Sweep over potentially unsafe calls to ifnet_byindex() and wrap them
in epoch. Most of the code touched remains unsafe, as the returned
pointer is being used after epoch exit. Mark that with a comment.
Validate the index argument inside the function, reducing argument
validation requirement from the callers and making V_if_index
private to if.c.
Reviewed by: melifaro
Differential revision: https://reviews.freebsd.org/D33263
This reverts commit 266f97b5e9, reversing
changes made to a10253cffe.
A mismerge of a merge to catch up to main resulted in files being
committed which should not have been.
With introduction of epoch(9) synchronization to network stack the
inpcb database became protected by the network epoch together with
static network data (interfaces, addresses, etc). However, inpcb
aren't static in nature, they are created and destroyed all the
time, which creates some traffic on the epoch(9) garbage collector.
Fairly new feature of uma(9) - Safe Memory Reclamation allows to
safely free memory in page-sized batches, with virtually zero
overhead compared to uma_zfree(). However, unlike epoch(9), it
puts stricter requirement on the access to the protected memory,
needing the critical(9) section to access it. Details:
- The database is already build on CK lists, thanks to epoch(9).
- For write access nothing is changed.
- For a lookup in the database SMR section is now required.
Once the desired inpcb is found we need to transition from SMR
section to r/w lock on the inpcb itself, with a check that inpcb
isn't yet freed. This requires some compexity, since SMR section
itself is a critical(9) section. The complexity is hidden from
KPI users in inp_smr_lock().
- For a inpcb list traversal (a pcblist sysctl, or broadcast
notification) also a new KPI is provided, that hides internals of
the database - inp_next(struct inp_iterator *).
Reviewed by: rrs
Differential revision: https://reviews.freebsd.org/D33022
With upcoming changes to the inpcb synchronisation it is going to be
broken. Even its current status after the move of PCB synchronization
to the network epoch is very questionable.
This experimental feature was sponsored by Juniper but ended never to
be used in Juniper and doesn't exist in their source tree [sjg@, stevek@,
jtl@]. In the past (AFAIK, pre-epoch times) it was tried out at Netflix
[gallatin@, rrs@] with no positive result and at Yandex [ae@, melifaro@].
I'm up to resurrecting it back if there is any interest from anybody.
Reviewed by: rrs
Differential revision: https://reviews.freebsd.org/D33020
Drop packets arriving from the network that have our source IPv6
address. If maliciously crafted they can create evil effects
like an RST exchange between two of our listening TCP ports.
Such packets just can't be legitimate. Enable the tunable
by default. Long time due for a modern Internet host.
Reviewed by: melifaro, donner, kp
Differential revision: https://reviews.freebsd.org/D32915
In most cases blackholing for locally originated packets is undesired,
leads to different kind of lags and delays. Provide sysctls to enforce
it, e.g. for debugging purposes.
Reviewed by: rrs
Differential revision: https://reviews.freebsd.org/D32718
Previously in_pcbbind_setup returned EADDRNOTAVAIL for empty
V_in_ifaddrhead (i.e., no IPv4 addresses configured) and in6_pcbbind
did the same for empty V_in6_ifaddrhead (no IPv6 addresses).
An equivalent test has existed since 4.4-Lite. It was presumably done
to avoid extra work (assuming the address isn't going to be found
later).
In normal system operation *_ifaddrhead will not be empty: they will
at least have the loopback address(es). In practice no work will be
avoided.
Further, this case caused net/dhcpd to fail when run early in boot
before assignment of any addresses. It should be possible to bind the
unspecified address even if no addresses have been configured yet, so
just remove the tests.
The now-removed "XXX broken" comments were added in 59562606b9,
which converted the ifaddr lists to TAILQs. As far as I (emaste) can
tell the brokenness is the issue described above, not some aspect of
the TAILQ conversion.
PR: 253166
Reviewed by: ae, bz, donner, emaste, glebius
MFC after: 1 month
Differential Revision: https://reviews.freebsd.org/D32563
This function was originally carved out of in6_pcbbind(), which
is in in6_pcb.c. This function also uses KPI private to the PCB
database - in_pcb_lport().
