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| author | Aurelien Jarno <aurelien@aurel32.net> | 2019-04-09 17:53:55 +0300 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2019-05-16 20:44:43 +0300 |
| commit | 15c2ac78cb731e948c7b3095b4b4ee909e37a97e (patch) | |
| tree | 99df309c4289ef7868964e4c7085f9c198efeb79 /arch/mips | |
| parent | fd49607468bacd5003cd146de2c4e0f135bff777 (diff) | |
| download | linux-15c2ac78cb731e948c7b3095b4b4ee909e37a97e.tar.xz | |
MIPS: scall64-o32: Fix indirect syscall number load
commit 79b4a9cf0e2ea8203ce777c8d5cfa86c71eae86e upstream.
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
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.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 87c697181d25..4faff3e77b25 100644 --- a/arch/mips/kernel/scall64-o32.S +++ b/arch/mips/kernel/scall64-o32.S @@ -126,7 +126,7 @@ 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 |