[PATCH] Drivers: hv: vmbus: Use after free in __vmbus_open()

From: Dan Carpenter
Date: Tue Apr 13 2021 - 06:50:39 EST


The "open_info" variable is added to the &vmbus_connection.chn_msg_list,
but the error handling frees "open_info" without removing it from the
list. This will result in a use after free. First remove it from the
list, and then free it.

Fixes: 6f3d791f3006 ("Drivers: hv: vmbus: Fix rescind handling issues")
Signed-off-by: Dan Carpenter <dan.carpenter@xxxxxxxxxx>
---
>From static analysis. Untested etc. There is almost certainly a good
reason to add it to the list before checking "newchannel->rescind" but I
don't know the code well enough to know what the reason is.

drivers/hv/channel.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/hv/channel.c b/drivers/hv/channel.c
index db30be8f9cce..1c5a418c1962 100644
--- a/drivers/hv/channel.c
+++ b/drivers/hv/channel.c
@@ -653,7 +653,7 @@ static int __vmbus_open(struct vmbus_channel *newchannel,

if (newchannel->rescind) {
err = -ENODEV;
- goto error_free_info;
+ goto error_clean_msglist;
}

err = vmbus_post_msg(open_msg,
--
2.30.2