Re: [PATCH v6 5/6] arm64: add SIGSYS siginfo for compat task

[Kees Cook]

On Thu, Aug 21, 2014 at 3:56 AM, AKASHI Takahiro
<takahiro.akashi@xxxxxxxxxx> wrote:
> SIGSYS is primarily used in secure computing to notify tracer.
> This patch allows signal handler on compat task to get correct information
> with SA_SYSINFO specified when this signal is delivered.
>
> Signed-off-by: AKASHI Takahiro <takahiro.akashi@xxxxxxxxxx>

I'm unable to test this myself, but if you've got the test suite
passing in compat mode, then this patch must be correct. :)

Reviewed-by: Kees Cook <keescook@xxxxxxxxxxxx>

-Kees

> ---
>  arch/arm64/include/asm/compat.h |    7 +++++++
>  arch/arm64/kernel/signal32.c    |    8 ++++++++
>  2 files changed, 15 insertions(+)
>
> diff --git a/arch/arm64/include/asm/compat.h b/arch/arm64/include/asm/compat.h
> index 253e33b..c877915 100644
> --- a/arch/arm64/include/asm/compat.h
> +++ b/arch/arm64/include/asm/compat.h
> @@ -205,6 +205,13 @@ typedef struct compat_siginfo {
>                         compat_long_t _band;    /* POLL_IN, POLL_OUT, POLL_MSG */
>                         int _fd;
>                 } _sigpoll;
> +
> +               /* SIGSYS */
> +               struct {
> +                       compat_uptr_t _call_addr; /* calling user insn */
> +                       int _syscall;   /* triggering system call number */
> +                       unsigned int _arch;     /* AUDIT_ARCH_* of syscall */
> +               } _sigsys;
>         } _sifields;
>  } compat_siginfo_t;
>
> diff --git a/arch/arm64/kernel/signal32.c b/arch/arm64/kernel/signal32.c
> index 1b9ad02..aa550d6 100644
> --- a/arch/arm64/kernel/signal32.c
> +++ b/arch/arm64/kernel/signal32.c
> @@ -186,6 +186,14 @@ int copy_siginfo_to_user32(compat_siginfo_t __user *to, const siginfo_t *from)
>                 err |= __put_user(from->si_uid, &to->si_uid);
>                 err |= __put_user((compat_uptr_t)(unsigned long)from->si_ptr, &to->si_ptr);
>                 break;
> +#ifdef __ARCH_SIGSYS
> +       case __SI_SYS:
> +               err |= __put_user((compat_uptr_t)(unsigned long)
> +                               from->si_call_addr, &to->si_call_addr);
> +               err |= __put_user(from->si_syscall, &to->si_syscall);
> +               err |= __put_user(from->si_arch, &to->si_arch);
> +               break;
> +#endif
>         default: /* this is just in case for now ... */
>                 err |= __put_user(from->si_pid, &to->si_pid);
>                 err |= __put_user(from->si_uid, &to->si_uid);
> --
> 1.7.9.5
>



-- 
Kees Cook
Chrome OS Security
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