cifs: check rsp for NULL before dereferencing in SMB2_open

In SMB2_open there are several paths where the SendReceive2
call will return an error before it sets rsp_iov.iov_base
thus leaving iov_base uninitialized.

Thus we need to check rsp before we dereference it in
the call to get_rfc1002_length().

A report of this issue was previously reported in
http://www.spinics.net/lists/linux-cifs/msg12846.html

RH-bugzilla : 1476151

Version 2 :
* Lets properly initialize rsp_iov before we use it.

Signed-off-by: Ronnie Sahlberg <lsahlber@redhat.com>
Reviewed-by: Pavel Shilovsky <pshilov@microsoft.com>.
Signed-off-by: Steve French <smfrench@gmail.com>
Reported-by: Xiaoli Feng <xifeng@redhat.com>
CC: Stable <stable@vger.kernel.org>
This commit is contained in:
Ronnie Sahlberg 2017-09-08 10:37:35 +10:00 committed by Steve French
parent 52269718dc
commit bf2afee14e

View File

@ -1634,7 +1634,7 @@ SMB2_open(const unsigned int xid, struct cifs_open_parms *oparms, __le16 *path,
struct cifs_tcon *tcon = oparms->tcon;
struct cifs_ses *ses = tcon->ses;
struct kvec iov[4];
struct kvec rsp_iov;
struct kvec rsp_iov = {NULL, 0};
int resp_buftype;
int uni_path_len;
__le16 *copy_path = NULL;
@ -1763,7 +1763,7 @@ SMB2_open(const unsigned int xid, struct cifs_open_parms *oparms, __le16 *path,
if (rc != 0) {
cifs_stats_fail_inc(tcon, SMB2_CREATE_HE);
if (err_buf)
if (err_buf && rsp)
*err_buf = kmemdup(rsp, get_rfc1002_length(rsp) + 4,
GFP_KERNEL);
goto creat_exit;