linux-stable/Documentation
Eric Dumazet 8e39cbc03d tcp: add tcp_min_snd_mss sysctl
commit 5f3e2bf008 upstream.

Some TCP peers announce a very small MSS option in their SYN and/or
SYN/ACK messages.

This forces the stack to send packets with a very high network/cpu
overhead.

Linux has enforced a minimal value of 48. Since this value includes
the size of TCP options, and that the options can consume up to 40
bytes, this means that each segment can include only 8 bytes of payload.

In some cases, it can be useful to increase the minimal value
to a saner value.

We still let the default to 48 (TCP_MIN_SND_MSS), for compatibility
reasons.

Note that TCP_MAXSEG socket option enforces a minimal value
of (TCP_MIN_MSS). David Miller increased this minimal value
in commit c39508d6f1 ("tcp: Make TCP_MAXSEG minimum more correct.")
from 64 to 88.

We might in the future merge TCP_MIN_SND_MSS and TCP_MIN_MSS.

CVE-2019-11479 -- tcp mss hardcoded to 48

Signed-off-by: Eric Dumazet <edumazet@google.com>
Suggested-by: Jonathan Looney <jtl@netflix.com>
Acked-by: Neal Cardwell <ncardwell@google.com>
Cc: Yuchung Cheng <ycheng@google.com>
Cc: Tyler Hicks <tyhicks@canonical.com>
Cc: Bruce Curtis <brucec@netflix.com>
Cc: Jonathan Lemon <jonathan.lemon@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-06-17 19:53:33 +02:00
..
80211 docs-rst: sphinxify 802.11 documentation 2016-10-11 16:19:17 -06:00
ABI Documentation: Add MDS vulnerability documentation 2019-05-14 19:19:41 +02:00
accounting tools: move accounting tool from Documentation 2016-09-23 13:07:15 -06:00
acpi Merge branches 'acpi-button', 'acpi-battery' and 'acpi-doc' 2016-10-02 01:40:20 +02:00
aoe
arm ARM: 8833/1: Ensure that NEON code always compiles with Clang 2019-04-05 22:29:11 +02:00
arm64 arm64: Add work around for Arm Cortex-A55 Erratum 1024718 2018-05-16 10:08:42 +02:00
auxdisplay samples: move auxdisplay example code from Documentation 2016-09-23 11:52:32 -06:00
backlight
blackfin samples: move blackfin gptimers-example from Documentation 2016-10-10 07:12:02 -06:00
block block: remove remnant refs to hardsect 2016-09-14 08:44:57 -06:00
blockdev
bus-devices
cdrom
cgroup-v1 Three fixes for the docs build, including removing an annoying warning on 2016-08-07 10:23:17 -04:00
cma
connector
console
cpu-freq cpufreq-stats: Minor documentation fix 2016-09-08 23:05:07 +02:00
cpuidle
cris
crypto
dev-tools mm: kmemleak: avoid using __va() on addresses that don't have a lowmem mapping 2016-10-11 15:06:33 -07:00
development-process docs-rst: add inter-document cross references 2016-09-21 15:43:09 -06:00
device-mapper dm thin: fix documentation relative to low water mark threshold 2018-05-30 07:50:20 +02:00
devicetree dt-bindings: eeprom: at24: add "atmel,24c2048" compatible string 2019-02-20 10:18:24 +01:00
dmaengine dmaengine: documentation to the new callback mechanism 2016-08-08 08:11:42 +05:30
DocBook A single commit converting the mac80211 DocBook template over to Sphinx. 2016-10-14 14:11:22 -07:00
driver-api docs: Don't format internal MPT docs 2016-09-06 09:15:48 -06:00
driver-model power supply and reset changes for the v4.9 series 2016-10-06 18:21:15 -07:00
early-userspace
EDID
extcon
fault-injection
fb
features Documentation: MIPS supports HAVE_REGS_AND_STACK_ACCESS_API 2016-10-13 17:19:19 +02:00
filesystems mm, proc: be more verbose about unstable VMA flags in /proc/<pid>/smaps 2019-01-26 09:38:36 +01:00
firmware_class
fmc
fpga
frv
gpio gpio/board.txt: point to gpiod_set_value 2016-10-20 14:14:11 +02:00
gpu Merge tag 'drm-for-v4.9' of git://people.freedesktop.org/~airlied/linux 2016-10-11 18:12:22 -07:00
hid Documentation: HID: Intel ISH HID document 2016-08-17 11:13:07 +02:00
hw-vuln Documentation: Correct the possible MDS sysfs values 2019-05-14 19:19:42 +02:00
hwmon hwmon: (ina2xx) fix sysfs shunt resistor read access 2018-10-03 17:01:52 -07:00
i2c i2c: Documentation: i2c-topology: fix minor whitespace nit 2016-11-10 21:18:56 +01:00
ia64 selftests: move ia64 tests from Documentation/ia64 2016-09-20 09:58:12 -06:00
ide
iio iio: Documentation: Correct the path used to create triggers. 2016-10-01 00:49:58 -06:00
infiniband IB/hfi1: Document new sysfs entries for hfi1 driver 2016-10-02 08:42:19 -04:00
input Input: ALPS - add V8 protocol documentation 2016-10-04 11:47:02 -07:00
ioctl doc: ioctl: Add some clarifications to botching-up-ioctls 2016-09-06 06:00:22 -06:00
isdn
ja_JP
kbuild Merge branch 'kbuild' of git://git.kernel.org/pub/scm/linux/kernel/git/mmarek/kbuild 2016-10-14 14:26:58 -07:00
kdump Documentation: kdump: Add description of enable multi-cpus support 2016-09-20 18:02:54 -06:00
ko_KR locking/Documentation: Add Korean translation 2016-08-12 08:24:14 +02:00
laptops tools: move laptops dslm tool from Documentation 2016-09-23 13:07:21 -06:00
leds Merge branch 'for-next' of git://git.kernel.org/pub/scm/linux/kernel/git/j.anaszewski/linux-leds 2016-10-04 10:25:53 -07:00
livepatch Documentation: livepatch: add section about arch-specific code 2016-08-18 23:41:56 +02:00
locking locking/lglock: Remove lglock implementation 2016-09-22 15:25:56 +02:00
m68k
media videodev2.h: go back to limited range Y'CbCr for SRGB and, ADOBERGB 2017-02-23 17:44:37 +01:00
memory-devices
metag
mic samples: move mic/mpssd example code from Documentation 2016-09-20 12:38:48 -06:00
mips
misc-devices samples: move misc-devices/mei example code from Documentation 2016-09-23 11:51:43 -06:00
mmc
mn10300
mtd
namespaces
netlabel
networking tcp: add tcp_min_snd_mss sysctl 2019-06-17 19:53:33 +02:00
nfc
nios2
nvdimm
nvmem
parisc
PCI PCI changes for the v4.9 merge window: 2016-10-07 11:46:37 -07:00
pcmcia tools: move pcmcia crc32hash tool from Documentation 2016-09-23 13:07:27 -06:00
perf perf: xgene: Add APM X-Gene SoC Performance Monitoring Unit driver 2016-09-15 11:20:55 -07:00
phy
platform
power power supply and reset changes for the v4.9 series 2016-10-06 18:21:15 -07:00
powerpc powerpc updates for 4.9 2016-10-07 20:19:31 -07:00
pps
prctl selftests: move prctl tests from Documentation/prctl 2016-09-20 09:09:09 -06:00
pti
ptp selftests: move ptp tests from Documentation/ptp 2016-09-20 09:54:38 -06:00
rapidio rapidio/documentation/mport_cdev: add missing parameter description 2016-09-01 17:52:02 -07:00
RCU kthread: kthread worker API cleanup 2016-10-11 15:06:33 -07:00
s390
scheduler sched/deadline: Document behavior of sched_yield() 2016-09-10 11:17:41 +02:00
scsi scsi: g_NCR5380: Stop using scsi_module.c 2016-09-29 21:52:43 -04:00
security
serial Documentation: rs485: Do not define manually the ioctl 2016-08-18 11:08:33 -06:00
sh
sound
sphinx docs: sphinx-extensions: make rstFlatTable work with docutils 0.13 2017-01-09 08:32:18 +01:00
sphinx-static This is the documentation update pull for the 4.9 merge window. 2016-10-04 13:54:07 -07:00
spi Doc: update 00-INDEX files to reflect the runnable code move 2016-10-10 07:12:09 -06:00
sysctl namei: allow restricted O_CREAT of FIFOs and regular files 2018-12-01 09:44:25 +01:00
target
thermal thermal: Add support for hardware-tracked trip points 2016-09-27 14:02:16 +08:00
timers Doc: update 00-INDEX files to reflect the runnable code move 2016-10-10 07:12:09 -06:00
tpm
trace This release cycle is rather small. Just a few fixes to tracing. 2016-10-06 11:48:41 -07:00
usb USB: core: Fix bug caused by duplicate interface PM usage counter 2019-05-08 07:19:08 +02:00
virtual KVM: Reject device ioctls from processes other than the VM's creator 2019-04-03 06:24:19 +02:00
vm Three fixes for the docs build, including removing an annoying warning on 2016-08-07 10:23:17 -04:00
w1
watchdog linux-kselftest-4.9-rc1-update 2016-10-14 15:17:12 -07:00
wimax
x86 x86/speculation/mds: Improve CPU buffer clear documentation 2019-05-21 18:48:56 +02:00
xtensa
zh_CN
.gitignore
00-INDEX Doc: update 00-INDEX files to reflect the runnable code move 2016-10-10 07:12:09 -06:00
adding-syscalls.txt
applying-patches.txt docs: Clean up bare :: lines 2016-09-20 18:46:36 -06:00
assoc_array.txt
atomic_ops.txt
bad_memory.txt
basic_profiling.txt
bcache.txt
binfmt_misc.txt
braille-console.txt
bt8xxgpio.txt
btmrvl.txt
BUG-HUNTING
bus-virt-phys-mapping.txt
cachetlb.txt
cgroup-v2.txt
Changes kbuild: verify that $DEPMOD is installed 2018-08-17 20:59:29 +02:00
circular-buffers.txt
clk.txt Documentation: clk: update file names containing referenced structures 2016-08-14 12:12:36 -06:00
CodeOfConflict URL changed for Linux Foundation TAB 2016-10-01 00:57:13 -06:00
CodingStyle docs: Remove space-before-label guidance from CodingStyle 2016-09-21 15:53:31 -06:00
conf.py docs: Fix conf.py for Sphinx 2.0 2019-06-11 12:22:43 +02:00
cpu-hotplug.txt
cpu-load.txt
cputopology.txt
crc32.txt
dcdbas.txt
debugging-modules.txt
debugging-via-ohci1394.txt
dell_rbu.txt
devices.txt
digsig.txt
DMA-API-HOWTO.txt Documentation: DMA-API-HOWTO: Fix a typo 2016-09-20 17:58:46 -06:00
DMA-API.txt dma-mapping: add dma_{map,unmap}_resource 2016-09-26 22:16:41 +05:30
DMA-attributes.txt dma-mapping: introduce the DMA_ATTR_NO_WARN attribute 2016-10-11 15:06:32 -07:00
dma-buf-sharing.txt
DMA-ISA-LPC.txt
docutils.conf doc-rst: add docutils config file 2016-08-14 11:52:40 -06:00
dontdiff
dynamic-debug-howto.txt
edac.txt
efi-stub.txt
eisa.txt
email-clients.txt Documentation/email-clients.txt: convert it to ReST markup 2016-09-21 15:41:50 -06:00
flexible-arrays.txt
futex-requeue-pi.txt
gcc-plugins.txt
highuid.txt
HOWTO docs: Clean up bare :: lines 2016-09-20 18:46:36 -06:00
hw_random.txt
hwspinlock.txt
index.rst Documentation: Move L1TF to separate directory 2019-05-14 19:19:41 +02:00
init.txt
initrd.txt
Intel-IOMMU.txt
intel_txt.txt
io-mapping.txt
io_ordering.txt
iostats.txt
