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=-9.8 required=3.0 tests=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=unavailable 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 0038BC742BA for ; Fri, 12 Jul 2019 12:25:07 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id BB61521670 for ; Fri, 12 Jul 2019 12:25:06 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1562934306; bh=EaKkSjxtQSGN5Zl5VRj13WaPEHAovzGIOX4xu5SmhOo=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=2m/m2p4a+aUWEOM3fce5p39mz2Ws/LhzLec4nJA4Hso4xf4GUPUKu7GgUQYKPLxSz 0yLrdltKJO4F+PeiS6AntIXSswcp8fiCSUD43vuqWXI6/50Yiq2rnll39YaIpf0O7r wm2lKF9Dt+aSdHdFFR5DwfwVlM0ITb4/DiI+yH3M= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728227AbfGLMZF (ORCPT ); Fri, 12 Jul 2019 08:25:05 -0400 Received: from mail.kernel.org ([198.145.29.99]:34532 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727368AbfGLMZC (ORCPT ); Fri, 12 Jul 2019 08:25:02 -0400 Received: from localhost (83-86-89-107.cable.dynamic.v4.ziggo.nl [83.86.89.107]) (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 5983821019; Fri, 12 Jul 2019 12:25:01 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1562934301; bh=EaKkSjxtQSGN5Zl5VRj13WaPEHAovzGIOX4xu5SmhOo=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=yxGjEDPbGm47UjId0uVoQfbRBPgr0uzQXxfuMSeSog8aVi6jqJQ4GaO8u3IbNZi6l 68KqxV7SedQvneqUGVakzmhjsyUsTVLgA9cTMNXK/VV2vKDWcsDK7BUV94CWbXZk3n zHtEQYQ3i1BuPRfaJQMlzylrZh8LSMmz/K09yki8= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Chang-Hsien Tsai , Daniel Borkmann , Sasha Levin Subject: [PATCH 5.1 011/138] samples, bpf: fix to change the buffer size for read() Date: Fri, 12 Jul 2019 14:17:55 +0200 Message-Id: <20190712121629.148244689@linuxfoundation.org> X-Mailer: git-send-email 2.22.0 In-Reply-To: <20190712121628.731888964@linuxfoundation.org> References: <20190712121628.731888964@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org [ 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 eae7b635343d..6e87cc831e84 100644 --- a/samples/bpf/bpf_load.c +++ b/samples/bpf/bpf_load.c @@ -678,7 +678,7 @@ 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