nfsd: fix unlikely NULL deref in mach_creds_match



We really shouldn't allow a client to be created with cl_mach_cred set
unless it also has a principal name.

This also allows us to fail such cases immediately on EXCHANGE_ID as
opposed to waiting and incorrectly returning WRONG_CRED on the following
CREATE_SESSION.

Signed-off-by: J. Bruce Fields <bfields@redhat.com>

parent 50c7b948

fs/nfsd/nfs4state.c

+9 −0

Original line number	Diff line number	Diff line
		@@ -2385,6 +2385,15 @@ nfsd4_exchange_id(struct svc_rqst *rqstp,
		status = nfserr_inval;
		goto out_nolock;
		}
		/*
		* Sometimes userspace doesn't give us a principal.
		* Which is a bug, really. Anyway, we can't enforce
		* MACH_CRED in that case, better to give up now:
		*/
		if (!new->cl_cred.cr_principal) {
		status = nfserr_serverfault;
		goto out_nolock;
		}
		new->cl_mach_cred = true;
		case SP4_NONE:
		break;