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 X-Spam-Level: X-Spam-Status: No, score=-9.1 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,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 799E4C48BD3 for ; Thu, 27 Jun 2019 00:36:35 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 4C61421852 for ; Thu, 27 Jun 2019 00:36:35 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1561595795; bh=JPrV1Cfb0IcgHVIWmpGp/W06hd3h69ULUvOSekD+YlE=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=s60eraVGhgeTA4aAAObhnQ48llHTPlxkHj2LqwMOnRLQFK0U/dAxLnpdw32gexf1K ibVn0lvPqmIPQ78CjXyxIOjsfoclW/mgQEmmxf6Nphh+2uHKLkoAXqyxm7xYjYXkRY mZpbDX9SqoXL9rcR3WHCzckACTQ0fRvvGJ3Hsc6A= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728339AbfF0Age (ORCPT ); Wed, 26 Jun 2019 20:36:34 -0400 Received: from mail.kernel.org ([198.145.29.99]:40986 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728081AbfF0Agb (ORCPT ); Wed, 26 Jun 2019 20:36:31 -0400 Received: from sasha-vm.mshome.net (unknown [107.242.116.147]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 1F718217F4; Thu, 27 Jun 2019 00:36:28 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1561595790; bh=JPrV1Cfb0IcgHVIWmpGp/W06hd3h69ULUvOSekD+YlE=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=ZJdVWVvSbHx/uCBucVKh4RzAgM57bfy474jrCk6/UE547Erj7xVkjx1FWpxK2G9kk rfe/HNXdnf0DCsfxftQUb7bvQCzbsBierih5OrWInlXX0VC2D9WuGeqm57Gg/rx0Z5 yCBGsEKTyECjOgvpZFJVuN97OZfwDPmb5VxELUbc= From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Chang-Hsien Tsai , Daniel Borkmann , Sasha Levin , netdev@vger.kernel.org, bpf@vger.kernel.org Subject: [PATCH AUTOSEL 4.19 04/60] samples, bpf: fix to change the buffer size for read() Date: Wed, 26 Jun 2019 20:35:19 -0400 Message-Id: <20190627003616.20767-4-sashal@kernel.org> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20190627003616.20767-1-sashal@kernel.org> References: <20190627003616.20767-1-sashal@kernel.org> MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Chang-Hsien Tsai [ Upstream commit f7c2d64bac1be2ff32f8e4f500c6e5429c1003e0 ] If the trace for read is larger than 4096, the return value sz will be 4096. This results in off-by-one error on buf: static char buf[4096]; ssize_t sz; sz = read(trace_fd, buf, sizeof(buf)); if (sz > 0) { buf[sz] = 0; puts(buf); } Signed-off-by: Chang-Hsien Tsai Signed-off-by: Daniel Borkmann Signed-off-by: Sasha Levin --- samples/bpf/bpf_load.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/samples/bpf/bpf_load.c b/samples/bpf/bpf_load.c index cf40a8284a38..5061a2ec4564 100644 --- a/samples/bpf/bpf_load.c +++ b/samples/bpf/bpf_load.c @@ -677,7 +677,7 @@ void read_trace_pipe(void) static char buf[4096]; ssize_t sz; - sz = read(trace_fd, buf, sizeof(buf)); + sz = read(trace_fd, buf, sizeof(buf) - 1); if (sz > 0) { buf[sz] = 0; puts(buf); -- 2.20.1