seccomp,x86,arm,mips,s390: Remove nr parameter from secure_computing
The secure_computing function took a syscall number parameter, but
it only paid any attention to that parameter if seccomp mode 1 was
enabled. Rather than coming up with a kludge to get the parameter
to work in mode 2, just remove the parameter.
To avoid churn in arches that don't have seccomp filters (and may
not even support syscall_get_nr right now), this leaves the
parameter in secure_computing_strict, which is now a real function.
For ARM, this is a bit ugly due to the fact that ARM conditionally
supports seccomp filters. Fixing that would probably only be a
couple of lines of code, but it should be coordinated with the audit
maintainers.
This will be a slight slowdown on some arches. The right fix is to
pass in all of seccomp_data instead of trying to make just the
syscall nr part be fast.
This is a prerequisite for making two-phase seccomp work cleanly.
Cc: Russell King <linux@arm.linux.org.uk>
Cc: linux-arm-kernel@lists.infradead.org
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: linux-mips@linux-mips.org
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: linux-s390@vger.kernel.org
Cc: x86@kernel.org
Cc: Kees Cook <keescook@chromium.org>
Signed-off-by: Andy Lutomirski <luto@amacapital.net>
Signed-off-by: Kees Cook <keescook@chromium.org>
diff --git a/include/linux/seccomp.h b/include/linux/seccomp.h
index 5d586a4..aa3c040 100644
--- a/include/linux/seccomp.h
+++ b/include/linux/seccomp.h
@@ -27,19 +27,17 @@
struct seccomp_filter *filter;
};
-extern int __secure_computing(int);
-static inline int secure_computing(int this_syscall)
+#ifdef CONFIG_HAVE_ARCH_SECCOMP_FILTER
+extern int __secure_computing(void);
+static inline int secure_computing(void)
{
if (unlikely(test_thread_flag(TIF_SECCOMP)))
- return __secure_computing(this_syscall);
+ return __secure_computing();
return 0;
}
-
-/* A wrapper for architectures supporting only SECCOMP_MODE_STRICT. */
-static inline void secure_computing_strict(int this_syscall)
-{
- BUG_ON(secure_computing(this_syscall) != 0);
-}
+#else
+extern void secure_computing_strict(int this_syscall);
+#endif
extern long prctl_get_seccomp(void);
extern long prctl_set_seccomp(unsigned long, char __user *);
@@ -56,8 +54,11 @@
struct seccomp { };
struct seccomp_filter { };
-static inline int secure_computing(int this_syscall) { return 0; }
+#ifdef CONFIG_HAVE_ARCH_SECCOMP_FILTER
+static inline int secure_computing(void) { return 0; }
+#else
static inline void secure_computing_strict(int this_syscall) { return; }
+#endif
static inline long prctl_get_seccomp(void)
{