fragmented packets.
When sending IPv4 and IPv6 fragmented packets and a fragment is lost,
the mbuf making up the fragment will remain in the temporary hashed
fragment list for a while. If the network interface departs before the
so-called slow timeout clears the packet, the fragment causes a panic
when the timeout kicks in due to accessing a freed network interface
structure.
Make sure that when a network device is departing, all hashed IPv4 and
IPv6 fragments belonging to it, get freed.
Backtrace:
panic()
icmp6_reflect()
hlim = ND_IFINFO(m->m_pkthdr.rcvif)->chlim;
^^^^ rcvif->if_afdata[AF_INET6] is NULL.
icmp6_error()
frag6_freef()
frag6_slowtimo()
pfslowtimo()
softclock_call_cc()
softclock()
ithread_loop()
Differential Revision: https://reviews.freebsd.org/D19622
Reviewed by: bz (network), adrian
MFC after: 1 week
Sponsored by: Mellanox Technologies
Add a stat counter to track ipv6 atomic fragments. Atomic fragments can be
generated in response to invalid path MTU values, but are also a potential
attack vector and considered harmful (see RFC6946 and RFC8021).
While here add tracking of the atomic fragment counter to netstat and systat.
Reviewed by: tuexen, jtl, bz
Approved by: jtl (mentor), bz (mentor)
Event: Aberdeen hackathon 2019
Differential Revision: https://reviews.freebsd.org/D17511
When dropping a fragment queue, account for the number of fragments in the
queue. This improves accounting between the number of fragments received and
the number of fragments dropped.
Reviewed by: jtl, bz, transport
Approved by: jtl (mentor), bz (mentor)
Differential Revision: https://review.freebsd.org/D17521
r337776 started hashing the fragments into buckets for faster lookup.
The hashkey is larger than intended. This results in random stack data being
included in the hashed data, which in turn means that fragments of the same
packet might end up in different buckets, causing the reassembly to fail.
Set the correct size for hashkey.
PR: 231045
Approved by: re (kib)
MFC after: 3 days
Currently, the limits are quite high. On machines with millions of
mbuf clusters, the reassembly queue limits can also run into
the millions. Lower these values.
Also, try to ensure that no bucket will have a reassembly
queue larger than approximately 100 items. This limits the cost to
find the correct reassembly queue when processing an incoming
fragment.
Due to the low limits on each bucket's length, increase the size of
the hash table from 64 to 1024.
Reviewed by: jhb
Security: FreeBSD-SA-18:10.ip
Security: CVE-2018-6923
Currently, we process IPv6 fragments with 0 bytes of payload, add them
to the reassembly queue, and do not recognize them as duplicating or
overlapping with adjacent 0-byte fragments. An attacker can exploit this
to create long fragment queues.
There is no legitimate reason for a fragment with no payload. However,
because IPv6 packets with an empty payload are acceptable, allow an
"atomic" fragment with no payload.
Reviewed by: jhb
Security: FreeBSD-SA-18:10.ip
Security: CVE-2018-6923
There is a hashing algorithm which should distribute IPv6 reassembly
queues across the available buckets in a relatively even way. However,
if there is a flaw in the hashing algorithm which allows a large number
of IPv6 fragment reassembly queues to end up in a single bucket, a per-
bucket limit could help mitigate the performance impact of this flaw.
Implement such a limit, with a default of twice the maximum number of
reassembly queues divided by the number of buckets. Recalculate the
limit any time the maximum number of reassembly queues changes.
However, allow the user to override the value using a sysctl
(net.inet6.ip6.maxfragbucketsize).
Reviewed by: jhb
Security: FreeBSD-SA-18:10.ip
Security: CVE-2018-6923
The IPv4 fragment reassembly code supports a limit on the number of
fragments per packet. The default limit is currently 17 fragments.
Among other things, this limit serves to limit the number of fragments
the code must parse when trying to reassembly a packet.
