Rework tcpopts_parse() to be more strict. Use const pointer. Add length
checks for specific TCP options. The main purpose of the change is
avoiding of possible out of mbuf's data access.
Reported by: Maxime Villard
Reviewed by: melifaro, emaste
MFC after: 1 week
datagrams.
Previously destination address from original datagram was used. That
looked confusing, especially in the traceroute6 output.
Also honor IPSTEALTH kernel option and do TTL/HLIM decrementing only
when stealth mode is disabled.
Reported by: Marco van Tol <marco at tols org>
Reviewed by: melifaro
MFC after: 2 weeks
Sponsored by: Yandex LLC
Differential Revision: https://reviews.freebsd.org/D22631
PULLUP_LEN_LOCKED().
PULLUP_LEN_LOCKED() could update mbuf and thus we need to update related
pointers that can be used in next opcodes.
Reported by: Maxime Villard <max at m00nbsd net>
MFC after: 1 week
When epoch(9) was introduced to network stack, it was basically
dropped in place of existing locking, which was mutexes and
rwlocks. For the sake of performance mutex covered areas were
as small as possible, so became epoch covered areas.
However, epoch doesn't introduce any contention, it just delays
memory reclaim. So, there is no point to minimise epoch covered
areas in sense of performance. Meanwhile entering/exiting epoch
also has non-zero CPU usage, so doing this less often is a win.
Not the least is also code maintainability. In the new paradigm
we can assume that at any stage of processing a packet, we are
inside network epoch. This makes coding both input and output
path way easier.
On output path we already enter epoch quite early - in the
ip_output(), in the ip6_output().
This patch does the same for the input path. All ISR processing,
network related callouts, other ways of packet injection to the
network stack shall be performed in net_epoch. Any leaf function
that walks network configuration now asserts epoch.
Tricky part is configuration code paths - ioctls, sysctls. They
also call into leaf functions, so some need to be changed.
This patch would introduce more epoch recursions (see EPOCH_TRACE)
than we had before. They will be cleaned up separately, as several
of them aren't trivial. Note, that unlike a lock recursion the
epoch recursion is safe and just wastes a bit of resources.
Reviewed by: gallatin, hselasky, cy, adrian, kristof
Differential Revision: https://reviews.freebsd.org/D19111
ACTION_PTR() returns pointer to the start of rule action section,
but rule can keep several rule modifiers like O_LOG, O_TAG and O_ALTQ,
and only then real action opcode is stored.
ipfw_get_action() function inspects the rule action section, skips
all modifiers and returns action opcode.
Use this function in ipfw_reset_eaction() and flush_nat_ptrs().
MFC after: 1 week
Sponsored by: Yandex LLC
After r343619 ipfw uses own locking for packets flow. PULLUP_LEN() macro
is used in ipfw_chk() to make m_pullup(). When m_pullup() fails, it just
returns via `goto pullup_failed`. There are two places where PULLUP_LEN()
is called with IPFW_PF_RLOCK() held.
Add PULLUP_LEN_LOCKED() macro to use in these places to be able release
the lock, when m_pullup() fails.
Sponsored by: Yandex LLC
After r343631 pfil hooks are invoked in net_epoch_preempt section,
this allows to avoid extra locking. Add NET_EPOCH_ASSER() assertion
to each ipfw_bpf_*tap*() call to require to be called from inside
epoch section.
Use NET_EPOCH_WAIT() in ipfw_clone_destroy() to wait until it becomes
safe to free() ifnet. And use on-stack ifnet pointer in each
ipfw_bpf_*tap*() call to avoid NULL pointer dereference in case when
V_*log_if global variable will become NULL during ipfw_bpf_*tap*() call.
Sponsored by: Yandex LLC
It is possible, that opcode at the ACTION_PTR() location is not real
action, but action modificator like "log", "tag" etc. In this case we
need to check for each opcode in the loop to find O_EXTERNAL_ACTION.
Obtained from: Yandex LLC
MFC after: 1 week
Sponsored by: Yandex LLC
With this opcode it is possible to match TCP packets with specified
MSS option, whose value corresponds to configured in opcode value.
