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=-6.0 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY, 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 AC616C43381 for ; Fri, 22 Mar 2019 11:34:35 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 717492183E for ; Fri, 22 Mar 2019 11:34:35 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1553254475; bh=JNhDEjgloo9yriyYL6qY7FDpUkwlmL4YfBYA89rdgE0=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=tLh+VhFh+dIHLCWp60B5oPlqGiyC9Ou0d1F4guB1ob1SITa9+I2GayScPoFHzZsMY Pi3b42/zAjavXcvJfPkrWXFdp0eYjvNlqmerJfxknmwzKvlzT1df6CzggAGU+f13la fzeXibgp43EDpsn8rSSyFRRMwJyIWM83UO1MYapE= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730441AbfCVLed (ORCPT ); Fri, 22 Mar 2019 07:34:33 -0400 Received: from mail.kernel.org ([198.145.29.99]:35122 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730414AbfCVLe2 (ORCPT ); Fri, 22 Mar 2019 07:34:28 -0400 Received: from localhost (83-86-89-107.cable.dynamic.v4.ziggo.nl [83.86.89.107]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 7DA0D2183E; Fri, 22 Mar 2019 11:34:27 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1553254468; bh=JNhDEjgloo9yriyYL6qY7FDpUkwlmL4YfBYA89rdgE0=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=ecJ6ObYgrWLwjz89B0pS0RktHShzKl+NCJIV6dzFC0071RazPP5hR4AvC9pNViIIN /MP6pNHBHMXorlxdiZwQTAPvT9XVxzBrMEqxbxSD8UnM0ic5AT97b7gZHKhWB0mI5q Eb26r6z4zoYrJb6ALcoU2aSboB53k7CLzMYt1KGo= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Eric Dumazet , Shankara Pailoor , "David S. Miller" , Guillaume Nault Subject: [PATCH 4.4 145/230] tcp/dccp: remove reqsk_put() from inet_child_forget() Date: Fri, 22 Mar 2019 12:14:43 +0100 Message-Id: <20190322111246.821855595@linuxfoundation.org> X-Mailer: git-send-email 2.21.0 In-Reply-To: <20190322111236.796964179@linuxfoundation.org> References: <20190322111236.796964179@linuxfoundation.org> User-Agent: quilt/0.65 X-stable: review X-Patchwork-Hint: ignore MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 4.4-stable review patch. If anyone has any objections, please let me know. ------------------ From: Eric Dumazet commit da8ab57863ed7e912d10b179b6bdc652f635bd19 upstream. Back in linux-4.4, I inadvertently put a call to reqsk_put() in inet_child_forget(), forgetting it could be called from two different points. In the case it is called from inet_csk_reqsk_queue_add(), we want to keep the reference on the request socket, since it is released later by the caller (tcp_v{4|6}_rcv()) This bug never showed up because atomic_dec_and_test() was not signaling the underflow, and SLAB_DESTROY_BY RCU semantic for request sockets prevented the request to be put in quarantine. Recent conversion of socket refcount from atomic_t to refcount_t finally exposed the bug. So move the reqsk_put() to inet_csk_listen_stop() to fix this. Thanks to Shankara Pailoor for using syzkaller and providing a nice set of .config and C repro. WARNING: CPU: 2 PID: 4277 at lib/refcount.c:186 refcount_sub_and_test+0x167/0x1b0 lib/refcount.c:186 Kernel panic - not syncing: panic_on_warn set ... CPU: 2 PID: 4277 Comm: syz-executor0 Not tainted 4.13.0-rc7 #3 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Ubuntu-1.8.2-1ubuntu1 04/01/2014 Call Trace: __dump_stack lib/dump_stack.c:16 [inline] dump_stack+0xf7/0x1aa lib/dump_stack.c:52 panic+0x1ae/0x3a7 kernel/panic.c:180 __warn+0x1c4/0x1d9 kernel/panic.c:541 report_bug+0x211/0x2d0 lib/bug.c:183 fixup_bug+0x40/0x90 arch/x86/kernel/traps.c:190 do_trap_no_signal arch/x86/kernel/traps.c:224 [inline] do_trap+0x260/0x390 arch/x86/kernel/traps.c:273 do_error_trap+0x118/0x340 arch/x86/kernel/traps.c:310 do_invalid_op+0x1b/0x20 arch/x86/kernel/traps.c:323 invalid_op+0x18/0x20 arch/x86/entry/entry_64.S:846 RIP: 0010:refcount_sub_and_test+0x167/0x1b0 