KASAN: use-after-free Read in br_dev_xmit

Status: fixed on 2020/04/15 17:19
Subsystems: bridge
[Documentation on labels]
Fix commit: 823d81b0fa2c net: bridge: fix stale eth hdr pointer in br_dev_xmit
First crash: 2366d, last: 2366d
▶ ▼ Discussions (6)
Title Replies (including bot) Last reply
[patch 001/127] kcov: cleanup debug messages 1 (1) 2020/06/04 23:45
[PATCH v4 0/7] kcov: collect coverage from usb soft interrupts 16 (16) 2020/06/04 13:46
[patch 151/166] kcov: cleanup debug messages 1 (1) 2020/04/07 03:12
[PATCH v3 0/7] kcov: collect coverage from usb soft interrupts 8 (8) 2020/03/19 22:11
[PATCH v2 0/3] kcov: collect coverage from usb soft interrupts 6 (6) 2020/03/13 14:56
[PATCH v1 0/3] kcov: collect coverage from usb soft interrupts 6 (6) 2020/02/27 15:44
▶ ▼ Similar bugs (1)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
linux-4.19 KASAN: use-after-free Read in br_dev_xmit 19 syz, C error 13 1349d 1704d 0/1 upstream: reported C repro on 2021/12/19 03:10

Sample crash report:
==================================================================
BUG: KASAN: use-after-free in br_dev_xmit+0x13b8/0x1540 net/bridge/br_device.c:64
Read of size 2 at addr ffff88804ef0400e by task syz-fuzzer/9815

CPU: 0 PID: 9815 Comm: syz-fuzzer Not tainted 5.6.0-rc2-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 <IRQ>
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack+0x197/0x210 lib/dump_stack.c:118
 print_address_description.constprop.0.cold+0xd4/0x30b mm/kasan/report.c:374
 __kasan_report.cold+0x1b/0x32 mm/kasan/report.c:506
 kasan_report+0x12/0x20 mm/kasan/common.c:641
 __asan_report_load_n_noabort+0xf/0x20 mm/kasan/generic_report.c:145
 br_dev_xmit+0x13b8/0x1540 net/bridge/br_device.c:64
 __netdev_start_xmit include/linux/netdevice.h:4523 [inline]
 netdev_start_xmit include/linux/netdevice.h:4537 [inline]
 xmit_one net/core/dev.c:3475 [inline]
 dev_hard_start_xmit+0x1a3/0x9b0 net/core/dev.c:3491
 sch_direct_xmit+0x372/0xd30 net/sched/sch_generic.c:313
 __dev_xmit_skb net/core/dev.c:3697 [inline]
 __dev_queue_xmit+0x1cc6/0x3080 net/core/dev.c:4019
 dev_queue_xmit+0x18/0x20 net/core/dev.c:4083
 vlan_dev_hard_start_xmit+0x41f/0x8d0 net/8021q/vlan_dev.c:125
 __netdev_start_xmit include/linux/netdevice.h:4523 [inline]
 netdev_start_xmit include/linux/netdevice.h:4537 [inline]
 xmit_one net/core/dev.c:3475 [inline]
 dev_hard_start_xmit+0x1a3/0x9b0 net/core/dev.c:3491
 __dev_queue_xmit+0x25df/0x3080 net/core/dev.c:4050
 dev_queue_xmit+0x18/0x20 net/core/dev.c:4083
 neigh_connected_output+0x3fc/0x5f0 net/core/neighbour.c:1516
 neigh_output include/net/neighbour.h:510 [inline]
 ip6_finish_output2+0x109a/0x25c0 net/ipv6/ip6_output.c:116
 __ip6_finish_output+0x444/0xaa0 net/ipv6/ip6_output.c:142
 ip6_finish_output+0x38/0x1f0 net/ipv6/ip6_output.c:152
 NF_HOOK_COND include/linux/netfilter.h:296 [inline]
 ip6_output+0x25e/0x880 net/ipv6/ip6_output.c:175
 dst_output include/net/dst.h:436 [inline]
 NF_HOOK include/linux/netfilter.h:307 [inline]
 NF_HOOK include/linux/netfilter.h:301 [inline]
 mld_sendpack+0x9c2/0xed0 net/ipv6/mcast.c:1682
 mld_send_cr net/ipv6/mcast.c:1978 [inline]
 mld_ifc_timer_expire+0x454/0x950 net/ipv6/mcast.c:2477
 call_timer_fn+0x1ac/0x780 kernel/time/timer.c:1404
 expire_timers kernel/time/timer.c:1449 [inline]
 __run_timers kernel/time/timer.c:1773 [inline]
 __run_timers kernel/time/timer.c:1740 [inline]
 run_timer_softirq+0x6c3/0x1790 kernel/time/timer.c:1786
 __do_softirq+0x262/0x98c kernel/softirq.c:292
 invoke_softirq kernel/softirq.c:373 [inline]
 irq_exit+0x19b/0x1e0 kernel/softirq.c:413
 exiting_irq arch/x86/include/asm/apic.h:546 [inline]
 smp_apic_timer_interrupt+0x1a3/0x610 arch/x86/kernel/apic/apic.c:1146
 apic_timer_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:829
 </IRQ>
RIP: 0033:0x40c2ee
Code: 48 8b 8c 24 a0 00 00 00 48 89 4c 24 08 b9 30 00 00 00 48 0f 44 f9 48 89 7c 24 38 48 89 7c 24 10 4c 89 44 24 18 e8 92 96 00 00 <48> 8b 84 24 a8 00 00 00 48 8b 08 48 8b 54 24 38 48 39 ca 76 2e 48
RSP: 002b:000000c0107d1c88 EFLAGS: 00000202 ORIG_RAX: ffffffffffffff13
RAX: 0000000000203004 RBX: 0000000000000008 RCX: 0000000000000030
RDX: 0000000000203004 RSI: 00007f02468e1e90 RDI: 0000000000000000
RBP: 000000c0107d1d18 R08: 00007f02468e1e8f R09: 0000000000203004
R10: 0000000000000008 R11: 0000000000000077 R12: 00000000000000ff
R13: 01ffffffffffffff R14: 0000000000ac74d8 R15: 0000000000000039

Allocated by task 9815:
 save_stack+0x23/0x90 mm/kasan/common.c:72
 set_track mm/kasan/common.c:80 [inline]
 __kasan_kmalloc mm/kasan/common.c:515 [inline]
 __kasan_kmalloc.constprop.0+0xcf/0xe0 mm/kasan/common.c:488
 kasan_kmalloc+0x9/0x10 mm/kasan/common.c:529
 __do_kmalloc_node mm/slab.c:3616 [inline]
 __kmalloc_node_track_caller+0x4e/0x70 mm/slab.c:3630
 __kmalloc_reserve.isra.0+0x40/0xf0 net/core/skbuff.c:142
 __alloc_skb+0x10b/0x5e0 net/core/skbuff.c:210
 alloc_skb include/linux/skbuff.h:1081 [inline]
 alloc_skb_with_frags+0x93/0x590 net/core/skbuff.c:5764
 sock_alloc_send_pskb+0x7ad/0x920 net/core/sock.c:2250
 sock_alloc_send_skb+0x32/0x40 net/core/sock.c:2267
 mld_newpack+0x1d7/0x7f0 net/ipv6/mcast.c:1609
 add_grhead.isra.0+0x299/0x370 net/ipv6/mcast.c:1713
 add_grec+0x7db/0x10b0 net/ipv6/mcast.c:1844
 mld_send_cr net/ipv6/mcast.c:1970 [inline]
 mld_ifc_timer_expire+0x3d3/0x950 net/ipv6/mcast.c:2477
 call_timer_fn+0x1ac/0x780 kernel/time/timer.c:1404
 expire_timers kernel/time/timer.c:1449 [inline]
 __run_timers kernel/time/timer.c:1773 [inline]
 __run_timers kernel/time/timer.c:1740 [inline]
 run_timer_softirq+0x6c3/0x1790 kernel/time/timer.c:1786
 __do_softirq+0x262/0x98c kernel/softirq.c:292

