From: Ralf Lici Date: Wed, 29 Jul 2026 10:21:41 +0000 (+0200) Subject: ovpn: fix NULL dereference when killing missing key X-Git-Tag: v7.2~27^2~2^2~3 X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=41d44ac7a61e2f74453af40d4fe1b82af9ea0ada;p=thirdparty%2Fkernel%2Flinux.git ovpn: fix NULL dereference when killing missing key ovpn_crypto_kill_key assumes both crypto slots are populated and dereferences each slot before checking it. That is not guaranteed: a peer can have only one installed key, and the kill path may be asked to remove a key that is not present. Read each slot once while holding the crypto state lock, check for NULL before looking at key_id, and only replace the slot that actually matches. Fixes: 89d3c0e4612a ("ovpn: kill key and notify userspace in case of IV exhaustion") Signed-off-by: Ralf Lici Signed-off-by: Antonio Quartulli --- diff --git a/drivers/net/ovpn/crypto.c b/drivers/net/ovpn/crypto.c index 90580e32052f..2e95f29514fc 100644 --- a/drivers/net/ovpn/crypto.c +++ b/drivers/net/ovpn/crypto.c @@ -58,15 +58,19 @@ void ovpn_crypto_state_release(struct ovpn_crypto_state *cs) bool ovpn_crypto_kill_key(struct ovpn_crypto_state *cs, u8 key_id) { struct ovpn_crypto_key_slot *ks = NULL; + struct ovpn_crypto_key_slot *tmp; + int slot = 0; spin_lock_bh(&cs->lock); - if (rcu_access_pointer(cs->slots[0])->key_id == key_id) { - ks = rcu_replace_pointer(cs->slots[0], NULL, - lockdep_is_held(&cs->lock)); - } else if (rcu_access_pointer(cs->slots[1])->key_id == key_id) { - ks = rcu_replace_pointer(cs->slots[1], NULL, - lockdep_is_held(&cs->lock)); + tmp = rcu_access_pointer(cs->slots[slot]); + if (!tmp || tmp->key_id != key_id) { + slot = 1; + tmp = rcu_access_pointer(cs->slots[slot]); } + + if (tmp && tmp->key_id == key_id) + ks = rcu_replace_pointer(cs->slots[slot], NULL, + lockdep_is_held(&cs->lock)); spin_unlock_bh(&cs->lock); if (ks)