From 43a1e3744548e6fd85873e6fb43e293eb4010694 Mon Sep 17 00:00:00 2001 From: Linus Torvalds Date: Thu, 28 May 2026 11:45:41 -0700 Subject: [PATCH] security/keys: fix missed RCU read section on lookup Nicholas Carlini reports that the keyring code calls assoc_array_find() in find_key_to_update() without holding the RCU read lock, while the assoc_array_gc() code really is designed around removing the node from the tree and then freeing it after an RCU grace-period. The regular key handling doesn't see this because holding the keyring semaphore hides any lifetime issues, but the persistent key handling uses a different model. Instead of extending the keyring locking, just do the simple RCU locking that the assoc_array was designed for. Reported-by: Nicholas Carlini Cc: David Howells Cc: Jarkko Sakkinen Cc: Paul Moore Cc: James Morris James Morris Cc: Serge E. Hallyn Signed-off-by: Linus Torvalds --- security/keys/keyring.c | 1 + 1 file changed, 1 insertion(+) diff --git a/security/keys/keyring.c b/security/keys/keyring.c index b39038f7dd31..5a9887d6b7be 100644 --- a/security/keys/keyring.c +++ b/security/keys/keyring.c @@ -1109,6 +1109,7 @@ key_ref_t find_key_to_update(key_ref_t keyring_ref, kenter("{%d},{%s,%s}", keyring->serial, index_key->type->name, index_key->description); + guard(rcu)(); object = assoc_array_find(&keyring->keys, &keyring_assoc_array_ops, index_key);