It is allowed to specify single value, range of values, or array of
specific values or ranges. E.g.
# ipfw add deny log tcp from any to any tcpmss 0-500
Reviewed by: melifaro,bcr
Obtained from: Yandex LLC
MFC after: 1 week
Sponsored by: Yandex LLC
- Perform ifp mismatch checks (to determine if a send tag is allocated
for a different ifp than the one the packet is being output on), in
ip_output() and ip6_output(). This avoids sending packets with send
tags to ifnet drivers that don't support send tags.
Since we are now checking for ifp mismatches before invoking
if_output, we can now try to allocate a new tag before invoking
if_output sending the original packet on the new tag if allocation
succeeds.
To avoid code duplication for the fragment and unfragmented cases,
add ip_output_send() and ip6_output_send() as wrappers around
if_output and nd6_output_ifp, respectively. All of the logic for
setting send tags and dealing with send tag-related errors is done
in these wrapper functions.
For pseudo interfaces that wrap other network interfaces (vlan and
lagg), wrapper send tags are now allocated so that ip*_output see
the wrapper ifp as the ifp in the send tag. The if_transmit
routines rewrite the send tags after performing an ifp mismatch
check. If an ifp mismatch is detected, the transmit routines fail
with EAGAIN.
- To provide clearer life cycle management of send tags, especially
in the presence of vlan and lagg wrapper tags, add a reference count
to send tags managed via m_snd_tag_ref() and m_snd_tag_rele().
Provide a helper function (m_snd_tag_init()) for use by drivers
supporting send tags. m_snd_tag_init() takes care of the if_ref
on the ifp meaning that code alloating send tags via if_snd_tag_alloc
no longer has to manage that manually. Similarly, m_snd_tag_rele
drops the refcount on the ifp after invoking if_snd_tag_free when
the last reference to a send tag is dropped.
This also closes use after free races if there are pending packets in
driver tx rings after the socket is closed (e.g. from tcpdrop).
In order for m_free to work reliably, add a new CSUM_SND_TAG flag in
csum_flags to indicate 'snd_tag' is set (rather than 'rcvif').
Drivers now also check this flag instead of checking snd_tag against
NULL. This avoids false positive matches when a forwarded packet
has a non-NULL rcvif that was treated as a send tag.
- cxgbe was relying on snd_tag_free being called when the inp was
detached so that it could kick the firmware to flush any pending
work on the flow. This is because the driver doesn't require ACK
messages from the firmware for every request, but instead does a
kind of manual interrupt coalescing by only setting a flag to
request a completion on a subset of requests. If all of the
in-flight requests don't have the flag when the tag is detached from
the inp, the flow might never return the credits. The current
snd_tag_free command issues a flush command to force the credits to
return. However, the credit return is what also frees the mbufs,
and since those mbufs now hold references on the tag, this meant
that snd_tag_free would never be called.
To fix, explicitly drop the mbuf's reference on the snd tag when the
mbuf is queued in the firmware work queue. This means that once the
inp's reference on the tag goes away and all in-flight mbufs have
been queued to the firmware, tag's refcount will drop to zero and
snd_tag_free will kick in and send the flush request. Note that we
need to avoid doing this in the middle of ethofld_tx(), so the
driver grabs a temporary reference on the tag around that loop to
defer the free to the end of the function in case it sends the last
mbuf to the queue after the inp has dropped its reference on the
tag.
- mlx5 preallocates send tags and was using the ifp pointer even when
the send tag wasn't in use. Explicitly use the ifp from other data
structures instead.
- Sprinkle some assertions in various places to assert that received
packets don't have a send tag, and that other places that overwrite
rcvif (e.g. 802.11 transmit) don't clobber a send tag pointer.
Reviewed by: gallatin, hselasky, rgrimes, ae
Sponsored by: Netflix
Differential Revision: https://reviews.freebsd.org/D20117
There are a few places that use hand crafted versions of the macros
from sys/netinet/in.h making it difficult to actually alter the
values in use by these macros. Correct that by replacing handcrafted
code with proper macro usage.
