[PATCH 4.9 11/92] selinux: Add __GFP_NOWARN to allocation at str_read()

[Greg Kroah-Hartman]

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

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

From: Tetsuo Handa <penguin-kernel@xxxxxxxxxxxxxxxxxxx>

commit 4458bba09788e70e8fb39ad003f087cd9dfbd6ac upstream.

syzbot is hitting warning at str_read() [1] because len parameter can
become larger than KMALLOC_MAX_SIZE. We don't need to emit warning for
this case.

[1] https://syzkaller.appspot.com/bug?id=7f2f5aad79ea8663c296a2eedb81978401a908f0

Signed-off-by: Tetsuo Handa <penguin-kernel@xxxxxxxxxxxxxxxxxxx>
Reported-by: syzbot <syzbot+ac488b9811036cea7ea0@xxxxxxxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Paul Moore <paul@xxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
 security/selinux/ss/policydb.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/security/selinux/ss/policydb.c
+++ b/security/selinux/ss/policydb.c
@@ -1097,7 +1097,7 @@ static int str_read(char **strp, gfp_t f
 	if ((len == 0) || (len == (u32)-1))
 		return -EINVAL;
 
-	str = kmalloc(len + 1, flags);
+	str = kmalloc(len + 1, flags | __GFP_NOWARN);
 	if (!str)
 		return -ENOMEM;