Add a limit to the IPv6 reassembly code. By default, limit a packet
to 65 fragments (64 on the queue, plus one final fragment to complete
the packet). This allows an average fragment size of 1,008 bytes, which
should be sufficient to hold a fragment. (Recall that the IPv6 minimum
MTU is 1280 bytes. Therefore, this configuration allows a full-size
IPv6 packet to be fragmented on a link with the minimum MTU and still
carry approximately 272 bytes of headers before the fragmented portion
of the packet.)
Users can adjust this limit using the net.inet6.ip6.maxfragsperpacket
sysctl.
Reviewed by: jhb
Security: FreeBSD-SA-18:10.ip
Security: CVE-2018-6923
The IPv6 reassembly fragment limit is based on the number of mbuf clusters,
which are a global resource. However, the limit is currently applied
on a per-VNET basis. Given enough VNETs (or given sufficient customization
on enough VNETs), it is possible that the sum of all the VNET fragment
limits will exceed the number of mbuf clusters available in the system.
Given the fact that the fragment limits are intended (at least in part) to
regulate access to a global resource, the IPv6 fragment limit should
be applied on a global basis.
Note that it is still possible to disable fragmentation for a particular
VNET by setting the net.inet6.ip6.maxfragpackets sysctl to 0 for that
VNET. In addition, it is now possible to disable fragmentation globally
by setting the net.inet6.ip6.maxfrags sysctl to 0.
Reviewed by: jhb
Security: FreeBSD-SA-18:10.ip
Security: CVE-2018-6923
Currently, all IPv6 fragment reassembly queues are kept in a flat
linked list. This has a number of implications. Two significant
implications are: all reassembly operations share a common lock,
and it is possible for the linked list to grow quite large.
Improve IPv6 reassembly performance by hashing fragments into buckets,
each of which has its own lock. Calculate the hash key using a Jenkins
hash with a random seed.
Reviewed by: jhb
Security: FreeBSD-SA-18:10.ip
Security: CVE-2018-6923
Instead of returning pointer to the previous header, return its offset.
In frag6_input() use m_copyback() and determined offset to store next
header instead of accessing to it by pointer and assuming that the memory
is contiguous.
In rip6_input() use offset returned by ip6_get_prevhdr() instead of
calculating it from pointers arithmetic, because IP header can belong
to another mbuf in the chain.
Reported by: Maxime Villard <max at m00nbsd dot net>
Reviewed by: kp
MFC after: 1 week
Differential Revision: https://reviews.freebsd.org/D14158
the first mbuf of the reassembled datagram should have a pkthdr.
This was discovered with cxgbe(4) + IPSEC + ping with payload more than
interface MTU. cxgbe can generate !M_WRITEABLE mbufs and this results
in m_unshare being called on the reassembled datagram, and it complains:
panic: m_unshare: m0 0xfffff80020f82600, m 0xfffff8005d054100 has M_PKTHDR
PR: 224922
Reviewed by: ae@
MFC after: 1 week
Sponsored by: Chelsio Communications
Differential Revision: https://reviews.freebsd.org/D14009
that had the IPv6 fragmentation header:
o Neighbor Solicitation
o Neighbor Advertisement
o Router Solicitation
o Router Advertisement
o Redirect
Introduce M_FRAGMENTED mbuf flag, and set it after IPv6 fragment reassembly
is completed. Then check the presence of this flag in correspondig ND6
handling routines.
PR: 224247
MFC after: 2 weeks
Mainly focus on files that use BSD 3-Clause license.
The Software Package Data Exchange (SPDX) group provides a specification
to make it easier for automated tools to detect and summarize well known
opensource licenses. We are gradually adopting the specification, noting
that the tags are considered only advisory and do not, in any way,
superceed or replace the license texts.
Special thanks to Wind River for providing access to "The Duke of
Highlander" tool: an older (2014) run over FreeBSD tree was useful as a
starting point.
and csum_flags using information from all fragments. This fixes
dropping of reassembled packets due to wrong checksum when the IPv6
checksum offloading is enabled on a network card.
Obtained from: Yandex LLC
MFC after: 1 week
Sponsored by: Yandex LLC
This is required for fragments and encapsulated data (eg tunneling) to be redistributed
to the RSS bucket based on the eventual IPv6 header and protocol (TCP, UDP, etc) header.
* Add an mbuf tag with the state of IPv6 options parsing before the frame is queued
into the direct dispatch handler;
* Continue processing and complete the frame reception in the correct RSS bucket /
netisr context.
Testing results are in the phabricator review.
Differential Revision: https://reviews.freebsd.org/D3563
Submitted by: Tiwei Bie <btw@mail.ustc.edu.cn>
It isn't safe to keep unreferenced ifaddrs. Use in6ifa_ifwithaddr() to
determine ifaddr corresponding to destination address. Since currently
we keep addresses with embedded scope zone, in6ifa_ifwithaddr is called
with zero zoneid and marked with XXX.
Also remove route and lle lookups from ip6_input. Use in6ifa_ifwithaddr()
instead.
Sponsored by: Yandex LLC
to this event, adding if_var.h to files that do need it. Also, include
all includes that now are included due to implicit pollution via if_var.h
Sponsored by: Netflix
Sponsored by: Nginx, Inc.
DPCPU_DEFINE and VNET_DEFINE macros, as these cause problems for various
people working on the affected files. A better long-term solution is
still being considered. This reversal may give some modules empty
set_pcpu or set_vnet sections, but these are harmless.
Changes reverted:
------------------------------------------------------------------------
r215318 | dim | 2010-11-14 21:40:55 +0100 (Sun, 14 Nov 2010) | 4 lines
Instead of unconditionally emitting .globl's for the __start_set_xxx and
__stop_set_xxx symbols, only emit them when the set_vnet or set_pcpu
sections are actually defined.
------------------------------------------------------------------------
r215317 | dim | 2010-11-14 21:38:11 +0100 (Sun, 14 Nov 2010) | 3 lines
Apply the STATIC_VNET_DEFINE and STATIC_DPCPU_DEFINE macros throughout
the tree.
------------------------------------------------------------------------
r215316 | dim | 2010-11-14 21:23:02 +0100 (Sun, 14 Nov 2010) | 2 lines
Add macros to define static instances of VNET_DEFINE and DPCPU_DEFINE.
"Whitspace" churn after the VIMAGE/VNET whirls.
Remove the need for some "init" functions within the network
stack, like pim6_init(), icmp_init() or significantly shorten
others like ip6_init() and nd6_init(), using static initialization
again where possible and formerly missed.
Move (most) variables back to the place they used to be before the
container structs and VIMAGE_GLOABLS (before r185088) and try to
reduce the diff to stable/7 and earlier as good as possible,
to help out-of-tree consumers to update from 6.x or 7.x to 8 or 9.
This also removes some header file pollution for putatively
static global variables.
Revert VIMAGE specific changes in ipfilter::ip_auth.c, that are
no longer needed.
Reviewed by: jhb
Discussed with: rwatson
Sponsored by: The FreeBSD Foundation
Sponsored by: CK Software GmbH
MFC after: 6 days
vnet.h, we now use jails (rather than vimages) as the abstraction
for virtualization management, and what remained was specific to
virtual network stacks. Minor cleanups are done in the process,
and comments updated to reflect these changes.
Reviewed by: bz
Approved by: re (vimage blanket)
unused custom mutex/condvar-based sleep locks with two locks: an
rwlock (for non-sleeping use) and sxlock (for sleeping use). Either
acquired for read is sufficient to stabilize the vnet list, but both
must be acquired for write to modify the list.
Replace previous no-op read locking macros, used in various places
in the stack, with actual locking to prevent race conditions. Callers
must declare when they may perform unbounded sleeps or not when
selecting how to lock.
Refactor vnet sysinits so that the vnet list and locks are initialized
before kernel modules are linked, as the kernel linker will use them
for modules loaded by the boot loader.
Update various consumers of these KPIs based on whether they may sleep
or not.
