From e807f9574e37a3f202e677feaaad1b7c5d2c0db8 Mon Sep 17 00:00:00 2001 From: Vlad Malov Date: Tue, 18 Nov 2008 15:05:46 -0800 Subject: MIPS: Fix potential DOS by untrusted user app. On a 64 bit kernel if an o32 syscall was made with a syscall number less than 4000, we would read the function from outside of the bounds of the syscall table. This led to non-deterministic behavior including system crashes. While we were at it we reworked the 32 bit version as well to use fewer instructions. Both 32 and 64 bit versions are use the same code now. Signed-off-by: Vlad Malov Signed-off-by: David Daney Signed-off-by: Ralf Baechle --- arch/mips/kernel/scall32-o32.S | 5 +---- 1 file changed, 1 insertion(+), 4 deletions(-) (limited to 'arch/mips/kernel/scall32-o32.S') diff --git a/arch/mips/kernel/scall32-o32.S b/arch/mips/kernel/scall32-o32.S index 759f68066b5d..34a4dbd76f24 100644 --- a/arch/mips/kernel/scall32-o32.S +++ b/arch/mips/kernel/scall32-o32.S @@ -262,14 +262,11 @@ bad_alignment: LEAF(sys_syscall) subu t0, a0, __NR_O32_Linux # check syscall number sltiu v0, t0, __NR_O32_Linux_syscalls + 1 + beqz t0, einval # do not recurse sll t1, t0, 3 beqz v0, einval - lw t2, sys_call_table(t1) # syscall routine - li v1, 4000 - __NR_O32_Linux # index of sys_syscall - beq t0, v1, einval # do not recurse - /* Some syscalls like execve get their arguments from struct pt_regs and claim zero arguments in the syscall table. Thus we have to assume the worst case and shuffle around all potential arguments. -- cgit v1.2.3