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=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,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 AA6C1C04AB4 for ; Sun, 19 May 2019 17:46:33 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 7352920657 for ; Sun, 19 May 2019 17:46:33 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="I4TkRwAT" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728123AbfESRqc (ORCPT ); Sun, 19 May 2019 13:46:32 -0400 Received: from mail-pl1-f195.google.com ([209.85.214.195]:43824 "EHLO mail-pl1-f195.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727444AbfESRqc (ORCPT ); Sun, 19 May 2019 13:46:32 -0400 Received: by mail-pl1-f195.google.com with SMTP id gn7so1451796plb.10 for ; Sun, 19 May 2019 10:46:32 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=from:to:cc:subject:date:message-id; bh=siH0h08bo+poMfukgf+UGGSFOKy0KYXUk3xeaWxbyWE=; b=I4TkRwAT64red0QDk3HQlz4iknuK2VcaB3gY746KtgtKKeEIukghgr6mLLkx2yAGdq KiqZX7dJH3xObqbNjO0NEwfoQfSF5M9uWK5pSmpYwHm1wMt+PQOx0PAtfTlNYY5fhdRA vIdtrXLJcvkyAI88hfyaLPjvZw3v8gWM0qMoRnTi8+oJk7yR2c2AL7Ii4uHrRJZrFMfs oIWUQl8HmVA9hHIkshQSkaEr29CNKraPopZTslvZtrPdIJwGwMtzOQnwLznf5Jv4033a mjqVMxrqQfYR/Ob0X3R90t+6keAmUIRpT+qDkFGe5HmXqr70UZd4AT+bj43cRvbefS5+ TjKQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id; bh=siH0h08bo+poMfukgf+UGGSFOKy0KYXUk3xeaWxbyWE=; b=mIlv9HO4OeRFCevi0DeiY/994WAUCk3XHvyH7p77U7qCE2wHKVcYtJSfTJ95TDokgB pHgmIsEpOklsW3sjE1EQBFUC3IVDa3nX5g4svssf+l4QPwoyobnLtk7vzYfK9RTWB5O1 NVar0+HZCEh1lesLIofV1nc4a5bfU3KMedevsro2sX3W2QWtib2xNFGUKW535f7HcMGQ OnaqdscbgkfHPR+lrXua5rJt6KIQ8rKnhUyemcc7V9AAAppZd/j6i59usVMzqMIopa+h GOO9efdBKMYNMpC5tYroE4ZyWcfX/tbf9H48Aem7Hk2l/gKW1ipVpzn+HI5RonKJkXjE MGUA== X-Gm-Message-State: APjAAAXMkt4k2YDogS1Fb/pcsnadKSYaS/VXjfVwHWJzrnl4oOHRuLTb 97F5NiAofe0iQNcvV5fCM4soDRQ3Dmc= X-Google-Smtp-Source: APXvYqw/xuSSVEMCdtHOfEIrw3lwtN0X44TShs9bJNA7LDieetozQN6K8S9mmoW3H9VqF3p0A1isVQ== X-Received: by 2002:a17:902:e60a:: with SMTP id cm10mr60970246plb.316.1558256838378; Sun, 19 May 2019 02:07:18 -0700 (PDT) Received: from localhost.localdomain (220-135-242-219.HINET-IP.hinet.net. [220.135.242.219]) by smtp.googlemail.com with ESMTPSA id u134sm21544917pfc.61.2019.05.19.02.07.16 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Sun, 19 May 2019 02:07:17 -0700 (PDT) From: Chang-Hsien Tsai To: netdev@vger.kernel.org Cc: ast@kernel.org, daniel@iogearbox.net, kafai@fb.com, songliubraving@fb.com, yhs@fb.com, luke.tw@gmail.com Subject: [PATCH] samples: bpf: fix: change the buffer size for read() Date: Sun, 19 May 2019 09:05:44 +0000 Message-Id: <20190519090544.26971-1-luke.tw@gmail.com> X-Mailer: git-send-email 2.17.1 Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org 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 --- 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..d4da90070b58 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); -- 2.17.1