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Subject[PATCH] xen: xenbus_dev_frontend: Really return response string
Date
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>
---

PS: AFAICS this is not a security issue since /dev/xen/xenbus is
normally only accessible by root and giving xenstore access to a less
trusted entity probably has a bunch of other unintended consequences.

drivers/xen/xenbus/xenbus_dev_frontend.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/xen/xenbus/xenbus_dev_frontend.c b/drivers/xen/xenbus/xenbus_dev_frontend.c
index a493e99bed21..845a70fa7f79 100644
--- 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 xenbus_file_priv *u,
{
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 xenbus_file_priv *u,
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);
--
2.16.2
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