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authorJakub Kicinski <kuba@kernel.org>2025-09-17 18:10:24 -0700
committerJakub Kicinski <kuba@kernel.org>2025-09-17 18:10:25 -0700
commite218ae40241c162a752200efec92030d4de1b503 (patch)
tree7be50d092f843bb35adac6f55fe43f58e97388fd /net/mptcp/ctrl.c
parent6b957c0a36f5a68d9b210ed2db67fc191d873ba4 (diff)
parent893c49a78d9f85e4b8081b908fb7c407d018106a (diff)
Merge branch 'net-fix-uaf-of-sk_dst_get-sk-dev'
Kuniyuki Iwashima says: ==================== net: Fix UAF of sk_dst_get(sk)->dev. syzbot caught use-after-free of sk_dst_get(sk)->dev, which was not fetched under RCU nor RTNL. [0] Patch 1 ~ 5, 7 fix UAF in smc, tcp, ktls, mptcp Patch 6 fixes dst ref leak in mptcp [0]: https://lore.kernel.org/68c237c7.050a0220.3c6139.0036.GAE@google.com v1: https://lore.kernel.org/20250911030620.1284754-1-kuniyu@google.com ==================== Link: https://patch.msgid.link/20250916214758.650211-1-kuniyu@google.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Diffstat (limited to 'net/mptcp/ctrl.c')
-rw-r--r--net/mptcp/ctrl.c9
1 files changed, 7 insertions, 2 deletions
diff --git a/net/mptcp/ctrl.c b/net/mptcp/ctrl.c
index fed40dae5583..e8ffa62ec183 100644
--- a/net/mptcp/ctrl.c
+++ b/net/mptcp/ctrl.c
@@ -501,10 +501,15 @@ void mptcp_active_enable(struct sock *sk)
struct mptcp_pernet *pernet = mptcp_get_pernet(sock_net(sk));
if (atomic_read(&pernet->active_disable_times)) {
- struct dst_entry *dst = sk_dst_get(sk);
+ struct net_device *dev;
+ struct dst_entry *dst;
- if (dst && dst->dev && (dst->dev->flags & IFF_LOOPBACK))
+ rcu_read_lock();
+ dst = __sk_dst_get(sk);
+ dev = dst ? dst_dev_rcu(dst) : NULL;
+ if (dev && (dev->flags & IFF_LOOPBACK))
atomic_set(&pernet->active_disable_times, 0);
+ rcu_read_unlock();
}
}