target/linux/generic/pending-3.18/081-08-pppoe-fix-memory-corruption-in-padt-work-structure.patch

   1 From: Guillaume Nault <g.nault@alphalink.fr>
   2 Date: Thu, 3 Dec 2015 16:49:32 +0100
   3 Subject: [PATCH] pppoe: fix memory corruption in padt work structure
   4
   5 pppoe_connect() mustn't touch the padt_work field of pppoe sockets
   6 because that work could be already pending.
   7
   8 [   21.473147] BUG: unable to handle kernel NULL pointer dereference at 00000004
   9 [   21.474523] IP: [<c1043177>] process_one_work+0x29/0x31c
  10 [   21.475164] *pde = 00000000
  11 [   21.475513] Oops: 0000 [#1] SMP
  12 [   21.475910] Modules linked in: pppoe pppox ppp_generic slhc crc32c_intel aesni_intel virtio_net xts aes_i586 lrw gf128mul ablk_helper cryptd evdev acpi_cpufreq processor serio_raw button ext4 crc16 mbcache jbd2 virtio_blk virtio_pci virtio_ring virtio
  13 [   21.476168] CPU: 2 PID: 164 Comm: kworker/2:2 Not tainted 4.4.0-rc1 #1
  14 [   21.476168] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Debian-1.8.2-1 04/01/2014
  15 [   21.476168] task: f5f83c00 ti: f5e28000 task.ti: f5e28000
  16 [   21.476168] EIP: 0060:[<c1043177>] EFLAGS: 00010046 CPU: 2
  17 [   21.476168] EIP is at process_one_work+0x29/0x31c
  18 [   21.484082] EAX: 00000000 EBX: f678b2a0 ECX: 00000004 EDX: 00000000
  19 [   21.484082] ESI: f6c69940 EDI: f5e29ef0 EBP: f5e29f0c ESP: f5e29edc
  20 [   21.484082]  DS: 007b ES: 007b FS: 00d8 GS: 0000 SS: 0068
  21 [   21.484082] CR0: 80050033 CR2: 000000a4 CR3: 317ad000 CR4: 00040690
  22 [   21.484082] Stack:
  23 [   21.484082]  00000000 f6c69950 00000000 f6c69940 c0042338 f5e29f0c c1327945 00000000
  24 [   21.484082]  00000008 f678b2a0 f6c69940 f678b2b8 f5e29f30 c1043984 f5f83c00 f6c69970
  25 [   21.484082]  f678b2a0 c10437d3 f6775e80 f678b2a0 c10437d3 f5e29fac c1047059 f5e29f74
  26 [   21.484082] Call Trace:
  27 [   21.484082]  [<c1327945>] ? _raw_spin_lock_irq+0x28/0x30
  28 [   21.484082]  [<c1043984>] worker_thread+0x1b1/0x244
  29 [   21.484082]  [<c10437d3>] ? rescuer_thread+0x229/0x229
  30 [   21.484082]  [<c10437d3>] ? rescuer_thread+0x229/0x229
  31 [   21.484082]  [<c1047059>] kthread+0x8f/0x94
  32 [   21.484082]  [<c1327a32>] ? _raw_spin_unlock_irq+0x22/0x26
  33 [   21.484082]  [<c1327ee9>] ret_from_kernel_thread+0x21/0x38
  34 [   21.484082]  [<c1046fca>] ? kthread_parkme+0x19/0x19
  35 [   21.496082] Code: 5d c3 55 89 e5 57 56 53 89 c3 83 ec 24 89 d0 89 55 e0 8d 7d e4 e8 6c d8 ff ff b9 04 00 00 00 89 45 d8 8b 43 24 89 45 dc 8b 45 d8 <8b> 40 04 8b 80 e0 00 00 00 c1 e8 05 24 01 88 45 d7 8b 45 e0 8d
  36 [   21.496082] EIP: [<c1043177>] process_one_work+0x29/0x31c SS:ESP 0068:f5e29edc
  37 [   21.496082] CR2: 0000000000000004
  38 [   21.496082] ---[ end trace e362cc9cf10dae89 ]---
  39
  40 Reported-by: Andrew <nitr0@seti.kr.ua>
  41 Fixes: 287f3a943fef ("pppoe: Use workqueue to die properly when a PADT is received")
  42 Signed-off-by: Guillaume Nault <g.nault@alphalink.fr>
  43 Signed-off-by: David S. Miller <davem@davemloft.net>
  44 ---
  45
  46 --- a/drivers/net/ppp/pppoe.c
  47 +++ b/drivers/net/ppp/pppoe.c
  48 @@ -550,6 +550,9 @@ static int pppoe_create(struct net *net,
  49         sk->sk_family           = PF_PPPOX;
  50         sk->sk_protocol         = PX_PROTO_OE;
  51
  52 +       INIT_WORK(&pppox_sk(sk)->proto.pppoe.padt_work,
  53 +                 pppoe_unbind_sock_work);
  54 +
  55         return 0;
  56  }
  57
  58 @@ -614,8 +617,6 @@ static int pppoe_connect(struct socket *
  59
  60         lock_sock(sk);
  61
  62 -       INIT_WORK(&po->proto.pppoe.padt_work, pppoe_unbind_sock_work);
  63 -
  64         error = -EINVAL;
  65
  66         if (sockaddr_len != sizeof(struct sockaddr_pppox))
  67 @@ -649,8 +650,13 @@ static int pppoe_connect(struct socket *
  68                         po->pppoe_dev = NULL;
  69                 }
  70
  71 -               memset(sk_pppox(po) + 1, 0,
  72 -                      sizeof(struct pppox_sock) - sizeof(struct sock));
  73 +               po->pppoe_ifindex = 0;
  74 +               memset(&po->pppoe_pa, 0, sizeof(po->pppoe_pa));
  75 +               memset(&po->pppoe_relay, 0, sizeof(po->pppoe_relay));
  76 +               memset(&po->chan, 0, sizeof(po->chan));
  77 +               po->next = NULL;
  78 +               po->num = 0;
  79 +
  80                 sk->sk_state = PPPOX_NONE;
  81         }
  82