Date:   Tue, 20 Dec 2022 10:40:37 -0500
From:   Aaron Conole <aconole@...hat.com>
To:     Paolo Abeni <pabeni@...hat.com>
Cc:     syzbot <syzbot+8f4e2dcfcb3209ac35f9@...kaller.appspotmail.com>,
        davem@...emloft.net, dev@...nvswitch.org, edumazet@...gle.com,
        kuba@...nel.org, linux-kernel@...r.kernel.org,
        netdev@...r.kernel.org, pshelar@....org,
        syzkaller-bugs@...glegroups.com,
        Eelco Chaudron <echaudro@...hat.com>
Subject: Re: [syzbot] KASAN: use-after-free Read in ovs_vport_locate

Paolo Abeni <pabeni@...hat.com> writes:

> On Tue, 2022-12-20 at 00:22 -0800, syzbot wrote:
>> HEAD commit:    041fae9c105a Merge tag 'f2fs-for-6.2-rc1' of git://git.ker..
>> git tree:       upstream
>> console output: https://syzkaller.appspot.com/x/log.txt?x=15c5d020480000
>> kernel config:  https://syzkaller.appspot.com/x/.config?x=836aafbf33f4fa6c
>> dashboard link: https://syzkaller.appspot.com/bug?extid=8f4e2dcfcb3209ac35f9
>> compiler:       gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.2
>> 
>> Unfortunately, I don't have any reproducer for this issue yet.
>> 
>> Downloadable assets:
>> disk image: https://storage.googleapis.com/syzbot-assets/30e749b24df4/disk-041fae9c.raw.xz
>> vmlinux: https://storage.googleapis.com/syzbot-assets/dd6d972f5b02/vmlinux-041fae9c.xz
>> kernel image: https://storage.googleapis.com/syzbot-assets/405163d7c7cc/bzImage-041fae9c.xz
>> 
>> IMPORTANT: if you fix the issue, please add the following tag to the commit:
>> Reported-by: syzbot+8f4e2dcfcb3209ac35f9@...kaller.appspotmail.com
>> 
>> netlink: 208 bytes leftover after parsing attributes in process `syz-executor.4'.
>> ==================================================================
>> BUG: KASAN: use-after-free in read_pnet include/net/net_namespace.h:383 [inline]
>> BUG: KASAN: use-after-free in ovs_dp_get_net net/openvswitch/datapath.h:195 [inline]
>> BUG: KASAN: use-after-free in ovs_vport_locate+0x131/0x150 net/openvswitch/vport.c:103
>> Read of size 8 at addr ffff88802055e360 by task syz-executor.4/5621
>> 
>> CPU: 0 PID: 5621 Comm: syz-executor.4 Not tainted 6.1.0-syzkaller-10971-g041fae9c105a #0
>> Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/26/2022
>> Call Trace:
>>  <TASK>
>>  __dump_stack lib/dump_stack.c:88 [inline]
>>  dump_stack_lvl+0xd1/0x138 lib/dump_stack.c:106
>>  print_address_description mm/kasan/report.c:306 [inline]
>>  print_report+0x15e/0x461 mm/kasan/report.c:417
>>  kasan_report+0xbf/0x1f0 mm/kasan/report.c:517
>>  read_pnet include/net/net_namespace.h:383 [inline]
>>  ovs_dp_get_net net/openvswitch/datapath.h:195 [inline]
>>  ovs_vport_locate+0x131/0x150 net/openvswitch/vport.c:103
>>  lookup_datapath+0x54/0x3a0 net/openvswitch/datapath.c:1628
>>  ovs_dp_reset_user_features net/openvswitch/datapath.c:1639 [inline]
>>  ovs_dp_cmd_new+0xd5b/0x11c0 net/openvswitch/datapath.c:1848
>>  genl_family_rcv_msg_doit.isra.0+0x1e6/0x2d0 net/netlink/genetlink.c:968
