack_depth", inputs, NULL, NULL, NULL); gimple_asm_set_volatile(asm_call, true); if (after) @@ -151,11 +151,11 @@ static void add_stack_tracking(gimple_stmt_iterator *gsi, bool after) { /* * The 'no_caller_saved_registers' attribute is used for - * stackleak_track_stack(). If the compiler supports this attribute for - * the target arch, we can add calling stackleak_track_stack() in asm. + * __sanitizer_cov_stack_depth(). If the compiler supports this attribute for + * the target arch, we can add calling __sanitizer_cov_stack_depth() in asm. * That improves performance: we avoid useless operations with the * caller-saved registers in the functions from which we will remove - * stackleak_track_stack() call during the stackleak_cleanup pass. + * __sanitizer_cov_stack_depth() call during the stackleak_cleanup pass. */ if (lookup_attribute_spec(get_identifier("no_caller_saved_registers"))) add_stack_tracking_gasm(gsi, after); @@ -165,7 +165,7 @@ static void add_stack_tracking(gimple_stmt_iterator *gsi, bool after) /* * Work with the GIMPLE representation of the code. Insert the - * stackleak_track_stack() call after alloca() and into the beginning + * __sanitizer_cov_stack_depth() call after alloca() and into the beginning * of the function if it is not instrumented. */ static unsigned int stackleak_instrument_execute(void) @@ -205,7 +205,7 @@ static unsigned int stackleak_instrument_execute(void) DECL_NAME_POINTER(current_function_decl)); } - /* Insert stackleak_track_stack() call after alloca() */ + /* Insert __sanitizer_cov_stack_depth() call after alloca() */ add_stack_tracking(&gsi, true); if (bb == entry_bb) prologue_instrumented = true; @@ -241,7 +241,7 @@ static unsigned int stackleak_instrument_execute(void) return 0; } - /* Insert stackleak_track_stack() call at the function beginning */ + /* Insert __sanitizer_cov_stack_depth() call at the function beginning */ bb = entry_bb; if (!single_pred_p(bb)) { /* gcc_assert(bb_loop_depth(bb) || @@ -270,15 +270,15 @@ static void remove_stack_tracking_gcall(void) rtx_insn *insn, *next; /* - * Find stackleak_track_stack() calls. Loop through the chain of insns, + * Find __sanitizer_cov_stack_depth() calls. Loop through the chain of insns, * which is an RTL representation of the code for a function. * * The example of a matching insn: - * (call_insn 8 4 10 2 (call (mem (symbol_ref ("stackleak_track_stack") - * [flags 0x41] ) - * [0 stackleak_track_stack S1 A8]) (0)) 675 {*call} (expr_list - * (symbol_ref ("stackleak_track_stack") [flags 0x41] ) (expr_list (0) (nil))) (nil)) + * (call_insn 8 4 10 2 (call (mem (symbol_ref ("__sanitizer_cov_stack_depth") + * [flags 0x41] ) + * [0 __sanitizer_cov_stack_depth S1 A8]) (0)) 675 {*call} (expr_list + * (symbol_ref ("__sanitizer_cov_stack_depth") [flags 0x41] ) (expr_list (0) (nil))) (nil)) */ for (insn = get_insns(); insn; insn = next) { rtx body; @@ -318,7 +318,7 @@ static void remove_stack_tracking_gcall(void) if (SYMBOL_REF_DECL(body) != track_function_decl) continue; - /* Delete the stackleak_track_stack() call */ + /* Delete the __sanitizer_cov_stack_depth() call */ delete_insn_and_edges(insn); #if BUILDING_GCC_VERSION < 8000 if (GET_CODE(next) == NOTE && @@ -340,12 +340,12 @@ static bool remove_stack_tracking_gasm(void) gcc_assert(build_for_x86); /* - * Find stackleak_track_stack() asm calls. Loop through the chain of + * Find __sanitizer_cov_stack_depth() asm calls. Loop through the chain of * insns, which is an RTL representation of the code for a function. * * The example of a matching insn: * (insn 11 5 12 2 (parallel [ (asm_operands/v - * ("call stackleak_track_stack") ("") 0 + * ("call __sanitizer_cov_stack_depth") ("") 0 * [ (reg/v:DI 7 sp [ current_stack_pointer ]) ] * [ (asm_input:DI ("r")) ] []) * (clobber (reg:CC 17 flags)) ]) -1 (nil)) @@ -375,7 +375,7 @@ static bool remove_stack_tracking_gasm(void) continue; if (strcmp(ASM_OPERANDS_TEMPLATE(body), - "call stackleak_track_stack")) { + "call __sanitizer_cov_stack_depth")) { continue; } @@ -389,7 +389,7 @@ static bool remove_stack_tracking_gasm(void) /* * Work with the RTL representation of the code. - * Remove the unneeded stackleak_track_stack() calls from the functions + * Remove the unneeded __sanitizer_cov_stack_depth() calls from the functions * which don't call alloca() and don't have a large enough stack frame size. */ static unsigned int stackleak_cleanup_execute(void) @@ -474,13 +474,13 @@ static bool stackleak_gate(void) return track_frame_size >= 0; } -/* Build the function declaration for stackleak_track_stack() */ +/* Build the function declaration for __sanitizer_cov_stack_depth() */ static void stackleak_start_unit(void *gcc_data __unused, void *user_data __unused) { tree fntype; - /* void stackleak_track_stack(void) */ + /* void __sanitizer_cov_stack_depth(void) */ fntype = build_function_type_list(void_type_node, NULL_TREE); track_function_decl = build_fn_decl(track_function, fntype); DECL_ASSEMBLER_NAME(track_function_decl); /* for LTO */ diff --git a/security/Kconfig.hardening b/security/Kconfig.hardening index 125b35e2ef0f..f7aa2024ab25 100644 --- a/security/Kconfig.hardening +++ b/security/Kconfig.hardening @@ -129,8 +129,8 @@ config KSTACK_ERASE_TRACK_MIN_SIZE help The KSTACK_ERASE option instruments the kernel code for tracking the lowest border of the kernel stack (and for some other purposes). - It inserts the stackleak_track_stack() call for the functions with - a stack frame size greater than or equal to this parameter. + It inserts the __sanitizer_cov_stack_depth() call for the functions + with a stack frame size greater