Re: [PATCH] MIPS: Check the range of the syscall number for o32 syscall on 64bit kernel.

[David Daney <ddaney@caviumnetworks.com>]

David Daney wrote:
[...]
> diff --git a/arch/mips/kernel/scall64-o32.S 
> b/arch/mips/kernel/scall64-o32.S
> index 6c7ef83..d8b3cb1 100644
> --- a/arch/mips/kernel/scall64-o32.S
> +++ b/arch/mips/kernel/scall64-o32.S
> @@ -174,14 +174,14 @@ not_o32_scall:
>     END(handle_sys)
> 
> LEAF(sys32_syscall)
> -    sltu    v0, a0, __NR_O32_Linux + __NR_O32_Linux_syscalls + 1
> +    .set    noreorder
> +    subu    t0, a0, __NR_O32_Linux    # check syscall number
> +    beqz    t0, einval        # do not recurse
> +    sltu    v0, t0, __NR_O32_Linux_syscalls + 1
> +    dsll    t1, t0, 3
>     beqz    v0, einval
> -
> -    dsll    v0, a0, 3
> -    ld    t2, (sys_call_table - (__NR_O32_Linux * 8))(v0)
> -
> -    li    v1, 4000        # indirect syscall number
> -    beq    a0, v1, einval        # do not recurse
> +    .set    reorder
> +    lw    t2, sys_call_table(t1)        # syscall routine
> 

        ^^^ Clearly that should be ld not lw.  Not sure how that slipped 
in, Vlad's original patch had it correct.  Re-testing...


David Daney