Thread (10 messages) 10 messages, 1 author, 4d ago

[PATCH ipsec v4 5/9] xfrm: fix use-after-free of migrated state in xfrm_do_migrate_state()

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COOLING4d

From: Antony Antony <hidden>
Date: 2026-10-06 07:06:07
Also in: linux-doc, lkml
Subsystem: networking [general], networking [ipsec], the rest · Maintainers: "David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Steffen Klassert, Herbert Xu, Linus Torvalds

Revision v4 of 4 in this series.

Revisions (4)
  1. v2 [diff vs current]
  2. v3 [diff vs current]
  3. v4 current
  4. v5 [diff vs current]
A concurrent delete can free the migrated state before
xfrm_do_migrate_state() finishes using it.

Fixes: a9d155ea9b44 ("xfrm: add XFRM_MSG_MIGRATE_STATE for single SA migration")
Reported-by: Sashiko <sashiko-bot@kernel.org>
Signed-off-by: Antony Antony <redacted>
---
 net/xfrm/xfrm_user.c | 3 +++
 1 file changed, 3 insertions(+)
diff --git a/net/xfrm/xfrm_user.c b/net/xfrm/xfrm_user.c
index 5a9f729b4fcb..8640838dcda0 100644
--- a/net/xfrm/xfrm_user.c
+++ b/net/xfrm/xfrm_user.c
@@ -3509,6 +3509,7 @@ static int xfrm_do_migrate_state(struct sk_buff *skb, struct nlmsghdr *nlh,
 	__xfrm_state_delete(x);
 	spin_unlock_bh(&x->lock);
 
+	xfrm_state_hold(xc);
 	err = xfrm_state_migrate_install(x, xc, &m, extack);
 	if (err < 0) {
 		/*
@@ -3516,6 +3517,7 @@ static int xfrm_do_migrate_state(struct sk_buff *skb, struct nlmsghdr *nlh,
 		 * free under xfrm_cfg_mutex. Both SAs are gone if it does;
 		 * restoring x would risk SN/IV reuse.
 		 */
+		xfrm_state_put(xc);
 		goto out;
 	}
 
@@ -3534,6 +3536,7 @@ static int xfrm_do_migrate_state(struct sk_buff *skb, struct nlmsghdr *nlh,
 		err = 0;
 	}
 
+	xfrm_state_put(xc);
 out:
 	xfrm_state_put(x);
 	return err;
-- 
2.47.3
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