than or equal to this parameter. If unsure, leave the default value 100. config KSTACK_ERASE_METRICS diff --git a/tools/objtool/check.c b/tools/objtool/check.c index 5451bdbcf84a..b7e24684f592 100644 --- a/tools/objtool/check.c +++ b/tools/objtool/check.c @@ -1193,7 +1193,7 @@ static const char *uaccess_safe_builtin[] = { "__ubsan_handle_shift_out_of_bounds", "__ubsan_handle_load_invalid_value", /* KSTACK_ERASE */ - "stackleak_track_stack", + "__sanitizer_cov_stack_depth", /* TRACE_BRANCH_PROFILING */ "ftrace_likely_update", /* STACKPROTECTOR */ From 76261fc7d1be3fde06efed859cb10c95b1204055 Mon Sep 17 00:00:00 2001 From: Kees Cook Date: Thu, 17 Jul 2025 16:25:08 -0700 Subject: [PATCH 09/22] stackleak: Split KSTACK_ERASE_CFLAGS from GCC_PLUGINS_CFLAGS In preparation for Clang stack depth tracking for KSTACK_ERASE, split the stackleak-specific cflags out of GCC_PLUGINS_CFLAGS into KSTACK_ERASE_CFLAGS. Link: https://lore.kernel.org/r/20250717232519.2984886-3-kees@kernel.org Signed-off-by: Kees Cook --- MAINTAINERS | 2 ++ Makefile | 1 + arch/arm/vdso/Makefile | 2 +- arch/arm64/kernel/vdso/Makefile | 3 ++- arch/sparc/vdso/Makefile | 3 ++- arch/x86/entry/vdso/Makefile | 3 ++- scripts/Makefile.gcc-plugins | 16 ++-------------- scripts/Makefile.kstack_erase | 15 +++++++++++++++ 8 files changed, 27 insertions(+), 18 deletions(-) create mode 100644 scripts/Makefile.kstack_erase diff --git a/MAINTAINERS b/MAINTAINERS index 470d159d8fea..a7e5d0a551be 100644 --- a/MAINTAINERS +++ b/MAINTAINERS @@ -13094,6 +13094,8 @@ F: kernel/kstack_erase.c F: lib/tests/randstruct_kunit.c F: lib/tests/usercopy_kunit.c F: mm/usercopy.c +F: scripts/Makefile.kstack_erase +F: scripts/Makefile.randstruct F: security/Kconfig.hardening K: \b(add|choose)_random_kstack_offset\b K: \b__check_(object_size|heap_object)\b diff --git a/Makefile b/Makefile index ba0827a1fccd..57be26ff5f84 100644 --- a/Makefile +++ b/Makefile @@ -1086,6 +1086,7 @@ include-$(CONFIG_KMSAN) += scripts/Makefile.kmsan include-$(CONFIG_UBSAN) += scripts/Makefile.ubsan include-$(CONFIG_KCOV) += scripts/Makefile.kcov include-$(CONFIG_RANDSTRUCT) += scripts/Makefile.randstruct +include-$(CONFIG_KSTACK_ERASE) += scripts/Makefile.kstack_erase include-$(CONFIG_AUTOFDO_CLANG) += scripts/Makefile.autofdo include-$(CONFIG_PROPELLER_CLANG) += scripts/Makefile.propeller include-$(CONFIG_GCC_PLUGINS) += scripts/Makefile.gcc-plugins diff --git a/arch/arm/vdso/Makefile b/arch/arm/vdso/Makefile index cb044bfd145d..cf8cd39ab804 100644 --- a/arch/arm/vdso/Makefile +++ b/arch/arm/vdso/Makefile @@ -26,7 +26,7 @@ CPPFLAGS_vdso.lds += -P -C -U$(ARCH) CFLAGS_REMOVE_vdso.o = -pg # Force -O2 to avoid libgcc dependencies -CFLAGS_REMOVE_vgettimeofday.o = -pg -Os $(RANDSTRUCT_CFLAGS) $(GCC_PLUGINS_CFLAGS) +CFLAGS_REMOVE_vgettimeofday.o = -pg -Os $(RANDSTRUCT_CFLAGS) $(KSTACK_ERASE_CFLAGS) $(GCC_PLUGINS_CFLAGS) ifeq ($(c-gettimeofday-y),) CFLAGS_vgettimeofday.o = -O2 else diff --git a/arch/arm64/kernel/vdso/Makefile b/arch/arm64/kernel/vdso/Makefile index 5e27e46aa496..7dec05dd33b7 100644 --- a/arch/arm64/kernel/vdso/Makefile +++ b/arch/arm64/kernel/vdso/Makefile @@ -36,7 +36,8 @@ ccflags-y += -DDISABLE_BRANCH_PROFILING -DBUILD_VDSO # -Wmissing-prototypes and -Wmissing-declarations are removed from # the CFLAGS to make possible to build the kernel with CONFIG_WERROR enabled. CC_FLAGS_REMOVE_VDSO := $(CC_FLAGS_FTRACE) -Os $(CC_FLAGS_SCS) \ - $(RANDSTRUCT_CFLAGS) $(GCC_PLUGINS_CFLAGS) \ + $(RANDSTRUCT_CFLAGS) $(KSTACK_ERASE_CFLAGS) \ + $(GCC_PLUGINS_CFLAGS) \ $(CC_FLAGS_LTO) $(CC_FLAGS_CFI) \ -Wmissing-prototypes -Wmissing-declarations diff --git a/arch/sparc/vdso/Makefile b/arch/sparc/vdso/Makefile index fdc4a8f5a49c..683b2d408224 100644 --- a/arch/sparc/vdso/Makefile +++ b/arch/sparc/vdso/Makefile @@ -48,7 +48,7 @@ CFL := $(PROFILING) -mcmodel=medlow -fPIC -O2 -fasynchronous-unwind-tables -m64 SPARC_REG_CFLAGS = -ffixed-g4 -ffixed-g5 $(call cc-option,-fcall-used-g5) $(call cc-option,-fcall-used-g7) -$(vobjs): KBUILD_CFLAGS := $(filter-out $(RANDSTRUCT_CFLAGS) $(GCC_PLUGINS_CFLAGS) $(SPARC_REG_CFLAGS),$(KBUILD_CFLAGS)) $(CFL) +$(vobjs): KBUILD_CFLAGS := $(filter-out $(RANDSTRUCT_CFLAGS) $(KSTACK_ERASE_CFLAGS) $(GCC_PLUGINS_CFLAGS) $(SPARC_REG_CFLAGS),$(KBUILD_CFLAGS)) $(CFL) # # vDSO code runs in userspace and -pg doesn't help with profiling anyway. @@ -79,6 +79,7 @@ KBUILD_CFLAGS_32 := $(filter-out -m64,$(KBUILD_CFLAGS)) KBUILD_CFLAGS_32 := $(filter-out -mcmodel=medlow,$(KBUILD_CFLAGS_32)) KBUILD_CFLAGS_32 := $(filter-out -fno-pic,$(KBUILD_CFLAGS_32)) KBUILD_CFLAGS_32 := $(filter-out $(RANDSTRUCT_CFLAGS),$(KBUILD_CFLAGS_32)) +KBUILD_CFLAGS_32 := $(filter-out $(KSTACK_ERASE_CFLAGS),$(KBUILD_CFLAGS_32)) KBUILD_CFLAGS_32 := $(filter-out $(GCC_PLUGINS_CFLAGS),$(KBUILD_CFLAGS_32)) KBUILD_CFLAGS_32 := $(filter-out $(SPARC_REG_CFLAGS),$(KBUILD_CFLAGS_32)) KBUILD_CFLAGS_32 += -m32 -msoft-float -fpic diff --git a/arch/x86/entry/vdso/Makefile b/arch/x86/entry/vdso/Makefile index 54d3e9774d62..f247f5f5cb44 100644 --- a/arch/x86/entry/vdso/Makefile +++ b/arch/x86/entry/vdso/Makefile @@ -62,7 +62,7 @@ ifneq ($(RETPOLINE_VDSO_CFLAGS),) endif endif -$(vobjs): KBUILD_CFLAGS := $(filter-out $(PADDING_CFLAGS) $(CC_FLAGS_LTO) $(CC_FLAGS_CFI) $(RANDSTRUCT_CFLAGS) $(GCC_PLUGINS_CFLAGS) $(RETPOLINE_CFLAGS),$(KBUILD_CFLAGS)) $(CFL) +$(vobjs): KBUILD_CFLAGS := $(filter-out $(PADDING_CFLAGS) $(CC_FLAGS_LTO) $(CC_FLAGS_CFI) $(RANDSTRUCT_CFLAGS) $(KSTACK_ERASE_CFLAGS) $(GCC_PLUGINS_CFLAGS) $(RETPOLINE_CFLAGS),$(KBUILD_CFLAGS)) $(CFL) $(vobjs): KBUILD_AFLAGS += -DBUILD_VDSO # @@ -123,6 +123,7 @@ KBUILD_CFLAGS_32 := $(filter-out -mcmodel=kernel,$(KBUILD_CFLAGS_32)) KBUILD_CFLAGS_32 := $(filter-out -fno-pic,$(KBUILD_CFLAGS_32)) KBUILD_CFLAGS_32 := $(filter-out -mfentry,$(KBUILD_CFLAGS_32)) KBUILD_CFLAGS_32 := $(filter-out $(RANDSTRUCT_CFLAGS),$(KBUILD_CFLAGS_32)) +KBUILD_CFLAGS_32 := $(filter-out $(KSTACK_ERASE_CFLAGS),$(KBUILD_CFLAGS_32)) KBUILD_CFLAGS_32 := $(filter-out $(GCC_PLUGINS_CFLAGS),$(KBUILD_CFLAGS_32)) KBUILD_CFLAGS_32 := $(filter-out $(RETPOLINE_CFLAGS),$(KBUILD_CFLAGS_32)) KBUILD_CFLAGS_32 := $(filter-out $(CC_FLAGS_LTO),$(KBUILD_CFLAGS_32)) diff --git a/scripts/Makefile.gcc-plugins b/scripts/Makefile.gcc-plugins index 28b8867c4e84..b0e1423b09c2 100644 --- a/scripts/Makefile.gcc-plugins +++ b/scripts/Makefile.gcc-plugins @@ -8,20 +8,6 @@ ifdef CONFIG_GCC_PLUGIN_LATENT_ENTROPY endif export DISABLE_LATENT_ENTROPY_PLUGIN -gcc-plugin-$(CONFIG_GCC_PLUGIN_STACKLEAK) += stackleak_plugin.so -gcc-plugin-cflags-$(CONFIG_GCC_PLUGIN_STACKLEAK) \ - += -DSTACKLEAK_PLUGIN -gcc-plugin-cflags-$(CONFIG_GCC_PLUGIN_STACKLEAK) \ - += -fplugin-arg-stackleak_plugin-track-min-size=$(CONFIG_KSTACK_ERASE_TRACK_MIN_SIZE) -gcc-plugin-cflags-$(CONFIG_GCC_PLUGIN_STACKLEAK) \ - += -fplugin-arg-stackleak_plugin-arch=$(SRCARCH) -gcc-plugin-cflags-$(CONFIG_GCC_PLUGIN_STACKLEAK_VERBOSE) \ - += -fplugin-arg-stackleak_plugin-verbose -ifdef CONFIG_GCC_PLUGIN_STACKLEAK - DISABLE_KSTACK_ERASE += -fplugin-arg-stackleak_plugin-disable -endif -export DISABLE_KSTACK_ERASE - # All the plugin CFLAGS are collected here in case a build target needs to # filter them out of the KBUILD_CFLAGS. GCC_PLUGINS_CFLAGS := $(strip $(addprefix -fplugin=$(objtree)/scripts/gcc-plugins/, $(gcc-plugin-y)) $(gcc-plugin-cflags-y)) -DGCC_PLUGINS @@ -34,6 +20,8 @@ KBUILD_CFLAGS += $(GCC_PLUGINS_CFLAGS) # be included in GCC_PLUGIN so they can get built. gcc-plugin-external-$(CONFIG_GCC_PLUGIN_RANDSTRUCT) \ += randomize_layout_plugin.so +gcc-plugin-external-$(CONFIG_GCC_PLUGIN_STACKLEAK) \ + += stackleak_plugin.so # All enabled GCC plugins are collected here for building in # scripts/gcc-scripts/Makefile. diff --git a/scripts/Makefile.kstack_erase b/scripts/Makefile.kstack_erase new file mode 100644 index 000000000000..5223d3a35817 --- /dev/null +++ b/scripts/Makefile.kstack_erase @@ -0,0 +1,15 @@ +# SPDX-License-Identifier: GPL-2.0 + +ifdef CONFIG_GCC_PLUGIN_STACKLEAK +kstack-erase-cflags-y += -fplugin=$(objtree)/scripts/gcc-plugins/stackleak_plugin.so +kstack-erase-cflags-y += -fplugin-arg-stackleak_plugin-track-min-size=$(CONFIG_KSTACK_ERASE_TRACK_MIN_SIZE) +kstack-erase-cflags-y += -fplugin-arg-stackleak_plugin-arch=$(SRCARCH) +kstack-erase-cflags-$(CONFIG_GCC_PLUGIN_STACKLEAK_VERBOSE) += -fplugin-arg-stackleak_plugin-verbose +DISABLE_KSTACK_ERASE := -fplugin-arg-stackleak_plugin-disable +endif + +KSTACK_ERASE_CFLAGS := $(kstack-erase-cflags-y) + +export STACKLEAK_CFLAGS DISABLE_KSTACK_ERASE + +KBUILD_CFLAGS += $(KSTACK_ERASE_CFLAGS) From 4c56d9f7e75eb2a137584f708fa262d7e8c8a2d8 Mon Sep 17 00:00:00 2001 From: Kees Cook Date: Thu, 17 Jul 2025 16:25:17 -0700 Subject: [PATCH 10/22] configs/hardening: Enable CONFIG_KSTACK_ERASE Since we can wipe the stack with both Clang and GCC plugins, enable this for the "hardening.config" for wider testing. Link: https://lore.kernel.org/r/20250717232519.2984886-12-kees@kernel.org Signed-off-by: Kees Cook --- kernel/configs/hardening.config | 3 +++ 1 file changed, 3 insertions(+) diff --git a/kernel/configs/hardening.config b/kernel/configs/hardening.config index dd7c32fb5ac1..d24c2772d04d 100644 --- a/kernel/configs/hardening.config +++ b/kernel/configs/hardening.config @@ -63,6 +63,9 @@ CONFIG_INIT_ON_ALLOC_DEFAULT_ON=y # Initialize all stack variables to zero on function entry. CONFIG_INIT_STACK_ALL_ZERO=y +# Wipe kernel stack after syscall completion to reduce stale data lifetime. +CONFIG_KSTACK_ERASE=y + # Wipe RAM at reboot via EFI. For more details, see: # https://trustedcomputinggroup.org/resource/pc-client-work-group-platform-reset-attack-mitigation-specification/ # https://bugzilla.redhat.com/show_bug.cgi?id=1532058 From 437641a72d0a675242ae3e649a30b4c51b3ad450 Mon Sep 17 00:00:00 2001 From: Kees Cook Date: Thu, 17 Jul 2025 16:25:18 -0700 Subject: [PATCH 11/22] configs/hardening: Enable CONFIG_INIT_ON_FREE_DEFAULT_ON To reduce stale data lifetimes, enable CONFIG_INIT_ON_FREE_DEFAULT_ON as well. This matches the addition of CONFIG_STACKLEAK=y, which is doing similar for stack memory. Link: https://lore.kernel.org/r/20250717232519.2984886-13-kees@kernel.org Signed-off-by: Kees Cook --- kernel/configs/hardening.config | 3 +++ 1 file changed, 3 insertions(+) diff --git a/kernel/configs/hardening.config b/kernel/configs/hardening.config index d24c2772d04d..64caaf997fc0 100644 --- a/kernel/configs/hardening.config +++ b/kernel/configs/hardening.config @@ -60,6 +60,9 @@ CONFIG_LIST_HARDENED=y # Initialize all heap variables to zero on allocation. CONFIG_INIT_ON_ALLOC_DEFAULT_ON=y +# Initialize all heap variables to zero on free to reduce stale data lifetime. +CONFIG_INIT_ON_FREE_DEFAULT_ON=y + # Initialize all stack variables to zero on function entry. CONFIG_INIT_STACK_ALL_ZERO=y From 645d1b666498ef0d2c44c434a609b5560e9dc401 Mon Sep 17 00:00:00 2001 From: "Ritesh Harjani (IBM)" Date: Thu, 17 Jul 2025 16:25:13 -0700 Subject: [PATCH 12/22] powerpc/mm/book3s64: Move kfence and debug_pagealloc related calls to __init section Move a few kfence and debug_pagealloc related functions in hash_utils.c and radix_pgtable.c to __init sections since these are only invoked once by an __init function during system