Reviewed by: bz
Approved by: re (kib)
(DPCPU), as suggested by Peter Wemm, and implement a new per-virtual
network stack memory allocator. Modify vnet to use the allocator
instead of monolithic global container structures (vinet, ...). This
change solves many binary compatibility problems associated with
VIMAGE, and restores ELF symbols for virtualized global variables.
Each virtualized global variable exists as a "reference copy", and also
once per virtual network stack. Virtualized global variables are
tagged at compile-time, placing the in a special linker set, which is
loaded into a contiguous region of kernel memory. Virtualized global
variables in the base kernel are linked as normal, but those in modules
are copied and relocated to a reserved portion of the kernel's vnet
region with the help of a the kernel linker.
Virtualized global variables exist in per-vnet memory set up when the
network stack instance is created, and are initialized statically from
the reference copy. Run-time access occurs via an accessor macro, which
converts from the current vnet and requested symbol to a per-vnet
address. When "options VIMAGE" is not compiled into the kernel, normal
global ELF symbols will be used instead and indirection is avoided.
This change restores static initialization for network stack global
variables, restores support for non-global symbols and types, eliminates
the need for many subsystem constructors, eliminates large per-subsystem
structures that caused many binary compatibility issues both for
monitoring applications (netstat) and kernel modules, removes the
per-function INIT_VNET_*() macros throughout the stack, eliminates the
need for vnet_symmap ksym(2) munging, and eliminates duplicate
definitions of virtualized globals under VIMAGE_GLOBALS.
Bump __FreeBSD_version and update UPDATING.
Portions submitted by: bz
Reviewed by: bz, zec
Discussed with: gnn, jamie, jeff, jhb, julian, sam
Suggested by: peter
Approved by: re (kensmith)
rather than pointers, requiring callers to properly dispose of those
references. The following routines now return references:
ifaddr_byindex
ifa_ifwithaddr
ifa_ifwithbroadaddr
ifa_ifwithdstaddr
ifa_ifwithnet
ifaof_ifpforaddr
ifa_ifwithroute
ifa_ifwithroute_fib
rt_getifa
rt_getifa_fib
IFP_TO_IA
ip_rtaddr
in6_ifawithifp
in6ifa_ifpforlinklocal
in6ifa_ifpwithaddr
in6_ifadd
carp_iamatch6
ip6_getdstifaddr
Remove unused macro which didn't have required referencing:
IFP_TO_IA6
This closes many small races in which changes to interface
or address lists while an ifaddr was in use could lead to use of freed
memory (etc). In a few cases, add missing if_addr_list locking
required to safely acquire references.
Because of a lack of deep copying support, we accept a race in which
an in6_ifaddr pointed to by mbuf tags and extracted with
ip6_getdstifaddr() doesn't hold a reference while in transmit. Once
we have mbuf tag deep copy support, this can be fixed.
Reviewed by: bz
Obtained from: Apple, Inc. (portions)
MFC after: 6 weeks (portions)
and used in a large number of files, but also because an increasing number
of incorrect uses of MAC calls were sneaking in due to copy-and-paste of
MAC-aware code without the associated opt_mac.h include.
Discussed with: pjd
from existing functions for initializing global state.
At this stage, the new per-vnet initializer functions are
directly called from the existing global initialization code,
which should in most cases result in compiler inlining those
new functions, hence yielding a near-zero functional change.
Modify the existing initializer functions which are invoked via
protosw, like ip_init() et. al., to allow them to be invoked
multiple times, i.e. per each vnet. Global state, if any,
is initialized only if such functions are called within the
context of vnet0, which will be determined via the
IS_DEFAULT_VNET(curvnet) check (currently always true).
While here, V_irtualize a few remaining global UMA zones
used by net/netinet/netipsec networking code. While it is
not yet clear to me or anybody else whether this is the right
thing to do, at this stage this makes the code more readable,
and makes it easier to track uncollected UMA-zone-backed
objects on vnet removal. In the long run, it's quite possible
that some form of shared use of UMA zone pools among multiple
vnets should be considered.