Reviewed by: karels, kristof
Approved by: bde (mentor)
MFC after: 3 weeks
Sponsored by: John Gilmore
Differential Revision: https://reviews.freebsd.org/D19317
Now enabling ipfw(4) with sysctls controls only linkage of hooks to default
heads. When module is loaded fetch sysctls as tunables, to make it possible
to boot with ipfw(4) in kernel, but not linked to any pfil(9) hooks.
Update NAT64LSN implementation:
o most of data structures and relations were modified to be able support
large number of translation states. Now each supported protocol can
use full ports range. Ports groups now are belongs to IPv4 alias
addresses, not hosts. Each ports group can keep several states chunks.
This is controlled with new `states_chunks` config option. States
chunks allow to have several translation states for single alias address
and port, but for different destination addresses.
o by default all hash tables now use jenkins hash.
o ConcurrencyKit and epoch(9) is used to make NAT64LSN lockless on fast path.
o one NAT64LSN instance now can be used to handle several IPv6 prefixes,
special prefix "::" value should be used for this purpose when instance
is created.
o due to modified internal data structures relations, the socket opcode
that does states listing was changed.
Obtained from: Yandex LLC
MFC after: 1 month
Sponsored by: Yandex LLC
o most of data structures and relations were modified to be able support
large number of translation states. Now each supported protocol can
use full ports range. Ports groups now are belongs to IPv4 alias
addresses, not hosts. Each ports group can keep several states chunks.
This is controlled with new `states_chunks` config option. States
chunks allow to have several translation states for single alias address
and port, but for different destination addresses.
o by default all hash tables now use jenkins hash.
o ConcurrencyKit and epoch(9) is used to make NAT64LSN lockless on fast path.
o one NAT64LSN instance now can be used to handle several IPv6 prefixes,
special prefix "::" value should be used for this purpose when instance
is created.
o due to modified internal data structures relations, the socket opcode
that does states listing was changed.
Obtained from: Yandex LLC
MFC after: 1 month
Sponsored by: Yandex LLC
CLAT is customer-side translator that algorithmically translates 1:1
private IPv4 addresses to global IPv6 addresses, and vice versa.
It is implemented as part of ipfw_nat64 kernel module. When module
is loaded or compiled into the kernel, it registers "nat64clat" external
action. External action named instance can be created using `create`
command and then used in ipfw rules. The create command accepts two
IPv6 prefixes `plat_prefix` and `clat_prefix`. If plat_prefix is ommitted,
IPv6 NAT64 Well-Known prefix 64:ff9b::/96 will be used.
# ipfw nat64clat CLAT create clat_prefix SRC_PFX plat_prefix DST_PFX
# ipfw add nat64clat CLAT ip4 from IPv4_PFX to any out
# ipfw add nat64clat CLAT ip6 from DST_PFX to SRC_PFX in
Obtained from: Yandex LLC
Submitted by: Boris N. Lytochkin
MFC after: 1 month
Relnotes: yes
Sponsored by: Yandex LLC
Add second IPv6 prefix to generic config structure and rename another
fields to conform to RFC6877. Now it contains two prefixes and length:
PLAT is provider-side translator that translates N:1 global IPv6 addresses
to global IPv4 addresses. CLAT is customer-side translator (XLAT) that
algorithmically translates 1:1 IPv4 addresses to global IPv6 addresses.
Use PLAT prefix in stateless (nat64stl) and stateful (nat64lsn)
translators.
Modify nat64_extract_ip4() and nat64_embed_ip4() functions to accept
prefix length and use plat_plen to specify prefix length.
Retire net.inet.ip.fw.nat64_allow_private sysctl variable.
Add NAT64_ALLOW_PRIVATE flag and use "allow_private" config option to
configure this ability separately for each NAT64 instance.
Obtained from: Yandex LLC
MFC after: 1 month
Sponsored by: Yandex LLC
With new pfil(9) KPI it is possible to pass a void pointer with length
instead of mbuf pointer to a packet filter. Until this commit no filters
supported that, so pfil run through a shim function pfil_fake_mbuf().
Now the ipfw(4) hook named "default-link", that is instantiated when
net.link.ether.ipfw sysctl is on, supports processing pointer/length
packets natively.