initialization. i.e. - hash_debug_pagealloc_alloc_slots() - hash_kfence_alloc_pool() - hash_kfence_map_pool() The above 3 functions only gets called by __init htab_initialize(). - alloc_kfence_pool() - map_kfence_pool() The above 2 functions only gets called by __init radix_init_pgtable() This should also help fix warning msgs like: >> WARNING: modpost: vmlinux: section mismatch in reference: hash_debug_pagealloc_alloc_slots+0xb0 (section: .text) -> memblock_alloc_try_nid (section: .init.text) Reported-by: kernel test robot Closes: https://lore.kernel.org/oe-kbuild-all/202504190552.mnFGs5sj-lkp@intel.com/ Signed-off-by: Ritesh Harjani (IBM) Link: https://lore.kernel.org/r/20250717232519.2984886-8-kees@kernel.org Signed-off-by: Kees Cook --- arch/powerpc/mm/book3s64/hash_utils.c | 6 +++--- arch/powerpc/mm/book3s64/radix_pgtable.c | 4 ++-- 2 files changed, 5 insertions(+), 5 deletions(-) diff --git a/arch/powerpc/mm/book3s64/hash_utils.c b/arch/powerpc/mm/book3s64/hash_utils.c index 5158aefe4873..4693c464fc5a 100644 --- a/arch/powerpc/mm/book3s64/hash_utils.c +++ b/arch/powerpc/mm/book3s64/hash_utils.c @@ -343,7 +343,7 @@ static inline bool hash_supports_debug_pagealloc(void) static u8 *linear_map_hash_slots; static unsigned long linear_map_hash_count; static DEFINE_RAW_SPINLOCK(linear_map_hash_lock); -static void hash_debug_pagealloc_alloc_slots(void) +static __init void hash_debug_pagealloc_alloc_slots(void) { if (!hash_supports_debug_pagealloc()) return; @@ -409,7 +409,7 @@ static DEFINE_RAW_SPINLOCK(linear_map_kf_hash_lock); static phys_addr_t kfence_pool; -static inline void hash_kfence_alloc_pool(void) +static __init void hash_kfence_alloc_pool(void) { if (!kfence_early_init_enabled()) goto err; @@ -445,7 +445,7 @@ err: disable_kfence(); } -static inline void hash_kfence_map_pool(void) +static __init void hash_kfence_map_pool(void) { unsigned long kfence_pool_start, kfence_pool_end; unsigned long prot = pgprot_val(PAGE_KERNEL); diff --git a/arch/powerpc/mm/book3s64/radix_pgtable.c b/arch/powerpc/mm/book3s64/radix_pgtable.c index 9f764bc42b8c..376dba5992f2 100644 --- a/arch/powerpc/mm/book3s64/radix_pgtable.c +++ b/arch/powerpc/mm/book3s64/radix_pgtable.c @@ -363,7 +363,7 @@ static int __meminit create_physical_mapping(unsigned long start, } #ifdef CONFIG_KFENCE -static inline phys_addr_t alloc_kfence_pool(void) +static __init phys_addr_t alloc_kfence_pool(void) { phys_addr_t kfence_pool; @@ -393,7 +393,7 @@ no_kfence: return 0; } -static inline void map_kfence_pool(phys_addr_t kfence_pool) +static __init void map_kfence_pool(phys_addr_t kfence_pool) { if (!kfence_pool) return; From d01daf9d95c9918bd11f990e807517f214a83ea2 Mon Sep 17 00:00:00 2001 From: Kees Cook Date: Thu, 17 Jul 2025 16:25:14 -0700 Subject: [PATCH 13/22] mips: Handle KCOV __init vs inline mismatch When KCOV is enabled all functions get instrumented, unless the __no_sanitize_coverage attribute is used. To prepare for __no_sanitize_coverage being applied to __init functions, we have to handle differences in how GCC's inline optimizations get resolved. For mips this requires adding the __init annotation on init_mips_clocksource(). Reviewed-by: Huacai Chen Link: https://lore.kernel.org/r/20250717232519.2984886-9-kees@kernel.org Signed-off-by: Kees Cook --- arch/mips/include/asm/time.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/arch/mips/include/asm/time.h b/arch/mips/include/asm/time.h index e855a3611d92..5e7193b759f3 100644 --- a/arch/mips/include/asm/time.h +++ b/arch/mips/include/asm/time.h @@ -55,7 +55,7 @@ static inline int mips_clockevent_init(void) */ extern int init_r4k_clocksource(void); -static inline int init_mips_clocksource(void) +static inline __init int init_mips_clocksource(void) { #ifdef CONFIG_CSRC_R4K return init_r4k_clocksource(); From 2424fe1cac4fc8ea0520ba22ede7544c3ddc8dd1 Mon Sep 17 00:00:00 2001 From: Kees Cook Date: Thu, 17 Jul 2025 16:25:10 -0700 Subject: [PATCH 14/22] arm: Handle KCOV __init vs inline mismatches When KCOV is enabled all functions get instrumented, unless the __no_sanitize_coverage attribute is used. To prepare for __no_sanitize_coverage being applied to __init functions, we have to handle differences in how GCC's inline optimizations get resolved. For arm this exposed several places where __init annotations were missing but ended up being "accidentally correct". Fix these cases and force several functions to be inline with __always_inline. Acked-by: Nishanth Menon Acked-by: Lee Jones Reviewed-by: Nishanth Menon Link: https://lore.kernel.org/r/20250717232519.2984886-5-kees@kernel.org Signed-off-by: Kees Cook --- arch/arm/mm/cache-feroceon-l2.c | 2 +- arch/arm/mm/cache-tauros2.c | 2 +- drivers/clocksource/timer-orion.c | 2 +- drivers/soc/ti/pm33xx.c | 2 +- include/linux/mfd/dbx500-prcmu.h | 2 +- 5 files changed, 5 insertions(+), 5 deletions(-) diff --git a/arch/arm/mm/cache-feroceon-l2.c b/arch/arm/mm/cache-feroceon-l2.c index 25dbd84a1aaf..2bfefb252ffd 100644 --- a/arch/arm/mm/cache-feroceon-l2.c +++ b/arch/arm/mm/cache-feroceon-l2.c @@ -295,7 +295,7 @@ static inline u32 read_extra_features(void) return u; } -static inline void write_extra_features(u32 u) +static inline void __init write_extra_features(u32 u) { __asm__("mcr p15, 1, %0, c15, c1, 0" : : "r" (u)); } diff --git a/arch/arm/mm/cache-tauros2.c b/arch/arm/mm/cache-tauros2.c index b1e1aba602f7..bfe166ccace0 100644 --- a/arch/arm/mm/cache-tauros2.c +++ b/arch/arm/mm/cache-tauros2.c @@ -177,7 +177,7 @@ static inline void __init write_actlr(u32 actlr) __asm__("mcr p15, 0, %0, c1, c0, 1\n" : : "r" (actlr)); } -static void enable_extra_feature(unsigned