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Tadeusz Struk 4c46091ee9 bpf: Fix KASAN use-after-free Read in compute_effective_progs
Syzbot found a Use After Free bug in compute_effective_progs().
The reproducer creates a number of BPF links, and causes a fault
injected alloc to fail, while calling bpf_link_detach on them.
Link detach triggers the link to be freed by bpf_link_free(),
which calls __cgroup_bpf_detach() and update_effective_progs().
If the memory allocation in this function fails, the function restores
the pointer to the bpf_cgroup_link on the cgroup list, but the memory
gets freed just after it returns. After this, every subsequent call to
update_effective_progs() causes this already deallocated pointer to be
dereferenced in prog_list_length(), and triggers KASAN UAF error.

To fix this issue don't preserve the pointer to the prog or link in the
list, but remove it and replace it with a dummy prog without shrinking
the table. The subsequent call to __cgroup_bpf_detach() or
__cgroup_bpf_detach() will correct it.

Fixes: af6eea5743 ("bpf: Implement bpf_link-based cgroup BPF program attachment")
Reported-by: <syzbot+f264bffdfbd5614f3bb2@syzkaller.appspotmail.com>
Signed-off-by: Tadeusz Struk <tadeusz.struk@linaro.org>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Cc: <stable@vger.kernel.org>
Link: https://syzkaller.appspot.com/bug?id=8ebf179a95c2a2670f7cf1ba62429ec044369db4
Link: https://lore.kernel.org/bpf/20220517180420.87954-1-tadeusz.struk@linaro.org
2022-06-02 16:26:47 -07:00
arch bpf, riscv: Support riscv jit to provide bpf_line_info 2022-06-02 16:26:01 -07:00
block Page cache changes for 5.19 2022-05-24 19:55:07 -07:00
certs Kbuild updates for v5.19 2022-05-26 12:09:50 -07:00
crypto This update includes the following changes: 2022-05-27 18:06:49 -07:00
Documentation Networking fixes for 5.19-rc1, including fixes from bpf, and netfilter. 2022-06-02 12:50:16 -07:00
drivers Networking fixes for 5.19-rc1, including fixes from bpf, and netfilter. 2022-06-02 12:50:16 -07:00
fs A big pile of assorted fixes and improvements for the filesystem with 2022-06-02 08:59:39 -07:00
include Networking fixes for 5.19-rc1, including fixes from bpf, and netfilter. 2022-06-02 12:50:16 -07:00
init RISC-V Patches for the 5.19 Merge Window, Part 1 2022-05-31 14:10:54 -07:00
ipc ipc/mqueue: use get_tree_nodev() in mqueue_get_tree() 2022-05-09 18:29:21 -07:00
kernel bpf: Fix KASAN use-after-free Read in compute_effective_progs 2022-06-02 16:26:47 -07:00
lib assoc_array: Fix BUG_ON during garbage collect 2022-06-01 18:29:06 -07:00
LICENSES LICENSES/LGPL-2.1: Add LGPL-2.1-or-later as valid identifiers 2021-12-16 14:33:10 +01:00
mm RISC-V Patches for the 5.19 Merge Window, Part 1 2022-05-31 14:10:54 -07:00
net xdp: Directly use ida_alloc()/free() APIs 2022-06-02 16:25:30 -07:00
samples drm for 5.19-rc1 2022-05-25 16:18:27 -07:00
scripts Not a lot of material this cycle. Many singleton patches against various 2022-05-27 11:22:03 -07:00
security linux-kselftest-kunit-5.19-rc1 2022-05-25 11:32:53 -07:00
sound m68knommu: changes for linux 5.19 2022-05-30 10:56:18 -07:00
tools bpftool: Check for NULL ptr of btf in codegen_asserts 2022-06-02 16:26:43 -07:00
usr Not a lot of material this cycle. Many singleton patches against various 2022-05-27 11:22:03 -07:00
virt VFIO updates for v5.19-rc1 2022-06-01 13:49:15 -07:00
.clang-format clang-format: Fix space after for_each macros 2022-05-20 19:27:16 +02:00
.cocciconfig
.get_maintainer.ignore
.gitattributes .gitattributes: use 'dts' diff driver for dts files 2019-12-04 19:44:11 -08:00
.gitignore kbuild: split the second line of *.mod into *.usyms 2022-05-08 03:16:59 +09:00
.mailmap MAINTAINERS: Update Lorenzo Pieralisi's email address 2022-05-31 15:06:19 -05:00
COPYING COPYING: state that all contributions really are covered by this file 2020-02-10 13:32:20 -08:00
CREDITS MAINTAINERS: replace a Microchip AT91 maintainer 2022-02-09 11:30:01 +01:00
Kbuild kbuild: rename hostprogs-y/always to hostprogs/always-y 2020-02-04 01:53:07 +09:00
Kconfig kbuild: ensure full rebuild when the compiler is updated 2020-05-12 13:28:33 +09:00
MAINTAINERS pci-v5.19-fixes-1 2022-06-02 12:11:25 -07:00
Makefile Kbuild updates for v5.19 2022-05-26 12:09:50 -07:00
README

Linux kernel
============

There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.  The formatted documentation can also be read online at:

    https://www.kernel.org/doc/html/latest/

There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.

Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.