linux-stable.git/drivers/net/tun.c, branch v4.9.78

tun: allow positive return values on dev_get_valid_name() call

2017-11-18T10:22:23+00:00

[ Upstream commit 5c25f65fd1e42685f7ccd80e0621829c105785d9 ]

If the name argument of dev_get_valid_name() contains "%d", it will try
to assign it a unit number in __dev__alloc_name() and return either the
unit number (>= 0) or an error code (< 0).
Considering positive values as error values prevent tun device creations
relying this mechanism, therefor we should only consider negative values
as errors here.

Signed-off-by: Julien Gomes 
Acked-by: Cong Wang 
Signed-off-by: David S. Miller 
Signed-off-by: Greg Kroah-Hartman

tun: call dev_get_valid_name() before register_netdevice()

2017-11-18T10:22:21+00:00

[ Upstream commit 0ad646c81b2182f7fa67ec0c8c825e0ee165696d ]

register_netdevice() could fail early when we have an invalid
dev name, in which case ->ndo_uninit() is not called. For tun
device, this is a problem because a timer etc. are already
initialized and it expects ->ndo_uninit() to clean them up.

We could move these initializations into a ->ndo_init() so
that register_netdevice() knows better, however this is still
complicated due to the logic in tun_detach().

Therefore, I choose to just call dev_get_valid_name() before
register_netdevice(), which is quicker and much easier to audit.
And for this specific case, it is already enough.

Fixes: 96442e42429e ("tuntap: choose the txq based on rxq")
Reported-by: Dmitry Alexeev 
Cc: Jason Wang 
Cc: "Michael S. Tsirkin" 
Signed-off-by: Cong Wang 
Signed-off-by: David S. Miller 
Signed-off-by: Greg Kroah-Hartman

tun/tap: sanitize TUNSETSNDBUF input

2017-11-18T10:22:21+00:00

[ Upstream commit 93161922c658c714715686cd0cf69b090cb9bf1d ]

Syzkaller found several variants of the lockup below by setting negative
values with the TUNSETSNDBUF ioctl.  This patch adds a sanity check
to both the tun and tap versions of this ioctl.

  watchdog: BUG: soft lockup - CPU#0 stuck for 22s! [repro:2389]
  Modules linked in:
  irq event stamp: 329692056
  hardirqs last  enabled at (329692055): [] _raw_spin_unlock_irqrestore+0x31/0x75
  hardirqs last disabled at (329692056): [] apic_timer_interrupt+0x98/0xb0
  softirqs last  enabled at (35659740): [] __do_softirq+0x328/0x48c
  softirqs last disabled at (35659731): [] irq_exit+0xbc/0xd0
  CPU: 0 PID: 2389 Comm: repro Not tainted 4.14.0-rc7 #23
  Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Bochs 01/01/2011
  task: ffff880009452140 task.stack: ffff880006a20000
  RIP: 0010:_raw_spin_lock_irqsave+0x11/0x80
  RSP: 0018:ffff880006a27c50 EFLAGS: 00000282 ORIG_RAX: ffffffffffffff10
  RAX: ffff880009ac68d0 RBX: ffff880006a27ce0 RCX: 0000000000000000
  RDX: 0000000000000001 RSI: ffff880006a27ce0 RDI: ffff880009ac6900
  RBP: ffff880006a27c60 R08: 0000000000000000 R09: 0000000000000000
  R10: 0000000000000001 R11: 000000000063ff00 R12: ffff880009ac6900
  R13: ffff880006a27cf8 R14: 0000000000000001 R15: ffff880006a27cf8
  FS:  00007f4be4838700(0000) GS:ffff88000cc00000(0000) knlGS:0000000000000000
  CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
  CR2: 0000000020101000 CR3: 0000000009616000 CR4: 00000000000006f0
  Call Trace:
   prepare_to_wait+0x26/0xc0
   sock_alloc_send_pskb+0x14e/0x270
   ? remove_wait_queue+0x60/0x60
   tun_get_user+0x2cc/0x19d0
   ? __tun_get+0x60/0x1b0
   tun_chr_write_iter+0x57/0x86
   __vfs_write+0x156/0x1e0
   vfs_write+0xf7/0x230
   SyS_write+0x57/0xd0
   entry_SYSCALL_64_fastpath+0x1f/0xbe
  RIP: 0033:0x7f4be4356df9
  RSP: 002b:00007ffc18101c08 EFLAGS: 00000293 ORIG_RAX: 0000000000000001
  RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f4be4356df9
  RDX: 0000000000000046 RSI: 0000000020101000 RDI: 0000000000000005
  RBP: 00007ffc18101c40 R08: 0000000000000001 R09: 0000000000000001
  R10: 0000000000000001 R11: 0000000000000293 R12: 0000559c75f64780
  R13: 00007ffc18101d30 R14: 0000000000000000 R15: 0000000000000000

