releases/4.4.133/sock_diag-fix-use-after-free-read-in-__sk_free.patch

   1 From foo@baz Tue May 22 21:07:28 CEST 2018
   2 From: Eric Dumazet <edumazet@google.com>
   3 Date: Fri, 18 May 2018 04:47:55 -0700
   4 Subject: sock_diag: fix use-after-free read in __sk_free
   5
   6 From: Eric Dumazet <edumazet@google.com>
   7
   8 [ Upstream commit 9709020c86f6bf8439ca3effc58cfca49a5de192 ]
   9
  10 We must not call sock_diag_has_destroy_listeners(sk) on a socket
  11 that has no reference on net structure.
  12
  13 BUG: KASAN: use-after-free in sock_diag_has_destroy_listeners include/linux/sock_diag.h:75 [inline]
  14 BUG: KASAN: use-after-free in __sk_free+0x329/0x340 net/core/sock.c:1609
  15 Read of size 8 at addr ffff88018a02e3a0 by task swapper/1/0
  16
  17 CPU: 1 PID: 0 Comm: swapper/1 Not tainted 4.17.0-rc5+ #54
  18 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
  19 Call Trace:
  20  <IRQ>
  21  __dump_stack lib/dump_stack.c:77 [inline]
  22  dump_stack+0x1b9/0x294 lib/dump_stack.c:113
  23  print_address_description+0x6c/0x20b mm/kasan/report.c:256
  24  kasan_report_error mm/kasan/report.c:354 [inline]
  25  kasan_report.cold.7+0x242/0x2fe mm/kasan/report.c:412
  26  __asan_report_load8_noabort+0x14/0x20 mm/kasan/report.c:433
  27  sock_diag_has_destroy_listeners include/linux/sock_diag.h:75 [inline]
  28  __sk_free+0x329/0x340 net/core/sock.c:1609
  29  sk_free+0x42/0x50 net/core/sock.c:1623
  30  sock_put include/net/sock.h:1664 [inline]
  31  reqsk_free include/net/request_sock.h:116 [inline]
  32  reqsk_put include/net/request_sock.h:124 [inline]
  33  inet_csk_reqsk_queue_drop_and_put net/ipv4/inet_connection_sock.c:672 [inline]
  34  reqsk_timer_handler+0xe27/0x10e0 net/ipv4/inet_connection_sock.c:739
  35  call_timer_fn+0x230/0x940 kernel/time/timer.c:1326
  36  expire_timers kernel/time/timer.c:1363 [inline]
  37  __run_timers+0x79e/0xc50 kernel/time/timer.c:1666
  38  run_timer_softirq+0x4c/0x70 kernel/time/timer.c:1692
  39  __do_softirq+0x2e0/0xaf5 kernel/softirq.c:285
  40  invoke_softirq kernel/softirq.c:365 [inline]
  41  irq_exit+0x1d1/0x200 kernel/softirq.c:405
  42  exiting_irq arch/x86/include/asm/apic.h:525 [inline]
  43  smp_apic_timer_interrupt+0x17e/0x710 arch/x86/kernel/apic/apic.c:1052
  44  apic_timer_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:863
  45  </IRQ>
  46 RIP: 0010:native_safe_halt+0x6/0x10 arch/x86/include/asm/irqflags.h:54
  47 RSP: 0018:ffff8801d9ae7c38 EFLAGS: 00000282 ORIG_RAX: ffffffffffffff13
  48 RAX: dffffc0000000000 RBX: 1ffff1003b35cf8a RCX: 0000000000000000
  49 RDX: 1ffffffff11a30d0 RSI: 0000000000000001 RDI: ffffffff88d18680
  50 RBP: ffff8801d9ae7c38 R08: ffffed003b5e46c3 R09: 0000000000000000
  51 R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000001
  52 R13: ffff8801d9ae7cf0 R14: ffffffff897bef20 R15: 0000000000000000
  53  arch_safe_halt arch/x86/include/asm/paravirt.h:94 [inline]
  54  default_idle+0xc2/0x440 arch/x86/kernel/process.c:354
  55  arch_cpu_idle+0x10/0x20 arch/x86/kernel/process.c:345
  56  default_idle_call+0x6d/0x90 kernel/sched/idle.c:93
  57  cpuidle_idle_call kernel/sched/idle.c:153 [inline]
  58  do_idle+0x395/0x560 kernel/sched/idle.c:262
  59  cpu_startup_entry+0x104/0x120 kernel/sched/idle.c:368
  60  start_secondary+0x426/0x5b0 arch/x86/kernel/smpboot.c:269