- ip_fw_args now has union for either mbuf or void *, and if flags have
non-zero length, then we use the void *.
- through ipfw_chk() we handle mem/mbuf cases differently.
- ether_header goes away from args. It is ipfw_chk() responsibility
to do parsing of Ethernet header.
- ipfw_log() now uses different bpf APIs to log packets.
Although ipfw_chk() is now capable to process pointer/length packets,
this commit adds support for the link level hook only, see
ipfw_check_frame(). Potentially the IP processing hook ipfw_check_packet()
can be improved too, but that requires more changes since the hook
supports more complex actions: NAT, divert, etc.
Reviewed by: ae
Differential Revision: https://reviews.freebsd.org/D19357
IPFW_ARGS_OUT are utilized. They are intented to substitute the "dir"
parameter that is often passes together with args.
- Rename ip_fw_args.oif to ifp and now it is set to either input or
output interface, depending on IPFW_ARGS_IN/OUT bit set.
It will be used by upcoming NAT64 changes. We use separate code
to avoid propogating EACCES error code to user level applications
when NAT64 consumes a packet.
Obtained from: Yandex LLC
MFC after: 1 week
Sponsored by: Yandex LLC
It is possible, that a processed packet was originated by local host,
in this case m->m_pkthdr.rcvif is NULL. Check and set it to V_loif to
avoid NULL pointer dereference in IP input code, since it is expected
that packet has valid receiving interface when netisr processes it.
Obtained from: Yandex LLC
MFC after: 1 week
Sponsored by: Yandex LLC
dyn_install_state() uses `rule` pointer when it creates state.
For O_LIMIT states this pointer actually is not struct ip_fw,
it is pointer to O_LIMIT_PARENT state, that keeps actual pointer
to ip_fw parent rule. Thus we need to cache rule id and number
before calling dyn_get_parent_state(), so we can use them later
when the `rule` pointer is overrided.
PR: 236292
MFC after: 3 days
Initially it was introduced because parent rule pointer could be freed,
and rule's information could become inaccessible. In r341471 this was
changed. And now we don't need this information, and also it can become
stale. E.g. rule can be moved from one set to another. This can lead
to parent's set and state's set will not match. In this case it is
possible that static rule will be freed, but dynamic state will not.
This can happen when `ipfw delete set N` command is used to delete
rules, that were moved to another set.
To fix the problem we will use the set number from parent rule.
Obtained from: Yandex LLC
MFC after: 1 week
Sponsored by: Yandex LLC
The KPI have been reviewed and cleansed of features that were planned
back 20 years ago and never implemented. The pfil(9) internals have
been made opaque to protocols with only returned types and function
declarations exposed. The KPI is made more strict, but at the same time
more extensible, as kernel uses same command structures that userland
ioctl uses.
In nutshell [KA]PI is about declaring filtering points, declaring
filters and linking and unlinking them together.
New [KA]PI makes it possible to reconfigure pfil(9) configuration:
change order of hooks, rehook filter from one filtering point to a
different one, disconnect a hook on output leaving it on input only,
prepend/append a filter to existing list of filters.
Now it possible for a single packet filter to provide multiple rulesets
that may be linked to different points. Think of per-interface ACLs in
Cisco or Juniper. None of existing packet filters yet support that,
however limited usage is already possible, e.g. default ruleset can
be moved to single interface, as soon as interface would pride their
filtering points.
Another future feature is possiblity to create pfil heads, that provide
not an mbuf pointer but just a memory pointer with length. That would
allow filtering at very early stages of a packet lifecycle, e.g. when
packet has just been received by a NIC and no mbuf was yet allocated.
Differential Revision: https://reviews.freebsd.org/D18951
The pfil(9) system is about to be converted to epoch(9) synchronization, so
we need [temporarily] go back with ipfw internal locking.
Discussed with: ae
handling for protocols without ports numbers.
Since port numbers were uninitialized for protocols like ICMP/ICMPv6,
ipfw_chk() used some non-zero values to create dynamic states, and due
this it failed to match replies with created states.
Reported by: Oliver Hartmann, Boris Lytochkin
Obtained from: Yandex LLC
X-MFC after: r342908