Fixes: 33dccbb050bb ("tun: Limit amount of queued packets per device")
Fixes: 20d29d7a916a ("net: macvtap driver")
Signed-off-by: Craig Gallek 
Reviewed-by: Eric Dumazet 
Signed-off-by: David S. Miller 
Signed-off-by: Greg Kroah-Hartman

tun: bail out from tun_get_user() if the skb is empty

2017-10-12T09:51:22+00:00

[ Upstream commit 2580c4c17aee3ad58e9751012bad278dd074ccae ]

KMSAN (https://github.com/google/kmsan) reported accessing uninitialized
skb->data[0] in the case the skb is empty (i.e. skb->len is 0):

================================================
BUG: KMSAN: use of uninitialized memory in tun_get_user+0x19ba/0x3770
CPU: 0 PID: 3051 Comm: probe Not tainted 4.13.0+ #3140
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Bochs 01/01/2011
Call Trace:
...
 __msan_warning_32+0x66/0xb0 mm/kmsan/kmsan_instr.c:477
 tun_get_user+0x19ba/0x3770 drivers/net/tun.c:1301
 tun_chr_write_iter+0x19f/0x300 drivers/net/tun.c:1365
 call_write_iter ./include/linux/fs.h:1743
 new_sync_write fs/read_write.c:457
 __vfs_write+0x6c3/0x7f0 fs/read_write.c:470
 vfs_write+0x3e4/0x770 fs/read_write.c:518
 SYSC_write+0x12f/0x2b0 fs/read_write.c:565
 SyS_write+0x55/0x80 fs/read_write.c:557
 do_syscall_64+0x242/0x330 arch/x86/entry/common.c:284
 entry_SYSCALL64_slow_path+0x25/0x25 arch/x86/entry/entry_64.S:245
...
origin:
...
 kmsan_poison_shadow+0x6e/0xc0 mm/kmsan/kmsan.c:211
 slab_alloc_node mm/slub.c:2732
 __kmalloc_node_track_caller+0x351/0x370 mm/slub.c:4351
 __kmalloc_reserve net/core/skbuff.c:138
 __alloc_skb+0x26a/0x810 net/core/skbuff.c:231
 alloc_skb ./include/linux/skbuff.h:903
 alloc_skb_with_frags+0x1d7/0xc80 net/core/skbuff.c:4756
 sock_alloc_send_pskb+0xabf/0xfe0 net/core/sock.c:2037
 tun_alloc_skb drivers/net/tun.c:1144
 tun_get_user+0x9a8/0x3770 drivers/net/tun.c:1274
 tun_chr_write_iter+0x19f/0x300 drivers/net/tun.c:1365
 call_write_iter ./include/linux/fs.h:1743
 new_sync_write fs/read_write.c:457
 __vfs_write+0x6c3/0x7f0 fs/read_write.c:470
 vfs_write+0x3e4/0x770 fs/read_write.c:518
 SYSC_write+0x12f/0x2b0 fs/read_write.c:565
 SyS_write+0x55/0x80 fs/read_write.c:557
 do_syscall_64+0x242/0x330 arch/x86/entry/common.c:284
 return_from_SYSCALL_64+0x0/0x6a arch/x86/entry/entry_64.S:245
================================================

Make sure tun_get_user() doesn't touch skb->data[0] unless there is
actual data.

C reproducer below:
==========================
    // autogenerated by syzkaller (http://github.com/google/syzkaller)

    #define _GNU_SOURCE

    #include 
    #include 
    #include 
    #include 
    #include 
    #include 

    int main()
    {
      int sock = socket(PF_INET, SOCK_STREAM, IPPROTO_IP);
      int tun_fd = open("/dev/net/tun", O_RDWR);
      struct ifreq req;
      memset(&req, 0, sizeof(struct ifreq));
      strcpy((char*)&req.ifr_name, "gre0");
      req.ifr_flags = IFF_UP | IFF_MULTICAST;
      ioctl(tun_fd, TUNSETIFF, &req);
      ioctl(sock, SIOCSIFFLAGS, "gre0");
      write(tun_fd, "hi", 0);
      return 0;
    }
==========================

Signed-off-by: Alexander Potapenko 
Signed-off-by: David S. Miller 
Signed-off-by: Greg Kroah-Hartman

tun: fix premature POLLOUT notification on tun devices

2017-03-22T11:43:34+00:00

[ Upstream commit b20e2d54789c6acbf6bd0efdbec2cf5fa4d90ef1 ]

aszlig observed failing ssh tunnels (-w) during initialization since
commit cc9da6cc4f56e0 ("ipv6: addrconf: use stable address generator for
ARPHRD_NONE"). We already had reports that the mentioned commit breaks
Juniper VPN connections. I can't clearly say that the Juniper VPN client
has the same problem, but it is worth a try to hint to this patch.

