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

Greg Kroah-Hartman
2018-06-18T09:07:58Z

From: Simon Gaiser <simon@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 <simon@invisiblethingslab.com>
Reviewed-by: Juergen Gross <jgross@suse.com>
Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@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);