This is a note to let you know that I've just added the patch titled
sunrpc: correct the computation for page_ptr when truncating
to the 4.9-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
sunrpc-correct-the-computation-for-page_ptr-when-truncating.patch
and it can be found in the queue-4.9 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 5d7a5bcb67c70cbc904057ef52d3fcfeb24420bb Mon Sep 17 00:00:00 2001
From: Frank Sorenson <sorenson@xxxxxxxxxx>
Date: Tue, 30 Oct 2018 15:10:40 -0500
Subject: sunrpc: correct the computation for page_ptr when truncating
From: Frank Sorenson <sorenson@xxxxxxxxxx>
commit 5d7a5bcb67c70cbc904057ef52d3fcfeb24420bb upstream.
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: Frank Sorenson <sorenson@xxxxxxxxxx>
Cc: stable@xxxxxxxxxxxxxxx
Signed-off-by: J. Bruce Fields <bfields@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
net/sunrpc/xdr.c | 5 ++---
1 file changed, 2 insertions(+), 3 deletions(-)
--- a/net/sunrpc/xdr.c
+++ b/net/sunrpc/xdr.c
@@ -639,11 +639,10 @@ void xdr_truncate_encode(struct xdr_stre
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;
Patches currently in stable-queue which might be from sorenson@xxxxxxxxxx are
queue-4.9/sunrpc-correct-the-computation-for-page_ptr-when-truncating.patch
