Re: [syzbot] [ecryptfs?] KASAN: slab-out-of-bounds Read in ecryptfs_verify_auth_tok_from_key

[Edward Adam Davis]

From: Edward Aadm Davis <eadavis@xxxxxxxx>

#syz test: upstream f6e7b42bf05b

diff --git a/fs/ecryptfs/keystore.c b/fs/ecryptfs/keystore.c
index 51651314b7a6..a52ede408f1c 100644
--- a/fs/ecryptfs/keystore.c
+++ b/fs/ecryptfs/keystore.c
@@ -455,6 +455,9 @@ ecryptfs_verify_auth_tok_from_key(struct key *auth_tok_key,
 {
 	int rc = 0;
 
+	if (auth_tok_key->datalen < sizeof(**auth_tok))
+		return -EINVAL;
+
 	(*auth_tok) = ecryptfs_get_key_payload_data(auth_tok_key);
 	if (IS_ERR(*auth_tok)) {
 		rc = PTR_ERR(*auth_tok);