From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Google-Smtp-Source: AB8JxZqqTQ6lGA9PMJadkJ50MisstNUBWEwBZYhKXsKnTjALG6HRHIsLNmq/hoLAPPn/PaF4CKr9 ARC-Seal: i=1; a=rsa-sha256; t=1526937793; cv=none; d=google.com; s=arc-20160816; b=O+tBZVPnnb4G63PrZQoXGLS1O8qHeXP04/1IfN6Ym0CQlv++dP2vWJSWVHTCZcwfeo YTEViiaVeDK/fk/FXJ7b9iLDjO1S8s1epRdWoH5w6+sFEbAl0oEAWxZfV9fwR2llHLQO crV0p/W/0HqzjU7bR8HewHtLRQyGEhlDuQMGzt7B2AY6AsTXGWoUormqqhNeY6ZhkNdZ vBg2Dtttwox+WeL6affiecckqW2HrEm0aW3PWFtfHSo+GFpUWQOLolr85yQTxi70RM0J x3BgRd21qmraYCk93U0hEWKBtswAiWNQR83velV8WaoaGVCCDHNefzjFRhrkzKW64xpC nxcA== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=mime-version:user-agent:references:in-reply-to:message-id:date :subject:cc:to:from:dkim-signature:arc-authentication-results; bh=Hcfngx9tZnH1LObmjBzXhmBfL9MFVo3Tjmji5wEhG9c=; b=b1glTPMgnML08koT/eTDjVZ/WMti/SVGmvV8ajhC7Xz9GDF7+MfSTZ+Qg/rR0wUtTn OYVrN6dvl/Of87q6cAPzY7TFvLtS8sVlYJAXhQO9ixrO0glK0OA3Co41U5m8CMNuloL/ OFDk/GLMErMTHP6Hf6RplNFs+oUuWOZIYBJ1QDZWgxIwoeKH9iweM1tyb/Z8aDLpSMMx sVPeo9XyRNJjKaboOkZXksgn3TuO7w7lCdT55D+C0rtF6nO95oNhvBfvrQWgyK9qXBz6 /3HFbAPwg22UmDXARuokShibOqXL7mM9au03F171sCwS6Uyj1tK0EXl8yg8ACZFjSvWC KqTA== ARC-Authentication-Results: i=1; mx.google.com; dkim=pass header.i=@kernel.org header.s=default header.b=l+QxA2zU; spf=pass (google.com: domain of srs0=nia/=ii=linuxfoundation.org=gregkh@kernel.org designates 198.145.29.99 as permitted sender) smtp.mailfrom=SRS0=nia/=II=linuxfoundation.org=gregkh@kernel.org Authentication-Results: mx.google.com; dkim=pass header.i=@kernel.org header.s=default header.b=l+QxA2zU; spf=pass (google.com: domain of srs0=nia/=ii=linuxfoundation.org=gregkh@kernel.org designates 198.145.29.99 as permitted sender) smtp.mailfrom=SRS0=nia/=II=linuxfoundation.org=gregkh@kernel.org From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Florian Westphal , Pablo Neira Ayuso Subject: [PATCH 4.16 027/110] netfilter: nf_tables: cant fail after linking rule into active rule list Date: Mon, 21 May 2018 23:11:24 +0200 Message-Id: <20180521210506.224261442@linuxfoundation.org> X-Mailer: git-send-email 2.17.0 In-Reply-To: <20180521210503.823249477@linuxfoundation.org> References: <20180521210503.823249477@linuxfoundation.org> User-Agent: quilt/0.65 X-stable: review MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 X-getmail-retrieved-from-mailbox: INBOX X-GMAIL-LABELS: =?utf-8?b?IlxcU2VudCI=?= X-GMAIL-THRID: =?utf-8?q?1601109783674177294?= X-GMAIL-MSGID: =?utf-8?q?1601110324250909582?= X-Mailing-List: linux-kernel@vger.kernel.org List-ID: 4.16-stable review patch. If anyone has any objections, please let me know. ------------------ From: Florian Westphal commit 569ccae68b38654f04b6842b034aa33857f605fe upstream. rules in nftables a free'd using kfree, but protected by rcu, i.e. we must wait for a grace period to elapse. Normal removal patch does this, but nf_tables_newrule() doesn't obey this rule during error handling. It calls nft_trans_rule_add() *after* linking rule, and, if that fails to allocate memory, it unlinks the rule and then kfree() it -- this is unsafe. Switch order -- first add rule to transaction list, THEN link it to public list. Note: nft_trans_rule_add() uses GFP_KERNEL; it will not fail so this is not a problem in practice (spotted only during code review). Fixes: 0628b123c96d12 ("netfilter: nfnetlink: add batch support and use it from nf_tables") Signed-off-by: Florian Westphal Signed-off-by: Pablo Neira Ayuso Signed-off-by: Greg Kroah-Hartman --- net/netfilter/nf_tables_api.c | 59 ++++++++++++++++++++++-------------------- 1 file changed, 32 insertions(+), 27 deletions(-) --- a/net/netfilter/nf_tables_api.c +++ b/net/netfilter/nf_tables_api.c @@ -2357,41 +2357,46 @@ static int nf_tables_newrule(struct net } if (nlh->nlmsg_flags & NLM_F_REPLACE) { - if (nft_is_active_next(net, old_rule)) { - trans = nft_trans_rule_add(&ctx, NFT_MSG_DELRULE, - old_rule); - if (trans == NULL) { - err = -ENOMEM; - goto err2; - } - nft_deactivate_next(net, old_rule); - chain->use--; - list_add_tail_rcu(&rule->list, &old_rule->list); - } else { + if (!nft_is_active_next(net, old_rule)) { err = -ENOENT; goto err2; } - } else if (nlh->nlmsg_flags & NLM_F_APPEND) - if (old_rule) - list_add_rcu(&rule->list, &old_rule->list); - else - list_add_tail_rcu(&rule->list, &chain->rules); - else { - if (old_rule) - list_add_tail_rcu(&rule->list, &old_rule->list); - else - list_add_rcu(&rule->list, &chain->rules); - } + trans = nft_trans_rule_add(&ctx, NFT_MSG_DELRULE, + old_rule); + if (trans == NULL) { + err = -ENOMEM; + goto err2; + } + nft_deactivate_next(net, old_rule); + chain->use--; + + if (nft_trans_rule_add(&ctx, NFT_MSG_NEWRULE, rule) == NULL) { + err = -ENOMEM; + goto err2; + } - if (nft_trans_rule_add(&ctx, NFT_MSG_NEWRULE, rule) == NULL) { - err = -ENOMEM; - goto err3; + list_add_tail_rcu(&rule->list, &old_rule->list); + } else { + if (nft_trans_rule_add(&ctx, NFT_MSG_NEWRULE, rule) == NULL) { + err = -ENOMEM; + goto err2; + } + + if (nlh->nlmsg_flags & NLM_F_APPEND) { + if (old_rule) + list_add_rcu(&rule->list, &old_rule->list); + else + list_add_tail_rcu(&rule->list, &chain->rules); + } else { + if (old_rule) + list_add_tail_rcu(&rule->list, &old_rule->list); + else + list_add_rcu(&rule->list, &chain->rules); + } } chain->use++; return 0; -err3: - list_del_rcu(&rule->list); err2: nf_tables_rule_destroy(&ctx, rule); err1: