nfs: Fix GETATTR bitmap verification

When decoding GETATTR replies, the client checks the attribute bitmap
for which attributes the server has sent.  It misses bits at the word
boundaries, though; fix that.

Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

1 files changed, 23 insertions, 0 deletions

diff --git a/fs/nfs/nfs4xdr.c b/fs/nfs/nfs4xdr.c
index 22a1ddd4fe96..dfed4f5c8fcc 100644
--- a/fs/nfs/nfs4xdr.c
+++ b/fs/nfs/nfs4xdr.c
@@ -4375,6 +4375,11 @@ static int decode_statfs(struct xdr_stream *xdr, struct nfs_fsstat *fsstat)
                 goto xdr_error;
         if ((status = decode_attr_files_total(xdr, bitmap, &fsstat->tfiles)) != 0)
                 goto xdr_error;
+
+        status = -EIO;
+        if (unlikely(bitmap[0]))
+                goto xdr_error;
+
         if ((status = decode_attr_space_avail(xdr, bitmap, &fsstat->abytes)) != 0)
                 goto xdr_error;
         if ((status = decode_attr_space_free(xdr, bitmap, &fsstat->fbytes)) != 0)
@@ -4574,6 +4579,10 @@ static int decode_getfattr_attrs(struct xdr_stream *xdr, uint32_t *bitmap,
                 goto xdr_error;
         fattr->valid |= status;
 
+        status = -EIO;
+        if (unlikely(bitmap[0]))
+                goto xdr_error;
+
         status = decode_attr_mode(xdr, bitmap, &fmode);
         if (status < 0)
                 goto xdr_error;
@@ -4627,6 +4636,10 @@ static int decode_getfattr_attrs(struct xdr_stream *xdr, uint32_t *bitmap,
                 goto xdr_error;
         fattr->valid |= status;
 
+        status = -EIO;
+        if (unlikely(bitmap[1]))
+                goto xdr_error;
+
         status = decode_attr_mdsthreshold(xdr, bitmap, fattr->mdsthreshold);
         if (status < 0)
                 goto xdr_error;
@@ -4811,12 +4824,22 @@ static int decode_fsinfo(struct xdr_stream *xdr, struct nfs_fsinfo *fsinfo)
         if ((status = decode_attr_maxwrite(xdr, bitmap, &fsinfo->wtmax)) != 0)
                 goto xdr_error;
         fsinfo->wtpref = fsinfo->wtmax;
+
+        status = -EIO;
+        if (unlikely(bitmap[0]))
+                goto xdr_error;
+
         status = decode_attr_time_delta(xdr, bitmap, &fsinfo->time_delta);
         if (status != 0)
                 goto xdr_error;
         status = decode_attr_pnfstype(xdr, bitmap, &fsinfo->layouttype);
         if (status != 0)
                 goto xdr_error;
+
+        status = -EIO;
+        if (unlikely(bitmap[1]))
+                goto xdr_error;
+
         status = decode_attr_layout_blksize(xdr, bitmap, &fsinfo->blksize);
         if (status)
                 goto xdr_error;