linux-stable.git/drivers/net/tun.c, branch v4.20

tun: remove skb access after netif_receive_skb

2018-12-03T22:10:27+00:00

In tun.c skb->len was accessed while doing stats accounting after a
call to netif_receive_skb. We can not access skb after this call
because buffers may be dropped.

The fix for this bug would be to store skb->len in local variable and
then use it after netif_receive_skb(). IMO using xdp data size for
accounting bytes will be better because input for tun_xdp_one() is
xdp_buff.

Hence this patch:
- fixes a bug by removing skb access after netif_receive_skb()
- uses xdp data size for accounting bytes

[613.019057] BUG: KASAN: use-after-free in tun_sendmsg+0x77c/0xc50 [tun]
[613.021062] Read of size 4 at addr ffff8881da9ab7c0 by task vhost-1115/1155
[613.023073]
[613.024003] CPU: 0 PID: 1155 Comm: vhost-1115 Not tainted 4.20.0-rc3-vm+ #232
[613.026029] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.10.2-1ubuntu1 04/01/2014
[613.029116] Call Trace:
[613.031145]  dump_stack+0x5b/0x90
[613.032219]  print_address_description+0x6c/0x23c
[613.034156]  ? tun_sendmsg+0x77c/0xc50 [tun]
[613.036141]  kasan_report.cold.5+0x241/0x308
[613.038125]  tun_sendmsg+0x77c/0xc50 [tun]
[613.040109]  ? tun_get_user+0x1960/0x1960 [tun]
[613.042094]  ? __isolate_free_page+0x270/0x270
[613.045173]  vhost_tx_batch.isra.14+0xeb/0x1f0 [vhost_net]
[613.047127]  ? peek_head_len.part.13+0x90/0x90 [vhost_net]
[613.049096]  ? get_tx_bufs+0x5a/0x2c0 [vhost_net]
[613.051106]  ? vhost_enable_notify+0x2d8/0x420 [vhost]
[613.053139]  handle_tx_copy+0x2d0/0x8f0 [vhost_net]
[613.053139]  ? vhost_net_buf_peek+0x340/0x340 [vhost_net]
[613.053139]  ? __mutex_lock+0x8d9/0xb30
[613.053139]  ? finish_task_switch+0x8f/0x3f0
[613.053139]  ? handle_tx+0x32/0x120 [vhost_net]
[613.053139]  ? mutex_trylock+0x110/0x110
[613.053139]  ? finish_task_switch+0xcf/0x3f0
[613.053139]  ? finish_task_switch+0x240/0x3f0
[613.053139]  ? __switch_to_asm+0x34/0x70
[613.053139]  ? __switch_to_asm+0x40/0x70
[613.053139]  ? __schedule+0x506/0xf10
[613.053139]  handle_tx+0xc7/0x120 [vhost_net]
[613.053139]  vhost_worker+0x166/0x200 [vhost]
[613.053139]  ? vhost_dev_init+0x580/0x580 [vhost]
[613.053139]  ? __kthread_parkme+0x77/0x90
[613.053139]  ? vhost_dev_init+0x580/0x580 [vhost]
[613.053139]  kthread+0x1b1/0x1d0
[613.053139]  ? kthread_park+0xb0/0xb0
[613.053139]  ret_from_fork+0x35/0x40
[613.088705]
[613.088705] Allocated by task 1155:
[613.088705]  kasan_kmalloc+0xbf/0xe0
[613.088705]  kmem_cache_alloc+0xdc/0x220
[613.088705]  __build_skb+0x2a/0x160
[613.088705]  build_skb+0x14/0xc0
[613.088705]  tun_sendmsg+0x4f0/0xc50 [tun]
[613.088705]  vhost_tx_batch.isra.14+0xeb/0x1f0 [vhost_net]
[613.088705]  handle_tx_copy+0x2d0/0x8f0 [vhost_net]
[613.088705]  handle_tx+0xc7/0x120 [vhost_net]
[613.088705]  vhost_worker+0x166/0x200 [vhost]
[613.088705]  kthread+0x1b1/0x1d0
[613.088705]  ret_from_fork+0x35/0x40
[613.088705]
[613.088705] Freed by task 1155:
[613.088705]  __kasan_slab_free+0x12e/0x180
[613.088705]  kmem_cache_free+0xa0/0x230
[613.088705]  ip6_mc_input+0x40f/0x5a0
[613.088705]  ipv6_rcv+0xc9/0x1e0
[613.088705]  __netif_receive_skb_one_core+0xc1/0x100
[613.088705]  netif_receive_skb_internal+0xc4/0x270
[613.088705]  br_pass_frame_up+0x2b9/0x2e0
[613.088705]  br_handle_frame_finish+0x2fb/0x7a0
[613.088705]  br_handle_frame+0x30f/0x6c0
[613.088705]  __netif_receive_skb_core+0x61a/0x15b0
[613.088705]  __netif_receive_skb_one_core+0x8e/0x100
[613.088705]  netif_receive_skb_internal+0xc4/0x270
[613.088705]  tun_sendmsg+0x738/0xc50 [tun]
[613.088705]  vhost_tx_batch.isra.14+0xeb/0x1f0 [vhost_net]
[613.088705]  handle_tx_copy+0x2d0/0x8f0 [vhost_net]
[613.088705]  handle_tx+0xc7/0x120 [vhost_net]
[613.088705]  vhost_worker+0x166/0x200 [vhost]
[613.088705]  kthread+0x1b1/0x1d0
[613.088705]  ret_from_fork+0x35/0x40
[613.088705]
[613.088705] The buggy address belongs to the object at ffff8881da9ab740
[613.088705]  which belongs to the cache skbuff_head_cache of size 232

