libceph: don't WARN() if user tries to add invalid key

commit b11270853fa3654f08d4a6a03b23ddb220512d8d upstream.

The WARN_ON(!key->len) in set_secret() in net/ceph/crypto.c is hit if a
user tries to add a key of type "ceph" with an invalid payload as
follows (assuming CONFIG_CEPH_LIB=y):

    echo -e -n '\x01\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00' \
	| keyctl padd ceph desc @s

This can be hit by fuzzers.  As this is merely bad input and not a
kernel bug, replace the WARN_ON() with return -EINVAL.

Fixes: 7af3ea189a9a ("libceph: stop allocating a new cipher on every crypto request")
Signed-off-by: Eric Biggers <ebiggers@google.com>
Reviewed-by: Ilya Dryomov <idryomov@gmail.com>
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/net/ceph/crypto.c b/net/ceph/crypto.c
index 489610a..bf9d079 100644 (file)
--- a/net/ceph/crypto.c
+++ b/net/ceph/crypto.c
@@ -37,7 +37,9 @@ static int set_secret(struct ceph_crypto_key *key, void *buf)
                return -ENOTSUPP;
        }
 
-       WARN_ON(!key->len);
+       if (!key->len)
+               return -EINVAL;
+
        key->key = kmemdup(buf, key->len, GFP_NOIO);
        if (!key->key) {
                ret = -ENOMEM;