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Bjørn Mork 81c895072d tun: fix vlan packet truncation
Bogus trimming in tun_net_xmit() causes truncated vlan packets.

skb->len is correct whether or not skb_vlan_tag_present() is true. There
is no more reason to adjust the skb length on xmit in this driver than
any other driver. tun_put_user() adds 4 bytes to the total for tagged
packets because it transmits the tag inline to userspace.  This is
similar to a nic transmitting the tag inline on the wire.

Reproducing the bug by sending any tagged packet through back-to-back
connected tap interfaces:

 socat TUN,tun-type=tap,iff-up,tun-name=in TUN,tun-type=tap,iff-up,tun-name=out &
 ip link add link in name in.20 type vlan id 20
 ip addr add 10.9.9.9/24 dev in.20
 ip link set in.20 up
 tshark -nxxi in -f arp -c1 2>/dev/null &
 tshark -nxxi out -f arp -c1 2>/dev/null &
 ping -c 1 10.9.9.5 >/dev/null 2>&1

The output from the 'in' and 'out' interfaces are different when the
bug is present:

 Capturing on 'in'
 0000  ff ff ff ff ff ff 76 cf 76 37 d5 0a 81 00 00 14   ......v.v7......
 0010  08 06 00 01 08 00 06 04 00 01 76 cf 76 37 d5 0a   ..........v.v7..
 0020  0a 09 09 09 00 00 00 00 00 00 0a 09 09 05         ..............

 Capturing on 'out'
 0000  ff ff ff ff ff ff 76 cf 76 37 d5 0a 81 00 00 14   ......v.v7......
 0010  08 06 00 01 08 00 06 04 00 01 76 cf 76 37 d5 0a   ..........v.v7..
 0020  0a 09 09 09 00 00 00 00 00 00                     ..........

Fixes: aff3d70a07 ("tun: allow to attach ebpf socket filter")
Cc: Jason Wang <jasowang@redhat.com>
Signed-off-by: Bjørn Mork <bjorn@mork.no>
Acked-by: Jason Wang <jasowang@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2018-04-18 13:50:29 -04:00
arch xen: fixes for 4.17-rc1 2018-04-12 11:04:35 -07:00
block for-4.17/block-20180402 2018-04-05 14:27:02 -07:00
certs certs/blacklist_nohashes.c: fix const confusion in certs blacklist 2018-02-21 15:35:43 -08:00
crypto MIPS changes for 4.17 2018-04-10 11:39:22 -07:00
Documentation textsearch: fix kernel-doc warnings and add kernel-api section 2018-04-16 18:53:13 -04:00
drivers tun: fix vlan packet truncation 2018-04-18 13:50:29 -04:00
firmware kbuild: remove all dummy assignments to obj- 2017-11-18 11:46:06 +09:00
fs This pull request contains updates for both UBI and UBIFS: 2018-04-11 16:39:34 -07:00
include vlan: Fix reading memory beyond skb->tail in skb_vlan_tagged_multi 2018-04-17 13:59:28 -04:00
init seq_file: allocate seq_file from kmem_cache 2018-04-11 10:28:36 -07:00
ipc ipc/shm.c: shm_split(): remove unneeded test for NULL shm_file_data.vm_ops 2018-04-11 10:28:38 -07:00
kernel * Fix 2032 time access issues and new compiler warnings 2018-04-12 10:21:19 -07:00
lib textsearch: fix kernel-doc warnings and add kernel-api section 2018-04-16 18:53:13 -04:00
LICENSES LICENSES: Add MPL-1.1 license 2018-01-06 10:59:44 -07:00
mm page cache: use xa_lock 2018-04-11 10:28:39 -07:00
net tipc: fix infinite loop when dumping link monitor summary 2018-04-18 13:48:43 -04:00
samples remoteproc updates for v4.17 2018-04-10 12:09:27 -07:00
scripts asm-generic fixes for v4.17-rc1 2018-04-12 09:15:48 -07:00
security ipc/msg: introduce msgctl(MSG_STAT_ANY) 2018-04-11 10:28:37 -07:00
sound sound fixes for 4.17-rc1 2018-04-10 10:16:04 -07:00
tools selftests: net: add in_netns.sh to TEST_PROGS 2018-04-12 21:52:47 -04:00
usr kbuild: rename built-in.o to built-in.a 2018-03-26 02:01:19 +09:00
virt KVM/ARM updates for v4.17 2018-03-28 16:09:09 +02:00
.clang-format clang-format: add configuration file 2018-04-11 10:28:35 -07:00
.cocciconfig
.get_maintainer.ignore
.gitattributes .gitattributes: set git diff driver for C source code files 2016-10-07 18:46:30 -07:00
.gitignore clang-format: add configuration file 2018-04-11 10:28:35 -07:00
.mailmap Merge candidates for 4.17 merge window 2018-04-06 17:35:43 -07:00
COPYING COPYING: use the new text with points to the license files 2018-03-23 12:41:45 -06:00
CREDITS MAINTAINERS/CREDITS: Drop METAG ARCHITECTURE 2018-03-05 16:34:24 +00:00
Kbuild Kbuild updates for v4.15 2017-11-17 17:45:29 -08:00
Kconfig License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
MAINTAINERS ARM: SoC fixes for 4.17 2018-04-11 16:12:21 -07:00
Makefile Kconfig updates for v4.17 2018-04-03 16:28:01 -07:00
README Docs: Added a pointer to the formatted docs to README 2018-03-21 09:02:53 -06:00

Linux kernel
============

There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.  The formatted documentation can also be read online at:

    https://www.kernel.org/doc/html/latest/

There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
See Documentation/00-INDEX for a list of what is contained in each file.

Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.