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Vladimir Oltean a74dbce9d4 net: enetc: don't disable VLAN filtering in IFF_PROMISC mode
Quoting from the blamed commit:

    In promiscuous mode, it is more intuitive that all traffic is received,
    including VLAN tagged traffic. It appears that it is necessary to set
    the flag in PSIPVMR for that to be the case, so VLAN promiscuous mode is
    also temporarily enabled. On exit from promiscuous mode, the setting
    made by ethtool is restored.

Intuitive or not, there isn't any definition issued by a standards body
which says that promiscuity has anything to do with VLAN filtering - it
only has to do with accepting packets regardless of destination MAC address.

In fact people are already trying to use this misunderstanding/bug of
the enetc driver as a justification to transform promiscuity into
something it never was about: accepting every packet (maybe that would
be the "rx-all" netdev feature?):
https://lore.kernel.org/netdev/20201110153958.ci5ekor3o2ekg3ky@ipetronik.com/

This is relevant because there are use cases in the kernel (such as
tc-flower rules with the protocol 802.1Q and a vlan_id key) which do not
(yet) use the vlan_vid_add API to be compatible with VLAN-filtering NICs
such as enetc, so for those, disabling rx-vlan-filter is currently the
only right solution to make these setups work:
https://lore.kernel.org/netdev/CA+h21hoxwRdhq4y+w8Kwgm74d4cA0xLeiHTrmT-VpSaM7obhkg@mail.gmail.com/
The blamed patch has unintentionally introduced one more way for this to
work, which is to enable IFF_PROMISC, however this is non-portable
because port promiscuity is not meant to disable VLAN filtering.
Therefore, it could invite people to write broken scripts for enetc, and
then wonder why they are broken when migrating to other drivers that
don't handle promiscuity in the same way.

Fixes: 7070eea5e9 ("enetc: permit configuration of rx-vlan-filter with ethtool")
Cc: Markus Blöchl <Markus.Bloechl@ipetronik.com>
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2021-03-01 13:34:47 -08:00
arch Merge https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf 2021-02-26 13:16:31 -08:00
block for-5.12/block-ipi-2021-02-21 2021-02-22 10:53:05 -08:00
certs certs: Replace K{U,G}IDT_INIT() with GLOBAL_ROOT_{U,G}ID 2021-01-21 16:16:10 +00:00
crypto Keyrings miscellany 2021-02-23 16:09:23 -08:00
Documentation pwm: Changes for v5.12-rc1 2021-02-25 12:23:49 -08:00
drivers net: enetc: don't disable VLAN filtering in IFF_PROMISC mode 2021-03-01 13:34:47 -08:00
fs Miscellaneous ext4 cleanups and bug fixes. Pretty boring this 2021-02-25 10:06:55 -08:00
include Merge https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf 2021-02-26 13:16:31 -08:00
init Kbuild updates for v5.12 2021-02-25 10:17:31 -08:00
ipc fs: make helpers idmap mount aware 2021-01-24 14:27:20 +01:00
kernel Merge https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf 2021-02-26 13:16:31 -08:00
lib Kbuild updates for v5.12 2021-02-25 10:17:31 -08:00
LICENSES LICENSES: Add the CC-BY-4.0 license 2020-12-08 10:33:27 -07:00
mm mm/hugetlb: change hugetlb_reserve_pages() to type bool 2021-02-24 13:38:35 -08:00
net inetpeer: use div64_ul() and clamp_val() calculate inet_peer_threshold 2021-03-01 13:32:12 -08:00
samples Char/Misc driver patches for 5.12-rc1 2021-02-24 10:25:37 -08:00
scripts Kbuild updates for v5.12 2021-02-25 10:17:31 -08:00
security Keyrings miscellany 2021-02-23 16:09:23 -08:00
sound ARM updates for 5.12-rc1: 2021-02-22 14:27:07 -08:00
tools selftests: forwarding: Fix race condition in mirror installation 2021-02-26 15:47:52 -08:00
usr Kbuild updates for v5.12 2021-02-25 10:17:31 -08:00
virt KVM/arm64 fixes for 5.11, take #2 2021-02-12 14:07:39 +00:00
.clang-format cxl for 5.12 2021-02-24 09:38:36 -08:00
.cocciconfig scripts: add Linux .cocciconfig for coccinelle 2016-07-22 12:13:39 +02:00
.get_maintainer.ignore Opt out of scripts/get_maintainer.pl 2019-05-16 10:53:40 -07:00
.gitattributes .gitattributes: use 'dts' diff driver for dts files 2019-12-04 19:44:11 -08:00
.gitignore clang-lto series for v5.12-rc1 2021-02-23 09:28:51 -08:00
.mailmap Merge branch 'linus' of git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6 2021-02-21 17:23:56 -08:00
COPYING COPYING: state that all contributions really are covered by this file 2020-02-10 13:32:20 -08:00
CREDITS CREDITS: update email address and home address 2021-01-27 21:03:50 +02:00
Kbuild kbuild: rename hostprogs-y/always to hostprogs/always-y 2020-02-04 01:53:07 +09:00
Kconfig kbuild: ensure full rebuild when the compiler is updated 2020-05-12 13:28:33 +09:00
MAINTAINERS wireless-drivers fixes for v5.12 2021-02-26 13:17:44 -08:00
Makefile Kbuild updates for v5.12 2021-02-25 10:17:31 -08:00
README Drop all 00-INDEX files from Documentation/ 2018-09-09 15:08:58 -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.

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.