int features) +static void __init enable_extra_feature(unsigned int features) { u32 u; diff --git a/drivers/clocksource/timer-orion.c b/drivers/clocksource/timer-orion.c index 49e86cb70a7a..61f1e27fc41e 100644 --- a/drivers/clocksource/timer-orion.c +++ b/drivers/clocksource/timer-orion.c @@ -43,7 +43,7 @@ static struct delay_timer orion_delay_timer = { .read_current_timer = orion_read_timer, }; -static void orion_delay_timer_init(unsigned long rate) +static void __init orion_delay_timer_init(unsigned long rate) { orion_delay_timer.freq = rate; register_current_timer_delay(&orion_delay_timer); diff --git a/drivers/soc/ti/pm33xx.c b/drivers/soc/ti/pm33xx.c index dfdff186c805..dc52a2197d24 100644 --- a/drivers/soc/ti/pm33xx.c +++ b/drivers/soc/ti/pm33xx.c @@ -145,7 +145,7 @@ static int am33xx_do_sram_idle(u32 wfi_flags) return pm_ops->cpu_suspend(am33xx_do_wfi_sram, wfi_flags); } -static int __init am43xx_map_gic(void) +static int am43xx_map_gic(void) { gic_dist_base = ioremap(AM43XX_GIC_DIST_BASE, SZ_4K); diff --git a/include/linux/mfd/dbx500-prcmu.h b/include/linux/mfd/dbx500-prcmu.h index 98567623c9df..828362b7860c 100644 --- a/include/linux/mfd/dbx500-prcmu.h +++ b/include/linux/mfd/dbx500-prcmu.h @@ -213,7 +213,7 @@ struct prcmu_fw_version { #if defined(CONFIG_UX500_SOC_DB8500) -static inline void prcmu_early_init(void) +static inline void __init prcmu_early_init(void) { db8500_prcmu_early_init(); } From c64d6be1a6f8c93274bb861ec75c59453508093a Mon Sep 17 00:00:00 2001 From: Kees Cook Date: Thu, 17 Jul 2025 16:25:12 -0700 Subject: [PATCH 15/22] s390: Handle KCOV __init vs inline mismatches When KCOV is enabled all functions get instrumented, unless the __no_sanitize_coverage attribute is used. To prepare for __no_sanitize_coverage being applied to __init functions, we have to handle differences in how GCC's inline optimizations get resolved. For s390 this exposed a place where the __init annotation was missing but ended up being "accidentally correct". Fix this cases and force a couple functions to be inline with __always_inline. Acked-by: Heiko Carstens Link: https://lore.kernel.org/r/20250717232519.2984886-7-kees@kernel.org Signed-off-by: Kees Cook --- arch/s390/hypfs/hypfs.h | 2 +- arch/s390/hypfs/hypfs_diag.h | 2 +- arch/s390/mm/init.c | 2 +- 3 files changed, 3 insertions(+), 3 deletions(-) diff --git a/arch/s390/hypfs/hypfs.h b/arch/s390/hypfs/hypfs.h index 83ebf54cca6b..4dc2e068e0ff 100644 --- a/arch/s390/hypfs/hypfs.h +++ b/arch/s390/hypfs/hypfs.h @@ -48,7 +48,7 @@ void hypfs_sprp_exit(void); int __hypfs_fs_init(void); -static inline int hypfs_fs_init(void) +static __always_inline int hypfs_fs_init(void) { if (IS_ENABLED(CONFIG_S390_HYPFS_FS)) return __hypfs_fs_init(); diff --git a/arch/s390/hypfs/hypfs_diag.h b/arch/s390/hypfs/hypfs_diag.h index 7090eff27fef..b5218135b8fe 100644 --- a/arch/s390/hypfs/hypfs_diag.h +++ b/arch/s390/hypfs/hypfs_diag.h @@ -19,7 +19,7 @@ int diag204_store(void *buf, int pages); int __hypfs_diag_fs_init(void); void __hypfs_diag_fs_exit(void); -static inline int hypfs_diag_fs_init(void) +static __always_inline int hypfs_diag_fs_init(void) { if (IS_ENABLED(CONFIG_S390_HYPFS_FS)) return __hypfs_diag_fs_init(); diff --git a/arch/s390/mm/init.c b/arch/s390/mm/init.c index 074bf4fb4ce2..e4953453d254 100644 --- a/arch/s390/mm/init.c +++ b/arch/s390/mm/init.c @@ -142,7 +142,7 @@ bool force_dma_unencrypted(struct device *dev) } /* protected virtualization */ -static void pv_init(void) +static void __init pv_init(void) { if (!is_prot_virt_guest()) return; From 65c430906efffee9bd7551d474f01a6b1197df90 Mon Sep 17 00:00:00 2001 From: Kees Cook Date: Wed, 23 Jul 2025 22:50:25 -0700 Subject: [PATCH 16/22] arm64: Handle KCOV __init vs inline mismatches GCC appears to have kind of fragile inlining heuristics, in the sense that it can change whether or not it inlines something based on optimizations. It looks like the kcov instrumentation being added (or in this case, removed) from a function changes the optimization results, and some functions marked "inline" are _not_ inlined. In that case, we end up with __init code calling a function not marked __init, and we get the build warnings I'm trying to eliminate in the coming patch that adds __no_sanitize_coverage to __init functions: WARNING: modpost: vmlinux: section mismatch in reference: acpi_get_enable_method+0x1c (section: .text.unlikely) -> acpi_psci_present (section: .init.text) This problem is somewhat fragile (though using either __always_inline or __init will deterministically solve it), but we've tripped over this before with GCC and the solution has usually been to just use __always_inline and move on. For arm64 this requires forcing one ACPI function to be inlined with __always_inline. Link: https://lore.kernel.org/r/20250724055029.3623499-1-kees@kernel.org Signed-off-by: Kees Cook --- arch/arm64/include/asm/acpi.