audit: fix two bugs in the new execve audit code
copy_from_user() returns the number of bytes not copied, hence 0 is the
expected output.
axi->mm might not be valid anymore when not equal to current->mm, do not
dereference before checking that - thanks to Al for spotting that.
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Tested-by: Steve Grubb <sgrubb@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/kernel/auditsc.c b/kernel/auditsc.c
index bde1124..a777d37 100644
--- a/kernel/auditsc.c
+++ b/kernel/auditsc.c
@@ -824,12 +824,14 @@
{
int i;
long len, ret;
- const char __user *p = (const char __user *)axi->mm->arg_start;
+ const char __user *p;
char *buf;
if (axi->mm != current->mm)
return; /* execve failed, no additional info */
+ p = (const char __user *)axi->mm->arg_start;
+
for (i = 0; i < axi->argc; i++, p += len) {
len = strnlen_user(p, MAX_ARG_STRLEN);
/*
@@ -855,7 +857,7 @@
* copied them here, and the mm hasn't been exposed to user-
* space yet.
*/
- if (!ret) {
+ if (ret) {
WARN_ON(1);
send_sig(SIGKILL, current, 0);
}