Fixes: 043d222f93ab ("tuntap: accept an array of XDP buffs through sendmsg()")
Reviewed-by: Toshiaki Makita 
Signed-off-by: Prashant Bhole 
Acked-by: Jason Wang 
Acked-by: Michael S. Tsirkin 
Signed-off-by: David S. Miller

tun: forbid iface creation with rtnl ops

2018-12-01T01:31:03+00:00

It's not supported right now (the goal of the initial patch was to support
'ip link del' only).

Before the patch:
$ ip link add foo type tun
[  239.632660] BUG: unable to handle kernel NULL pointer dereference at 0000000000000000
[snip]
[  239.636410] RIP: 0010:register_netdevice+0x8e/0x3a0

This panic occurs because dev->netdev_ops is not set by tun_setup(). But to
have something usable, it will require more than just setting
netdev_ops.

Fixes: f019a7a594d9 ("tun: Implement ip link del tunXXX")
CC: Eric W. Biederman 
Signed-off-by: Nicolas Dichtel 
Signed-off-by: David S. Miller

tuntap: fix multiqueue rx

2018-11-19T03:05:43+00:00

When writing packets to a descriptor associated with a combined queue, the
packets should end up on that queue.

Before this change all packets written to any descriptor associated with a
tap interface end up on rx-0, even when the descriptor is associated with a
different queue.

The rx traffic can be generated by either of the following.
  1. a simple tap program which spins up multiple queues and writes packets
     to each of the file descriptors
  2. tx from a qemu vm with a tap multiqueue netdev

The queue for rx traffic can be observed by either of the following (done
on the hypervisor in the qemu case).
  1. a simple netmap program which opens and reads from per-queue
     descriptors
  2. configuring RPS and doing per-cpu captures with rxtxcpu

Alternatively, if you printk() the return value of skb_get_rx_queue() just
before each instance of netif_receive_skb() in tun.c, you will get 65535
for every skb.

Calling skb_record_rx_queue() to set the rx queue to the queue_index fixes
the association between descriptor and rx queue.

Signed-off-by: Matthew Cover 
Signed-off-by: David S. Miller

tun: Consistently configure generic netdev params via rtnetlink

2018-10-16T04:40:31+00:00

Configuring generic network device parameters on tun will fail in
presence of IFLA_INFO_KIND attribute in IFLA_LINKINFO nested attribute
since tun_validate() always return failure.

This can be visualized with following ip-link(8) command sequences:

  # ip link set dev tun0 group 100
  # ip link set dev tun0 group 100 type tun
  RTNETLINK answers: Invalid argument

with contrast to dummy and veth drivers:

  # ip link set dev dummy0 group 100
  # ip link set dev dummy0 type dummy

  # ip link set dev veth0 group 100
  # ip link set dev veth0 group 100 type veth

Fix by returning zero in tun_validate() when @data is NULL that is
always in case since rtnl_link_ops->maxtype is zero in tun driver.

Fixes: f019a7a594d9 ("tun: Implement ip link del tunXXX")
Signed-off-by: Serhey Popovych 
Signed-off-by: David S. Miller

net: tun: remove useless codes of tun_automq_select_queue

2018-10-11T05:35:22+00:00

Because the function __skb_get_hash_symmetric always returns non-zero.

Signed-off-by: Zhang Yu 
Signed-off-by: Wang Li 
Signed-off-by: David S. Miller

Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net

2018-10-04T04:00:17+00:00

Minor conflict in net/core/rtnetlink.c, David Ahern's bug fix in 'net'
overlapped the renaming of a netlink attribute in net-next.

Signed-off-by: David S. Miller

tun: napi flags belong to tfile

2018-10-02T06:27:28+00:00

Since tun->flags might be shared by multiple tfile structures,
it is better to make sure tun_get_user() is using the flags
for the current tfile.

