Subject: KASAN: stack-out-of-bounds Read in __netif_receive_skb_core

From: syzbot <[email-masked]>
Date: Wed, 04 Jul 2018 21:59:02 -0700

Hello,

syzbot found the following crash on:

HEAD commit:    2bdea157b999 Merge branch 'sctp-fully-support-for-dscp-and..
git tree:       bpf-next
console output: https://syzkaller.appspot.com/x/log.txt?x=178c5e68400000
kernel config:  https://syzkaller.appspot.com/x/.config?x=f62553dc846b0692
dashboard link: https://syzkaller.appspot.com/bug?extid=4e955f82549d361ed655
compiler:       gcc (GCC) 8.0.1 20180413 (experimental)
syzkaller repro:https://syzkaller.appspot.com/x/repro.syz?x=15038ad0400000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=1465b670400000

IMPORTANT: if you fix the bug, please add the following tag to the commit:
Reported-by: [email-masked]

==================================================================
BUG: KASAN: stack-out-of-bounds in __read_once_size  
include/linux/compiler.h:188 [inline]
BUG: KASAN: stack-out-of-bounds in __netif_receive_skb_core+0x2e09/0x3680  
net/core/dev.c:4657
Read of size 8 at addr ffff8801a852d1e8 by task swapper/0/0

CPU: 0 PID: 0 Comm: swapper/0 Not tainted 4.18.0-rc3+ #45
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+0x1c9/0x2b4 lib/dump_stack.c:113
  print_address_description+0x6c/0x20b mm/kasan/report.c:256
  kasan_report_error mm/kasan/report.c:354 [inline]
  kasan_report.cold.7+0x242/0x2fe mm/kasan/report.c:412
  __asan_report_load8_noabort+0x14/0x20 mm/kasan/report.c:433
  __read_once_size include/linux/compiler.h:188 [inline]
  __netif_receive_skb_core+0x2e09/0x3680 net/core/dev.c:4657
  __netif_receive_skb+0x2c/0x1e0 net/core/dev.c:4807
  netif_receive_skb_internal+0x12e/0x680 net/core/dev.c:4881
  napi_skb_finish net/core/dev.c:5270 [inline]
  napi_gro_receive+0x465/0x5c0 net/core/dev.c:5301
  receive_buf+0xc97/0x2bf0 drivers/net/virtio_net.c:996
  virtnet_receive drivers/net/virtio_net.c:1252 [inline]
  virtnet_poll+0x3d5/0xe3d drivers/net/virtio_net.c:1334
  napi_poll net/core/dev.c:5926 [inline]
  net_rx_action+0x7a5/0x1950 net/core/dev.c:5992
  __do_softirq+0x2e8/0xb17 kernel/softirq.c:288
  invoke_softirq kernel/softirq.c:368 [inline]
  irq_exit+0x1d1/0x200 kernel/softirq.c:408
  exiting_irq arch/x86/include/asm/apic.h:527 [inline]
  do_IRQ+0xf1/0x190 arch/x86/kernel/irq.c:257
  common_interrupt+0xf/0xf arch/x86/entry/entry_64.S:642
  </IRQ>
RIP: 0010:native_safe_halt+0x6/0x10 arch/x86/include/asm/irqflags.h:54
Code: c7 48 89 45 d8 e8 7a b1 25 fa 48 8b 45 d8 e9 d2 fe ff ff 48 89 df e8  
69 b1 25 fa eb 8a 90 90 90 90 90 90 90 55 48 89 e5 fb f4 <5d> c3 0f 1f 84  
00 00 00 00 00 55 48 89 e5 f4 5d c3 90 90 90 90 90
RSP: 0018:ffffffff88e07bc0 EFLAGS: 00000282 ORIG_RAX: ffffffffffffffd9
RAX: dffffc0000000000 RBX: 1ffffffff11c0f7b RCX: ffffffff81667982
RDX: 1ffffffff11e3610 RSI: 0000000000000004 RDI: ffffffff88f1b080
RBP: ffffffff88e07bc0 R08: ffffed003b5c46d7 R09: ffffed003b5c46d6
R10: ffffed003b5c46d6 R11: ffff8801dae236b3 R12: 0000000000000000
R13: ffffffff88e07c78 R14: ffffffff899ebe60 R15: 0000000000000000
  arch_safe_halt arch/x86/include/asm/paravirt.h:94 [inline]
  default_idle+0xc7/0x450 arch/x86/kernel/process.c:500
  arch_cpu_idle+0x10/0x20 arch/x86/kernel/process.c:491
  default_idle_call+0x6d/0x90 kernel/sched/idle.c:93
  cpuidle_idle_call kernel/sched/idle.c:153 [inline]
  do_idle+0x3aa/0x570 kernel/sched/idle.c:262
  cpu_startup_entry+0x10c/0x120 kernel/sched/idle.c:368
  rest_init+0xe1/0xe4 init/main.c:442
  start_kernel+0x90e/0x949 init/main.c:738
  x86_64_start_reservations+0x29/0x2b arch/x86/kernel/head64.c:452
  x86_64_start_kernel+0x76/0x79 arch/x86/kernel/head64.c:433
  secondary_startup_64+0xa5/0xb0 arch/x86/kernel/head_64.S:242

Allocated by task 0:
(stack is not available)

Freed by task 0:
(stack is not available)

The buggy address belongs to the object at ffff8801a852ca80
  which belongs to the cache kmalloc-2048 of size 2048
The buggy address is located 1896 bytes inside of
  2048-byte region [ffff8801a852ca80, ffff8801a852d280)
The buggy address belongs to the page:
page:ffffea0006a14b00 count:1 mapcount:0 mapping:ffff8801da800c40 index:0x0  
compound_mapcount: 0
flags: 0x2fffc0000008100(slab|head)
raw: 02fffc0000008100 ffffea0006c6bd08 ffffea0006c7f688 ffff8801da800c40
raw: 0000000000000000 ffff8801a852c200 0000000100000003 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
  ffff8801a852d080: f2 f2 f2 f8 f2 f2 f2 f2 f2 f2 f2 00 f2 f2 f2 00
  ffff8801a852d100: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
> ffff8801a852d180: 00 00 00 00 f1 f1 f1 f1 00 f2 f2 f2 f2 f2 f2 f2
                                                           ^
  ffff8801a852d200: 00 f2 f2 f2 f2 f2 f2 f2 00 f2 f2 f2 f2 f2 f2 f2
  ffff8801a852d280: f8 f2 f2 f2 f2 f2 f2 f2 00 f2 f2 f2 00 00 00 00
==================================================================

---
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