Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18;
Date:   Tue, 13 Apr 2021 13:50:04 +0300
From:   Dan Carpenter <dan.carpenter@oracle.com>
To:     "K. Y. Srinivasan" <kys@microsoft.com>
Cc:     Haiyang Zhang <haiyangz@microsoft.com>,
        Stephen Hemminger <sthemmin@microsoft.com>,
        Wei Liu <wei.liu@kernel.org>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        Dexuan Cui <decui@microsoft.com>, linux-hyperv@vger.kernel.org,
        linux-kernel@vger.kernel.org, kernel-janitors@vger.kernel.org
Subject: [PATCH] Drivers: hv: vmbus: Use after free in __vmbus_open()
Message-ID: <YHV3XLCot6xBS44r@mwanda>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
Precedence: bulk

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@oracle.com>
---
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