Because of the early generation of link local addresses, the kernel now
can start asking for routers on the local subnet much earlier than usual.
Those router solicitation packets arrive inside the ssh channels and
should be transmitted to the tun fd before the configuration scripts
might have upped the interface and made it ready for transmission.

ssh polls on the interface and receives back a POLL_OUT. It tries to send
the earily router solicitation packet to the tun interface.  Unfortunately
it hasn't been up'ed yet by config scripts, thus failing with -EIO. ssh
doesn't retry again and considers the tun interface broken forever.

Link: https://bugzilla.kernel.org/show_bug.cgi?id=121131
Fixes: cc9da6cc4f56 ("ipv6: addrconf: use stable address generator for ARPHRD_NONE")
Cc: Bjørn Mork 
Reported-by: Valdis Kletnieks 
Cc: Valdis Kletnieks 
Reported-by: Jonas Lippuner 
Cc: Jonas Lippuner 
Reported-by: aszlig 
Cc: aszlig 
Signed-off-by: Hannes Frederic Sowa 
Signed-off-by: David S. Miller 
Signed-off-by: Greg Kroah-Hartman

tun: read vnet_hdr_sz once

2017-02-18T14:11:42+00:00

[ Upstream commit e1edab87faf6ca30cd137e0795bc73aa9a9a22ec ]

When IFF_VNET_HDR is enabled, a virtio_net header must precede data.
Data length is verified to be greater than or equal to expected header
length tun->vnet_hdr_sz before copying.

Read this value once and cache locally, as it can be updated between
the test and use (TOCTOU).

Signed-off-by: Willem de Bruijn 
Reported-by: Dmitry Vyukov 
CC: Eric Dumazet 
Acked-by: Eric Dumazet 
Signed-off-by: David S. Miller 
Signed-off-by: Greg Kroah-Hartman

virtio-net: restore VIRTIO_HDR_F_DATA_VALID on receiving

2017-02-04T08:47:09+00:00

[ Upstream commit 6391a4481ba0796805d6581e42f9f0418c099e34 ]

Commit 501db511397f ("virtio: don't set VIRTIO_NET_HDR_F_DATA_VALID on
xmit") in fact disables VIRTIO_HDR_F_DATA_VALID on receiving path too,
fixing this by adding a hint (has_data_valid) and set it only on the
receiving path.

Cc: Rolf Neugebauer 
Signed-off-by: Jason Wang 
Acked-by: Rolf Neugebauer 
Signed-off-by: David S. Miller 
Signed-off-by: Greg Kroah-Hartman

tun: handle ubuf refcount correctly when meet errors

2016-11-30T20:06:01+00:00

We trigger uarg->callback() immediately after we decide do datacopy
even if caller want to do zerocopy. This will cause the callback
(vhost_net_zerocopy_callback) decrease the refcount. But when we meet
an error afterwards, the error handling in vhost handle_tx() will try
to decrease it again. This is wrong and fix this by delay the
uarg->callback() until we're sure there's no errors.

Reported-by: wangyunjian 
Signed-off-by: Jason Wang 
Acked-by: Michael S. Tsirkin 
Signed-off-by: David S. Miller

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

2016-08-30T04:54:02+00:00

All three conflicts were cases of simple overlapping
changes.

Signed-off-by: David S. Miller

tun: fix transmit timestamp support

2016-08-24T06:09:27+00:00

Instead of using sock_tx_timestamp, use skb_tx_timestamp to record
software transmit timestamp of a packet.

sock_tx_timestamp resets and overrides the tx_flags of the skb.
The function is intended to be called from within the protocol
layer when creating the skb, not from a device driver. This is
inconsistent with other drivers and will cause issues for TCP.

In TCP, we intend to sample the timestamps for the last byte
for each sendmsg/sendpage. For that reason, tcp_sendmsg calls
tcp_tx_timestamp only with the last skb that it generates.
For example, if a 128KB message is split into two 64KB packets
we want to sample the SND timestamp of the last packet. The current
code in the tun driver, however, will result in sampling the SND
timestamp for both packets.

Also, when the last packet is split into smaller packets for
retranmission (see tcp_fragment), the tun driver will record
timestamps for all of the retransmitted packets and not only the
last packet.

Fixes: eda297729171 (tun: Support software transmit time stamping.)
Signed-off-by: Soheil Hassas Yeganeh 
Signed-off-by: Francis Yan 
Acked-by: Eric Dumazet 
Signed-off-by: David S. Miller