lkml.org 
[lkml]   [2019]   [Jan]   [15]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
From
Subject[PATCH 4.14 08/27] cifs: Fix potential OOB access of lock element array
Date
4.14-stable review patch.  If anyone has any objections, please let me know.

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

From: Ross Lagerwall <ross.lagerwall@citrix.com>

commit b9a74cde94957d82003fb9f7ab4777938ca851cd upstream.

If maxBuf is small but non-zero, it could result in a zero sized lock
element array which we would then try and access OOB.

Signed-off-by: Ross Lagerwall <ross.lagerwall@citrix.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
CC: Stable <stable@vger.kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
fs/cifs/file.c | 8 ++++----
fs/cifs/smb2file.c | 4 ++--
2 files changed, 6 insertions(+), 6 deletions(-)

--- a/fs/cifs/file.c
+++ b/fs/cifs/file.c
@@ -1120,10 +1120,10 @@ cifs_push_mandatory_locks(struct cifsFil

/*
* Accessing maxBuf is racy with cifs_reconnect - need to store value
- * and check it for zero before using.
+ * and check it before using.
*/
max_buf = tcon->ses->server->maxBuf;
- if (!max_buf) {
+ if (max_buf < (sizeof(struct smb_hdr) + sizeof(LOCKING_ANDX_RANGE))) {
free_xid(xid);
return -EINVAL;
}
@@ -1460,10 +1460,10 @@ cifs_unlock_range(struct cifsFileInfo *c

/*
* Accessing maxBuf is racy with cifs_reconnect - need to store value
- * and check it for zero before using.
+ * and check it before using.
*/
max_buf = tcon->ses->server->maxBuf;
- if (!max_buf)
+ if (max_buf < (sizeof(struct smb_hdr) + sizeof(LOCKING_ANDX_RANGE)))
return -EINVAL;

max_num = (max_buf - sizeof(struct smb_hdr)) /
--- a/fs/cifs/smb2file.c
+++ b/fs/cifs/smb2file.c
@@ -124,10 +124,10 @@ smb2_unlock_range(struct cifsFileInfo *c

/*
* Accessing maxBuf is racy with cifs_reconnect - need to store value
- * and check it for zero before using.
+ * and check it before using.
*/
max_buf = tcon->ses->server->maxBuf;
- if (!max_buf)
+ if (max_buf < sizeof(struct smb2_lock_element))
return -EINVAL;

max_num = max_buf / sizeof(struct smb2_lock_element);

\
 
 \ /
  Last update: 2019-01-15 17:58    [W:0.160 / U:1.768 seconds]
©2003-2018 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site