Freed by task 9815:
 save_stack+0x23/0x90 mm/kasan/common.c:72
 set_track mm/kasan/common.c:80 [inline]
 kasan_set_free_info mm/kasan/common.c:337 [inline]
 __kasan_slab_free+0x102/0x150 mm/kasan/common.c:476
 kasan_slab_free+0xe/0x10 mm/kasan/common.c:485
 __cache_free mm/slab.c:3426 [inline]
 kfree+0x10a/0x2c0 mm/slab.c:3757
 skb_free_head+0x93/0xb0 net/core/skbuff.c:590
 pskb_expand_head+0x2bd/0xff0 net/core/skbuff.c:1660
 __skb_cow include/linux/skbuff.h:3169 [inline]
 skb_cow_head include/linux/skbuff.h:3203 [inline]
 __vlan_insert_inner_tag include/linux/if_vlan.h:339 [inline]
 vlan_insert_inner_tag include/linux/if_vlan.h:409 [inline]
 vlan_insert_tag include/linux/if_vlan.h:434 [inline]
 vlan_insert_tag_set_proto include/linux/if_vlan.h:453 [inline]
 __allowed_ingress net/bridge/br_vlan.c:498 [inline]
 br_allowed_ingress+0x4a2/0x1900 net/bridge/br_vlan.c:587
 br_dev_xmit+0x45e/0x1540 net/bridge/br_device.c:60
 __netdev_start_xmit include/linux/netdevice.h:4523 [inline]
 netdev_start_xmit include/linux/netdevice.h:4537 [inline]
 xmit_one net/core/dev.c:3475 [inline]
 dev_hard_start_xmit+0x1a3/0x9b0 net/core/dev.c:3491
 sch_direct_xmit+0x372/0xd30 net/sched/sch_generic.c:313
 __dev_xmit_skb net/core/dev.c:3697 [inline]
 __dev_queue_xmit+0x1cc6/0x3080 net/core/dev.c:4019
 dev_queue_xmit+0x18/0x20 net/core/dev.c:4083
 vlan_dev_hard_start_xmit+0x41f/0x8d0 net/8021q/vlan_dev.c:125
 __netdev_start_xmit include/linux/netdevice.h:4523 [inline]
 netdev_start_xmit include/linux/netdevice.h:4537 [inline]
 xmit_one net/core/dev.c:3475 [inline]
 dev_hard_start_xmit+0x1a3/0x9b0 net/core/dev.c:3491
 __dev_queue_xmit+0x25df/0x3080 net/core/dev.c:4050
 dev_queue_xmit+0x18/0x20 net/core/dev.c:4083
 neigh_connected_output+0x3fc/0x5f0 net/core/neighbour.c:1516
 neigh_output include/net/neighbour.h:510 [inline]
 ip6_finish_output2+0x109a/0x25c0 net/ipv6/ip6_output.c:116
 __ip6_finish_output+0x444/0xaa0 net/ipv6/ip6_output.c:142
 ip6_finish_output+0x38/0x1f0 net/ipv6/ip6_output.c:152
 NF_HOOK_COND include/linux/netfilter.h:296 [inline]
 ip6_output+0x25e/0x880 net/ipv6/ip6_output.c:175
 dst_output include/net/dst.h:436 [inline]
 NF_HOOK include/linux/netfilter.h:307 [inline]
 NF_HOOK include/linux/netfilter.h:301 [inline]
 mld_sendpack+0x9c2/0xed0 net/ipv6/mcast.c:1682
 mld_send_cr net/ipv6/mcast.c:1978 [inline]
 mld_ifc_timer_expire+0x454/0x950 net/ipv6/mcast.c:2477
 call_timer_fn+0x1ac/0x780 kernel/time/timer.c:1404
 expire_timers kernel/time/timer.c:1449 [inline]
 __run_timers kernel/time/timer.c:1773 [inline]
 __run_timers kernel/time/timer.c:1740 [inline]
 run_timer_softirq+0x6c3/0x1790 kernel/time/timer.c:1786
 __do_softirq+0x262/0x98c kernel/softirq.c:292

The buggy address belongs to the object at ffff88804ef04000
 which belongs to the cache kmalloc-2k of size 2048
The buggy address is located 14 bytes inside of
 2048-byte region [ffff88804ef04000, ffff88804ef04800)
The buggy address belongs to the page:
page:ffffea00013bc100 refcount:1 mapcount:0 mapping:ffff8880aa400e00 index:0x0
flags: 0xfffe0000000200(slab)
raw: 00fffe0000000200 ffffea00015a4908 ffffea0001759848 ffff8880aa400e00
raw: 0000000000000000 ffff88804ef04000 0000000100000001 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff88804ef03f00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffff88804ef03f80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>ffff88804ef04000: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                      ^
 ffff88804ef04080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff88804ef04100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2020/02/26 00:37 net-next-old c3e042f54107 59b57593 .config console log report ci-upstream-net-kasan-gce
* Struck through repros no longer work on HEAD.