Bump __FreeBSD_version due to changes in layout of structs
vnet_ipfw, vnet_inet and vnet_net.
Approved by: julian (mentor)
from the inet6 stack along with statistics and make sure we
properly free the rt in all cases.
While the current situation is not better performance wise it
prevents panics seen more often these days.
After more inet6 and ipsec cleanup we should be able to improve
the situation again passing the rt to ip6_forward directly.
Leave the ip6_forward_rt entry in struct vinet6 but mark it
for removal.
PR: kern/128247, kern/131038
MFC after: 25 days
Committed from: Bugathon #6
Tested by: Denis Ahrens <denis@h3q.com> (different initial version)
directly include only the header files needed. This reduces the
unneeded spamming of various headers into lots of files.
For now, this leaves us with very few modules including vnet.h
and thus needing to depend on opt_route.h.
Reviewed by: brooks, gnn, des, zec, imp
Sponsored by: The FreeBSD Foundation
for virtualization.
Instead of initializing the affected global variables at instatiation,
assign initial values to them in initializer functions. As a rule,
initialization at instatiation for such variables should never be
introduced again from now on. Furthermore, enclose all instantiations
of such global variables in #ifdef VIMAGE_GLOBALS blocks.
Essentialy, this change should have zero functional impact. In the next
phase of merging network stack virtualization infrastructure from
p4/vimage branch, the new initialization methology will allow us to
switch between using global variables and their counterparts residing in
virtualization containers with minimum code churn, and in the long run
allow us to intialize multiple instances of such container structures.
Discussed at: devsummit Strassburg
Reviewed by: bz, julian
Approved by: julian (mentor)
Obtained from: //depot/projects/vimage-commit2/...
X-MFC after: never
Sponsored by: NLnet Foundation, The FreeBSD Foundation
fragment reassembly queues.
This allows policies to label reassembly queues, perform access
control checks when matching fragments to a queue, update a queue
label when fragments are matched, and label the resulting
reassembled datagram.
Obtained from: TrustedBSD Project
from the vimage project, as per plan established at devsummit 08/08:
http://wiki.freebsd.org/Image/Notes200808DevSummit
Introduce INIT_VNET_*() initializer macros, VNET_FOREACH() iterator
macros, and CURVNET_SET() context setting macros, all currently
resolving to NOPs.
Prepare for virtualization of selected SYSCTL objects by introducing a
family of SYSCTL_V_*() macros, currently resolving to their global
counterparts, i.e. SYSCTL_V_INT() == SYSCTL_INT().
Move selected #defines from sys/sys/vimage.h to newly introduced header
files specific to virtualized subsystems (sys/net/vnet.h,
sys/netinet/vinet.h etc.).
All the changes are verified to have zero functional impact at this
point in time by doing MD5 comparision between pre- and post-change
object files(*).
(*) netipsec/keysock.c did not validate depending on compile time options.
Implemented by: julian, bz, brooks, zec
Reviewed by: julian, bz, brooks, kris, rwatson, ...
Approved by: julian (mentor)
Obtained from: //depot/projects/vimage-commit2/...
X-MFC after: never
Sponsored by: NLnet Foundation, The FreeBSD Foundation
virtualization work done by Marko Zec (zec@).
This is the first in a series of commits over the course
of the next few weeks.
Mark all uses of global variables to be virtualized
with a V_ prefix.
Use macros to map them back to their global names for
now, so this is a NOP change only.
We hope to have caught at least 85-90% of what is needed
so we do not invalidate a lot of outstanding patches again.
Obtained from: //depot/projects/vimage-commit2/...
Reviewed by: brooks, des, ed, mav, julian,
jamie, kris, rwatson, zec, ...
(various people I forgot, different versions)
md5 (with a bit of help)
Sponsored by: NLnet Foundation, The FreeBSD Foundation
X-MFC after: never
V_Commit_Message_Reviewed_By: more people than the patch
code is believed to be MPSAFE, and leaving aside the IPv6 route cache in
forwarding, Giant appears not to adequately synchronize the data structures
in the input or forwarding paths.
