From patchwork Wed May 18 04:39:44 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Thadeu Lima de Souza Cascardo X-Patchwork-Id: 1632612 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Authentication-Results: bilbo.ozlabs.org; dkim=fail reason="signature verification failed" (2048-bit key; unprotected) header.d=canonical.com header.i=@canonical.com header.a=rsa-sha256 header.s=20210705 header.b=I9no05ZL; dkim-atps=neutral Authentication-Results: ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=lists.ubuntu.com (client-ip=91.189.94.19; helo=huckleberry.canonical.com; envelope-from=kernel-team-bounces@lists.ubuntu.com; receiver=) Received: from huckleberry.canonical.com (huckleberry.canonical.com [91.189.94.19]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by bilbo.ozlabs.org (Postfix) with ESMTPS id 4L30gH0WG6z9s2R for ; Wed, 18 May 2022 14:41:15 +1000 (AEST) Received: from localhost ([127.0.0.1] helo=huckleberry.canonical.com) by huckleberry.canonical.com with esmtp (Exim 4.86_2) (envelope-from ) id 1nrBUk-0007qY-98; Wed, 18 May 2022 04:41:10 +0000 Received: from smtp-relay-canonical-1.internal ([10.131.114.174] helo=smtp-relay-canonical-1.canonical.com) by huckleberry.canonical.com with esmtps (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.86_2) (envelope-from ) id 1nrBUi-0007or-7o for kernel-team@lists.ubuntu.com; Wed, 18 May 2022 04:41:08 +0000 Received: from localhost.localdomain (1.general.cascardo.us.vpn [10.172.70.58]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by smtp-relay-canonical-1.canonical.com (Postfix) with ESMTPSA id 0EF39418EE for ; Wed, 18 May 2022 04:41:06 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=canonical.com; s=20210705; t=1652848868; bh=5LCoGOypgxQ6ZUpF8B2nS/d7FGPacgjit8Mz8KVAEDU=; h=From:To:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version; b=I9no05ZLhPl8VTrQEaMN03/ARgvJNQTtnY/6X7GbmnqWnMfMJoDo0/mkfr6cqJ2Yb 4+T7fNdOuPvh37COwd65CXvDRtKlXKZfmfVO8DZJhIiQHvvCTtXVYHR3G6ViSCSjFR GNa/7IM9TnyVnKNIQEy5SOfJ3pF7Xy6axfTJ9RBoMv8bT2LhKcIIAv7aPD3aA64SHk x3m2vfhPXDCMSCt7/+6UbziW0y11o0EyTbUITIyeMe6O5wHqbXdupyJ4+tbUYrtBFq tPVP2DWUvr8MKZZClM9okwkuudI2N09DiJpQ1zXsPzRF8N2luPqf/dvLLm3FWv8lQ9 Se7jGrKfm4y9g== From: Thadeu Lima de Souza Cascardo To: kernel-team@lists.ubuntu.com Subject: [SRU Jammy] net/sched: cls_u32: fix netns refcount changes in u32_change() Date: Wed, 18 May 2022 01:39:44 -0300 Message-Id: <20220518043945.1089944-4-cascardo@canonical.com> X-Mailer: git-send-email 2.32.0 In-Reply-To: <20220518043945.1089944-1-cascardo@canonical.com> References: <20220518043945.1089944-1-cascardo@canonical.com> MIME-Version: 1.0 X-BeenThere: kernel-team@lists.ubuntu.com X-Mailman-Version: 2.1.20 Precedence: list List-Id: Kernel team discussions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: kernel-team-bounces@lists.ubuntu.com Sender: "kernel-team" From: Eric Dumazet We are now able to detect extra put_net() at the moment they happen, instead of much later in correct code paths. u32_init_knode() / tcf_exts_init() populates the ->exts.net pointer, but as mentioned in tcf_exts_init(), the refcount on netns has not been elevated yet. The refcount is taken only once tcf_exts_get_net() is called. So the two u32_destroy_key() calls from u32_change() are attempting to release an invalid reference on the netns. syzbot report: refcount_t: decrement hit 0; leaking memory. WARNING: CPU: 0 PID: 21708 at lib/refcount.c:31 refcount_warn_saturate+0xbf/0x1e0 lib/refcount.c:31 Modules linked in: CPU: 0 PID: 21708 Comm: syz-executor.5 Not tainted 5.18.0-rc2-next-20220412-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 RIP: 0010:refcount_warn_saturate+0xbf/0x1e0 lib/refcount.c:31 Code: 1d 14 b6 b2 09 31 ff 89 de e8 6d e9 89 fd 84 db 75 e0 e8 84 e5 89 fd 48 c7 c7 40 aa 26 8a c6 05 f4 b5 b2 09 01 e8 e5 81 2e 05 <0f> 0b eb c4 e8 68 e5 89 fd 0f b6 1d e3 b5 b2 09 31 ff 89 de e8 38 RSP: 0018:ffffc900051af1b0 EFLAGS: 00010286 RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000000 RDX: 0000000000040000 RSI: ffffffff8160a0c8 RDI: fffff52000a35e28 RBP: 0000000000000004 R08: 0000000000000000 R09: 0000000000000000 R10: ffffffff81604a9e R11: 0000000000000000 R12: 1ffff92000a35e3b R13: 00000000ffffffef R14: ffff8880211a0194 R15: ffff8880577d0a00 FS: 00007f25d183e700(0000) GS:ffff8880b9c00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f19c859c028 CR3: 0000000051009000 CR4: 00000000003506f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: __refcount_dec include/linux/refcount.h:344 [inline] refcount_dec include/linux/refcount.h:359 [inline] ref_tracker_free+0x535/0x6b0 lib/ref_tracker.c:118 netns_tracker_free include/net/net_namespace.h:327 [inline] put_net_track include/net/net_namespace.h:341 [inline] tcf_exts_put_net include/net/pkt_cls.h:255 [inline] u32_destroy_key.isra.0+0xa7/0x2b0 net/sched/cls_u32.c:394 u32_change+0xe01/0x3140 net/sched/cls_u32.c:909 tc_new_tfilter+0x98d/0x2200 net/sched/cls_api.c:2148 rtnetlink_rcv_msg+0x80d/0xb80 net/core/rtnetlink.c:6016 netlink_rcv_skb+0x153/0x420 net/netlink/af_netlink.c:2495 netlink_unicast_kernel net/netlink/af_netlink.c:1319 [inline] netlink_unicast+0x543/0x7f0 net/netlink/af_netlink.c:1345 netlink_sendmsg+0x904/0xe00 net/netlink/af_netlink.c:1921 sock_sendmsg_nosec net/socket.c:705 [inline] sock_sendmsg+0xcf/0x120 net/socket.c:725 ____sys_sendmsg+0x6e2/0x800 net/socket.c:2413 ___sys_sendmsg+0xf3/0x170 net/socket.c:2467 __sys_sendmsg+0xe5/0x1b0 net/socket.c:2496 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x44/0xae RIP: 0033:0x7f25d0689049 Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 b8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007f25d183e168 EFLAGS: 00000246 ORIG_RAX: 000000000000002e RAX: ffffffffffffffda RBX: 00007f25d079c030 RCX: 00007f25d0689049 RDX: 0000000000000000 RSI: 0000000020000340 RDI: 0000000000000005 RBP: 00007f25d06e308d R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007ffd0b752e3f R14: 00007f25d183e300 R15: 0000000000022000 Fixes: 35c55fc156d8 ("cls_u32: use tcf_exts_get_net() before call_rcu()") Signed-off-by: Eric Dumazet Reported-by: syzbot Cc: Cong Wang Cc: Jiri Pirko Acked-by: Jamal Hadi Salim Signed-off-by: Jakub Kicinski (cherry picked from commit 3db09e762dc79584a69c10d74a6b98f89a9979f8) CVE-2022-29581 Signed-off-by: Thadeu Lima de Souza Cascardo --- net/sched/cls_u32.c | 16 ++++++++++------ 1 file changed, 10 insertions(+), 6 deletions(-) diff --git a/net/sched/cls_u32.c b/net/sched/cls_u32.c index 4272814487f0..81f933ebee05 100644 --- a/net/sched/cls_u32.c +++ b/net/sched/cls_u32.c @@ -386,14 +386,19 @@ static int u32_init(struct tcf_proto *tp) return 0; } -static int u32_destroy_key(struct tc_u_knode *n, bool free_pf) +static void __u32_destroy_key(struct tc_u_knode *n) { struct tc_u_hnode *ht = rtnl_dereference(n->ht_down); tcf_exts_destroy(&n->exts); - tcf_exts_put_net(&n->exts); if (ht && --ht->refcnt == 0) kfree(ht); + kfree(n); +} + +static void u32_destroy_key(struct tc_u_knode *n, bool free_pf) +{ + tcf_exts_put_net(&n->exts); #ifdef CONFIG_CLS_U32_PERF if (free_pf) free_percpu(n->pf); @@ -402,8 +407,7 @@ static int u32_destroy_key(struct tc_u_knode *n, bool free_pf) if (free_pf) free_percpu(n->pcpu_success); #endif - kfree(n); - return 0; + __u32_destroy_key(n); } /* u32_delete_key_rcu should be called when free'ing a copied @@ -898,13 +902,13 @@ static int u32_change(struct net *net, struct sk_buff *in_skb, tca[TCA_RATE], flags, extack); if (err) { - u32_destroy_key(new, false); + __u32_destroy_key(new); return err; } err = u32_replace_hw_knode(tp, new, flags, extack); if (err) { - u32_destroy_key(new, false); + __u32_destroy_key(new); return err; }