>>  genl_family_rcv_msg net/netlink/genetlink.c:1048 [inline]
>>  genl_rcv_msg+0x4ff/0x7e0 net/netlink/genetlink.c:1065
>>  netlink_rcv_skb+0x165/0x440 net/netlink/af_netlink.c:2564
>>  genl_rcv+0x28/0x40 net/netlink/genetlink.c:1076
>>  netlink_unicast_kernel net/netlink/af_netlink.c:1330 [inline]
>>  netlink_unicast+0x547/0x7f0 net/netlink/af_netlink.c:1356
>>  netlink_sendmsg+0x91b/0xe10 net/netlink/af_netlink.c:1932
>>  sock_sendmsg_nosec net/socket.c:714 [inline]
>>  sock_sendmsg+0xd3/0x120 net/socket.c:734
>>  ____sys_sendmsg+0x712/0x8c0 net/socket.c:2476
>>  ___sys_sendmsg+0x110/0x1b0 net/socket.c:2530
>>  __sys_sendmsg+0xf7/0x1c0 net/socket.c:2559
>>  do_syscall_x64 arch/x86/entry/common.c:50 [inline]
>>  do_syscall_64+0x39/0xb0 arch/x86/entry/common.c:80
>>  entry_SYSCALL_64_after_hwframe+0x63/0xcd
>> RIP: 0033:0x7f142348c0d9
>> Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 f1 19 00 00 90 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:00007f14240ff168 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
>> RAX: ffffffffffffffda RBX: 00007f14235abf80 RCX: 00007f142348c0d9
>> RDX: 0000000000000800 RSI: 0000000020000100 RDI: 0000000000000003
>> RBP: 00007f14234e7ae9 R08: 0000000000000000 R09: 0000000000000000
>> R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
>> R13: 00007ffdd965a34f R14: 00007f14240ff300 R15: 0000000000022000
>>  </TASK>
>> 
>> Allocated by task 5564:
>>  kasan_save_stack+0x22/0x40 mm/kasan/common.c:45
>>  kasan_set_track+0x25/0x30 mm/kasan/common.c:52
>>  ____kasan_kmalloc mm/kasan/common.c:371 [inline]
>>  ____kasan_kmalloc mm/kasan/common.c:330 [inline]
>>  __kasan_kmalloc+0xa3/0xb0 mm/kasan/common.c:380
>>  kmalloc include/linux/slab.h:580 [inline]
>>  kzalloc include/linux/slab.h:720 [inline]
>>  ovs_dp_cmd_new+0x1a3/0x11c0 net/openvswitch/datapath.c:1796
>>  genl_family_rcv_msg_doit.isra.0+0x1e6/0x2d0 net/netlink/genetlink.c:968
>>  genl_family_rcv_msg net/netlink/genetlink.c:1048 [inline]
>>  genl_rcv_msg+0x4ff/0x7e0 net/netlink/genetlink.c:1065
>>  netlink_rcv_skb+0x165/0x440 net/netlink/af_netlink.c:2564
>>  genl_rcv+0x28/0x40 net/netlink/genetlink.c:1076
>>  netlink_unicast_kernel net/netlink/af_netlink.c:1330 [inline]
>>  netlink_unicast+0x547/0x7f0 net/netlink/af_netlink.c:1356
>>  netlink_sendmsg+0x91b/0xe10 net/netlink/af_netlink.c:1932
>>  sock_sendmsg_nosec net/socket.c:714 [inline]
>>  sock_sendmsg+0xd3/0x120 net/socket.c:734
>>  ____sys_sendmsg+0x712/0x8c0 net/socket.c:2476
>>  ___sys_sendmsg+0x110/0x1b0 net/socket.c:2530
>>  __sys_sendmsg+0xf7/0x1c0 net/socket.c:2559
>>  do_syscall_x64 arch/x86/entry/common.c:50 [inline]
>>  do_syscall_64+0x39/0xb0 arch/x86/entry/common.c:80
>>  entry_SYSCALL_64_after_hwframe+0x63/0xcd
>> 
>> Freed by task 5564:
>>  kasan_save_stack+0x22/0x40 mm/kasan/common.c:45
>>  kasan_set_track+0x25/0x30 mm/kasan/common.c:52
>>  kasan_save_free_info+0x2b/0x40 mm/kasan/generic.c:518
