Received-SPF: pass (google.com: domain of linux-wireless-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20;
From:   Johannes Berg <johannes@sipsolutions.net>
To:     linux-wireless@vger.kernel.org
Cc:     Johannes Berg <johannes.berg@intel.com>, stable@vger.kernel.org,
        Stefan Agner <stefan@agner.ch>,
        Wolfgang Walter <linux@stwm.de>,
        Jason Self <jason@bluehome.net>,
        Dominik Behr <dominik@dominikbehr.com>,
        =?UTF-8?q?Marek=20Marczykowski-G=C3=B3recki?= 
        <marmarek@invisiblethingslab.com>
Subject: [PATCH] iwlwifi: fix use-after-free
Date:   Tue,  8 Feb 2022 11:47:30 +0100
Message-Id: <20220208114728.e6b514cf4c85.Iffb575ca2a623d7859b542c33b2a507d01554251@changeid>
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit
Precedence: bulk

From: Johannes Berg <johannes.berg@intel.com>

If no firmware was present at all (or, presumably, all of the
firmware files failed to parse), we end up unbinding by calling
device_release_driver(), which calls remove(), which then in
iwlwifi calls iwl_drv_stop(), freeing the 'drv' struct. However
the new code I added will still erroneously access it after it
was freed.

Set 'failure=false' in this case to avoid the access, all data
was already freed anyway.

Cc: stable@vger.kernel.org
Reported-by: Stefan Agner <stefan@agner.ch>
Reported-by: Wolfgang Walter <linux@stwm.de>
Reported-by: Jason Self <jason@bluehome.net>
Reported-by: Dominik Behr <dominik@dominikbehr.com>
Reported-by: Marek Marczykowski-Górecki <marmarek@invisiblethingslab.com>
Fixes: ab07506b0454 ("iwlwifi: fix leaks/bad data after failed firmware load")
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
---
 drivers/net/wireless/intel/iwlwifi/iwl-drv.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/net/wireless/intel/iwlwifi/iwl-drv.c b/drivers/net/wireless/intel/iwlwifi/iwl-drv.c
index 83e3b731ad29..6651e78b39ec 100644
--- a/drivers/net/wireless/intel/iwlwifi/iwl-drv.c
+++ b/drivers/net/wireless/intel/iwlwifi/iwl-drv.c
@@ -1707,6 +1707,8 @@ static void iwl_req_fw_callback(const struct firmware *ucode_raw, void *context)
  out_unbind:
 	complete(&drv->request_firmware_complete);
 	device_release_driver(drv->trans->dev);
+	/* drv has just been freed by the release */
+	failure = false;
  free:
 	if (failure)
 		iwl_dealloc_ucode(drv);
-- 
2.34.1