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author | Aurelien Jarno <aurelien@aurel32.net> | 2019-04-09 16:53:55 +0200 |
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committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2019-05-16 09:17:13 +0200 |
commit | d1a3145b6b48b30fc437e38bcfcfe727040bb53a (patch) | |
tree | 8c7e2cbfebef38c282391e4a26d089203d4d8511 | |
parent | dc3e913edf94d54de5678e726cf95b38327e5d09 (diff) | |
download | linux-stable-d1a3145b6b48b30fc437e38bcfcfe727040bb53a.tar.gz linux-stable-d1a3145b6b48b30fc437e38bcfcfe727040bb53a.tar.bz2 linux-stable-d1a3145b6b48b30fc437e38bcfcfe727040bb53a.zip |
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>
-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 680f2cc13a6d..435d6f86079a 100644 --- a/arch/mips/kernel/scall64-o32.S +++ b/arch/mips/kernel/scall64-o32.S @@ -124,7 +124,7 @@ 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 |