>>  ____kasan_slab_free mm/kasan/common.c:236 [inline]
>>  ____kasan_slab_free+0x13b/0x1a0 mm/kasan/common.c:200
>>  kasan_slab_free include/linux/kasan.h:177 [inline]
>>  __cache_free mm/slab.c:3394 [inline]
>>  __do_kmem_cache_free mm/slab.c:3580 [inline]
>>  __kmem_cache_free+0xcd/0x3b0 mm/slab.c:3587
>>  ovs_dp_cmd_new+0x25e/0x11c0 net/openvswitch/datapath.c:1884
>>  genl_family_rcv_msg_doit.isra.0+0x1e6/0x2d0 net/netlink/genetlink.c:968
>>  genl_family_rcv_msg net/netlink/genetlink.c:1048 [inline]
>>  genl_rcv_msg+0x4ff/0x7e0 net/netlink/genetlink.c:1065
>>  netlink_rcv_skb+0x165/0x440 net/netlink/af_netlink.c:2564
>>  genl_rcv+0x28/0x40 net/netlink/genetlink.c:1076
>>  netlink_unicast_kernel net/netlink/af_netlink.c:1330 [inline]
>>  netlink_unicast+0x547/0x7f0 net/netlink/af_netlink.c:1356
>>  netlink_sendmsg+0x91b/0xe10 net/netlink/af_netlink.c:1932
>>  sock_sendmsg_nosec net/socket.c:714 [inline]
>>  sock_sendmsg+0xd3/0x120 net/socket.c:734
>>  ____sys_sendmsg+0x712/0x8c0 net/socket.c:2476
>>  ___sys_sendmsg+0x110/0x1b0 net/socket.c:2530
>>  __sys_sendmsg+0xf7/0x1c0 net/socket.c:2559
>>  do_syscall_x64 arch/x86/entry/common.c:50 [inline]
>>  do_syscall_64+0x39/0xb0 arch/x86/entry/common.c:80
>>  entry_SYSCALL_64_after_hwframe+0x63/0xcd
>> 
>> Last potentially related work creation:
>>  kasan_save_stack+0x22/0x40 mm/kasan/common.c:45
>>  __kasan_record_aux_stack+0x7b/0x90 mm/kasan/generic.c:488
>>  insert_work+0x48/0x350 kernel/workqueue.c:1358
>>  __queue_work+0x693/0x13b0 kernel/workqueue.c:1517
>>  queue_work_on+0xf2/0x110 kernel/workqueue.c:1545
>>  queue_work include/linux/workqueue.h:503 [inline]
>>  addr_event.part.0+0x33e/0x4f0 drivers/infiniband/core/roce_gid_mgmt.c:853
>>  addr_event drivers/infiniband/core/roce_gid_mgmt.c:824 [inline]
>>  inet6addr_event+0x142/0x1c0 drivers/infiniband/core/roce_gid_mgmt.c:883
>>  notifier_call_chain+0xb5/0x200 kernel/notifier.c:87
>>  atomic_notifier_call_chain+0x74/0x180 kernel/notifier.c:225
>>  ipv6_add_addr+0x1266/0x1de0 net/ipv6/addrconf.c:1165
>>  addrconf_add_linklocal+0x1cc/0x590 net/ipv6/addrconf.c:3215
>>  addrconf_addr_gen+0x326/0x370 net/ipv6/addrconf.c:3346
>>  addrconf_dev_config+0x255/0x410 net/ipv6/addrconf.c:3391
>>  addrconf_notify+0xfb6/0x1c80 net/ipv6/addrconf.c:3635
>>  notifier_call_chain+0xb5/0x200 kernel/notifier.c:87
>>  call_netdevice_notifiers_info+0xb5/0x130 net/core/dev.c:1944
>>  netdev_state_change net/core/dev.c:1319 [inline]
>>  netdev_state_change+0x104/0x130 net/core/dev.c:1312
>>  linkwatch_do_dev+0x10e/0x150 net/core/link_watch.c:182
>>  __linkwatch_run_queue+0x23f/0x6a0 net/core/link_watch.c:235
>>  linkwatch_event+0x4e/0x70 net/core/link_watch.c:278
>>  process_one_work+0x9bf/0x1710 kernel/workqueue.c:2289
>>  worker_thread+0x669/0x1090 kernel/workqueue.c:2436
>>  kthread+0x2e8/0x3a0 kernel/kthread.c:376
>>  ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:308
>> 
>> Second to last potentially related work creation:
>>  kasan_save_stack+0x22/0x40 mm/kasan/common.c:45
>>  __kasan_record_aux_stack+0x7b/0x90 mm/kasan/generic.c:488
>>  insert_work+0x48/0x350 kernel/workqueue.c:1358
>>  __queue_work+0x693/0x13b0 kernel/workqueue.c:1517
>>  queue_work_on+0xf2/0x110 kernel/workqueue.c:1545
>>  queue_work include/linux/workqueue.h:503 [inline]
>>  netdevice_queue_work drivers/infiniband/core/roce_gid_mgmt.c:659 [inline]
>>  netdevice_event+0x5e9/0x8f0 drivers/infiniband/core/roce_gid_mgmt.c:802
>>  notifier_call_chain+0xb5/0x200 kernel/notifier.c:87
>>  call_netdevice_notifiers_info+0xb5/0x130 net/core/dev.c:1944
>>  call_netdevice_notifiers_extack net/core/dev.c:1982 [inline]
>>  call_netdevice_notifiers net/core/dev.c:1996 [inline]
>>  register_netdevice+0xfb4/0x1640 net/core/dev.c:10078
>>  bond_newlink drivers/net/bonding/bond_netlink.c:560 [inline]
>>  bond_newlink+0x4b/0xa0 drivers/net/bonding/bond_netlink.c:550
>>  rtnl_newlink_create net/core/rtnetlink.c:3407 [inline]
>>  __rtnl_newlink+0x10c2/0x1840 net/core/rtnetlink.c:3624
>>  rtnl_newlink+0x68/0xa0 net/core/rtnetlink.c:3637
>>  rtnetlink_rcv_msg+0x43e/0xca0 net/core/rtnetlink.c:6141
>>  netlink_rcv_skb+0x165/0x440 net/netlink/af_netlink.c:2564
>>  netlink_unicast_kernel net/netlink/af_netlink.c:1330 [inline]
>>  netlink_unicast+0x547/0x7f0 net/netlink/af_netlink.c:1356
>>  netlink_sendmsg+0x91b/0xe10 net/netlink/af_netlink.c:1932
>>  sock_sendmsg_nosec net/socket.c:714 [inline]
>>  sock_sendmsg+0xd3/0x120 net/socket.c:734
>>  __sys_sendto+0x23a/0x340 net/socket.c:2117
>>  __do_sys_sendto net/socket.c:2129 [inline]
>>  __se_sys_sendto net/socket.c:2125 [inline]
>>  __x64_sys_sendto+0xe1/0x1b0 net/socket.c:2125
>>  do_syscall_x64 arch/x86/entry/common.c:50 [inline]
>>  do_syscall_64+0x39/0xb0 arch/x86/entry/common.c:80
>>  entry_SYSCALL_64_after_hwframe+0x63/0xcd
>> 
>> The buggy address belongs to the object at ffff88802055e300
>>  which belongs to the cache kmalloc-192 of size 192
>> The buggy address is located 96 bytes inside of
>>  192-byte region [ffff88802055e300, ffff88802055e3c0)
>> 
>> The buggy address belongs to the physical page:
>> page:ffffea0000815780 refcount:1 mapcount:0 mapping:0000000000000000 index:0xffff88802055ef00 pfn:0x2055e
>> flags: 0xfff00000000200(slab|node=0|zone=1|lastcpupid=0x7ff)
>> raw: 00fff00000000200 ffff888012040000 ffffea0000873fd0 ffffea000083f490
>> raw: ffff88802055ef00 ffff88802055e000 000000010000000e 0000000000000000
>> page dumped because: kasan: bad access detected
>> page_owner tracks the page as allocated
>> page last allocated via order 0, migratetype Unmovable, gfp_mask 0x2420c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_COMP|__GFP_THISNODE), pid 1, tgid 1 (swapper/0), ts 8303233753, free_ts 8269599359
>>  prep_new_page mm/page_alloc.c:2531 [inline]
>>  get_page_from_freelist+0x119c/0x2ce0 mm/page_alloc.c:4283
>>  __alloc_pages+0x1cb/0x5b0 mm/page_alloc.c:5549
>>  __alloc_pages_node include/linux/gfp.h:237 [inline]
