s3-credentials: protect netlogon_creds_server_step() against NULL creds.

Found by SCHANNEL torture tests.

Guenther
(cherry picked from commit c578c66569eed3ae19b42c9787399eb70b935e0a)

diff --git a/source/libsmb/credentials.c b/source/libsmb/credentials.c
index 9d33e6d93d7298070da5092a409f71e6a60bcdac..4bfa2318c44820790ba633d7c83e8ceeb470b400 100644 (file)
--- a/source/libsmb/credentials.c
+++ b/source/libsmb/credentials.c
@@ -255,6 +255,10 @@ bool netlogon_creds_server_step(struct dcinfo *dc,
        bool ret;
        struct dcinfo tmp_dc = *dc;
 
+       if (!received_cred || !cred_out) {
+               return false;
+       }
+
        /* Do all operations on a temporary copy of the dc,
           which we throw away if the checks fail. */