linux-toradex.git/drivers/net/tun.c, branch v4.9.60

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

tun: Rename a jump label in update_filter()

2016-08-21T02:11:33+00:00

Adjust a jump target according to the Linux coding style convention.

Signed-off-by: Markus Elfring 
Signed-off-by: David S. Miller

tun: Use memdup_user() rather than duplicating its implementation

2016-08-21T02:11:33+00:00

Reuse existing functionality from memdup_user() instead of keeping
duplicate source code.

This issue was detected by using the Coccinelle software.

Signed-off-by: Markus Elfring 
Reviewed-by: Shmulik Ladkani 
Signed-off-by: David S. Miller

tun: Don't assume type tun in tun_device_event

2016-07-09T03:58:57+00:00

The referenced change added a netlink notifier for processing
device queue size events.  These events are fired for all devices
but the registered callback assumed they only occurred for tun
devices.  This fix adds a check (borrowed from macvtap.c) to discard
non-tun device events.

For reference, this fixes the following splat:
[   71.505935] BUG: unable to handle kernel NULL pointer dereference at 0000000000000010
[   71.513870] IP: [] tun_device_event+0x110/0x340
[   71.519906] PGD 3f41f56067 PUD 3f264b7067 PMD 0
[   71.524497] Oops: 0002 [#1] SMP DEBUG_PAGEALLOC
[   71.529374] gsmi: Log Shutdown Reason 0x03
[   71.533417] Modules linked in:[   71.533826] mlx4_en: eth1: Link Up

[   71.539616]  bonding w1_therm wire cdc_acm ehci_pci ehci_hcd mlx4_en ib_uverbs mlx4_ib ib_core mlx4_core
[   71.549282] CPU: 12 PID: 7915 Comm: set.ixion-haswe Not tainted 4.7.0-dbx-DEV #8
[   71.556586] Hardware name: Intel Grantley,Wellsburg/Ixion_IT_15, BIOS 2.58.0 05/03/2016
[   71.564495] task: ffff887f00bb20c0 ti: ffff887f00798000 task.ti: ffff887f00798000
[   71.571894] RIP: 0010:[]  [] tun_device_event+0x110/0x340
[   71.580327] RSP: 0018:ffff887f0079bbd8  EFLAGS: 00010202
[   71.585576] RAX: fffffffffffffae8 RBX: ffff887ef6d03378 RCX: 0000000000000000
[   71.592624] RDX: 0000000000000000 RSI: 0000000000000028 RDI: 0000000000000000
[   71.599675] RBP: ffff887f0079bc48 R08: 0000000000000000 R09: 0000000000000001
[   71.606730] R10: 0000000000000004 R11: 0000000000000000 R12: 0000000000000010
[   71.613780] R13: 0000000000000000 R14: 0000000000000001 R15: ffff887f0079bd00
[   71.620832] FS:  00007f5cdc581700(0000) GS:ffff883f7f700000(0000) knlGS:0000000000000000
[   71.628826] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[   71.634500] CR2: 0000000000000010 CR3: 0000003f3eb62000 CR4: 00000000001406e0
[   71.641549] Stack:
[   71.643533]  ffff887f0079bc08 0000000000000246 000000000000001e ffff887ef6d00000
[   71.650871]  ffff887f0079bd00 0000000000000000 0000000000000000 ffffffff00000000
[   71.658210]  ffff887f0079bc48 ffffffff81d24070 00000000fffffff9 ffffffff81cec7a0
[   71.665549] Call Trace:
[   71.667975]  [] notifier_call_chain+0x5d/0x80
[   71.673823]  [] ? show_tx_maxrate+0x30/0x30
[   71.679502]  [] __raw_notifier_call_chain+0xe/0x10
[   71.685778]  [] raw_notifier_call_chain+0x16/0x20
[   71.691976]  [] call_netdevice_notifiers_info+0x40/0x70
[   71.698681]  [] call_netdevice_notifiers+0x16/0x20
[   71.704956]  [] change_tx_queue_len+0x66/0x90
[   71.710807]  [] netdev_store.isra.5+0xbf/0xd0
[   71.716658]  [] tx_queue_len_store+0x50/0x60
[   71.722431]  [] dev_attr_store+0x18/0x30
[   71.727857]  [] sysfs_kf_write+0x4f/0x70
[   71.733274]  [] kernfs_fop_write+0x147/0x1d0
[   71.739045]  [] ? rcu_read_lock_sched_held+0x8f/0xa0
[   71.745499]  [] __vfs_write+0x28/0x120
[   71.750748]  [] ? percpu_down_read+0x57/0x90
[   71.756516]  [] ? __sb_start_write+0xc8/0xe0
[   71.762278]  [] ? __sb_start_write+0xc8/0xe0
[   71.768038]  [] vfs_write+0xbe/0x1b0
[   71.773113]  [] SyS_write+0x52/0xa0
[   71.778110]  [] entry_SYSCALL_64_fastpath+0x18/0xa8
[   71.784472] Code: 45 31 f6 48 8b 93 78 33 00 00 48 81 c3 78 33 00 00 48 39 d3 48 8d 82 e8 fa ff ff 74 25 48 8d b0 40 05 00 00 49 63 d6 41 83 c6 01 <49> 89 34 d4 48 8b 90 18 05 00 00 48 39 d3 48 8d 82 e8 fa ff ff
[   71.803655] RIP  [] tun_device_event+0x110/0x340
[   71.809769]  RSP 
[   71.813213] CR2: 0000000000000010
[   71.816512] ---[ end trace 4db6449606319f73 ]---

Fixes: 1576d9860599 ("tun: switch to use skb array for tx")
Signed-off-by: Craig Gallek 
Acked-by: Jason Wang 
Signed-off-by: David S. Miller