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/arch/arm64/include/asm/acpi.h b/arch/arm64/include/asm/acpi.h index a407f9cd549e..c07a58b96329 100644 --- a/arch/arm64/include/asm/acpi.h +++ b/arch/arm64/include/asm/acpi.h @@ -150,7 +150,7 @@ acpi_set_mailbox_entry(int cpu, struct acpi_madt_generic_interrupt *processor) {} #endif -static inline const char *acpi_get_enable_method(int cpu) +static __always_inline const char *acpi_get_enable_method(int cpu) { if (acpi_psci_present()) return "psci"; From 8245d47cfaba8a38337a447230b4d01f9946f5e1 Mon Sep 17 00:00:00 2001 From: Kees Cook Date: Wed, 23 Jul 2025 22:50:26 -0700 Subject: [PATCH 17/22] x86: Handle KCOV __init vs inline mismatches GCC appears to have kind of fragile inlining heuristics, in the sense that it can change whether or not it inlines something based on optimizations. It looks like the kcov instrumentation being added (or in this case, removed) from a function changes the optimization results, and some functions marked "inline" are _not_ inlined. In that case, we end up with __init code calling a function not marked __init, and we get the build warnings I'm trying to eliminate in the coming patch that adds __no_sanitize_coverage to __init functions: WARNING: modpost: vmlinux: section mismatch in reference: xbc_exit+0x8 (section: .text.unlikely) -> _xbc_exit (section: .init.text) WARNING: modpost: vmlinux: section mismatch in reference: real_mode_size_needed+0x15 (section: .text.unlikely) -> real_mode_blob_end (section: .init.data) WARNING: modpost: vmlinux: section mismatch in reference: __set_percpu_decrypted+0x16 (section: .text.unlikely) -> early_set_memory_decrypted (section: .init.text) WARNING: modpost: vmlinux: section mismatch in reference: memblock_alloc_from+0x26 (section: .text.unlikely) -> memblock_alloc_try_nid (section: .init.text) WARNING: modpost: vmlinux: section mismatch in reference: acpi_arch_set_root_pointer+0xc (section: .text.unlikely) -> x86_init (section: .init.data) WARNING: modpost: vmlinux: section mismatch in reference: acpi_arch_get_root_pointer+0x8 (section: .text.unlikely) -> x86_init (section: .init.data) WARNING: modpost: vmlinux: section mismatch in reference: efi_config_table_is_usable+0x16 (section: .text.unlikely) -> xen_efi_config_table_is_usable (section: .init.text) This problem is somewhat fragile (though using either __always_inline or __init will deterministically solve it), but we've tripped over this before with GCC and the solution has usually been to just use __always_inline and move on. For x86 this means forcing several functions to be inline with __always_inline. Link: https://lore.kernel.org/r/20250724055029.3623499-2-kees@kernel.org Signed-off-by: Kees Cook --- arch/x86/include/asm/acpi.h | 4 ++-- arch/x86/include/asm/realmode.h | 2 +- arch/x86/kernel/kvm.c | 2 +- arch/x86/mm/init_64.c | 2 +- include/linux/acpi.h | 4 ++-- include/linux/bootconfig.h | 2 +- include/linux/efi.h | 2 +- include/linux/memblock.h | 2 +- include/linux/smp.h | 2 +- kernel/kexec_handover.c | 4 ++-- 10 files changed, 13 insertions(+), 13 deletions(-) diff --git a/arch/x86/include/asm/acpi.h b/arch/x86/include/asm/acpi.h index 5ab1a4598d00..a03aa6f999d1 100644 --- a/arch/x86/include/asm/acpi.h +++ b/arch/x86/include/asm/acpi.h @@ -158,13 +158,13 @@ static inline bool acpi_has_cpu_in_madt(void) } #define ACPI_HAVE_ARCH_SET_ROOT_POINTER -static inline void acpi_arch_set_root_pointer(u64 addr) +static __always_inline void acpi_arch_set_root_pointer(u64 addr) { x86_init.acpi.set_root_pointer(addr); } #define ACPI_HAVE_ARCH_GET_ROOT_POINTER -static inline u64 acpi_arch_get_root_pointer(void) +static __always_inline u64 acpi_arch_get_root_pointer(void) { return x86_init.acpi.get_root_pointer(); } diff --git a/arch/x86/include/asm/realmode.h b/arch/x86/include/asm/realmode.h index f607081a022a..e406a1e92c63 100644 --- a/arch/x86/include/asm/realmode.h +++ b/arch/x86/include/asm/realmode.h @@ -78,7 +78,7 @@ extern unsigned char secondary_startup_64[]; extern unsigned char secondary_startup_64_no_verify[]; #endif -static inline size_t real_mode_size_needed(void) +static __always_inline size_t real_mode_size_needed(void) { if (real_mode_header) return 0; /* already allocated. */ diff --git a/arch/x86/kernel/kvm.c b/arch/x86/kernel/kvm.c index 921c1c783bc1..8ae750cde0c6 100644 --- a/arch/x86/kernel/kvm.c +++ b/arch/x86/kernel/kvm.c @@ -420,7 +420,7 @@ static u64 kvm_steal_clock(int cpu) return steal; } -static inline void __set_percpu_decrypted(void *ptr, unsigned long size) +static inline __init void __set_percpu_decrypted(void *ptr, unsigned long size) { early_set_memory_decrypted((unsigned long) ptr, size); } diff --git a/arch/x86/mm/init_64.c b/arch/x86/mm/init_64.c index ee66fae9ebcc..c02029cd27e1 100644 --- a/arch/x86/mm/init_64.c +++ b/arch/x86/mm/init_64.c @@ -806,7 +806,7 @@ kernel_physical_mapping_change(unsigned long paddr_start, } #ifndef CONFIG_NUMA -static inline void x86_numa_init(void) +static __always_inline void x86_numa_init(void) { memblock_set_node(0, PHYS_ADDR_MAX, &memblock.memory, 0); } diff --git a/include/linux/acpi.h b/include/linux/acpi.h index f102c0fe3431..fc7f5e039074 100644 --- a/include/linux/acpi.h +++ b/include/linux/acpi.h @@ -759,13 +759,13 @@ int acpi_arch_timer_mem_init(struct arch_timer_mem *timer_mem, int *timer_count) #endif #ifndef ACPI_HAVE_ARCH_SET_ROOT_POINTER -static inline void acpi_arch_set_root_pointer(u64 addr) +static __always_inline void acpi_arch_set_root_pointer(u64 addr) { } #endif #ifndef ACPI_HAVE_ARCH_GET_ROOT_POINTER -static inline u64 acpi_arch_get_root_pointer(void) +static __always_inline u64 acpi_arch_get_root_pointer(void) { return 0; } diff --git a/include/linux/bootconfig.h b/include/linux/bootconfig.h index 3f4b4ac527ca..25df9260d206 100644 --- a/include/linux/bootconfig.h +++ b/include/linux/bootconfig.h @@ -290,7 +290,7 @@ int __init xbc_get_info(int *node_size, size_t *data_size); /* XBC cleanup data structures */ void __init _xbc_exit(bool early); -static inline void xbc_exit(void) +static __always_inline void xbc_exit(void) { _xbc_exit(false); } diff --git a/include/linux/efi.h b/include/linux/efi.h index 7d63d1d75f22..e3776d9cad07 100644 --- a/include/linux/efi.h +++ b/include/linux/efi.h @@ -1334,7 +1334,7 @@ struct linux_efi_initrd { bool