[PATCH 4.9 082/207] smackfs: use __GFP_NOFAIL for smk_cipso_doi()

Greg Kroah-Hartman
2021-11-24T12:19:28Z

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

[ Upstream commit f91488ee15bd3cac467e2d6a361fc2d34d1052ae ]

syzbot is reporting kernel panic at smk_cipso_doi() due to memory
allocation fault injection [1]. The reason for need to use panic() was
not explained. But since no fix was proposed for 18 months, for now
let's use __GFP_NOFAIL for utilizing syzbot resource on other bugs.

Link: https://syzkaller.appspot.com/bug?extid=89731ccb6fec15ce1c22 [1]
Reported-by: syzbot <syzbot+89731ccb6fec15ce1c22@syzkaller.appspotmail.com>
Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
security/smack/smackfs.c | 4 +---
1 file changed, 1 insertion(+), 3 deletions(-)

diff --git a/security/smack/smackfs.c b/security/smack/smackfs.c
index e26e7fbb89657..cf1f92a04359a 100644
--- a/security/smack/smackfs.c
+++ b/security/smack/smackfs.c
@@ -716,9 +716,7 @@ static void smk_cipso_doi(void)
printk(KERN_WARNING "%s:%d remove rc = %d\n",
__func__, __LINE__, rc);

- doip = kmalloc(sizeof(struct cipso_v4_doi), GFP_KERNEL);
- if (doip == NULL)
- panic("smack: Failed to initialize cipso DOI.\n");
+ doip = kmalloc(sizeof(struct cipso_v4_doi), GFP_KERNEL | __GFP_NOFAIL);
doip->map.std = NULL;
doip->doi = smk_cipso_doi_value;
doip->type = CIPSO_V4_MAP_PASS;
--
2.33.0