On 08/22/2014 02:54 AM, Kees Cook wrote:

On Thu, Aug 21, 2014 at 3:56 AM, AKASHI Takahiro
[off-list ref] wrote:

quoted

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.

typo: SA_SIGINFO

quoted

Signed-off-by: AKASHI Takahiro <redacted>

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. :)

Thanks.
Actually I found this bug when I ran your test programs, TRAP.handler, on 32bit userland.

-Takahiro AKASHI

Reviewed-by: Kees Cook <redacted>

-Kees

quoted

---
  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