From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id B604C12C487; Tue, 30 Apr 2024 10:44:34 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1714473874; cv=none; b=f5SuIMpkvhOjN63CbjuFe6g1pcdtxsBHw6wvWGdNAf17ATRfMeAag/tQx0JxF9SRL8RZMyjuXAtk5M10auzsIERwaW+CrmDHvh9/yQdw7BYAN+tJnA8X70x9oRapAUBh56PAnnA27akwU/WMcOZdYoi6e220RiabuIn2zHWl9QE= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1714473874; c=relaxed/simple; bh=tN0N32CmE39x1Rc+6zIClPvwYlNHb3YwawRyGN5OxtE=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=qm6f3nGuv5Gcy36Nn5JL+P1pSFH8KcrU+eXO4GGLLcwk48m/PRJNDETYItuHjxbblmN8VmH7XIJM52CszIRd164JVFUimKF/cIJrwf3ZZsRMUW3beM0ugDfaPkWhEXQTy5GxCynRzDDcscF8OtI6jv7A2DXAvQp3iRbPw61CHiw= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=2Zi9qj+e; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="2Zi9qj+e" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 34C20C2BBFC; Tue, 30 Apr 2024 10:44:34 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1714473874; bh=tN0N32CmE39x1Rc+6zIClPvwYlNHb3YwawRyGN5OxtE=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=2Zi9qj+eHshH3ZQDQbPy9YPle4jlzZi6ZeuyxjcdJ1ZT6gIgsSDGcNf6xulOrhPxv kfQARmDPKx4d5QyL463+KGvI66Lu9e9PKPt0Pp2byOWFP379D1E3XZ852MQh4RhAPE BoRUM0DYWhm1XKP2CAQxMEZvFbPvSKdshZhTqWCI= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, syzbot , Eric Dumazet , Kuniyuki Iwashima , Jakub Kicinski , Zhengchao Shao Subject: [PATCH 4.19 68/77] tcp: Clean up kernel listeners reqsk in inet_twsk_purge() Date: Tue, 30 Apr 2024 12:39:47 +0200 Message-ID: <20240430103043.146240320@linuxfoundation.org> X-Mailer: git-send-email 2.44.0 In-Reply-To: <20240430103041.111219002@linuxfoundation.org> References: <20240430103041.111219002@linuxfoundation.org> User-Agent: quilt/0.67 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 4.19-stable review patch. If anyone has any objections, please let me know. ------------------ From: Kuniyuki Iwashima commit 740ea3c4a0b2e326b23d7cdf05472a0e92aa39bc upstream. Eric Dumazet reported a use-after-free related to the per-netns ehash series. [0] When we create a TCP socket from userspace, the socket always holds a refcnt of the netns. This guarantees that a reqsk timer is always fired before netns dismantle. Each reqsk has a refcnt of its listener, so the listener is not freed before the reqsk, and the net is not freed before the listener as well. OTOH, when in-kernel users create a TCP socket, it might not hold a refcnt of its netns. Thus, a reqsk timer can be fired after the netns dismantle and access freed per-netns ehash. To avoid the use-after-free, we need to clean up TCP_NEW_SYN_RECV sockets in inet_twsk_purge() if the netns uses a per-netns ehash. [0]: https://lore.kernel.org/netdev/CANn89iLXMup0dRD_Ov79Xt8N9FM0XdhCHEN05sf3eLwxKweM6w@mail.gmail.com/ BUG: KASAN: use-after-free in tcp_or_dccp_get_hashinfo include/net/inet_hashtables.h:181 [inline] BUG: KASAN: use-after-free in reqsk_queue_unlink+0x320/0x350 net/ipv4/inet_connection_sock.c:913 Read of size 8 at addr ffff88807545bd80 by task syz-executor.2/8301 CPU: 1 PID: 8301 Comm: syz-executor.2 Not tainted 6.0.0-syzkaller-02757-gaf7d23f9d96a #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/22/2022 Call Trace: __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0xcd/0x134 lib/dump_stack.c:106 print_address_description mm/kasan/report.c:317 [inline] print_report.cold+0x2ba/0x719 mm/kasan/report.c:433 kasan_report+0xb1/0x1e0 mm/kasan/report.c:495 tcp_or_dccp_get_hashinfo include/net/inet_hashtables.h:181 [inline] reqsk_queue_unlink+0x320/0x350 net/ipv4/inet_connection_sock.c:913 inet_csk_reqsk_queue_drop net/ipv4/inet_connection_sock.c:927 [inline] inet_csk_reqsk_queue_drop_and_put net/ipv4/inet_connection_sock.c:939 [inline] reqsk_timer_handler+0x724/0x1160 net/ipv4/inet_connection_sock.c:1053 call_timer_fn+0x1a0/0x6b0 kernel/time/timer.c:1474 expire_timers kernel/time/timer.c:1519 [inline] __run_timers.part.0+0x674/0xa80 kernel/time/timer.c:1790 __run_timers kernel/time/timer.c:1768 [inline] run_timer_softirq+0xb3/0x1d0 kernel/time/timer.c:1803 __do_softirq+0x1d0/0x9c8 kernel/softirq.c:571 invoke_softirq kernel/softirq.c:445 [inline] __irq_exit_rcu+0x123/0x180 kernel/softirq.c:650 irq_exit_rcu+0x5/0x20 kernel/softirq.c:662 sysvec_apic_timer_interrupt+0x93/0xc0 arch/x86/kernel/apic/apic.c:1107 Fixes: d1e5e6408b30 ("tcp: Introduce optional per-netns ehash.") Reported-by: syzbot Reported-by: Eric Dumazet Suggested-by: Eric Dumazet Signed-off-by: Kuniyuki Iwashima Reviewed-by: Eric Dumazet Link: https://lore.kernel.org/r/20221012145036.74960-1-kuniyu@amazon.com Signed-off-by: Jakub Kicinski [shaozhengchao: resolved conflicts in 5.10] Signed-off-by: Zhengchao Shao Signed-off-by: Greg Kroah-Hartman --- net/ipv4/inet_timewait_sock.c | 15 ++++++++++++++- 1 file changed, 14 insertions(+), 1 deletion(-) --- a/net/ipv4/inet_timewait_sock.c +++ b/net/ipv4/inet_timewait_sock.c @@ -267,8 +267,21 @@ restart_rcu: rcu_read_lock(); restart: sk_nulls_for_each_rcu(sk, node, &head->chain) { - if (sk->sk_state != TCP_TIME_WAIT) + if (sk->sk_state != TCP_TIME_WAIT) { + /* A kernel listener socket might not hold refcnt for net, + * so reqsk_timer_handler() could be fired after net is + * freed. Userspace listener and reqsk never exist here. + */ + if (unlikely(sk->sk_state == TCP_NEW_SYN_RECV && + hashinfo->pernet)) { + struct request_sock *req = inet_reqsk(sk); + + inet_csk_reqsk_queue_drop_and_put(req->rsk_listener, req); + } + continue; + } + tw = inet_twsk(sk); if ((tw->tw_family != family) || refcount_read(&twsk_net(tw)->count))