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| author | Aurelien Jarno <aurelien@aurel32.net> | 2019-04-09 16:53:55 +0200 |
|---|---|---|
| committer | Paul Burton <paul.burton@mips.com> | 2019-04-15 10:35:12 -0700 |
| commit | 79b4a9cf0e2ea8203ce777c8d5cfa86c71eae86e (patch) | |
| tree | 20d389f358cb71e9283186041acf53d92256c508 /arch/mips | |
| parent | 1bfb97b9a51901103677a4d1a2386d223c15bc71 (diff) | |
| download | linux-79b4a9cf0e2ea8203ce777c8d5cfa86c71eae86e.tar.bz2 | |
MIPS: scall64-o32: Fix indirect syscall number load
Commit 4c21b8fd8f14 (MIPS: seccomp: Handle indirect system calls (o32))
added indirect syscall detection for O32 processes running on MIPS64,
but it did not work correctly for big endian kernel/processes. The
reason is that the syscall number is loaded from ARG1 using the lw
instruction while this is a 64-bit value, so zero is loaded instead of
the syscall number.
Fix the code by using the ld instruction instead. When running a 32-bit
processes on a 64 bit CPU, the values are properly sign-extended, so it
ensures the value passed to syscall_trace_enter is correct.
Recent systemd versions with seccomp enabled whitelist the getpid
syscall for their internal processes (e.g. systemd-journald), but call
it through syscall(SYS_getpid). This fix therefore allows O32 big endian
systems with a 64-bit kernel to run recent systemd versions.
Signed-off-by: Aurelien Jarno <aurelien@aurel32.net>
Cc: <stable@vger.kernel.org> # v3.15+
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Signed-off-by: Paul Burton <paul.burton@mips.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: James Hogan <jhogan@kernel.org>
Cc: linux-mips@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Diffstat (limited to 'arch/mips')
| -rw-r--r-- | arch/mips/kernel/scall64-o32.S | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/arch/mips/kernel/scall64-o32.S b/arch/mips/kernel/scall64-o32.S index f158c5894a9a..feb2653490df 100644 --- a/arch/mips/kernel/scall64-o32.S +++ b/arch/mips/kernel/scall64-o32.S @@ -125,7 +125,7 @@ trace_a_syscall: subu t1, v0, __NR_O32_Linux move a1, v0 bnez t1, 1f /* __NR_syscall at offset 0 */ - lw a1, PT_R4(sp) /* Arg1 for __NR_syscall case */ + ld a1, PT_R4(sp) /* Arg1 for __NR_syscall case */ .set pop 1: jal syscall_trace_enter |