From patchwork Sat Mar 6 12:12:20 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Pablo Neira Ayuso X-Patchwork-Id: 394843 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=-16.7 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI, 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 6DDABC43333 for ; Sat, 6 Mar 2021 12:13:22 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 4DF906501D for ; Sat, 6 Mar 2021 12:13:22 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230492AbhCFMMw (ORCPT ); Sat, 6 Mar 2021 07:12:52 -0500 Received: from correo.us.es ([193.147.175.20]:46382 "EHLO mail.us.es" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230426AbhCFMMk (ORCPT ); Sat, 6 Mar 2021 07:12:40 -0500 Received: from antivirus1-rhel7.int (unknown [192.168.2.11]) by mail.us.es (Postfix) with ESMTP id AC288C517F for ; Sat, 6 Mar 2021 13:12:33 +0100 (CET) Received: from antivirus1-rhel7.int (localhost [127.0.0.1]) by antivirus1-rhel7.int (Postfix) with ESMTP id 9542ADA791 for ; Sat, 6 Mar 2021 13:12:33 +0100 (CET) Received: by antivirus1-rhel7.int (Postfix, from userid 99) id 8A6A7DA78C; Sat, 6 Mar 2021 13:12:33 +0100 (CET) Received: from antivirus1-rhel7.int (localhost [127.0.0.1]) by antivirus1-rhel7.int (Postfix) with ESMTP id 2DC99DA73F; Sat, 6 Mar 2021 13:12:31 +0100 (CET) Received: from 192.168.1.97 (192.168.1.97) by antivirus1-rhel7.int (F-Secure/fsigk_smtp/550/antivirus1-rhel7.int); Sat, 06 Mar 2021 13:12:31 +0100 (CET) X-Virus-Status: clean(F-Secure/fsigk_smtp/550/antivirus1-rhel7.int) Received: from localhost.localdomain (unknown [90.77.255.23]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) (Authenticated sender: pneira@us.es) by entrada.int (Postfix) with ESMTPSA id 04D2642DC6E2; Sat, 6 Mar 2021 13:12:30 +0100 (CET) X-SMTPAUTHUS: auth mail.us.es From: Pablo Neira Ayuso To: netfilter-devel@vger.kernel.org Cc: davem@davemloft.net, netdev@vger.kernel.org, kuba@kernel.org Subject: [PATCH net 6/9] netfilter: x_tables: gpf inside xt_find_revision() Date: Sat, 6 Mar 2021 13:12:20 +0100 Message-Id: <20210306121223.28711-7-pablo@netfilter.org> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20210306121223.28711-1-pablo@netfilter.org> References: <20210306121223.28711-1-pablo@netfilter.org> MIME-Version: 1.0 X-Virus-Scanned: ClamAV using ClamSMTP Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org From: Vasily Averin nested target/match_revfn() calls work with xt[NFPROTO_UNSPEC] lists without taking xt[NFPROTO_UNSPEC].mutex. This can race with module unload and cause host to crash: general protection fault: 0000 [#1] Modules linked in: ... [last unloaded: xt_cluster] CPU: 0 PID: 542455 Comm: iptables RIP: 0010:[] [] strcmp+0x18/0x40 RDX: 0000000000000003 RSI: ffff9a5a5d9abe10 RDI: dead000000000111 R13: ffff9a5a5d9abe10 R14: ffff9a5a5d9abd8c R15: dead000000000100 (VvS: %R15 -- &xt_match, %RDI -- &xt_match.name, xt_cluster unregister match in xt[NFPROTO_UNSPEC].match list) Call Trace: [] match_revfn+0x54/0xc0 [] match_revfn+0xaf/0xc0 [] xt_find_revision+0x6e/0xf0 [] do_ipt_get_ctl+0x100/0x420 [ip_tables] [] nf_getsockopt+0x4f/0x70 [] ip_getsockopt+0xde/0x100 [] raw_getsockopt+0x25/0x50 [] sock_common_getsockopt+0x1a/0x20 [] SyS_getsockopt+0x7d/0xf0 [] system_call_fastpath+0x25/0x2a Fixes: 656caff20e1 ("netfilter 04/09: x_tables: fix match/target revision lookup") Signed-off-by: Vasily Averin Reviewed-by: Florian Westphal Signed-off-by: Pablo Neira Ayuso --- net/netfilter/x_tables.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) diff --git a/net/netfilter/x_tables.c b/net/netfilter/x_tables.c index acce622582e3..bce6ca203d46 100644 --- a/net/netfilter/x_tables.c +++ b/net/netfilter/x_tables.c @@ -330,6 +330,7 @@ static int match_revfn(u8 af, const char *name, u8 revision, int *bestp) const struct xt_match *m; int have_rev = 0; + mutex_lock(&xt[af].mutex); list_for_each_entry(m, &xt[af].match, list) { if (strcmp(m->name, name) == 0) { if (m->revision > *bestp) @@ -338,6 +339,7 @@ static int match_revfn(u8 af, const char *name, u8 revision, int *bestp) have_rev = 1; } } + mutex_unlock(&xt[af].mutex); if (af != NFPROTO_UNSPEC && !have_rev) return match_revfn(NFPROTO_UNSPEC, name, revision, bestp); @@ -350,6 +352,7 @@ static int target_revfn(u8 af, const char *name, u8 revision, int *bestp) const struct xt_target *t; int have_rev = 0; + mutex_lock(&xt[af].mutex); list_for_each_entry(t, &xt[af].target, list) { if (strcmp(t->name, name) == 0) { if (t->revision > *bestp) @@ -358,6 +361,7 @@ static int target_revfn(u8 af, const char *name, u8 revision, int *bestp) have_rev = 1; } } + mutex_unlock(&xt[af].mutex); if (af != NFPROTO_UNSPEC && !have_rev) return target_revfn(NFPROTO_UNSPEC, name, revision, bestp); @@ -371,12 +375,10 @@ int xt_find_revision(u8 af, const char *name, u8 revision, int target, { int have_rev, best = -1; - mutex_lock(&xt[af].mutex); if (target == 1) have_rev = target_revfn(af, name, revision, &best); else have_rev = match_revfn(af, name, revision, &best); - mutex_unlock(&xt[af].mutex); /* Nothing at all? Return 0 to try loading module. */ if (best == -1) {