>>  kmem_getpages mm/slab.c:1363 [inline]
>>  cache_grow_begin+0x94/0x390 mm/slab.c:2574
>>  cache_alloc_refill+0x27f/0x380 mm/slab.c:2947
>>  ____cache_alloc mm/slab.c:3023 [inline]
>>  ____cache_alloc mm/slab.c:3006 [inline]
>>  __do_cache_alloc mm/slab.c:3206 [inline]
>>  slab_alloc_node mm/slab.c:3254 [inline]
>>  __kmem_cache_alloc_node+0x44f/0x510 mm/slab.c:3544
>>  kmalloc_trace+0x26/0x60 mm/slab_common.c:1062
>>  kmalloc include/linux/slab.h:580 [inline]
>>  kzalloc include/linux/slab.h:720 [inline]
>>  call_usermodehelper_setup+0x9c/0x340 kernel/umh.c:366
>>  kobject_uevent_env+0xed3/0x1620 lib/kobject_uevent.c:614
>>  device_add+0xb76/0x1e90 drivers/base/core.c:3498
>>  rfkill_register+0x1a9/0xb00 net/rfkill/core.c:1070
>>  wiphy_register+0x24ae/0x2ae0 net/wireless/core.c:1007
>>  virt_wifi_make_wiphy drivers/net/wireless/virt_wifi.c:383 [inline]
>>  virt_wifi_init_module+0x352/0x3da drivers/net/wireless/virt_wifi.c:665
>>  do_one_initcall+0x141/0x790 init/main.c:1306
>>  do_initcall_level init/main.c:1379 [inline]
>>  do_initcalls init/main.c:1395 [inline]
>>  do_basic_setup init/main.c:1414 [inline]
>>  kernel_init_freeable+0x6f9/0x782 init/main.c:1634
>>  kernel_init+0x1e/0x1d0 init/main.c:1522
>>  ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:308
>> page last free stack trace:
>>  reset_page_owner include/linux/page_owner.h:24 [inline]
>>  free_pages_prepare mm/page_alloc.c:1446 [inline]
>>  free_pcp_prepare+0x65c/0xc00 mm/page_alloc.c:1496
>>  free_unref_page_prepare mm/page_alloc.c:3369 [inline]
>>  free_unref_page+0x1d/0x490 mm/page_alloc.c:3464
>>  __vunmap+0x85d/0xd30 mm/vmalloc.c:2727
>>  free_work+0x5c/0x80 mm/vmalloc.c:100
>>  process_one_work+0x9bf/0x1710 kernel/workqueue.c:2289
>>  worker_thread+0x669/0x1090 kernel/workqueue.c:2436
>>  kthread+0x2e8/0x3a0 kernel/kthread.c:376
>>  ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:308
>> 
>> Memory state around the buggy address:
>>  ffff88802055e200: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>>  ffff88802055e280: 00 00 00 00 fc fc fc fc fc fc fc fc fc fc fc fc
>> > ffff88802055e300: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>>                                                        ^
>>  ffff88802055e380: fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc
>>  ffff88802055e400: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>> ==================================================================
>
> @Eelco, @Aaron: could you please have a look? I think the
> ovs_dp_cmd_new() error path does not clean correctly the to-be-deleted
> datapath, possibly a ovs_dp_detach_port() call for the internal one is
> missing.

Okay - I'll have a look.  I guess there could be some missing protection
as well during allocation / reference.  Either way, building a KASAN
kernel now.  Thanks for the report!

> Thanks,
>
> Paolo

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