Presence of the READ_ONCE() in tun_napi_frags_enabled() gave a hint
of what could happen, but we need something stronger to please
syzbot.

kasan: CONFIG_KASAN_INLINE enabled
kasan: GPF could be caused by NULL-ptr deref or user memory access
general protection fault: 0000 [#1] PREEMPT SMP KASAN
CPU: 0 PID: 13647 Comm: syz-executor5 Not tainted 4.19.0-rc5+ #59
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
RIP: 0010:dev_gro_receive+0x132/0x2720 net/core/dev.c:5427
Code: 48 c1 ea 03 80 3c 02 00 0f 85 6e 20 00 00 48 b8 00 00 00 00 00 fc ff df 4d 8b 6e 10 49 8d bd d0 00 00 00 48 89 fa 48 c1 ea 03 <80> 3c 02 00 0f 85 59 20 00 00 4d 8b a5 d0 00 00 00 31 ff 41 81 e4
RSP: 0018:ffff8801c400f410 EFLAGS: 00010202
RAX: dffffc0000000000 RBX: 0000000000000000 RCX: ffffffff8618d325
RDX: 000000000000001a RSI: ffffffff86189f97 RDI: 00000000000000d0
RBP: ffff8801c400f608 R08: ffff8801c8fb4300 R09: 0000000000000000
R10: ffffed0038801ed7 R11: 0000000000000003 R12: ffff8801d327d358
R13: 0000000000000000 R14: ffff8801c16dd8c0 R15: 0000000000000004
FS:  00007fe003615700(0000) GS:ffff8801dac00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fe1f3c43db8 CR3: 00000001bebb2000 CR4: 00000000001406f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 napi_gro_frags+0x3f4/0xc90 net/core/dev.c:5715
 tun_get_user+0x31d5/0x42a0 drivers/net/tun.c:1922
 tun_chr_write_iter+0xb9/0x154 drivers/net/tun.c:1967
 call_write_iter include/linux/fs.h:1808 [inline]
 new_sync_write fs/read_write.c:474 [inline]
 __vfs_write+0x6b8/0x9f0 fs/read_write.c:487
 vfs_write+0x1fc/0x560 fs/read_write.c:549
 ksys_write+0x101/0x260 fs/read_write.c:598
 __do_sys_write fs/read_write.c:610 [inline]
 __se_sys_write fs/read_write.c:607 [inline]
 __x64_sys_write+0x73/0xb0 fs/read_write.c:607
 do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x457579
Code: 1d b4 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 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 0f 83 eb b3 fb ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007fe003614c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 0000000000457579
RDX: 0000000000000012 RSI: 0000000020000000 RDI: 000000000000000a
RBP: 000000000072c040 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007fe0036156d4
R13: 00000000004c5574 R14: 00000000004d8e98 R15: 00000000ffffffff
Modules linked in:

RIP: 0010:dev_gro_receive+0x132/0x2720 net/core/dev.c:5427
Code: 48 c1 ea 03 80 3c 02 00 0f 85 6e 20 00 00 48 b8 00 00 00 00 00 fc ff df 4d 8b 6e 10 49 8d bd d0 00 00 00 48 89 fa 48 c1 ea 03 <80> 3c 02 00 0f 85 59 20 00 00 4d 8b a5 d0 00 00 00 31 ff 41 81 e4
RSP: 0018:ffff8801c400f410 EFLAGS: 00010202
RAX: dffffc0000000000 RBX: 0000000000000000 RCX: ffffffff8618d325
RDX: 000000000000001a RSI: ffffffff86189f97 RDI: 00000000000000d0
RBP: ffff8801c400f608 R08: ffff8801c8fb4300 R09: 0000000000000000
R10: ffffed0038801ed7 R11: 0000000000000003 R12: ffff8801d327d358
R13: 0000000000000000 R14: ffff8801c16dd8c0 R15: 0000000000000004
FS:  00007fe003615700(0000) GS:ffff8801dac00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fe1f3c43db8 CR3: 00000001bebb2000 CR4: 00000000001406f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400

Fixes: 90e33d459407 ("tun: enable napi_gro_frags() for TUN/TAP driver")
Signed-off-by: Eric Dumazet 
Reported-by: syzbot 
Signed-off-by: David S. Miller

tun: initialize napi_mutex unconditionally

2018-10-02T06:27:28+00:00

This is the first part to fix following syzbot report :

console output: https://syzkaller.appspot.com/x/log.txt?x=145378e6400000
kernel config:  https://syzkaller.appspot.com/x/.config?x=443816db871edd66
dashboard link: https://syzkaller.appspot.com/bug?extid=e662df0ac1d753b57e80

Following patch is fixing the race condition, but it seems safer
to initialize this mutex at tfile creation anyway.

Fixes: 90e33d459407 ("tun: enable napi_gro_frags() for TUN/TAP driver")
Signed-off-by: Eric Dumazet 
Reported-by: syzbot+e662df0ac1d753b57e80@syzkaller.appspotmail.com
Signed-off-by: David S. Miller

tun: remove unused parameters

2018-10-02T06:27:28+00:00

tun_napi_disable() and tun_napi_del() do not need
a pointer to the tun_struct

Signed-off-by: Eric Dumazet 
Signed-off-by: David S. Miller

Merge ra.kernel.org:/pub/scm/linux/kernel/git/davem/net

2018-09-25T17:35:29+00:00

Version bump conflict in batman-adv, take what's in net-next.

iavf conflict, adjustment of netdev_ops in net-next conflicting
with poll controller method removal in net.

Signed-off-by: David S. Miller