Patch "cifs: check rsp for NULL before dereferencing in SMB2_open" has been added to the 4.13-stable tree

This is a note to let you know that I've just added the patch titled

cifs: check rsp for NULL before dereferencing in SMB2_open

to the 4.13-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:
cifs-check-rsp-for-null-before-dereferencing-in-smb2_open.patch
and it can be found in the queue-4.13 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.

From: Ronnie Sahlberg <[email protected]>
Date: Fri, 8 Sep 2017 10:37:35 +1000
Subject: cifs: check rsp for NULL before dereferencing in SMB2_open

From: Ronnie Sahlberg <[email protected]>

commit bf2afee14e07de16d3cafc67edbfc2a3cc65e4bc upstream.

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.

---
 fs/cifs/smb2pdu.c |    4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

@@ -1622,7 +1622,7 @@ SMB2_open(const unsigned int xid, struct
 	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;

@@ -1751,7 +1751,7 @@ SMB2_open(const unsigned int xid, struct
 
 	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;

Patches currently in stable-queue which might be from [email protected] are

queue-4.13/cifs-release-cifs-root_cred-after-exit_cifs.patch queue-4.13/cifs-check-rsp-for-null-before-dereferencing-in-smb2_open.patch queue-4.13/cifs-release-auth_key.response-for-reconnect.patch