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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        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>,
        Johannes Berg <johannes.berg@intel.com>,
        Kalle Valo <kvalo@kernel.org>
Subject: [PATCH 5.4 27/80] iwlwifi: fix use-after-free
Date:   Mon, 21 Feb 2022 09:49:07 +0100
Message-Id: <20220221084916.473428932@linuxfoundation.org>
In-Reply-To: <20220221084915.554151737@linuxfoundation.org>
References: <20220221084915.554151737@linuxfoundation.org>
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From: Johannes Berg <johannes.berg@intel.com>

commit bea2662e7818e15d7607d17d57912ac984275d94 upstream.

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>
Signed-off-by: Kalle Valo <kvalo@kernel.org>
Link: https://lore.kernel.org/r/20220208114728.e6b514cf4c85.Iffb575ca2a623d7859b542c33b2a507d01554251@changeid
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 drivers/net/wireless/intel/iwlwifi/iwl-drv.c |    2 ++
 1 file changed, 2 insertions(+)

--- a/drivers/net/wireless/intel/iwlwifi/iwl-drv.c
+++ b/drivers/net/wireless/intel/iwlwifi/iwl-drv.c
@@ -1616,6 +1616,8 @@ static void iwl_req_fw_callback(const st
  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);