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 4F089C001DB for ; Sun, 13 Aug 2023 16:01:44 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232084AbjHMQBj (ORCPT ); Sun, 13 Aug 2023 12:01:39 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:55006 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231808AbjHMQBV (ORCPT ); Sun, 13 Aug 2023 12:01:21 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [IPv6:2604:1380:4641:c500::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 7EB2D1700; Sun, 13 Aug 2023 09:01:07 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id 9E41163468; Sun, 13 Aug 2023 16:00:48 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 8F5EDC433C8; Sun, 13 Aug 2023 16:00:46 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1691942448; bh=rR/SM1Ly68agvs8ERsZDBUA99gNaHKnNPEQwi4PLxAA=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=ZkfB8txjV34NW57rhAjHDnvlbgGgGdxyP0NrfhqB+nrFPGbCAUOb3gMaF/c+y3gHM pEEWQ9OQM5nuRIlflb3SEvTSPEr3aoYNN7bbGAojdB9jsWQ3N4Y8KbmIuflVaf2D60 aC4+oxAYX2QJbB0e/gynH6IDQawHxoua5aTrm5J/p5xdpxZftyAMeIwSGhgTSYdJZR kjI1jsB0gU4Z0YzDK/nsp7LnxDxLsSHqwrypsT4jIrIO7jV+G0MMJ3OTPdC1l84nMc wkuOXMH+khdKHR3Kjz2unkkzqu+JmkKpVIklkp5jPcYjqZ5zXtWrR2uR0LY1msNwN3 phFyP1oy7bNag== From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Dominique Martinet , Simon Horman , Eric Van Hensbergen , Sasha Levin , lucho@ionkov.net, davem@davemloft.net, edumazet@google.com, kuba@kernel.org, pabeni@redhat.com, v9fs@lists.linux.dev, netdev@vger.kernel.org Subject: [PATCH AUTOSEL 6.1 07/47] 9p: virtio: fix unlikely null pointer deref in handle_rerror Date: Sun, 13 Aug 2023 11:59:02 -0400 Message-Id: <20230813160006.1073695-7-sashal@kernel.org> X-Mailer: git-send-email 2.40.1 In-Reply-To: <20230813160006.1073695-1-sashal@kernel.org> References: <20230813160006.1073695-1-sashal@kernel.org> MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore X-stable-base: Linux 6.1.45 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Dominique Martinet [ Upstream commit 13ade4ac5c28e8a014fa85278f5a4270b215f906 ] handle_rerror can dereference the pages pointer, but it is not necessarily set for small payloads. In practice these should be filtered out by the size check, but might as well double-check explicitly. This fixes the following scan-build warnings: net/9p/trans_virtio.c:401:24: warning: Dereference of null pointer [core.NullDereference] memcpy_from_page(to, *pages++, offs, n); ^~~~~~~~ net/9p/trans_virtio.c:406:23: warning: Dereference of null pointer (loaded from variable 'pages') [core.NullDereference] memcpy_from_page(to, *pages, offs, size); ^~~~~~ Reviewed-by: Simon Horman Signed-off-by: Dominique Martinet Signed-off-by: Eric Van Hensbergen Signed-off-by: Sasha Levin --- net/9p/trans_virtio.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/net/9p/trans_virtio.c b/net/9p/trans_virtio.c index 3f3eb03cda7d6..6a4a29a2703de 100644 --- a/net/9p/trans_virtio.c +++ b/net/9p/trans_virtio.c @@ -385,7 +385,7 @@ static void handle_rerror(struct p9_req_t *req, int in_hdr_len, void *to = req->rc.sdata + in_hdr_len; // Fits entirely into the static data? Nothing to do. - if (req->rc.size < in_hdr_len) + if (req->rc.size < in_hdr_len || !pages) return; // Really long error message? Tough, truncate the reply. Might get -- 2.40.1