Commit 5d7a5bcb authored by Frank Sorenson's avatar Frank Sorenson Committed by J. Bruce Fields
Browse files

sunrpc: correct the computation for page_ptr when truncating



When truncating the encode buffer, the page_ptr is getting
advanced, causing the next page to be skipped while encoding.
The page is still included in the response, so the response
contains a page of bogus data.

We need to adjust the page_ptr backwards to ensure we encode
the next page into the correct place.

We saw this triggered when concurrent directory modifications caused
nfsd4_encode_direct_fattr() to return nfserr_noent, and the resulting
call to xdr_truncate_encode() corrupted the READDIR reply.
Signed-off-by: default avatarFrank Sorenson <sorenson@redhat.com>
Cc: stable@vger.kernel.org
Signed-off-by: default avatarJ. Bruce Fields <bfields@redhat.com>
parent 65102238
......@@ -673,11 +673,10 @@ void xdr_truncate_encode(struct xdr_stream *xdr, size_t len)
WARN_ON_ONCE(xdr->iov);
return;
}
if (fraglen) {
if (fraglen)
xdr->end = head->iov_base + head->iov_len;
xdr->page_ptr--;
}
/* (otherwise assume xdr->end is already set) */
xdr->page_ptr--;
head->iov_len = len;
buf->len = len;
xdr->p = head->iov_base + head->iov_len;
......
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