From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 017B4C433F5 for ; Fri, 29 Apr 2022 10:42:45 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1357808AbiD2Kp7 (ORCPT ); Fri, 29 Apr 2022 06:45:59 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:58670 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1357693AbiD2KpS (ORCPT ); Fri, 29 Apr 2022 06:45:18 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id A8880C6EEB; Fri, 29 Apr 2022 03:41:56 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id 3F90B6235C; Fri, 29 Apr 2022 10:41:56 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 4B298C385A4; Fri, 29 Apr 2022 10:41:55 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1651228915; bh=VtJerBDQCYbUCgpxXLdGU8t1nlWfii6eDosdmY9hF0w=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=qsIvg/8koiR/jibFaflGX+sd8V0/R6CX0ojZ3EUhf6ZesaWD3PI8z2SFe1I4M7177 f6XSLQJsNsmzYwLVcNpt0OO5ZMIUePOCNKF2/0lrbzRLTk0T6Vvo7SeNQgna7g7CB6 KWEOttgo4BN8/+Mk1C1lQW1NCDRKmFKdEIbZWeP4= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Lin Ma , Jakub Kicinski , Ovidiu Panait Subject: [PATCH 4.19 04/12] hamradio: remove needs_free_netdev to avoid UAF Date: Fri, 29 Apr 2022 12:41:21 +0200 Message-Id: <20220429104048.588599421@linuxfoundation.org> X-Mailer: git-send-email 2.36.0 In-Reply-To: <20220429104048.459089941@linuxfoundation.org> References: <20220429104048.459089941@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Lin Ma commit 81b1d548d00bcd028303c4f3150fa753b9b8aa71 upstream. The former patch "defer 6pack kfree after unregister_netdev" reorders the kfree of two buffer after the unregister_netdev to prevent the race condition. It also adds free_netdev() function in sixpack_close(), which is a direct copy from the similar code in mkiss_close(). However, in sixpack driver, the flag needs_free_netdev is set to true in sp_setup(), hence the unregister_netdev() will free the netdev automatically. Therefore, as the sp is netdev_priv, use-after-free occurs. This patch removes the needs_free_netdev = true and just let the free_netdev to finish this deallocation task. Fixes: 0b9111922b1f ("hamradio: defer 6pack kfree after unregister_netdev") Signed-off-by: Lin Ma Link: https://lore.kernel.org/r/20211111141402.7551-1-linma@zju.edu.cn Signed-off-by: Jakub Kicinski Signed-off-by: Ovidiu Panait Signed-off-by: Greg Kroah-Hartman --- drivers/net/hamradio/6pack.c | 1 - 1 file changed, 1 deletion(-) --- a/drivers/net/hamradio/6pack.c +++ b/drivers/net/hamradio/6pack.c @@ -311,7 +311,6 @@ static void sp_setup(struct net_device * { /* Finish setting up the DEVICE info. */ dev->netdev_ops = &sp_netdev_ops; - dev->needs_free_netdev = true; dev->mtu = SIXP_MTU; dev->hard_header_len = AX25_MAX_HEADER_LEN; dev->header_ops = &ax25_header_ops;