[PATCH 4.14 025/189] xen: xenbus_dev_frontend: Really return response string

[Greg Kroah-Hartman]

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

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

From: Simon Gaiser <si...@invisiblethingslab.com>

[ Upstream commit ebf04f331fa15a966262341a7dc6b1a0efd633e4 ]

xenbus_command_reply() did not actually copy the response string and
leaked stack content instead.

Fixes: 9a6161fe73bd ("xen: return xenstore command failures via response 
instead of rc")
Signed-off-by: Simon Gaiser <si...@invisiblethingslab.com>
Reviewed-by: Juergen Gross <jgr...@suse.com>
Signed-off-by: Boris Ostrovsky <boris.ostrov...@oracle.com>
Signed-off-by: Sasha Levin <alexander.le...@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gre...@linuxfoundation.org>
---
 drivers/xen/xenbus/xenbus_dev_frontend.c |    3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

--- a/drivers/xen/xenbus/xenbus_dev_frontend.c
+++ b/drivers/xen/xenbus/xenbus_dev_frontend.c
@@ -403,7 +403,7 @@ static int xenbus_command_reply(struct x
 {
        struct {
                struct xsd_sockmsg hdr;
-               const char body[16];
+               char body[16];
        } msg;
        int rc;
 
@@ -412,6 +412,7 @@ static int xenbus_command_reply(struct x
        msg.hdr.len = strlen(reply) + 1;
        if (msg.hdr.len > sizeof(msg.body))
                return -E2BIG;
+       memcpy(&msg.body, reply, msg.hdr.len);
 
        mutex_lock(&u->reply_mutex);
        rc = queue_reply(&u->read_buffers, &msg, sizeof(msg.hdr) + msg.hdr.len);