Celeste Liu 52449c17bd riscv: entry: set a0 = -ENOSYS only when syscall != -1 ... When we test seccomp with 6.4 kernel, we found errno has wrong value. If we deny NETLINK_AUDIT with EAFNOSUPPORT, after f0bddf5058, we will get ENOSYS instead. We got same result with commit 9c2598d435 ("riscv: entry: Save a0 prior syscall_enter_from_user_mode()"). After analysing code, we think that regs->a0 = -ENOSYS should only be executed when syscall != -1. In __seccomp_filter, when seccomp rejected this syscall with specified errno, they will set a0 to return number as syscall ABI, and then return -1. This return number is finally pass as return number of syscall_enter_from_user_mode, and then is compared with NR_syscalls after converted to ulong (so it will be ULONG_MAX). The condition syscall < NR_syscalls will always be false, so regs->a0 = -ENOSYS is always executed. It covered a0 set by seccomp, so we always get ENOSYS when match seccomp RET_ERRNO rule. Fixes: f0bddf5058 ("riscv: entry: Convert to generic entry") Reported-by: Felix Yan <felixonmars@archlinux.org> Co-developed-by: Ruizhe Pan <c141028@gmail.com> Signed-off-by: Ruizhe Pan <c141028@gmail.com> Co-developed-by: Shiqi Zhang <shiqi@isrc.iscas.ac.cn> Signed-off-by: Shiqi Zhang <shiqi@isrc.iscas.ac.cn> Signed-off-by: Celeste Liu <CoelacanthusHex@gmail.com> Tested-by: Felix Yan <felixonmars@archlinux.org> Tested-by: Emil Renner Berthing <emil.renner.berthing@canonical.com> Reviewed-by: Björn Töpel <bjorn@rivosinc.com> Reviewed-by: Guo Ren <guoren@kernel.org> Link: https://lore.kernel.org/r/20230801141607.435192-1-CoelacanthusHex@gmail.com Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>		2023-08-16 07:19:49 -07:00
..
boot	RISC-V Devicetrees for v6.5 Part 2	2023-06-20 23:06:54 +02:00
configs	RISC-V Patches for the 6.5 Merge Window, Part 1	2023-06-30 09:37:26 -07:00
errata	Merge patch series "riscv: some CMO alternative related clean up"	2023-07-06 10:32:38 -07:00
include	riscv: Implement flush_cache_vmap()	2023-08-10 08:54:29 -07:00
kernel	riscv: entry: set a0 = -ENOSYS only when syscall != -1	2023-08-16 07:19:49 -07:00
kvm	ARM64:	2023-07-03 15:32:22 -07:00
lib	riscv: Allow to downgrade paging mode from the command line	2023-04-26 07:30:52 -07:00
mm	riscv: mm: fix 2 instances of -Wmissing-variable-declarations	2023-08-08 15:31:34 -07:00
net	Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net	2023-03-09 22:22:11 -08:00
purgatory	hardening updates for v6.5-rc1	2023-06-27 21:24:18 -07:00
tools	riscv: Check relocations at compile time	2023-04-19 07:46:32 -07:00
Kbuild	riscv: move errata/ and kvm/ builds to arch/riscv/Kbuild	2022-06-01 22:26:32 -07:00
Kconfig	RISC-V Patches for the 6.5 Merge Window, Part 2	2023-07-07 10:07:19 -07:00
Kconfig.debug
Kconfig.errata	Merge patch series "RISC-V: Fixes for riscv_has_extension[un]likely()'s alternative dependency"	2023-03-29 12:26:38 -07:00
Kconfig.socs	RISC-V: make ARCH_THEAD preclude XIP_KERNEL	2023-07-05 22:21:23 +02:00
Makefile	riscv: Enable Vector code to be built	2023-06-08 07:16:56 -07:00
Makefile.postlink	riscv: Use --emit-relocs in order to move .rela.dyn in init	2023-04-19 07:46:33 -07:00