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[209.132.180.67]) by mx.google.com with ESMTP id h9-v6si1650916plk.461.2018.09.27.02.10.49; Thu, 27 Sep 2018 02:11:04 -0700 (PDT) Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67; Authentication-Results: mx.google.com; spf=pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728337AbeI0P1H (ORCPT + 99 others); Thu, 27 Sep 2018 11:27:07 -0400 Received: from mail.linuxfoundation.org ([140.211.169.12]:55092 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727057AbeI0P1H (ORCPT ); Thu, 27 Sep 2018 11:27:07 -0400 Received: from localhost (ip-213-127-77-73.ip.prioritytelecom.net [213.127.77.73]) by mail.linuxfoundation.org (Postfix) with ESMTPSA id 94F0D10A4; Thu, 27 Sep 2018 09:09:50 +0000 (UTC) From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Matteo Croce , Davide Caratti , Jiri Pirko , "David S. Miller" Subject: [PATCH 4.18 13/88] net/sched: act_sample: fix NULL dereference in the data path Date: Thu, 27 Sep 2018 11:02:54 +0200 Message-Id: <20180927090302.128011339@linuxfoundation.org> X-Mailer: git-send-email 2.19.0 In-Reply-To: <20180927090300.631426620@linuxfoundation.org> References: <20180927090300.631426620@linuxfoundation.org> User-Agent: quilt/0.65 X-stable: review 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 4.18-stable review patch. If anyone has any objections, please let me know. ------------------ From: Davide Caratti [ Upstream commit 34043d250f51368f214aed7f54c2dc29c819a8c7 ] Matteo reported the following splat, testing the datapath of TC 'sample': BUG: KASAN: null-ptr-deref in tcf_sample_act+0xc4/0x310 Read of size 8 at addr 0000000000000000 by task nc/433 CPU: 0 PID: 433 Comm: nc Not tainted 4.19.0-rc3-kvm #17 Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS ?-20180531_142017-buildhw-08.phx2.fedoraproject.org-1.fc28 04/01/2014 Call Trace: kasan_report.cold.6+0x6c/0x2fa tcf_sample_act+0xc4/0x310 ? dev_hard_start_xmit+0x117/0x180 tcf_action_exec+0xa3/0x160 tcf_classify+0xdd/0x1d0 htb_enqueue+0x18e/0x6b0 ? deref_stack_reg+0x7a/0xb0 ? htb_delete+0x4b0/0x4b0 ? unwind_next_frame+0x819/0x8f0 ? entry_SYSCALL_64_after_hwframe+0x44/0xa9 __dev_queue_xmit+0x722/0xca0 ? unwind_get_return_address_ptr+0x50/0x50 ? netdev_pick_tx+0xe0/0xe0 ? save_stack+0x8c/0xb0 ? kasan_kmalloc+0xbe/0xd0 ? __kmalloc_track_caller+0xe4/0x1c0 ? __kmalloc_reserve.isra.45+0x24/0x70 ? __alloc_skb+0xdd/0x2e0 ? sk_stream_alloc_skb+0x91/0x3b0 ? tcp_sendmsg_locked+0x71b/0x15a0 ? tcp_sendmsg+0x22/0x40 ? __sys_sendto+0x1b0/0x250 ? __x64_sys_sendto+0x6f/0x80 ? do_syscall_64+0x5d/0x150 ? entry_SYSCALL_64_after_hwframe+0x44/0xa9 ? __sys_sendto+0x1b0/0x250 ? __x64_sys_sendto+0x6f/0x80 ? do_syscall_64+0x5d/0x150 ? entry_SYSCALL_64_after_hwframe+0x44/0xa9 ip_finish_output2+0x495/0x590 ? ip_copy_metadata+0x2e0/0x2e0 ? skb_gso_validate_network_len+0x6f/0x110 ? ip_finish_output+0x174/0x280 __tcp_transmit_skb+0xb17/0x12b0 ? __tcp_select_window+0x380/0x380 tcp_write_xmit+0x913/0x1de0 ? __sk_mem_schedule+0x50/0x80 tcp_sendmsg_locked+0x49d/0x15a0 ? tcp_rcv_established+0x8da/0xa30 ? tcp_set_state+0x220/0x220 ? clear_user+0x1f/0x50 ? iov_iter_zero+0x1ae/0x590 ? __fget_light+0xa0/0xe0 tcp_sendmsg+0x22/0x40 __sys_sendto+0x1b0/0x250 ? __ia32_sys_getpeername+0x40/0x40 ? _copy_to_user+0x58/0x70 ? poll_select_copy_remaining+0x176/0x200 ? __pollwait+0x1c0/0x1c0 ? ktime_get_ts64+0x11f/0x140 ? kern_select+0x108/0x150 ? core_sys_select+0x360/0x360 ? vfs_read+0x127/0x150 ? kernel_write+0x90/0x90 __x64_sys_sendto+0x6f/0x80 do_syscall_64+0x5d/0x150 entry_SYSCALL_64_after_hwframe+0x44/0xa9 RIP: 0033:0x7fefef2b129d Code: ff ff ff ff eb b6 0f 1f 80 00 00 00 00 48 8d 05 51 37 0c 00 41 89 ca 8b 00 85 c0 75 20 45 31 c9 45 31 c0 b8 2c 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 6b f3 c3 66 0f 1f 84 00 00 00 00 00 41 56 41 RSP: 002b:00007fff2f5350c8 EFLAGS: 00000246 ORIG_RAX: 000000000000002c RAX: ffffffffffffffda RBX: 000056118d60c120 RCX: 00007fefef2b129d RDX: 0000000000002000 RSI: 000056118d629320 RDI: 0000000000000003 RBP: 000056118d530370 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000002000 R13: 000056118d5c2a10 R14: 000056118d5c2a10 R15: 000056118d5303b8 tcf_sample_act() tried to update its per-cpu stats, but tcf_sample_init() forgot to allocate them, because tcf_idr_create() was called with a wrong value of 'cpustats'. Setting it to true proved to fix the reported crash. Reported-by: Matteo Croce Fixes: 65a206c01e8e ("net/sched: Change act_api and act_xxx modules to use IDR") Fixes: 5c5670fae430 ("net/sched: Introduce sample tc action") Tested-by: Matteo Croce Signed-off-by: Davide Caratti Acked-by: Jiri Pirko Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman --- net/sched/act_sample.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- a/net/sched/act_sample.c +++ b/net/sched/act_sample.c @@ -64,7 +64,7 @@ static int tcf_sample_init(struct net *n if (!exists) { ret = tcf_idr_create(tn, parm->index, est, a, - &act_sample_ops, bind, false); + &act_sample_ops, bind, true); if (ret) return ret; ret = ACT_P_CREATED;