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

Greg Kroah-Hartman
2018-11-29T14:20:45Z

From: Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp>

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@I-love.SAKURA.ne.jp>
Reported-by: syzbot <syzbot+ac488b9811036cea7ea0@syzkaller.appspotmail.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
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;