[PATCH AUTOSEL 5.10 015/101] smackfs: Fix use-after-free in netlbl_catmap_walk()

[PATCH AUTOSEL 5.10 015/101] smackfs: Fix use-after-free in netlbl_catmap_walk()

[Sasha Levin]

From: Pawan Gupta <pawan.kumar.gupta@linux.intel.com>

[ Upstream commit 0817534ff9ea809fac1322c5c8c574be8483ea57 ]

Syzkaller reported use-after-free bug as described in [1]. The bug is
triggered when smk_set_cipso() tries to free stale category bitmaps
while there are concurrent reader(s) using the same bitmaps.

Wait for RCU grace period to finish before freeing the category bitmaps
in smk_set_cipso(). This makes sure that there are no more readers using
the stale bitmaps and freeing them should be safe.

[1] https://lore.kernel.org/netdev/000000000000a814c505ca657a4e@google.com/

Reported-by: syzbot+3f91de0b813cc3d19a80@syzkaller.appspotmail.com
Signed-off-by: Pawan Gupta <pawan.kumar.gupta@linux.intel.com>
Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 security/smack/smackfs.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/security/smack/smackfs.c b/security/smack/smackfs.c
index b88c1a9538334..e33f98d25fc02 100644
--- a/security/smack/smackfs.c
+++ b/security/smack/smackfs.c
@@ -831,6 +831,7 @@ static int smk_open_cipso(struct inode *inode, struct file *file)
 static ssize_t smk_set_cipso(struct file *file, const char __user *buf,
 				size_t count, loff_t *ppos, int format)
 {
+	struct netlbl_lsm_catmap *old_cat;
 	struct smack_known *skp;
 	struct netlbl_lsm_secattr ncats;
 	char mapcatset[SMK_CIPSOLEN];
@@ -920,9 +921,11 @@ static ssize_t smk_set_cipso(struct file *file, const char __user *buf,
 
 	rc = smk_netlbl_mls(maplevel, mapcatset, &ncats, SMK_CIPSOLEN);
 	if (rc >= 0) {
-		netlbl_catmap_free(skp->smk_netlabel.attr.mls.cat);
+		old_cat = skp->smk_netlabel.attr.mls.cat;
 		skp->smk_netlabel.attr.mls.cat = ncats.attr.mls.cat;
 		skp->smk_netlabel.attr.mls.lvl = ncats.attr.mls.lvl;
+		synchronize_rcu();
+		netlbl_catmap_free(old_cat);
 		rc = count;
 		/*
 		 * This mapping may have been cached, so clear the cache.
-- 
2.33.0

[PATCH AUTOSEL 5.10 017/101] NET: IPV4: fix error "do not initialise globals to 0"

[Sasha Levin]

From: wangzhitong <wangzhitong@uniontech.com>

[ Upstream commit db9c8e2b1e246fc2dc20828932949437793146cc ]

this patch fixes below Errors reported by checkpatch
    ERROR: do not initialise globals to 0
    +int cipso_v4_rbm_optfmt = 0;

Signed-off-by: wangzhitong <wangzhitong@uniontech.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 net/ipv4/cipso_ipv4.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/net/ipv4/cipso_ipv4.c b/net/ipv4/cipso_ipv4.c
index ca217a6f488f6..112f1d5b5dc7c 100644
--- a/net/ipv4/cipso_ipv4.c
+++ b/net/ipv4/cipso_ipv4.c
@@ -73,7 +73,7 @@ struct cipso_v4_map_cache_entry {
 static struct cipso_v4_map_cache_bkt *cipso_v4_cache;
 
 /* Restricted bitmap (tag #1) flags */
-int cipso_v4_rbm_optfmt = 0;
+int cipso_v4_rbm_optfmt;
 int cipso_v4_rbm_strictvalid = 1;
 
 /*
-- 
2.33.0