Hello,
Aurelien Jarno wrote:
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
Applied to mips-fixes.
Thanks, Paul
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