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-Url: https://git.stricted.de/?a=commitdiff_plain;h=980608fb50aea34993ba956b71cd4602aa42b14b;p=GitHub%2FLineageOS%2Fandroid_kernel_motorola_exynos9610.git

nfsd4: disallow SEEK with special stateids

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>
Cc: stable@vger.kernel.org
Reported-by: Christoph Hellwig <hch@infradead.org>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
---

diff --git a/fs/nfsd/nfs4proc.c b/fs/nfsd/nfs4proc.c
index d0848fc6529e..4a8314f08a0e 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: