linux-stable.git/Documentation/networking, branch v4.17.2

netdev-FAQ: clarify DaveM's position for stable backports

2018-06-11T20:43:18+00:00

[ Upstream commit 75d4e704fa8d2cf33ff295e5b441317603d7f9fd ]

Per discussion with David at netconf 2018, let's clarify
DaveM's position of handling stable backports in netdev-FAQ.

This is important for people relying on upstream -stable
releases.

Cc: Greg Kroah-Hartman 
Signed-off-by: Cong Wang 
Signed-off-by: David S. Miller 
Signed-off-by: Greg Kroah-Hartman

ppp: remove the PPPIOCDETACH ioctl

2018-05-25T02:55:07+00:00

The PPPIOCDETACH ioctl effectively tries to "close" the given ppp file
before f_count has reached 0, which is fundamentally a bad idea.  It
does check 'f_count < 2', which excludes concurrent operations on the
file since they would only be possible with a shared fd table, in which
case each fdget() would take a file reference.  However, it fails to
account for the fact that even with 'f_count == 1' the file can still be
linked into epoll instances.  As reported by syzbot, this can trivially
be used to cause a use-after-free.

Yet, the only known user of PPPIOCDETACH is pppd versions older than
ppp-2.4.2, which was released almost 15 years ago (November 2003).
Also, PPPIOCDETACH apparently stopped working reliably at around the
same time, when the f_count check was added to the kernel, e.g. see
https://lkml.org/lkml/2002/12/31/83.  Also, the current 'f_count < 2'
check makes PPPIOCDETACH only work in single-threaded applications; it
always fails if called from a multithreaded application.

All pppd versions released in the last 15 years just close() the file
descriptor instead.

Therefore, instead of hacking around this bug by exporting epoll
internals to modules, and probably missing other related bugs, just
remove the PPPIOCDETACH ioctl and see if anyone actually notices.  Leave
a stub in place that prints a one-time warning and returns EINVAL.

Reported-by: syzbot+16363c99d4134717c05b@syzkaller.appspotmail.com
Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Signed-off-by: Eric Biggers 
Acked-by: Paul Mackerras 
Reviewed-by: Guillaume Nault 
Tested-by: Guillaume Nault 
Signed-off-by: David S. Miller

Merge tag 'staging-4.17-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/staging

2018-04-27T16:37:12+00:00

Pull staging fixes from Greg KH:
 "Here are two staging driver fixups for 4.17-rc3.

  The first is the remaining stragglers of the irda code removal that
  you pointed out during the merge window. The second is a fix for the
  wilc1000 driver due to a patch that got merged in 4.17-rc1.

  Both of these have been in linux-next for a while with no reported
  issues"

* tag 'staging-4.17-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/staging:
  staging: wilc1000: fix NULL pointer exception in host_int_parse_assoc_resp_info()
  staging: irda: remove remaining remants of irda code removal

docs: ip-sysctl.txt: fix name of some ipv6 variables

2018-04-19T19:20:09+00:00

The name of the following proc/sysctl entries were incorrectly
documented:

    /proc/sys/net/ipv6/conf//max_dst_opts_number
    /proc/sys/net/ipv6/conf//max_hbt_opts_number
    /proc/sys/net/ipv6/conf//max_dst_opts_length
    /proc/sys/net/ipv6/conf//max_hbt_length

Their name was set to the name of the symbol in the .data field of the
control table instead of their .proc name.

Signed-off-by: Olivier Gayot 
Signed-off-by: David S. Miller

staging: irda: remove remaining remants of irda code removal

2018-04-16T09:26:49+00:00

There were some documentation locations that irda was mentioned, as well
as an old MAINTAINERS entry and the networking sysctl entries.  Clean
these all out as this stuff really is finally gone.

Reported-by: Linus Torvalds 
Signed-off-by: Greg Kroah-Hartman

filter.txt: update 'tools/net/' to 'tools/bpf/'

2018-04-16T00:45:27+00:00

The tools are located at tootls/bpf/ instead of tools/net/.
Update the filter.txt doc.

Signed-off-by: Wang Sheng-Hui 
Signed-off-by: David S. Miller

Merge tag 'staging-4.17-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/staging

2018-04-05T01:56:27+00:00

Pull staging/IIO updates from Greg KH:
 "Here is the big set of Staging/IIO driver patches for 4.17-rc1.

  It is a lot, over 500 changes, but not huge by previous kernel release
  standards. We deleted more lines than we added again (27k added vs.
  91k remvoed), thanks to finally being able to delete the IRDA drivers
  and networking code.

  We also deleted the ccree crypto driver, but that's coming back in
  through the crypto tree to you, in a much cleaned-up form.

  Added this round is at lot of "mt7621" device support, which is for an
  embedded device that Neil Brown cares about, and of course a handful
  of new IIO drivers as well.

  And finally, the fsl-mc core code moved out of the staging tree to the
  "real" part of the kernel, which is nice to see happen as well.

  Full details are in the shortlog, which has all of the tiny cleanup
  patches described.

  All of these have been in linux-next for a while with no reported
  issues"

* tag 'staging-4.17-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/staging: (579 commits)
  staging: rtl8723bs: Remove yield call, replace with cond_resched()
  staging: rtl8723bs: Replace yield() call with cond_resched()
  staging: rtl8723bs: Remove unecessary newlines from 'odm.h'.
  staging: rtl8723bs: Rework 'struct _ODM_Phy_Status_Info_' coding style.
  staging: rtl8723bs: Rework 'struct _ODM_Per_Pkt_Info_' coding style.
  staging: rtl8723bs: Replace NULL pointer comparison with '!'.
  staging: rtl8723bs: Factor out rtl8723bs_recv_tasklet() sections.
  staging: rtl8723bs: Fix function signature that goes over 80 characters.
  staging: rtl8723bs: Fix lines too long in update_recvframe_attrib().
  staging: rtl8723bs: Remove unnecessary blank lines in 'rtl8723bs_recv.c'.
  staging: rtl8723bs: Change camel case to snake case in 'rtl8723bs_recv.c'.
  staging: rtl8723bs: Add missing braces in else statement.
  staging: rtl8723bs: Add spaces around ternary operators.
  staging: rtl8723bs: Fix lines with trailing open parentheses.
  staging: rtl8723bs: Remove unnecessary length #define's.
  staging: rtl8723bs: Fix IEEE80211 authentication algorithm constants.
  staging: rtl8723bs: Fix alignment in rtw_wx_set_auth().
  staging: rtl8723bs: Remove braces from single statement conditionals.
  staging: rtl8723bs: Remove unecessary braces from switch statement.
  staging: rtl8723bs: Fix newlines in rtw_wx_set_auth().
  ...

Merge tag 'kconfig-v4.17' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild

2018-04-03T23:28:01+00:00

Pull Kconfig updates from Masahiro Yamada:

 - improve checkpatch for more precise Kconfig code checking

 - clarify effective selects by grouping reverse dependencies in help

 - do not write out '# CONFIG_FOO is not set' from invisible symbols

 - make oldconfig as silent as it should be

 - rename 'silentoldconfig' to 'syncconfig'

 - add unit-test framework and several test cases

 - warn unmet dependency of tristate symbols

 - make unmet dependency warnings readable, removing false positives

 - improve recursive include detection

 - use yylineno to simplify the line number tracking

 - misc cleanups

* tag 'kconfig-v4.17' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild: (30 commits)
  kconfig: use yylineno option instead of manual lineno increments
  kconfig: detect recursive inclusion earlier
  kconfig: remove duplicated file name and lineno of recursive inclusion
  kconfig: do not include both curses.h and ncurses.h for nconfig
  kconfig: make unmet dependency warnings readable
  kconfig: warn unmet direct dependency of tristate symbols selected by y
  kconfig: tests: test if recursive inclusion is detected
  kconfig: tests: test if recursive dependencies are detected
  kconfig: tests: test randconfig for choice in choice
  kconfig: tests: test defconfig when two choices interact
  kconfig: tests: check visibility of tristate choice values in y choice
  kconfig: tests: check unneeded "is not set" with unmet dependency
  kconfig: tests: test if new symbols in choice are asked
  kconfig: tests: test automatic submenu creation
  kconfig: tests: add basic choice tests
  kconfig: tests: add framework for Kconfig unit testing
  kbuild: add PYTHON2 and PYTHON3 variables
  kconfig: remove redundant streamline_config.pl prerequisite
  kconfig: rename silentoldconfig to syncconfig
  kconfig: invoke oldconfig instead of silentoldconfig from local*config
  ...

inet: frags: break the 2GB limit for frags storage

2018-04-01T03:25:39+00:00

Some users are willing to provision huge amounts of memory to be able
to perform reassembly reasonnably well under pressure.

Current memory tracking is using one atomic_t and integers.

Switch to atomic_long_t so that 64bit arches can use more than 2GB,
without any cost for 32bit arches.

Note that this patch avoids an overflow error, if high_thresh was set
to ~2GB, since this test in inet_frag_alloc() was never true :

if (... || frag_mem_limit(nf) > nf->high_thresh)

Tested:

$ echo 16000000000 >/proc/sys/net/ipv4/ipfrag_high_thresh



$ grep FRAG /proc/net/sockstat
FRAG: inuse 14705885 memory 16000002880

$ nstat -n ; sleep 1 ; nstat | grep Reas
IpReasmReqds                    3317150            0.0
IpReasmFails                    3317112            0.0

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

inet: frags: use rhashtables for reassembly units

2018-04-01T03:25:39+00:00

Some applications still rely on IP fragmentation, and to be fair linux
reassembly unit is not working under any serious load.

It uses static hash tables of 1024 buckets, and up to 128 items per bucket (!!!)

A work queue is supposed to garbage collect items when host is under memory
pressure, and doing a hash rebuild, changing seed used in hash computations.

This work queue blocks softirqs for up to 25 ms when doing a hash rebuild,
occurring every 5 seconds if host is under fire.

Then there is the problem of sharing this hash table for all netns.

It is time to switch to rhashtables, and allocate one of them per netns
to speedup netns dismantle, since this is a critical metric these days.

Lookup is now using RCU. A followup patch will even remove
the refcount hold/release left from prior implementation and save
a couple of atomic operations.

Before this patch, 16 cpus (16 RX queue NIC) could not handle more
than 1 Mpps frags DDOS.

After the patch, I reach 9 Mpps without any tuning, and can use up to 2GB
of storage for the fragments (exact number depends on frags being evicted
after timeout)

$ grep FRAG /proc/net/sockstat
FRAG: inuse 1966916 memory 2140004608

A followup patch will change the limits for 64bit arches.

Signed-off-by: Eric Dumazet 
Cc: Kirill Tkhai 
Cc: Herbert Xu 
Cc: Florian Westphal 
Cc: Jesper Dangaard Brouer 
Cc: Alexander Aring 
Cc: Stefan Schmidt 
Signed-off-by: David S. Miller