  61  secondary_startup_64+0xa5/0xb0 arch/x86/kernel/head_64.S:242
  62
  63 Allocated by task 4557:
  64  save_stack+0x43/0xd0 mm/kasan/kasan.c:448
  65  set_track mm/kasan/kasan.c:460 [inline]
  66  kasan_kmalloc+0xc4/0xe0 mm/kasan/kasan.c:553
  67  kasan_slab_alloc+0x12/0x20 mm/kasan/kasan.c:490
  68  kmem_cache_alloc+0x12e/0x760 mm/slab.c:3554
  69  kmem_cache_zalloc include/linux/slab.h:691 [inline]
  70  net_alloc net/core/net_namespace.c:383 [inline]
  71  copy_net_ns+0x159/0x4c0 net/core/net_namespace.c:423
  72  create_new_namespaces+0x69d/0x8f0 kernel/nsproxy.c:107
  73  unshare_nsproxy_namespaces+0xc3/0x1f0 kernel/nsproxy.c:206
  74  ksys_unshare+0x708/0xf90 kernel/fork.c:2408
  75  __do_sys_unshare kernel/fork.c:2476 [inline]
  76  __se_sys_unshare kernel/fork.c:2474 [inline]
  77  __x64_sys_unshare+0x31/0x40 kernel/fork.c:2474
  78  do_syscall_64+0x1b1/0x800 arch/x86/entry/common.c:287
  79  entry_SYSCALL_64_after_hwframe+0x49/0xbe
  80
  81 Freed by task 69:
  82  save_stack+0x43/0xd0 mm/kasan/kasan.c:448
  83  set_track mm/kasan/kasan.c:460 [inline]
  84  __kasan_slab_free+0x11a/0x170 mm/kasan/kasan.c:521
  85  kasan_slab_free+0xe/0x10 mm/kasan/kasan.c:528
  86  __cache_free mm/slab.c:3498 [inline]
  87  kmem_cache_free+0x86/0x2d0 mm/slab.c:3756
  88  net_free net/core/net_namespace.c:399 [inline]
  89  net_drop_ns.part.14+0x11a/0x130 net/core/net_namespace.c:406
  90  net_drop_ns net/core/net_namespace.c:405 [inline]
  91  cleanup_net+0x6a1/0xb20 net/core/net_namespace.c:541
  92  process_one_work+0xc1e/0x1b50 kernel/workqueue.c:2145
  93  worker_thread+0x1cc/0x1440 kernel/workqueue.c:2279
  94  kthread+0x345/0x410 kernel/kthread.c:240
  95  ret_from_fork+0x3a/0x50 arch/x86/entry/entry_64.S:412
  96
  97 The buggy address belongs to the object at ffff88018a02c140
  98  which belongs to the cache net_namespace of size 8832
  99 The buggy address is located 8800 bytes inside of
 100  8832-byte region [ffff88018a02c140, ffff88018a02e3c0)
 101 The buggy address belongs to the page:
 102 page:ffffea0006280b00 count:1 mapcount:0 mapping:ffff88018a02c140 index:0x0 compound_mapcount: 0
 103 flags: 0x2fffc0000008100(slab|head)
 104 raw: 02fffc0000008100 ffff88018a02c140 0000000000000000 0000000100000001
 105 raw: ffffea00062a1320 ffffea0006268020 ffff8801d9bdde40 0000000000000000
 106 page dumped because: kasan: bad access detected
 107
 108 Fixes: b922622ec6ef ("sock_diag: don't broadcast kernel sockets")
 109 Signed-off-by: Eric Dumazet <edumazet@google.com>
 110 Cc: Craig Gallek <kraig@google.com>
 111 Reported-by: syzbot <syzkaller@googlegroups.com>
 112 Signed-off-by: David S. Miller <davem@davemloft.net>
 113 Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
 114 ---
 115  net/core/sock.c |    2 +-
 116  1 file changed, 1 insertion(+), 1 deletion(-)
 117
 118 --- a/net/core/sock.c
 119 +++ b/net/core/sock.c
 120 @@ -1474,7 +1474,7 @@ void sk_destruct(struct sock *sk)
 121
 122  static void __sk_free(struct sock *sk)
 123  {
 124 -       if (unlikely(sock_diag_has_destroy_listeners(sk) && sk->sk_net_refcnt))
 125 +       if (unlikely(sk->sk_net_refcnt && sock_diag_has_destroy_listeners(sk)))
 126                 sock_diag_broadcast_destroy(sk);
 127         else
 128                 sk_destruct(sk);