From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-wm0-f65.google.com ([74.125.82.65]:51461 "EHLO mail-wm0-f65.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752170AbeCOOV7 (ORCPT ); Thu, 15 Mar 2018 10:21:59 -0400 Received: by mail-wm0-f65.google.com with SMTP id h21so10782539wmd.1 for ; Thu, 15 Mar 2018 07:21:58 -0700 (PDT) Date: Thu, 15 Mar 2018 15:21:57 +0100 From: Jiri Pirko To: Davide Caratti Cc: Cong Wang , Manish Kurup , "David S. Miller" , netdev@vger.kernel.org Subject: Re: [PATCH net] net/sched: fix NULL dereference in the error path of tcf_vlan_init() Message-ID: <20180315142157.GG2130@nanopsycho> References: <1d301fb86becf863283ee1be107f17e837ef4255.1521122595.git.dcaratti@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1d301fb86becf863283ee1be107f17e837ef4255.1521122595.git.dcaratti@redhat.com> Sender: netdev-owner@vger.kernel.org List-ID: Thu, Mar 15, 2018 at 03:06:30PM CET, dcaratti@redhat.com wrote: >when the following command > > # tc actions replace action vlan pop index 100 > >is run for the first time, and tcf_vlan_init() fails allocating struct >tcf_vlan_params, tcf_vlan_cleanup() calls kfree_rcu(NULL, ...). This causes >the following error: > > BUG: unable to handle kernel NULL pointer dereference at 0000000000000018 > IP: __call_rcu+0x23/0x2b0 > PGD 80000000760a2067 P4D 80000000760a2067 PUD 742c1067 PMD 0 > Oops: 0002 [#1] SMP PTI > Modules linked in: act_vlan(E) ip6table_filter ip6_tables iptable_filter binfmt_misc ext4 snd_hda_codec_generic snd_hda_intel mbcache snd_hda_codec jbd2 snd_hda_core crct10dif_pclmul crc32_pclmul ghash_clmulni_intel pcbc snd_hwdep snd_seq snd_seq_device snd_pcm aesni_intel crypto_simd snd_timer glue_helper snd cryptd joydev soundcore virtio_balloon pcspkr i2c_piix4 nfsd auth_rpcgss nfs_acl lockd grace sunrpc ip_tables xfs libcrc32c ata_generic pata_acpi qxl drm_kms_helper syscopyarea sysfillrect sysimgblt fb_sys_fops ttm drm virtio_console virtio_blk virtio_net ata_piix crc32c_intel libata virtio_pci i2c_core virtio_ring serio_raw virtio floppy dm_mirror dm_region_hash dm_log dm_mod [last unloaded: act_vlan] > CPU: 3 PID: 3119 Comm: tc Tainted: G E 4.16.0-rc4.act_vlan.orig+ #403 > Hardware name: Red Hat KVM, BIOS 0.5.1 01/01/2011 > RIP: 0010:__call_rcu+0x23/0x2b0 > RSP: 0018:ffffaac3005fb798 EFLAGS: 00010246 > RAX: ffffffffc0704080 RBX: ffff97f2b4bbe900 RCX: 00000000ffffffff > RDX: ffffffffabca5f00 RSI: 0000000000000010 RDI: 0000000000000010 > RBP: 0000000000000010 R08: 0000000000000001 R09: 0000000000000044 > R10: 00000000fd003000 R11: ffff97f2faab5b91 R12: 0000000000000000 > R13: ffffffffabca5f00 R14: ffff97f2fb80202c R15: 00000000fffffff4 > FS: 00007f68f75b4740(0000) GS:ffff97f2ffd80000(0000) knlGS:0000000000000000 > CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 > CR2: 0000000000000018 CR3: 0000000072b52001 CR4: 00000000001606e0 > Call Trace: > __tcf_idr_release+0x79/0xf0 > tcf_vlan_init+0x168/0x270 [act_vlan] > tcf_action_init_1+0x2cc/0x430 > tcf_action_init+0xd3/0x1b0 > tc_ctl_action+0x18b/0x240 > rtnetlink_rcv_msg+0x29c/0x310 > ? _cond_resched+0x15/0x30 > ? __kmalloc_node_track_caller+0x1b9/0x270 > ? rtnl_calcit.isra.28+0x100/0x100 > netlink_rcv_skb+0xd2/0x110 > netlink_unicast+0x17c/0x230 > netlink_sendmsg+0x2cd/0x3c0 > sock_sendmsg+0x30/0x40 > ___sys_sendmsg+0x27a/0x290 > ? filemap_map_pages+0x34a/0x3a0 > ? __handle_mm_fault+0xbfd/0xe20 > __sys_sendmsg+0x51/0x90 > do_syscall_64+0x6e/0x1a0 > entry_SYSCALL_64_after_hwframe+0x3d/0xa2 > RIP: 0033:0x7f68f69c5ba0 > RSP: 002b:00007fffd79c1118 EFLAGS: 00000246 ORIG_RAX: 000000000000002e > RAX: ffffffffffffffda RBX: 00007fffd79c1240 RCX: 00007f68f69c5ba0 > RDX: 0000000000000000 RSI: 00007fffd79c1190 RDI: 0000000000000003 > RBP: 000000005aaa708e R08: 0000000000000002 R09: 0000000000000000 > R10: 00007fffd79c0ba0 R11: 0000000000000246 R12: 0000000000000000 > R13: 00007fffd79c1254 R14: 0000000000000001 R15: 0000000000669f60 > Code: 5d e9 42 da ff ff 66 90 0f 1f 44 00 00 41 57 41 56 41 55 49 89 d5 41 54 55 48 89 fd 53 48 83 ec 08 40 f6 c7 07 0f 85 19 02 00 00 <48> 89 75 08 48 c7 45 00 00 00 00 00 9c 58 0f 1f 44 00 00 49 89 > RIP: __call_rcu+0x23/0x2b0 RSP: ffffaac3005fb798 > CR2: 0000000000000018 > >fix this in tcf_vlan_cleanup(), ensuring that kfree_rcu(p, ...) is called >only when p is not NULL. > >Fixes: 4c5b9d9642c8 ("act_vlan: VLAN action rewrite to use RCU lock/unlock and update") >Signed-off-by: Davide Caratti Acked-by: Jiri Pirko