IPMI.txt
IRQ-affinity.txt
IRQ-domain.txt
IRQ.txt
irqflags-tracing.txt
isa.txt
isapnp.txt
java.txt
kernel-doc-nano-HOWTO.txt
kernel-docs.txt Documentation/kernel-docs.txt: reorder based on timestamp 2016-09-20 18:54:42 -06:00
kernel-documentation.rst This is the documentation update pull for the 4.9 merge window. 2016-10-04 13:54:07 -07:00
kernel-parameters.txt x86/speculation/mds: Add 'mitigations=' support for MDS 2019-05-14 19:19:42 +02:00
kernel-per-CPU-kthreads.txt Documenation: update cgroup's document path 2016-08-03 15:43:58 -06:00
kobject.txt
kprobes.txt Documentation: kprobes: Document jprobes stack copying limitations 2016-08-15 10:19:11 -06:00
kref.txt
kselftest.txt kselftest: kselftest documentation improvement 2016-09-20 08:58:27 -06:00
ldm.txt
local_ops.txt
lockup-watchdogs.txt
logo.gif
logo.txt
lzo.txt
magic-number.txt
mailbox.txt
Makefile samples: move blackfin gptimers-example from Documentation 2016-10-10 07:12:02 -06:00
Makefile.sphinx doc-rst: generic way to build PDF of sub-folders 2016-09-01 08:49:23 -06:00
ManagementStyle Documentation/HOWTO: add cross-references to other documents 2016-09-20 18:41:04 -06:00
md-cluster.txt
md.txt
memory-barriers.txt locking/Documentation: Fix a typo of example result 2016-08-12 08:24:13 +02:00
memory-hotplug.txt
men-chameleon-bus.txt
module-signing.txt
mono.txt
nommu-mmap.txt
ntb.txt
numastat.txt
oops-tracing.txt
padata.txt
parport-lowlevel.txt
parport.txt
percpu-rw-semaphore.txt
phy.txt
pi-futex.txt
pinctrl.txt
pnp.txt
preempt-locking.txt
printk-formats.txt lib/vsprintf: Remove atomic-unsafe support for %pCr 2018-07-03 11:23:06 +02:00
pwm.txt
ramoops.txt ramoops: use DT reserved-memory bindings 2016-08-05 11:21:36 -07:00
rbtree.txt
remoteproc.txt remoteproc: Split driver and consumer dereferencing 2016-10-02 22:50:21 -07:00
rfkill.txt
robust-futex-ABI.txt
robust-futexes.txt
rpmsg.txt
rtc.txt
SAK.txt
SecurityBugs Documentation/HOWTO: add cross-references to other documents 2016-09-20 18:41:04 -06:00
serial-console.txt
sgi-ioc4.txt
SM501.txt
smsc_ece1099.txt
spec_ctrl.txt x86/speculation: Add prctl() control for indirect branch speculation 2019-05-14 19:19:39 +02:00
speculation.txt Documentation: Document array_index_nospec 2018-02-13 12:35:59 +01:00
stable_api_nonsense.txt Documentation/HOWTO: add cross-references to other documents 2016-09-20 18:41:04 -06:00
stable_kernel_rules.txt Documentation: stable-kernel-rules: fix stable-tag format 2017-04-12 12:41:15 +02:00
static-keys.txt jump_labels: Allow array initialisers 2016-09-07 09:41:11 +01:00
SubmitChecklist docs-rst: add inter-document cross references 2016-09-21 15:43:09 -06:00
SubmittingDrivers docs-rst: add inter-document cross references 2016-09-21 15:43:09 -06:00
SubmittingPatches docs-rst: add inter-document cross references 2016-09-21 15:43:09 -06:00
svga.txt
sync_file.txt Documentation: add doc for sync_file_get_fence() 2016-08-11 15:33:24 +05:30
sysfs-rules.txt
sysrq.txt
this_cpu_ops.txt
unaligned-memory-access.txt
unicode.txt
unshare.txt
vfio.txt
VGA-softcursor.txt
video-output.txt
vme_api.txt vme: Update documentation to match api 2016-08-31 13:20:16 +02:00
volatile-considered-harmful.txt
workqueue.txt
xillybus.txt
xz.txt
zorro.txt