cifs: Fix potential OOB access of lock element array

commit b9a74cde94 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>
This commit is contained in:
Ross Lagerwall 2019-01-08 18:30:57 +00:00 committed by Greg Kroah-Hartman
parent 4092ad400e
commit 5c467ac09d
2 changed files with 6 additions and 6 deletions

View file

@ -1120,10 +1120,10 @@ cifs_push_mandatory_locks(struct cifsFileInfo *cfile)
/*
* 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 *cfile, struct file_lock *flock,
/*
* 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)) /

View file

@ -124,10 +124,10 @@ smb2_unlock_range(struct cifsFileInfo *cfile, struct file_lock *flock,
/*
* 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);