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=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 D54CFC48BD6 for ; Thu, 27 Jun 2019 00:44:07 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id A2BA6208E3 for ; Thu, 27 Jun 2019 00:44:07 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1561596247; bh=gvVSKaqZrybsWTI5v1Ft2O1Gzqx5r/tj7z0gtcZMpDY=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=XerTYFbCdJ2RNz8/rdKph0x3m5+z7dU6+PsfxxCWqQpMwSTGsTqmjAqtvdmWi8D1D Ix2olSkpY9u0uHJiG5gVpwaAkriKzf7Is2pXR6hYyxZc8PFB6pCHiFJGBSVyiNxKXv JkXuRzhZqQZOomiCtHr81T6b48kLIV5VVrc8CAXw= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729776AbfF0Amp (ORCPT ); Wed, 26 Jun 2019 20:42:45 -0400 Received: from mail.kernel.org ([198.145.29.99]:46566 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727621AbfF0Amo (ORCPT ); Wed, 26 Jun 2019 20:42:44 -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 1124F21871; Thu, 27 Jun 2019 00:42:41 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1561596164; bh=gvVSKaqZrybsWTI5v1Ft2O1Gzqx5r/tj7z0gtcZMpDY=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=yiRQ21FHSIdViRnVJPAzmzQXEPNMbO/E2voEQK3fQiUmGPiaGA9Ic+P5JPrQ4MN4N RgBiu+n4i9Wc/1hLyDuICDCw92L6bWgLfAXXvf73zvgUodZv8dp9miVa18XisaEYy7 chEenH9tziKJINuZkQy8E0O+bu5OAVaMvTf0JisM= 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 4.4 02/12] samples, bpf: fix to change the buffer size for read() Date: Wed, 26 Jun 2019 20:42:24 -0400 Message-Id: <20190627004236.21909-2-sashal@kernel.org> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20190627004236.21909-1-sashal@kernel.org> References: <20190627004236.21909-1-sashal@kernel.org> MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit Sender: bpf-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: bpf@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 da86a8e0a95a..e836b5ff2060 100644 --- a/samples/bpf/bpf_load.c +++ b/samples/bpf/bpf_load.c @@ -336,7 +336,7 @@ 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