nfsd4: buffer-length check for SUPPATTR_EXCLCREAT

This was an omission from 8c18f2052e756e7d5dea712fc6e7ed70c00e8a39
"nfsd41: SUPPATTR_EXCLCREAT attribute".

Cc: Benny Halevy <bhalevy@primarydata.com>
Cc: stable@vger.kernel.org
Signed-off-by: J. Bruce Fields <bfields@redhat.com>

1 files changed, 2 insertions, 0 deletions

diff --git a/fs/nfsd/nfs4xdr.c b/fs/nfsd/nfs4xdr.c
index 63f2395c57ed..668bfe1fcdec 100644
--- a/fs/nfsd/nfs4xdr.c
+++ b/fs/nfsd/nfs4xdr.c
@@ -2483,6 +2483,8 @@ out_acl:
                         goto out;
         }
         if (bmval2 & FATTR4_WORD2_SUPPATTR_EXCLCREAT) {
+                if ((buflen -= 16) < 0)
+                        goto out_resource;
                 WRITE32(3);
                 WRITE32(NFSD_SUPPATTR_EXCLCREAT_WORD0);
                 WRITE32(NFSD_SUPPATTR_EXCLCREAT_WORD1);