From patchwork Tue Sep 15 14:11:45 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Greg Kroah-Hartman X-Patchwork-Id: 263905 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-15.7 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED, DKIM_VALID, HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH, MAILING_LIST_MULTI, SIGNED_OFF_BY, SPF_HELO_NONE, SPF_PASS, URIBL_BLOCKED, USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 378CCC43461 for ; Tue, 15 Sep 2020 23:44:36 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id E870E221E3 for ; Tue, 15 Sep 2020 23:44:35 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1600213476; bh=EV1baJKNerMt/tzQ4G/KOBjXGRC1nK+tDGVmbMJlEG4=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=ZwSXMH/7cCoY31W7wyQJufXvblY3D/yLleAVWmX5/RUoYfPJ46JAL4LlSShA7Dhaz ycE5SRpIa2SUJtBEhPblZQPTgA9TUu+sHy4Yzf0tPFugwbWc9uhoWN2RnPjbCnIZoZ RgBYrKOvS49vdRDq+KlKUCyLvngmnmO7PFk2EV6U= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727343AbgIOXob (ORCPT ); Tue, 15 Sep 2020 19:44:31 -0400 Received: from mail.kernel.org ([198.145.29.99]:46458 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727009AbgIOOd4 (ORCPT ); Tue, 15 Sep 2020 10:33:56 -0400 Received: from localhost (83-86-74-64.cable.dynamic.v4.ziggo.nl [83.86.74.64]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 99C6223C19; Tue, 15 Sep 2020 14:25:10 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1600179911; bh=EV1baJKNerMt/tzQ4G/KOBjXGRC1nK+tDGVmbMJlEG4=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=fbjSiWf7dn66pzYCJVjk35DiQcrTlFODU1MOScYfX+yCIrC0u7kElR3Jh5FZMCfMP KjrV/5E68dun/SHV5hwAT7gfeyvK9CcztlKNLGSBTwWCtK4G9PPrkU57cje+xHFy0C uuJEpmJOwkvyd5voC6mpzX8kpsVgMZPNGwjHi0Lw= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Tom Rix , Nick Desaulniers , Pierre-Louis Bossart , Vinod Koul , Sasha Levin Subject: [PATCH 5.8 034/177] soundwire: fix double free of dangling pointer Date: Tue, 15 Sep 2020 16:11:45 +0200 Message-Id: <20200915140655.278498663@linuxfoundation.org> X-Mailer: git-send-email 2.28.0 In-Reply-To: <20200915140653.610388773@linuxfoundation.org> References: <20200915140653.610388773@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Sender: stable-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Tom Rix [ Upstream commit 3fbbf2148a406b3e350fe91e6fdd78eb42ecad24 ] clang static analysis flags this problem stream.c:844:9: warning: Use of memory after it is freed kfree(bus->defer_msg.msg->buf); ^~~~~~~~~~~~~~~~~~~~~~~ This happens in an error handler cleaning up memory allocated for elements in a list. list_for_each_entry(m_rt, &stream->master_list, stream_node) { bus = m_rt->bus; kfree(bus->defer_msg.msg->buf); kfree(bus->defer_msg.msg); } And is triggered when the call to sdw_bank_switch() fails. There are a two problems. First, when sdw_bank_switch() fails, though it frees memory it does not clear bus's reference 'defer_msg.msg' to that memory. The second problem is the freeing msg->buf. In some cases msg will be NULL so this will dereference a null pointer. Need to check before freeing. Fixes: 99b8a5d608a6 ("soundwire: Add bank switch routine") Signed-off-by: Tom Rix Reviewed-by: Nick Desaulniers Reviewed-by: Pierre-Louis Bossart Link: https://lore.kernel.org/r/20200902202650.14189-1-trix@redhat.com Signed-off-by: Vinod Koul Signed-off-by: Sasha Levin --- drivers/soundwire/stream.c | 8 +++++--- 1 file changed, 5 insertions(+), 3 deletions(-) diff --git a/drivers/soundwire/stream.c b/drivers/soundwire/stream.c index a9a72574b34ab..684761e86d4fc 100644 --- a/drivers/soundwire/stream.c +++ b/drivers/soundwire/stream.c @@ -716,6 +716,7 @@ error: kfree(wbuf); error_1: kfree(wr_msg); + bus->defer_msg.msg = NULL; return ret; } @@ -839,9 +840,10 @@ static int do_bank_switch(struct sdw_stream_runtime *stream) error: list_for_each_entry(m_rt, &stream->master_list, stream_node) { bus = m_rt->bus; - - kfree(bus->defer_msg.msg->buf); - kfree(bus->defer_msg.msg); + if (bus->defer_msg.msg) { + kfree(bus->defer_msg.msg->buf); + kfree(bus->defer_msg.msg); + } } msg_unlock: