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=-15.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,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 09116C433DB for ; Sun, 24 Jan 2021 15:13:53 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id D640C22DD6 for ; Sun, 24 Jan 2021 15:13:52 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726298AbhAXPN1 (ORCPT ); Sun, 24 Jan 2021 10:13:27 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:56506 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726302AbhAXPM2 (ORCPT ); Sun, 24 Jan 2021 10:12:28 -0500 Received: from mail-wr1-x42e.google.com (mail-wr1-x42e.google.com [IPv6:2a00:1450:4864:20::42e]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id C9B9BC0613ED for ; Sun, 24 Jan 2021 07:11:47 -0800 (PST) Received: by mail-wr1-x42e.google.com with SMTP id g10so9770790wrx.1 for ; Sun, 24 Jan 2021 07:11:47 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=from:to:cc:subject:date:message-id:mime-version :content-transfer-encoding; bh=2dH/AnIKGD78Wvb6nm+25r2o7zcq5zifnjOd4aJrWHE=; b=YqrDGUDZ3rZ+FcKB4zeOdI1c3beQPed6Y+1jvRl45tH+tTIuSDRm3PuPv4wI7I04B7 FY0XFvp5djmJlIXLs+sj36fmDzQHpn4KfrWC7HSS4IJGwWHTIYz1Y+aTV0b3SHClmqer 6UjLIqLTprQRpdoXWFfjE2uWeb8FHBkeyTj6emm3v8KVLFgGT+fEdVEOhMT+GuphfkkU Pj0+P3L36LHjTphLvoDRhdL1yobJMaNlidx7St+JIkVpOrWraVX11HvPj4V7B2gdy+J5 7irtEEIr6LoHWXfyz9cjS9TNfu2iDqbaQ3wZWJco07xxhxPvkDRH0NY6gJCGxrb27crr a5zg== 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:mime-version :content-transfer-encoding; bh=2dH/AnIKGD78Wvb6nm+25r2o7zcq5zifnjOd4aJrWHE=; b=Q7UyCVQm6O5FvZze3og5IhoSeApGJwuzTv6iY6+gYiiZ4fSGxU6r8ac+B2sbaCvW4O woTIEJKFjua40SbLU/WDhnDSUaHNkTGHqQzyABNACxOuZRG25IaD7+19C1XtHtoWrKEr PYKk4BnCyLpSAcXcQsfgFeoywB6vqZlPm/hoiJySP5Dd59GOQ2/0erti5pW9899catIx 6KZtjPecn6enl1SrW3f7ZrycERu5oXX3tz2/G7RhQin3+IUH3euCz6ER5gFoP/D7iaKp Fi8LIDlLaer1o1HX6Z2DyI7WH/WaC+upg4/vwQ7W3ZifBpEFL23VwsoA9bDAobU42kOF z+ig== X-Gm-Message-State: AOAM530XWKnhiXkTyP8DPKH6x6C6KkuikalqkzXTnuwX/eog9mE+GEYI 1eUBxXZCpKA5hAAtvViLGJk= X-Google-Smtp-Source: ABdhPJxoxSNre+i6iQQB1sHDLkfWMOx7j/h8WQNH3IERQmFSohdC5J6Ea774OR6JhAB0DX7t4q0qDw== X-Received: by 2002:a5d:5051:: with SMTP id h17mr1000765wrt.164.1611501106619; Sun, 24 Jan 2021 07:11:46 -0800 (PST) Received: from debian.vlc ([170.253.51.130]) by smtp.gmail.com with ESMTPSA id j2sm18480099wrh.78.2021.01.24.07.11.45 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sun, 24 Jan 2021 07:11:46 -0800 (PST) From: Alejandro Colomar To: mtk.manpages@gmail.com Cc: linux-man@vger.kernel.org, =?UTF-8?q?Pali=20Roh=C3=A1r?= , Alejandro Colomar Subject: [PATCH] sock_diag.7: Fix recvmsg() usage in the example Date: Sun, 24 Jan 2021 16:10:39 +0100 Message-Id: <20210124151035.70536-6-alx.manpages@gmail.com> X-Mailer: git-send-email 2.30.0 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-man@vger.kernel.org From: Pali Rohár The msg_name field for recvmsg() call points to a caller-allocated buffer nladdr that is used to return the source address of the (netlink) socket. As recvmsg() does not read this buffer and fills it for a caller, do not initialize it and instead check its value in the example. Signed-off-by: Pali Rohár Signed-off-by: Alejandro Colomar --- man7/sock_diag.7 | 9 ++++++--- 1 file changed, 6 insertions(+), 3 deletions(-) diff --git a/man7/sock_diag.7 b/man7/sock_diag.7 index b732b2571..569106dd6 100644 --- a/man7/sock_diag.7 +++ b/man7/sock_diag.7 @@ -753,9 +753,7 @@ static int receive_responses(int fd) { long buf[8192 / sizeof(long)]; - struct sockaddr_nl nladdr = { - .nl_family = AF_NETLINK - }; + struct sockaddr_nl nladdr; struct iovec iov = { .iov_base = buf, .iov_len = sizeof(buf) @@ -782,6 +780,11 @@ receive_responses(int fd) if (ret == 0) return 0; + if (nladdr.nl_family != AF_NETLINK) { + fputs("!AF_NETLINK\en", stderr); + return \-1; + } + const struct nlmsghdr *h = (struct nlmsghdr *) buf; if (!NLMSG_OK(h, ret)) { -- 2.30.0