From patchwork Mon May 16 19:36:29 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Greg KH X-Patchwork-Id: 573819 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 DC191C4167B for ; Mon, 16 May 2022 19:53:16 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229616AbiEPTxO (ORCPT ); Mon, 16 May 2022 15:53:14 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:56802 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1346212AbiEPTux (ORCPT ); Mon, 16 May 2022 15:50:53 -0400 Received: from sin.source.kernel.org (sin.source.kernel.org [IPv6:2604:1380:40e1:4800::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 40E31443CE; Mon, 16 May 2022 12:45:30 -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 sin.source.kernel.org (Postfix) with ESMTPS id 982BCCE1798; Mon, 16 May 2022 19:45:28 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id A3EDEC34100; Mon, 16 May 2022 19:45:26 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1652730327; bh=eWA4IP9jXbZ4Dw5owvga1ugxXXjxeiJvUw4vGvqPllA=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=0taIAyD32eo4azoyz70fvJscoOHyCt4IX/xoyOKlVqtiS3oI1Z/On/LZ/2PxKSkh8 DnTxuV+rw8kXpMaeDmAxdj3TFd74vtakoS5NjYdWtOe1TpGNgE7VZ9hmuRNqWKlfG9 SGtzfjltktU8baqCApIsR7P9WbphfVUx9KIIckoM= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Maxim Mikityanskiy , Tariq Toukan , Jakub Kicinski , Sasha Levin Subject: [PATCH 5.10 29/66] tls: Fix context leak on tls_device_down Date: Mon, 16 May 2022 21:36:29 +0200 Message-Id: <20220516193620.257989798@linuxfoundation.org> X-Mailer: git-send-email 2.36.1 In-Reply-To: <20220516193619.400083785@linuxfoundation.org> References: <20220516193619.400083785@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Maxim Mikityanskiy [ Upstream commit 3740651bf7e200109dd42d5b2fb22226b26f960a ] The commit cited below claims to fix a use-after-free condition after tls_device_down. Apparently, the description wasn't fully accurate. The context stayed alive, but ctx->netdev became NULL, and the offload was torn down without a proper fallback, so a bug was present, but a different kind of bug. Due to misunderstanding of the issue, the original patch dropped the refcount_dec_and_test line for the context to avoid the alleged premature deallocation. That line has to be restored, because it matches the refcount_inc_not_zero from the same function, otherwise the contexts that survived tls_device_down are leaked. This patch fixes the described issue by restoring refcount_dec_and_test. After this change, there is no leak anymore, and the fallback to software kTLS still works. Fixes: c55dcdd435aa ("net/tls: Fix use-after-free after the TLS device goes down and up") Signed-off-by: Maxim Mikityanskiy Reviewed-by: Tariq Toukan Link: https://lore.kernel.org/r/20220512091830.678684-1-maximmi@nvidia.com Signed-off-by: Jakub Kicinski Signed-off-by: Sasha Levin --- net/tls/tls_device.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/net/tls/tls_device.c b/net/tls/tls_device.c index 1f56225a10e3..3c82286e5bcc 100644 --- a/net/tls/tls_device.c +++ b/net/tls/tls_device.c @@ -1345,7 +1345,10 @@ static int tls_device_down(struct net_device *netdev) /* Device contexts for RX and TX will be freed in on sk_destruct * by tls_device_free_ctx. rx_conf and tx_conf stay in TLS_HW. + * Now release the ref taken above. */ + if (refcount_dec_and_test(&ctx->refcount)) + tls_device_free_ctx(ctx); } up_write(&device_offload_lock);