All callers of sctp_aloc_assoc() mark the PCB as connected after a
successful call (for one-to-one-style sockets). In all cases this is
done without the PCB lock, so the PCB's flags can be corrupted. We also
do not atomically check whether a one-to-one-style socket is a listening
socket, which violates various assumptions in solisten_proto().
We need to hold the PCB lock across all of sctp_aloc_assoc() to fix
this. In order to do that without introducing lock order reversals, we
have to hold the global info lock as well.
So:
- Convert sctp_aloc_assoc() so that the inp and info locks are
consistently held. It returns with the association lock held, as
before.
- Fix an apparent bug where we failed to remove an association from a
global hash if sctp_add_remote_addr() fails.
- sctp_select_a_tag() is called when initializing an association, and it
acquires the global info lock. To avoid lock recursion, push locking
into its callers.
- Introduce sctp_aloc_assoc_connected(), which atomically checks for a
listening socket and sets SCTP_PCB_FLAGS_CONNECTED.
There is still one edge case in sctp_process_cookie_new() where we do
not update PCB/socket state correctly.
Reviewed by: tuexen
MFC after: 1 week
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D31908
- Protect the `expire_upcalls` callout with the MFC6 mutex. The callout
handler needs this mutex anyway.
- Convert the MROUTER6 mutex to a sleepable sx lock. It is only used
when configuring the global v6 multicast routing socket, so is only
used in system call paths where sleeping is safe. This lets us drain
the callout without having to drop the lock.
- For all locking macros in the file, convert to using a _LOCKPTR macro.
Reported by: mav
MFC after: 2 weeks
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D31836
Interface addresses with pending duplicate address detection (DAD) live
in a global queue. In this case, a callout is associated with each
entry. The callout transmits neighbour solicitations until the system
decides the address is no longer tentative, or until a duplicate address
is discovered. At this point the entry is dequeued and freed. DAD may
be manually stopped as well.
The callout currently runs (and potentially transmits packets) with
Giant held. Reorganize DAD queue locking to interlock properly with the
callout:
- Configure the callout to acquire the DAD queue lock before running.
The lock is dropped before transmitting any packets. Stop protecting
the callout with Giant.
- When looking up DAD queue entries for an incoming NS or NA, don't
bother fiddling with the DAD queue entry reference count.
- Split nd6_dad_starttimer() so that the caller is responsible to
transmitting a NS if it so desires.
- Remove the DAD entry from the queue before stopping the timer. Use a
temporary reference to make sure that the entry doesn't get freed by
the callout while we're draining.
Reported by: mav
Reviewed by: bz, hrs
Sponsored by: The FreeBSD Foundation
MFC after: 2 weeks
Differential Revision: https://reviews.freebsd.org/D31826
Currently we use pre-calculated headers inside LLE entries as prepend data
for `if_output` functions. Using these headers allows saving some
CPU cycles/memory accesses on the fast path.
However, this approach makes adding L2 header for IPv4 traffic with IPv6
nexthops more complex, as it is not possible to store multiple
pre-calculated headers inside lle. Additionally, the solution space is
limited by the fact that PCB caching saves LLEs in addition to the nexthop.
Thus, add support for creating special "child" LLEs for the purpose of holding
custom family encaps and store mbufs pending resolution. To simplify handling
of those LLEs, store them in a linked-list inside a "parent" (e.g. normal) LLE.
Such LLEs are not visible when iterating LLE table. Their lifecycle is bound
to the "parent" LLE - it is not possible to delete "child" when parent is alive.
Furthermore, "child" LLEs are static (RTF_STATIC), avoding complex state
machine used by the standard LLEs.
nd6_lookup() and nd6_resolve() now accepts an additional argument, family,
allowing to return such child LLEs. This change uses `LLE_SF()` macro which
packs family and flags in a single int field. This is done to simplify merging
back to stable/. Once this code lands, most of the cases will be converted to
use a dedicated `family` parameter.
