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=-14.3 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, 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 E636FC43468 for ; Mon, 21 Sep 2020 14:37:17 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id AFB2722574 for ; Mon, 21 Sep 2020 14:37:17 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=arista.com header.i=@arista.com header.b="Q001+qfE" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727937AbgIUOhQ (ORCPT ); Mon, 21 Sep 2020 10:37:16 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:42644 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727294AbgIUOhO (ORCPT ); Mon, 21 Sep 2020 10:37:14 -0400 Received: from mail-wr1-x443.google.com (mail-wr1-x443.google.com [IPv6:2a00:1450:4864:20::443]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 98344C0613D3 for ; Mon, 21 Sep 2020 07:37:12 -0700 (PDT) Received: by mail-wr1-x443.google.com with SMTP id j2so13030685wrx.7 for ; Mon, 21 Sep 2020 07:37:12 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=arista.com; s=googlenew; h=from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=/qlLBmSLkXX8+VWho1l+4lvAqtyGS8XDHRWiRzbfdT0=; b=Q001+qfEfU11Y7UoINCguwe49yZ95OIa3Dtvsd2N+mQGKjbZp+DAbLebQLXtUGBb49 enuj+gcu0OkBdDGQJ83p0ylqjAoQOtC/YfSYOoQA3hD3KR37inUKZgW8tGJWT8yk+VeX q377TB41SenHuTgpNx44CFEnjNNqF3DzJpmwdl/7cr97Q33RBA3029gMF/qVl+LMNghR JGLjS0g1/v/YW3C3qHy4zL3LY80S9K/SbwQKNGYq1AIfUMMa/NtA/MiE+TlpDoS+N8/U vkeXJegOlczyOceUflvCrMaXksoMhSHVXE+n8PFYRn5FR0bNPWcl2W2vkHGTtS1/yvZV LhRg== 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:in-reply-to :references:mime-version:content-transfer-encoding; bh=/qlLBmSLkXX8+VWho1l+4lvAqtyGS8XDHRWiRzbfdT0=; b=X2nlvpmJGeZRgupRTueXPpVS6eHEOVBPklXQjfAso7Car9utQcRrqp4aqm7v649Omt PAXejy40xFZw9aiiwUtl/ta9KszpDSN6r7egM7qk8APy74xwunMPUY/VdPVdLxuMNcx2 pwQqTvf+0d5UyO0r8VmFWIgtsMO3Iwo9p8QpuVDyGpNMypE3GkaJHySiIOnSKuyXwgqr PwVVzIv6IgEGaWnTnySfC3ecW5STo30a9BEQWQtbc+N+mVMPVYHGeBK36c7sqbhG/30Z Oi5Tuadir5fFITuKN1UxeDX9g5/pXIaQJrcz08A0/Mo81IAFFuF97aNtTjMvOzcU8afW 87TQ== X-Gm-Message-State: AOAM531Qv7L4DqHbC3rOG7HOx60UyseY/p4AQBlMF0NIl/IGEX0A2F5T qqelTz32P4YOLWfgzxsOw4rzwn5nb2ciWQ== X-Google-Smtp-Source: ABdhPJyeDwt3llJ1iiPKlXmXG5HaT72EzX6BpOjM8GwSM6TDgvyQwVjapGSKAZO2Up1n/3L5Hn4W4w== X-Received: by 2002:a5d:4d51:: with SMTP id a17mr96505wru.248.1600699031023; Mon, 21 Sep 2020 07:37:11 -0700 (PDT) Received: from localhost.localdomain ([2a02:8084:e84:2480:228:f8ff:fe6f:83a8]) by smtp.gmail.com with ESMTPSA id c14sm20370753wrv.12.2020.09.21.07.37.09 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 21 Sep 2020 07:37:10 -0700 (PDT) From: Dmitry Safonov To: linux-kernel@vger.kernel.org Cc: Dmitry Safonov <0x7f454c46@gmail.com>, Dmitry Safonov , "David S. Miller" , Florian Westphal , Herbert Xu , Jakub Kicinski , Johannes Berg , Steffen Klassert , Stephen Suryaputra , netdev@vger.kernel.org Subject: [PATCH v3 4/7] netlink/compat: Append NLMSG_DONE/extack to frag_list Date: Mon, 21 Sep 2020 15:36:54 +0100 Message-Id: <20200921143657.604020-5-dima@arista.com> X-Mailer: git-send-email 2.28.0 In-Reply-To: <20200921143657.604020-1-dima@arista.com> References: <20200921143657.604020-1-dima@arista.