[PATCH 3.5 56/88] audit: correct a type mismatch in audit_syscall_exit()

[Luis Henriques]

3.5.7.30 -stable review patch.  If anyone has any objections, please let me know.

------------------

From: AKASHI Takahiro <takahiro.akashi at linaro.org>

commit 06bdadd7634551cfe8ce071fe44d0311b3033d9e upstream.

audit_syscall_exit() saves a result of regs_return_value() in intermediate
"int" variable and passes it to __audit_syscall_exit(), which expects its
second argument as a "long" value.  This will result in truncating the
value returned by a system call and making a wrong audit record.

I don't know why gcc compiler doesn't complain about this, but anyway it
causes a problem at runtime on arm64 (and probably most 64-bit archs).

Signed-off-by: AKASHI Takahiro <takahiro.akashi at linaro.org>
Cc: Al Viro <viro at zeniv.linux.org.uk>
Cc: Eric Paris <eparis at redhat.com>
Signed-off-by: Andrew Morton <akpm at linux-foundation.org>
Signed-off-by: Eric Paris <eparis at redhat.com>
Signed-off-by: Luis Henriques <luis.henriques at canonical.com>
---
 include/linux/audit.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/include/linux/audit.h b/include/linux/audit.h
index 41b4e49..8858e95 100644
--- a/include/linux/audit.h
+++ b/include/linux/audit.h
@@ -488,7 +488,7 @@ static inline void audit_syscall_exit(void *pt_regs)
 {
 	if (unlikely(current->audit_context)) {
 		int success = is_syscall_success(pt_regs);
-		int return_code = regs_return_value(pt_regs);
+		long return_code = regs_return_value(pt_regs);
 
 		__audit_syscall_exit(success, return_code);
 	}
-- 
1.8.3.2