Differential Revision: https://reviews.freebsd.org/D31379
MFC after: 2 weeks
The keyword adds nothing as all operations on the var are performed
through atomic_*
Reviewed by: kp
Sponsored by: Rubicon Communications, LLC ("Netgate")
Differential Revision: https://reviews.freebsd.org/D31528
The use of Giant here is vestigal and does not provide any useful
synchronization. Furthermore, non-MPSAFE callouts can cause the
softclock threads to block waiting for long-running newbus operations to
complete.
Reported by: mav
Reviewed by: bz
MFC after: 1 week
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D31470
We need to do so to safely traverse the ifnet list.
Reviewed by: bz
MFC after: 1 week
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D31470
Fix getsockopt() for the IPPROTO_IPV6 level socket options with the
following names: IPV6_HOPOPTS, IPV6_RTHDR, IPV6_RTHDRDSTOPTS,
IPV6_DSTOPTS, and IPV6_NEXTHOP.
Reviewed by: markj
MFC after: 3 days
Sponsored by: Netflix, Inc.
Differential Revision: https://reviews.freebsd.org/D31458
Factor out lltable locking logic from lltable_try_set_entry_addr()
into a separate lltable_acquire_wlock(), so the latter can be used
in other parts of the code w/o duplication.
Create nd6_try_set_entry_addr() to avoid code duplication in nd6.c
and nd6_nbr.c.
Move lle creation logic from nd6_resolve_slow() into a separate
nd6_get_llentry() to simplify the former.
These changes serve as a pre-requisite for implementing
RFC8950 (IPv4 prefixes with IPv6 nexthops).
Differential Revision: https://reviews.freebsd.org/D31432
MFC after: 2 weeks
Add check that ifp supports IPv6 multicasts in in6_getmulti.
This fixes panic when user application tries to join into multicast
group on an interface that doesn't support IPv6 multicasts, like
IFT_PFLOG interfaces.
PR: 257302
Reviewed by: melifaro
MFC after: 1 week
Differential Revision: https://reviews.freebsd.org/D31420
Use newly-create llentry_request_feedback(),
llentry_mark_used() and llentry_get_hittime() to
request datapatch usage check and fetch the results
in the same fashion both in IPv4 and IPv6.
While here, simplify llentry_provide_feedback() wrapper
by eliminating 1 condition check.
MFC after: 2 weeks
Differential Revision: https://reviews.freebsd.org/D31390
SO_RERROR indicates that receive buffer overflows should be handled as
errors. Historically receive buffer overflows have been ignored and
programs could not tell if they missed messages or messages had been
truncated because of overflows. Since programs historically do not
expect to get receive overflow errors, this behavior is not the
default.
This is really really important for programs that use route(4) to keep
in sync with the system. If we loose a message then we need to reload
the full system state, otherwise the behaviour from that point is
undefined and can lead to chasing bogus bug reports.
Reviewed by: philip (network), kbowling (transport), gbe (manpages)
MFC after: 2 weeks
Differential Revision: https://reviews.freebsd.org/D26652
ip6_setpktopts() can look up ifnets via ifnet_by_index(), which
is only safe in the net epoch. Ensure that callers are in the net
epoch before calling this function.
Sponsored by: Dell EMC Isilon
MFC after: 4 weeks
Reviewed by: donner, kp
Differential Revision: https://reviews.freebsd.org/D30630
The various protocol implementations are not very consistent about
freeing mbufs in error paths. In general, all protocols must free both
"m" and "control" upon an error, except if PRUS_NOTREADY is specified
(this is only implemented by TCP and unix(4) and requires further work
not handled in this diff), in which case "control" still must be freed.
This diff plugs various leaks in the pru_send implementations.
Reviewed by: tuexen
MFC after: 2 weeks
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D30151
Commit 81728a538 ("Split rtinit() into multiple functions.") removed
the initialization of sa6, but not one of its uses. This meant that we
were passing an uninitialized sockaddr as the address to
lltable_prefix_free(). Remove the variable outright to fix the problem.
