From: Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp>
Date: Fri, 7 Sep 2018 16:42:58 +0000 (+0900)
Subject: selinux: Add __GFP_NOWARN to allocation at str_read()
X-Git-Tag: Ubuntu-4.15.0-56.62~484
X-Git-Url: https://git.proxmox.com/?p=mirror_ubuntu-bionic-kernel.git;a=commitdiff_plain;h=a64e8dd581c35562569402e0dcf29003d8ea99dd

selinux: Add __GFP_NOWARN to allocation at str_read()

BugLink: https://bugs.launchpad.net/bugs/1836968

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>
Signed-off-by: Kamal Mostafa <kamal@canonical.com>
Signed-off-by: Khalid Elmously <khalid.elmously@canonical.com>
---

diff --git a/security/selinux/ss/policydb.c b/security/selinux/ss/policydb.c
index 6e8c8056d7ad..6688ac5b991e 100644
--- a/security/selinux/ss/policydb.c
+++ b/security/selinux/ss/policydb.c
@@ -1099,7 +1099,7 @@ static int str_read(char **strp, gfp_t flags, void *fp, u32 len)
 	if ((len == 0) || (len == (u32)-1))
 		return -EINVAL;
 
-	str = kmalloc(len + 1, flags);
+	str = kmalloc(len + 1, flags | __GFP_NOWARN);
 	if (!str)
 		return -ENOMEM;