xen_efi_config_table_is_usable(const efi_guid_t *guid, unsigned long table); -static inline +static __always_inline bool efi_config_table_is_usable(const efi_guid_t *guid, unsigned long table) { if (!IS_ENABLED(CONFIG_XEN_EFI)) diff --git a/include/linux/memblock.h b/include/linux/memblock.h index bb19a2534224..b96746376e17 100644 --- a/include/linux/memblock.h +++ b/include/linux/memblock.h @@ -463,7 +463,7 @@ static inline void *memblock_alloc_raw(phys_addr_t size, NUMA_NO_NODE); } -static inline void *memblock_alloc_from(phys_addr_t size, +static __always_inline void *memblock_alloc_from(phys_addr_t size, phys_addr_t align, phys_addr_t min_addr) { diff --git a/include/linux/smp.h b/include/linux/smp.h index f1aa0952e8c3..84e948eb1c20 100644 --- a/include/linux/smp.h +++ b/include/linux/smp.h @@ -221,7 +221,7 @@ static inline void wake_up_all_idle_cpus(void) { } #ifdef CONFIG_UP_LATE_INIT extern void __init up_late_init(void); -static inline void smp_init(void) { up_late_init(); } +static __always_inline void smp_init(void) { up_late_init(); } #else static inline void smp_init(void) { } #endif diff --git a/kernel/kexec_handover.c b/kernel/kexec_handover.c index 69b953551677..f3f6bfe43d47 100644 --- a/kernel/kexec_handover.c +++ b/kernel/kexec_handover.c @@ -305,8 +305,8 @@ err_free: return -ENOMEM; } -static void deserialize_bitmap(unsigned int order, - struct khoser_mem_bitmap_ptr *elm) +static void __init deserialize_bitmap(unsigned int order, + struct khoser_mem_bitmap_ptr *elm) { struct kho_mem_phys_bits *bitmap = KHOSER_LOAD_PTR(elm->bitmap); unsigned long bit; From 431a380f935e2c74cbaeac65367c70fc18903315 Mon Sep 17 00:00:00 2001 From: Kees Cook Date: Fri, 25 Jul 2025 23:44:26 -0700 Subject: [PATCH 18/22] kstack_erase: Disable kstack_erase for all of arm compressed boot code When building with CONFIG_KSTACK_ERASE=y and CONFIG_ARM_ATAG_DTB_COMPAT=y, the compressed boot environment encounters an undefined symbol error: ld.lld: error: undefined symbol: __sanitizer_cov_stack_depth >>> referenced by atags_to_fdt.c:135 This occurs because the compiler instruments the atags_to_fdt() function with sanitizer coverage calls, but the minimal compressed boot environment lacks access to sanitizer runtime support. The compressed boot environment already disables stack protector with -fno-stack-protector. Similarly disable sanitizer coverage by adding $(DISABLE_KSTACK_ERASE) to the general compiler flags (and remove it from the one place it was noticed before), which contains the appropriate flags to prevent sanitizer instrumentation. This follows the same pattern used in other early boot contexts where sanitizer runtime support is unavailable. Reported-by: Linux Kernel Functional Testing Closes: https://lore.kernel.org/all/CA+G9fYtBk8qnpWvoaFwymCx5s5i-5KXtPGpmf=_+UKJddCOnLA@mail.gmail.com Reported-by: Nathan Chancellor Closes: https://lore.kernel.org/all/20250726004313.GA3650901@ax162 Suggested-by: Nathan Chancellor Tested-by: Nathan Chancellor Signed-off-by: Kees Cook --- arch/arm/boot/compressed/Makefile | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/arch/arm/boot/compressed/Makefile b/arch/arm/boot/compressed/Makefile index f9075edfd773..a159120d1e42 100644 --- a/arch/arm/boot/compressed/Makefile +++ b/arch/arm/boot/compressed/Makefile @@ -9,7 +9,6 @@ OBJS = HEAD = head.o OBJS += misc.o decompress.o -CFLAGS_decompress.o += $(DISABLE_KSTACK_ERASE) ifeq ($(CONFIG_DEBUG_UNCOMPRESS),y) OBJS += debug.o AFLAGS_head.o += -DDEBUG @@ -96,6 +95,7 @@ KBUILD_CFLAGS += -DDISABLE_BRANCH_PROFILING ccflags-y := -fpic $(call cc-option,-mno-single-pic-base,) -fno-builtin \ -I$(srctree)/scripts/dtc/libfdt -fno-stack-protector \ + $(DISABLE_KSTACK_ERASE) \ -I$(obj) ccflags-remove-$(CONFIG_FUNCTION_TRACER) += -pg asflags-y := -DZIMAGE From 381a38ea53d25ed6f93ba007b021db86c2a36bc6 Mon Sep 17 00:00:00 2001 From: Kees Cook Date: Wed, 23 Jul 2025 22:50:27 -0700 Subject: [PATCH 19/22] init.h: Disable sanitizer coverage for __init and __head While __noinstr already contained __no_sanitize_coverage, it needs to be added to __init and __head section markings to support the Clang implementation of CONFIG_KSTACK_ERASE. This is to make sure the stack depth tracking callback is not executed in unsupported contexts. The other sanitizer coverage options (trace-pc and trace-cmp) aren't needed in __head nor __init either ("We are interested in code coverage as a function of a syscall inputs"[1]), so this is fine to disable for them as well. Link: https://web.git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/kernel/kcov.c?h=v6.14#n179 [1] Acked-by: Marco Elver Link: https://lore.kernel.org/r/20250724055029.3623499-3-kees@kernel.org Signed-off-by: Kees Cook --- arch/x86/include/asm/init.h | 2 +- include/linux/init.h | 4 +++- 2 files changed, 4 insertions(+), 2 deletions(-) diff --git a/arch/x86/include/asm/init.h b/arch/x86/include/asm/init.h index 8b1b1abcef15..6bfdaeddbae8 100644 --- a/arch/x86/include/asm/init.h +++ b/arch/x86/include/asm/init.h @@ -5,7 +5,7 @@ #if defined(CONFIG_CC_IS_CLANG) && CONFIG_CLANG_VERSION < 170000 #define __head __section(".head.text") __no_sanitize_undefined __no_stack_protector #else -#define __head __section(".head.text") __no_sanitize_undefined +#define __head __section(".head.text") __no_sanitize_undefined __no_sanitize_coverage #endif struct x86_mapping_info { diff --git a/include/linux/init.h b/include/linux/init.h index ee1309473bc6..c65a050d52a7 100644 --- a/include/linux/init.h +++ b/include/linux/init.h @@ -49,7 +49,9 @@ /* These are for everybody (although not all archs will actually