The caller is expected to hold a reference on pr.
Fixes: 81728a538 ("Split rtinit() into multiple functions.")
Reported by: KMSAN
Reviewed by: donner
MFC after: 1 week
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D30166
Distinguish between truly invalid requests and those that fail because
we've already joined the group. Both cases fail, but differentiating
them allows userspace to make more informed decisions about what the
error means.
For example. radvd tries to join the all-routers group on every SIGHUP.
This fails, because it's already joined it, but this failure should be
ignored (rather than treated as a sign that the interface's multicast is
broken).
This puts us in line with OpenBSD, NetBSD and Linux.
Reviewed by: donner
MFC after: 1 week
Sponsored by: Rubicon Communications, LLC ("Netgate")
Differential Revision: https://reviews.freebsd.org/D30111
Several protocol methods take a sockaddr as input. In some cases the
sockaddr lengths were not being validated, or were validated after some
out-of-bounds accesses could occur. Add requisite checking to various
protocol entry points, and convert some existing checks to assertions
where appropriate.
Reported by: syzkaller+KASAN
Reviewed by: tuexen, melifaro
MFC after: 2 weeks
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D29519
This reverts a portion of 274579831b ("capsicum: Limit socket
operations in capability mode") as at least rtsol and dhcpcd rely on
being able to configure network interfaces while in capability mode.
Reported by: bapt, Greg V
Sponsored by: The FreeBSD Foundation
This is further rework of 08d9c92027. Now we carry the knowledge of
lock type all the way through tcp_input() and also into tcp_twcheck().
Ideally the rlocking for pure SYNs should propagate all the way into
the alternative TCP stacks, but not yet today.
This should close a race when socket is bind(2)-ed but not yet
listen(2)-ed and a SYN-packet arrives racing with listen(2), discovered
recently by pho@.
Adding support for TCP over UDP allows communication with
TCP stacks which can be implemented in userspace without
requiring special priviledges or specific support by the OS.
This is joint work with rrs.
Reviewed by: rrs
Sponsored by: Netflix, Inc.
MFC after: 1 week
Differential Revision: https://reviews.freebsd.org/D29469
When packet is a SYN packet, we don't need to modify any existing PCB.
Normally SYN arrives on a listening socket, we either create a syncache
entry or generate syncookie, but we don't modify anything with the
listening socket or associated PCB. Thus create a new PCB lookup
mode - rlock if listening. This removes the primary contention point
under SYN flood - the listening socket PCB.
Sidenote: when SYN arrives on a synchronized connection, we still
don't need write access to PCB to send a challenge ACK or just to
drop. There is only one exclusion - tcptw recycling. However,
existing entanglement of tcp_input + stacks doesn't allow to make
this change small. Consider this patch as first approach to the problem.
Reviewed by: rrs
Differential revision: https://reviews.freebsd.org/D29576
Capsicum did not prevent certain privileged networking operations,
specifically creation of raw sockets and network configuration ioctls.
However, these facilities can be used to circumvent some of the
restrictions that capability mode is supposed to enforce.
Add capability mode checks to disallow network configuration ioctls and
creation of sockets other than PF_LOCAL and SOCK_DGRAM/STREAM/SEQPACKET
internet sockets.
Reviewed by: oshogbo
Discussed with: emaste
Reported by: manu
Sponsored by: The FreeBSD Foundation
MFC after: 2 weeks
Differential Revision: https://reviews.freebsd.org/D29423
After length decisions, we've decided that the if_wg(4) driver and
related work is not yet ready to live in the tree. This driver has
larger security implications than many, and thus will be held to
more scrutiny than other drivers.
Please also see the related message sent to the freebsd-hackers@
and freebsd-arch@ lists by Kyle Evans <kevans@FreeBSD.org> on
2021/03/16, with the subject line "Removing WireGuard Support From Base"
for additional context.