lib/refcount.c:186 RSP: 0018:ffff88006e006b60 EFLAGS: 00010286 RAX: 0000000000000026 RBX: 0000000000000000 RCX: 0000000000000000 RDX: 0000000000000026 RSI: 1ffff1000dc00d2c RDI: ffffed000dc00d60 RBP: ffff88006e006bf0 R08: 0000000000000001 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000000 R12: 1ffff1000dc00d6d R13: 00000000ffffffff R14: 0000000000000001 R15: ffff88006ce9d340 refcount_dec_and_test+0x1a/0x20 lib/refcount.c:211 reqsk_put+0x71/0x2b0 include/net/request_sock.h:123 tcp_v4_rcv+0x259e/0x2e20 net/ipv4/tcp_ipv4.c:1729 ip_local_deliver_finish+0x2e2/0xba0 net/ipv4/ip_input.c:216 NF_HOOK include/linux/netfilter.h:248 [inline] ip_local_deliver+0x1ce/0x6d0 net/ipv4/ip_input.c:257 dst_input include/net/dst.h:477 [inline] ip_rcv_finish+0x8db/0x19c0 net/ipv4/ip_input.c:397 NF_HOOK include/linux/netfilter.h:248 [inline] ip_rcv+0xc3f/0x17d0 net/ipv4/ip_input.c:488 __netif_receive_skb_core+0x1fb7/0x31f0 net/core/dev.c:4298 __netif_receive_skb+0x2c/0x1b0 net/core/dev.c:4336 process_backlog+0x1c5/0x6d0 net/core/dev.c:5102 napi_poll net/core/dev.c:5499 [inline] net_rx_action+0x6d3/0x14a0 net/core/dev.c:5565 __do_softirq+0x2cb/0xb2d kernel/softirq.c:284 do_softirq_own_stack+0x1c/0x30 arch/x86/entry/entry_64.S:898 do_softirq.part.16+0x63/0x80 kernel/softirq.c:328 do_softirq kernel/softirq.c:176 [inline] __local_bh_enable_ip+0x84/0x90 kernel/softirq.c:181 local_bh_enable include/linux/bottom_half.h:31 [inline] rcu_read_unlock_bh include/linux/rcupdate.h:705 [inline] ip_finish_output2+0x8ad/0x1360 net/ipv4/ip_output.c:231 ip_finish_output+0x74e/0xb80 net/ipv4/ip_output.c:317 NF_HOOK_COND include/linux/netfilter.h:237 [inline] ip_output+0x1cc/0x850 net/ipv4/ip_output.c:405 dst_output include/net/dst.h:471 [inline] ip_local_out+0x95/0x160 net/ipv4/ip_output.c:124 ip_queue_xmit+0x8c6/0x1810 net/ipv4/ip_output.c:504 tcp_transmit_skb+0x1963/0x3320 net/ipv4/tcp_output.c:1123 tcp_send_ack.part.35+0x38c/0x620 net/ipv4/tcp_output.c:3575 tcp_send_ack+0x49/0x60 net/ipv4/tcp_output.c:3545 tcp_rcv_synsent_state_process net/ipv4/tcp_input.c:5795 [inline] tcp_rcv_state_process+0x4876/0x4b60 net/ipv4/tcp_input.c:5930 tcp_v4_do_rcv+0x58a/0x820 net/ipv4/tcp_ipv4.c:1483 sk_backlog_rcv include/net/sock.h:907 [inline] __release_sock+0x124/0x360 net/core/sock.c:2223 release_sock+0xa4/0x2a0 net/core/sock.c:2715 inet_wait_for_connect net/ipv4/af_inet.c:557 [inline] __inet_stream_connect+0x671/0xf00 net/ipv4/af_inet.c:643 inet_stream_connect+0x58/0xa0 net/ipv4/af_inet.c:682 SYSC_connect+0x204/0x470 net/socket.c:1628 SyS_connect+0x24/0x30 net/socket.c:1609 entry_SYSCALL_64_fastpath+0x18/0xad RIP: 0033:0x451e59 RSP: 002b:00007f474843fc08 EFLAGS: 00000216 ORIG_RAX: 000000000000002a RAX: ffffffffffffffda RBX: 0000000000718000 RCX: 0000000000451e59 RDX: 0000000000000010 RSI: 0000000020002000 RDI: 0000000000000007 RBP: 0000000000000046 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000216 R12: 0000000000000000 R13: 00007ffc040a0f8f R14: 00007f47484409c0 R15: 0000000000000000 Fixes: ebb516af60e1 ("tcp/dccp: fix race at listener dismantle phase") Signed-off-by: Eric Dumazet Reported-by: Shankara Pailoor Tested-by: Shankara Pailoor Signed-off-by: David S. Miller Cc: Guillaume Nault Signed-off-by: Greg Kroah-Hartman --- net/ipv4/inet_connection_sock.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- a/net/ipv4/inet_connection_sock.c +++ b/net/ipv4/inet_connection_sock.c @@ -787,7 +787,6 @@ static void inet_child_forget(struct soc tcp_sk(child)->fastopen_rsk = NULL; } inet_csk_destroy_sock(child); - reqsk_put(req); } struct sock *inet_csk_reqsk_queue_add(struct sock *sk, @@ -858,6 +857,7 @@ void inet_csk_listen_stop(struct sock *s sock_hold(child); inet_child_forget(sk, req, child); + reqsk_put(req); bh_unlock_sock(child); local_bh_enable(); sock_put(child);