discard it in modules) */ -#define __init __section(".init.text") __cold __latent_entropy __noinitretpoline +#define __init __section(".init.text") __cold __latent_entropy \ + __noinitretpoline \ + __no_sanitize_coverage #define __initdata __section(".init.data") #define __initconst __section(".init.rodata") #define __exitdata __section(".exit.data") From 6676fd3c99b016b9102c584e8b6dfcfad4fa059e Mon Sep 17 00:00:00 2001 From: Kees Cook Date: Sat, 26 Jul 2025 02:35:49 -0700 Subject: [PATCH 20/22] kstack_erase: Add -mgeneral-regs-only to silence Clang warnings Once CONFIG_KSTACK_ERASE is enabled with Clang on i386, the build warns: kernel/kstack_erase.c:168:2: warning: function with attribute 'no_caller_saved_registers' should only call a function with attribute 'no_caller_saved_registers' or be compiled with '-mgeneral-regs-only' [-Wexcessive-regsave] Add -mgeneral-regs-only for the kstack_erase handler, to make Clang feel better (it is effectively a no-op flag for the kernel). No binary changes encountered. Build & boot tested with Clang 21 on x86_64, and i386. Build tested with GCC 14.2.0 on x86_64, i386, arm64, and arm. Reported-by: Nathan Chancellor Closes: https://lore.kernel.org/all/20250726004313.GA3650901@ax162 Tested-by: Nathan Chancellor Signed-off-by: Kees Cook --- kernel/Makefile | 1 + 1 file changed, 1 insertion(+) diff --git a/kernel/Makefile b/kernel/Makefile index e4f01f1d4d0c..0ee9afd8b7cf 100644 --- a/kernel/Makefile +++ b/kernel/Makefile @@ -140,6 +140,7 @@ obj-$(CONFIG_RESOURCE_KUNIT_TEST) += resource_kunit.o obj-$(CONFIG_SYSCTL_KUNIT_TEST) += sysctl-test.o CFLAGS_kstack_erase.o += $(DISABLE_KSTACK_ERASE) +CFLAGS_kstack_erase.o += $(call cc-option,-mgeneral-regs-only) obj-$(CONFIG_KSTACK_ERASE) += kstack_erase.o KASAN_SANITIZE_kstack_erase.o := n KCSAN_SANITIZE_kstack_erase.o := n From a8f0b1f8ef628bd1003eed650862836e97b89fdd Mon Sep 17 00:00:00 2001 From: Kees Cook Date: Wed, 23 Jul 2025 22:50:28 -0700 Subject: [PATCH 21/22] kstack_erase: Support Clang stack depth tracking Wire up CONFIG_KSTACK_ERASE to Clang 21's new stack depth tracking callback[1] option. Link: https://clang.llvm.org/docs/SanitizerCoverage.html#tracing-stack-depth [1] Acked-by: Nicolas Schier Link: https://lore.kernel.org/r/20250724055029.3623499-4-kees@kernel.org Signed-off-by: Kees Cook --- scripts/Makefile.kstack_erase | 6 ++++++ security/Kconfig.hardening | 5 ++++- 2 files changed, 10 insertions(+), 1 deletion(-) diff --git a/scripts/Makefile.kstack_erase b/scripts/Makefile.kstack_erase index 5223d3a35817..c7bc2379e113 100644 --- a/scripts/Makefile.kstack_erase +++ b/scripts/Makefile.kstack_erase @@ -8,6 +8,12 @@ kstack-erase-cflags-$(CONFIG_GCC_PLUGIN_STACKLEAK_VERBOSE) += -fplugin-arg-stack DISABLE_KSTACK_ERASE := -fplugin-arg-stackleak_plugin-disable endif +ifdef CONFIG_CC_IS_CLANG +kstack-erase-cflags-y += -fsanitize-coverage=stack-depth +kstack-erase-cflags-y += -fsanitize-coverage-stack-depth-callback-min=$(CONFIG_KSTACK_ERASE_TRACK_MIN_SIZE) +DISABLE_KSTACK_ERASE := -fno-sanitize-coverage=stack-depth +endif + KSTACK_ERASE_CFLAGS := $(kstack-erase-cflags-y) export STACKLEAK_CFLAGS DISABLE_KSTACK_ERASE diff --git a/security/Kconfig.hardening b/security/Kconfig.hardening index f7aa2024ab25..b9a5bc3430aa 100644 --- a/security/Kconfig.hardening +++ b/security/Kconfig.hardening @@ -82,10 +82,13 @@ choice endchoice +config CC_HAS_SANCOV_STACK_DEPTH_CALLBACK + def_bool $(cc-option,-fsanitize-coverage-stack-depth-callback-min=1) + config KSTACK_ERASE bool "Poison kernel stack before returning from syscalls" depends on HAVE_ARCH_KSTACK_ERASE - depends on GCC_PLUGINS + depends on GCC_PLUGINS || CC_HAS_SANCOV_STACK_DEPTH_CALLBACK help This option makes the kernel erase the kernel stack before returning from system calls. This has the effect of leaving From 32e42ab9fc88a884435c27527a433f61c4d2b61b Mon Sep 17 00:00:00 2001 From: Kees Cook Date: Sat, 26 Jul 2025 00:29:54 -0700 Subject: [PATCH 22/22] sched/task_stack: Add missing const qualifier to end_of_stack() Add missing const qualifier to the non-CONFIG_THREAD_INFO_IN_TASK version of end_of_stack() to match the CONFIG_THREAD_INFO_IN_TASK version. Fixes a warning with CONFIG_KSTACK_ERASE=y on archs that don't select THREAD_INFO_IN_TASK (such as LoongArch): error: passing 'const struct task_struct *' to parameter of type 'struct task_struct *' discards qualifiers The stackleak_task_low_bound() function correctly uses a const task parameter, but the legacy end_of_stack() prototype didn't like that. Build tested on loongarch (with CONFIG_KSTACK_ERASE=y) and m68k (with CONFIG_DEBUG_STACK_USAGE=y). Fixes: a45728fd4120 ("LoongArch: Enable HAVE_ARCH_STACKLEAK") Reported-by: Nathan Chancellor Closes: https://lore.kernel.org/all/20250726004313.GA3650901@ax162 Cc: Youling Tang Cc: Huacai Chen Tested-by: Nathan Chancellor Signed-off-by: Kees Cook --- include/linux/sched/task_stack.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/include/linux/sched/task_stack.h b/include/linux/sched/task_stack.h index 85c5a6392e02..1fab7e9043a3 100644 --- a/include/linux/sched/task_stack.h +++ b/include/linux/sched/task_stack.h @@ -53,7 +53,7 @@ static inline void setup_thread_stack(struct task_struct *p, struct task_struct * When the stack grows up, this is the highest address. * Beyond that position, we corrupt data on the next page. */ -static inline unsigned long *end_of_stack(struct task_struct *p) +static inline unsigned long *end_of_stack(const struct task_struct *p) { #ifdef CONFIG_STACK_GROWSUP return (unsigned long *)((unsigned long)task_thread_info(p) + THREAD_SIZE) - 1;