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Modules those use netlink may supply a 2nd skb, (via frag_list) that contains an alternative data set meant for applications using 32bit compatibility mode. In such a case, netlink_recvmsg will use this 2nd skb instead of the original one. Without this patch, such compat applications will retrieve all netlink dump data, but will then get an unexpected EOF. Cc: Johannes Berg Signed-off-by: Florian Westphal Signed-off-by: Dmitry Safonov Reviewed-by: Johannes Berg --- net/netlink/af_netlink.c | 47 ++++++++++++++++++++++++++++------------ 1 file changed, 33 insertions(+), 14 deletions(-) diff --git a/net/netlink/af_netlink.c b/net/netlink/af_netlink.c index d2d1448274f5..de12dd3136f9 100644 --- a/net/netlink/af_netlink.c +++ b/net/netlink/af_netlink.c @@ -2186,13 +2186,35 @@ EXPORT_SYMBOL(__nlmsg_put); * It would be better to create kernel thread. */ +static int netlink_dump_done(struct netlink_sock *nlk, struct sk_buff *skb, + struct netlink_callback *cb, + struct netlink_ext_ack *extack) +{ + struct nlmsghdr *nlh; + + nlh = nlmsg_put_answer(skb, cb, NLMSG_DONE, sizeof(nlk->dump_done_errno), + NLM_F_MULTI | cb->answer_flags); + if (WARN_ON(!nlh)) + return -ENOBUFS; + + nl_dump_check_consistent(cb, nlh); + memcpy(nlmsg_data(nlh), &nlk->dump_done_errno, sizeof(nlk->dump_done_errno)); + + if (extack->_msg && nlk->flags & NETLINK_F_EXT_ACK) { + nlh->nlmsg_flags |= NLM_F_ACK_TLVS; + if (!nla_put_string(skb, NLMSGERR_ATTR_MSG, extack->_msg)) + nlmsg_end(skb, nlh); + } + + return 0; +} + static int netlink_dump(struct sock *sk) { struct netlink_sock *nlk = nlk_sk(sk); struct netlink_ext_ack extack = {}; struct netlink_callback *cb; struct sk_buff *skb = NULL; - struct nlmsghdr *nlh; struct module *module; int err = -ENOBUFS; int alloc_min_size; @@ -2258,22 +2280,19 @@ static int netlink_dump(struct sock *sk) return 0; } - nlh = nlmsg_put_answer(skb, cb, NLMSG_DONE, - sizeof(nlk->dump_done_errno), - NLM_F_MULTI | cb->answer_flags); - if (WARN_ON(!nlh)) + if (netlink_dump_done(nlk, skb, cb, &extack)) goto errout_skb; - nl_dump_check_consistent(cb, nlh); - - memcpy(nlmsg_data(nlh), &nlk->dump_done_errno, - sizeof(nlk->dump_done_errno)); - - if (extack._msg && nlk->flags & NETLINK_F_EXT_ACK) { - nlh->nlmsg_flags |= NLM_F_ACK_TLVS; - if (!nla_put_string(skb, NLMSGERR_ATTR_MSG, extack._msg)) - nlmsg_end(skb, nlh); +#ifdef CONFIG_COMPAT_NETLINK_MESSAGES + /* frag_list skb's data is used for compat tasks + * and the regular skb's data for normal (non-compat) tasks. + * See netlink_recvmsg(). + */ + if (unlikely(skb_shinfo(skb)->frag_list)) { + if (netlink_dump_done(nlk, skb_shinfo(skb)->frag_list, cb, &extack)) + goto errout_skb; } +#endif if (sk_filter(sk, skb)) kfree_skb(skb); -- 2.28.0