Allow the resending of DATA chunks to be controlled by the caller,
which allows retiring sctp_mtu_size_reset() in a separate commit.
Also improve the computaion of the overhead and use 32-bit integers
consistently.
Thanks to Timo Voelker for pointing me to the code.
MFC after: 3 days
This patch makes the handling of the SCTP_MAXSEG socket option
compliant with RFC 6458 (SCTP socket API) and fixes an issue
found by syzkaller.
Reported by: syzbot+a2791b89ab99121e3333@syzkaller.appspotmail.com
MFC after: 3 days
Callers are getting the stcb send lock, so just KASSERT that.
No need to signal this when calling stream scheduler functions.
No functional change intended.
MFC after: 1 week
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
When port reuse is enabled in a one-to-one-style socket, sctp_listen()
may call sctp_swap_inpcb_for_listen() to move the PCB out of the "TCP
pool". In so doing it will drop the PCB lock, yielding an LOR since we
now hold several socket locks. Reorder sctp_listen() so that it
performs this operation before beginning the conversion to a listening
socket. Also modify sctp_swap_inpcb_for_listen() to return with PCB
write-locked, since that's what sctp_listen() expects now.
Reviewed by: tuexen
Fixes: bd4a39cc93 ("socket: Properly interlock when transitioning to a listening socket")
MFC after: 1 month
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D31879
sctp_close() and sctp_abort() disassociate the PCB from its socket.
As a part of this, they attempt to free the PCB, which may end up
lingering. Fix some bugs in this area:
- For some reason, sctp_close() and sctp_abort() set
SCTP_PCB_FLAGS_SOCKET_GONE using an atomic compare-and-set without the
PCB lock held. This is racy since sctp_flags is normally updated
without atomics, using the PCB lock to synchronize. So, the update
can be lost, which can cause all sort of races with other SCTP
components which look for the _GONE flag. Fix the problem simply by
acquiring the PCB lock in order to set the flag. Note that we have to
drop and re-acquire the lock again in sctp_inpcb_free(), but I don't
see a good way around that for now. If it's a real problem, the _GONE
flag could be split out of sctp_flags and into a dedicated sctp_inpcb
field.
- In sctp_inpcb_free(), load sctp_socket after acquiring the PCB lock,
to avoid possible races with parallel sctp_inpcb_free() calls.
- Add an assertion sctp_inpcb_free() to verify that _ALLGONE is not set.
Reviewed by: tuexen
MFC after: 1 week
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D31811
Later in sctp_free_assoc(), when we clean up chunk lists,
sctp_free_spbufspace() is used to reset the byte count in the socket
send buffer. However, if the PCB is going away, the socket may already
have been detached from the PCB, in which case this becomes a use-after
free. Clear the socket reference from the association before detaching
it from the PCB, if the PCB has already lost its socket reference.
Reviewed by: tuexen
MFC after: 1 week
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D31753
This will be used by sctp_listen() to avoid dropping locks when
performing an implicit bind. No functional change intended.
Reviewed by: tuexen
MFC after: 1 week
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D31757
SCTP needs to avoid binding a given socket twice. The check used to
avoid this is racy since neither the inpcb lock nor the global info lock
is held. Fix it by synchronizing using the global info lock. In
particular, sctp_inpcb_bind() may drop the inpcb lock in some cases, but
the info lock is sufficient to prevent double insertion into PCB hash
tables.
Reported by: syzbot+548a8560d959669d0e12@syzkaller.appspotmail.com
Reviewed by: tuexen
MFC after: 1 week
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D31734
Eliminate a flag variable and reduce indentation. No functional change
intended.
Reviewed by: tuexen
MFC after: 1 week
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D31733
We only drop the inp lock when binding to a specific port. So, only
acquire an extra reference when required. This simplifies error
handling a bit.
Reviewed by: tuexen
MFC after: 1 week
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D31732
This avoids setting the association in an inconsistent
state, which could result in a use-after-free situation.
This can be triggered by a malicious peer, if the peer
can modify the cookie without the local endpoint recognizing
it.
Thanks to Ned Williamson for reporting the issue.
MFC after: 3 days
an ungraceful operation.
This fixes a use-after-free bug found and reported by Taylor
Brandstetter of Google by testing the userland stack.
MFC after: 1 week
This avoids a use-after-free reported for the userland stack.
Thanks to Taylor Brandstetter for suggesting a patch for
the userland stack.
MFC after: 1 week
This file is the only SCTP source file compiled into the kernel when
SCTP_SUPPORT is configured. sctp_delayed_checksum() references a couple
of counters defined in system_base_info, so the change allows these
counters to be referenced in a kernel compiled without "options SCTP".
Submitted by: tuexen
MFC with: r362338
cem noted that on FreeBSD snprintf() can not fail and code should not
check for that.
A followup commit will replace the usage of snprintf() in the SCTP
sources with a variadic macro SCTP_SNPRINTF, which will simply map to
snprintf() on FreeBSD and do a checking similar to r361209 on
other platforms.
