signal, x86: add SIGSYS info and make it synchronous.
This change enables SIGSYS, defines _sigfields._sigsys, and adds
x86 (compat) arch support. _sigsys defines fields which allow
a signal handler to receive the triggering system call number,
the relevant AUDIT_ARCH_* value for that number, and the address
of the callsite.
SIGSYS is added to the SYNCHRONOUS_MASK because it is desirable for it
to have setup_frame() called for it. The goal is to ensure that
ucontext_t reflects the machine state from the time-of-syscall and not
from another signal handler.
The first consumer of SIGSYS would be seccomp filter. In particular,
a filter program could specify a new return value, SECCOMP_RET_TRAP,
which would result in the system call being denied and the calling
thread signaled. This also means that implementing arch-specific
support can be dependent upon HAVE_ARCH_SECCOMP_FILTER.
Suggested-by: H. Peter Anvin <hpa@zytor.com>
Signed-off-by: Will Drewry <wad@chromium.org>
Acked-by: Serge Hallyn <serge.hallyn@canonical.com>
Reviewed-by: H. Peter Anvin <hpa@zytor.com>
Acked-by: Eric Paris <eparis@redhat.com>
v18: - added acked by, rebase
v17: - rebase and reviewed-by addition
v14: - rebase/nochanges
v13: - rebase on to 88ebdda6159ffc15699f204c33feb3e431bf9bdc
v12: - reworded changelog (oleg@redhat.com)
v11: - fix dropped words in the change description
- added fallback copy_siginfo support.
- added __ARCH_SIGSYS define to allow stepped arch support.
v10: - first version based on suggestion
Signed-off-by: James Morris <james.l.morris@oracle.com>
diff --git a/kernel/signal.c b/kernel/signal.c
index 17afcaf..1a006b5 100644
--- a/kernel/signal.c
+++ b/kernel/signal.c
@@ -160,7 +160,7 @@
#define SYNCHRONOUS_MASK \
(sigmask(SIGSEGV) | sigmask(SIGBUS) | sigmask(SIGILL) | \
- sigmask(SIGTRAP) | sigmask(SIGFPE))
+ sigmask(SIGTRAP) | sigmask(SIGFPE) | sigmask(SIGSYS))
int next_signal(struct sigpending *pending, sigset_t *mask)
{
@@ -2706,6 +2706,13 @@
err |= __put_user(from->si_uid, &to->si_uid);
err |= __put_user(from->si_ptr, &to->si_ptr);
break;
+#ifdef __ARCH_SIGSYS
+ case __SI_SYS:
+ err |= __put_user(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);