MIPS: Fix seccomp syscall argument for MIPS64 Commit 4c21b8fd8f14 ("MIPS: seccomp: Handle indirect system calls (o32)") fixed indirect system calls on O32 but it also introduced a bug for MIPS64 where it erroneously modified the v0 (syscall) register with the assumption that the sycall offset hasn't been taken into consideration. This breaks seccomp on MIPS64 n64 and n32 ABIs. We fix this by replacing the addition with a move instruction. Fixes: 4c21b8fd8f14 ("MIPS: seccomp: Handle indirect system calls (o32)") Cc: <firstname.lastname@example.org> # 3.15+ Reviewed-by: James Hogan <email@example.com> Signed-off-by: Markos Chandras <firstname.lastname@example.org> Cc: email@example.com Patchwork: https://patchwork.linux-mips.org/patch/10951/ Signed-off-by: Ralf Baechle <firstname.lastname@example.org>
This Linux change may have been applied to various maintained Linux releases and you can find Linux releases including commit 9f16143.
There are 4 lines of Linux source code added/deleted in this change. Code changes to Linux kernel are as follows.
arch/mips/kernel/scall64-64.S | 2 +- arch/mips/kernel/scall64-n32.S | 2 +- 2 files changed, 2 insertions(+), 2 deletions(-) diff --git a/arch/mips/kernel/scall64-64.S b/arch/mips/kernel/scall64-64.S index ad4d4463..a6f6b76 100644 --- a/arch/mips/kernel/scall64-64.S +++ b/arch/mips/kernel/scall64-64.S @@ -80,7 +80,7 @@ syscall_trace_entry: SAVE_STATIC move s0, t2 move a0, sp - daddiu a1, v0, __NR_64_Linux + move a1, v0 jal syscall_trace_enter bltz v0, 2f # seccomp failed? Skip syscall diff --git a/arch/mips/kernel/scall64-n32.S b/arch/mips/kernel/scall64-n32.S index 446cc65..4b20106 100644 --- a/arch/mips/kernel/scall64-n32.S +++ b/arch/mips/kernel/scall64-n32.S @@ -72,7 +72,7 @@ n32_syscall_trace_entry: SAVE_STATIC move s0, t2 move a0, sp - daddiu a1, v0, __NR_N32_Linux + move a1, v0 jal syscall_trace_enter bltz v0, 2f # seccomp failed? Skip syscall