linux-kernel - [PATCH 3.14 20/46] nfs: dont create zero-length requests

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-Id: <20160818135445.459722430@linuxfoundation.org>
Date:	Thu, 18 Aug 2016 15:54:42 +0200
From:	Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:	linux-kernel@...r.kernel.org
Cc:	Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
	stable@...r.kernel.org, Benjamin Coddington <bcodding@...hat.com>,
	Alexey Dobriyan <adobriyan@...il.com>,
	Weston Andros Adamson <dros@...marydata.com>,
	Trond Myklebust <trond.myklebust@...marydata.com>
Subject: [PATCH 3.14 20/46] nfs: dont create zero-length requests

3.14-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Benjamin Coddington <bcodding@...hat.com>

commit 149a4fddd0a72d526abbeac0c8deaab03559836a upstream.

NFS doesn't expect requests with wb_bytes set to zero and may make
unexpected decisions about how to handle that request at the page IO layer.
Skip request creation if we won't have any wb_bytes in the request.

Signed-off-by: Benjamin Coddington <bcodding@...hat.com>
Signed-off-by: Alexey Dobriyan <adobriyan@...il.com>
Reviewed-by: Weston Andros Adamson <dros@...marydata.com>
Signed-off-by: Trond Myklebust <trond.myklebust@...marydata.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>

---
 fs/nfs/write.c |    5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

--- a/fs/nfs/write.c
+++ b/fs/nfs/write.c
@@ -965,6 +965,9 @@ int nfs_updatepage(struct file *file, st
 	dprintk("NFS:       nfs_updatepage(%pD2 %d@...d)\n",
 		file, count, (long long)(page_file_offset(page) + offset));
 
+	if (!count)
+		goto out;
+
 	if (nfs_can_extend_write(file, page, inode)) {
 		count = max(count + offset, nfs_page_length(page));
 		offset = 0;
@@ -975,7 +978,7 @@ int nfs_updatepage(struct file *file, st
 		nfs_set_pageerror(page);
 	else
 		__set_page_dirty_nobuffers(page);
-
+out:
 	dprintk("NFS:       nfs_updatepage returns %d (isize %lld)\n",
 			status, (long long)i_size_read(inode));
 	return status;