This is a note to let you know that I've just added the patch titled
rpc: fix xdr_truncate_encode to handle buffer ending on page boundary
to the 3.18-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:
rpc-fix-xdr_truncate_encode-to-handle-buffer-ending-on-page-boundary.patch
and it can be found in the queue-3.18 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 49a068f82a1d30eb585d7804b05948376be6cf9a Mon Sep 17 00:00:00 2001
From: "J. Bruce Fields" <bfields@xxxxxxxxxx>
Date: Mon, 22 Dec 2014 16:14:51 -0500
Subject: rpc: fix xdr_truncate_encode to handle buffer ending on page boundary
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From: "J. Bruce Fields" <bfields@xxxxxxxxxx>
commit 49a068f82a1d30eb585d7804b05948376be6cf9a upstream.
A struct xdr_stream at a page boundary might point to the end of one
page or the beginning of the next, but xdr_truncate_encode isn't
prepared to handle the former.
This can cause corruption of NFSv4 READDIR replies in the case that a
readdir entry that would have exceeded the client's dircount/maxcount
limit would have ended exactly on a 4k page boundary. You're more
likely to hit this case on large directories.
Other xdr_truncate_encode callers are probably also affected.
Reported-by: Holger Hoffstätte <holger.hoffstaette@xxxxxxxxxxxxxx>
Tested-by: Holger Hoffstätte <holger.hoffstaette@xxxxxxxxxxxxxx>
Fixes: 3e19ce762b53 "rpc: xdr_truncate_encode"
Signed-off-by: J. Bruce Fields <bfields@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
net/sunrpc/xdr.c | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)
--- a/net/sunrpc/xdr.c
+++ b/net/sunrpc/xdr.c
@@ -606,7 +606,7 @@ void xdr_truncate_encode(struct xdr_stre
struct kvec *head = buf->head;
struct kvec *tail = buf->tail;
int fraglen;
- int new, old;
+ int new;
if (len > buf->len) {
WARN_ON_ONCE(1);
@@ -628,8 +628,8 @@ void xdr_truncate_encode(struct xdr_stre
buf->len -= fraglen;
new = buf->page_base + buf->page_len;
- old = new + fraglen;
- xdr->page_ptr -= (old >> PAGE_SHIFT) - (new >> PAGE_SHIFT);
+
+ xdr->page_ptr = buf->pages + (new >> PAGE_SHIFT);
if (buf->page_len && buf->len == len) {
xdr->p = page_address(*xdr->page_ptr);
Patches currently in stable-queue which might be from bfields@xxxxxxxxxx are
queue-3.18/nfsd4-fix-xdr4-count-of-server-in-fs_location4.patch
queue-3.18/rpc-fix-xdr_truncate_encode-to-handle-buffer-ending-on-page-boundary.patch
queue-3.18/nfsd4-fix-xdr4-inclusion-of-escaped-char.patch
queue-3.18/nfsd-fix-fi_delegees-leak-when-fi_had_conflict-returns-true.patch
queue-3.18/fs-nfsd-fix-signedness-bug-in-compare_blob.patch
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