From: J. Bruce Fields <bfields@redhat.com>
Date: Tue, 21 Apr 2015 19:25:39 +0000 (-0400)
Subject: nfsd4: disallow SEEK with special stateids
X-Git-Tag: v4.0.2~20
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=6fd154a83b18bc81aa3f1071e74c36d9076ff4b9;p=thirdparty%2Fkernel%2Fstable.git

nfsd4: disallow SEEK with special stateids

commit 980608fb50aea34993ba956b71cd4602aa42b14b upstream.

If the client uses a special stateid then we'll pass a NULL file to
vfs_llseek.

Fixes: 24bab491220f " NFSD: Implement SEEK"
Cc: Anna Schumaker <Anna.Schumaker@Netapp.com>
Reported-by: Christoph Hellwig <hch@infradead.org>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---

diff --git a/fs/nfsd/nfs4proc.c b/fs/nfsd/nfs4proc.c
index 5912967221171..5416968b3fb39 100644
--- a/fs/nfsd/nfs4proc.c
+++ b/fs/nfsd/nfs4proc.c
@@ -1071,6 +1071,8 @@ nfsd4_seek(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate,
 		dprintk("NFSD: nfsd4_seek: couldn't process stateid!\n");
 		return status;
 	}
+	if (!file)
+		return nfserr_bad_stateid;
 
 	switch (seek->seek_whence) {
 	case NFS4_CONTENT_DATA: