The existing AF_UNIX socket garbage collector destroys any socket
which may potentially be in a cycle, as indicated by its file reference
count being equal to its enqueue count. However, this can produce false
positives for in-flight sockets which aren't part of a cycle but are
part of one or more SCM_RIGHTS mssages and which have been closed
on the sending side. If the garbage collector happens to run at
exactly the wrong time, destruction of these sockets will render them
unusable on the receiving side, such that no previously-written data
may be read.
This change rewrites the garbage collector to precisely detect cycles:
1. The existing check of msgcount==f_count is still used to determine
whether the socket is potentially in a cycle.
2. The socket is now placed on a local "dead list", which is used to
reduce iteration time (and therefore contention on the global
unp_link_rwlock).
3. The first pass through the dead list removes each potentially-dead
socket's outgoing references from the graph of potentially-dead
sockets, using a gc-specific copy of the original reference count.
4. The second series of passes through the dead list removes from the
list any socket whose remaining gc refcount is non-zero, as this
indicates the socket is actually accessible outside of any possible
cycle. Iteration is repeated until no further sockets are removed
from the dead list.
5. Sockets remaining in the dead list are destroyed as before.
PR: 227285
Submitted by: jan.kokemueller@gmail.com (prior version)
Reviewed by: markj
Differential Revision: https://reviews.freebsd.org/D23142
Filesystems which want to use it in limited capacity can employ the
VOP_UNLOCK_FLAGS macro.
Reviewed by: kib (previous version)
Differential Revision: https://reviews.freebsd.org/D21427
As unp_internalize() processes the input control messages, it builds
an output mbuf chain containing the internalized representations of
those messages. In one special case, that of an empty SCM_RIGHTS
message, the message is simply discarded. However, the loop which
appends mbufs to the output chain assumed that each iteration would
produce an mbuf, resulting in a null pointer dereference if an empty
SCM_RIGHTS message was followed by a non-empty message.
Fix this by advancing the output mbuf chain tail pointer only if an
internalized control message was produced.
Reported by: syzbot+1b5cced0f7fad26ae382@syzkaller.appspotmail.com
MFC after: 1 week
Sponsored by: The FreeBSD Foundation
fget_unlocked() and fhold().
On sufficiently large machine, f_count can be legitimately very large,
e.g. malicious code can dup same fd up to the per-process
filedescriptors limit, and then fork as much as it can.
On some smaller machine, I see
kern.maxfilesperproc: 939132
kern.maxprocperuid: 34203
which already overflows u_int. More, the malicious code can create
transient references by sending fds over unix sockets.
I realized that this check is missed after reading
https://secfault-security.com/blog/FreeBSD-SA-1902.fd.html
Reviewed by: markj (previous version), mjg
Tested by: pho (previous version)
Sponsored by: The FreeBSD Foundation
MFC after: 1 week
Differential revision: https://reviews.freebsd.org/D20947
When sendmsg(2) sucessfully internalized one SCM_RIGHTS control
message, but failed to process some other control message later, both
file references and filedescent memory needs to be freed. This was not
done, only mbuf chain was freed.
Noted, test case written, reviewed by: markj
Sponsored by: The FreeBSD Foundation
MFC after: 1 week
Differential revision: https://reviews.freebsd.org/D21000
struct xucred. Do not bump XUCRED_VERSION as struct layout is not changed.
PR: 215202
Reviewed by: tijl
MFC after: 1 week
Differential Revision: https://reviews.freebsd.org/D20415
Various network protocol sysctl handlers were not zero-filling their
output buffers and thus would export uninitialized stack memory to
userland. Fix a number of such handlers.
Reported by: Thomas Barabosch, Fraunhofer FKIE
Reviewed by: tuexen
MFC after: 3 days
Security: kernel memory disclosure
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D18301
The code was incrementing a global variable in an unsafe manner.
Two different threads stating two different sockets could have resulted
in the same inode numbers assigned to both.
Creation is protected with a global lock, move the assigment there.
Since inode numbers are 64-bit now drop the check for overflows.
Sponsored by: The FreeBSD Foundation
If a recvmsg(2) or recvmmsg(2) caller doesn't provide sufficient space
for all control messages, the kernel sets MSG_CTRUNC in the message
flags to indicate truncation of the control messages. In the case
of SCM_RIGHTS messages, however, we were failing to dispose of the
rights that had already been externalized into the recipient's file
descriptor table. Add a new function and mbuf type to handle this
cleanup task, and use it any time we fail to copy control messages
out to the recipient. To simplify cleanup, control message truncation
is now only performed at control message boundaries.
The change also fixes a few related bugs:
- Rights could be leaked to the recipient process if an error occurred
while copying out a message's contents.
- We failed to set MSG_CTRUNC if the truncation occurred on a control
message boundary, e.g., if the caller received two control messages
and provided only the exact amount of buffer space needed for the
first.
PR: 131876
Reviewed by: ed (previous version)
MFC after: 1 month
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D16561
sosend_generic() performs an initial comparison of the amount of data
(including control messages) to be transmitted with the send buffer
size. When transmitting on a unix socket, we then compare the amount
of data being sent with the amount of space in the receive buffer size;
if insufficient space is available, sbappendcontrol() returns an error
and the data is lost. This is easily triggered by sending control
messages together with an amount of data roughly equal to the send
buffer size, since the control message size may change in uipc_send()
as file descriptors are internalized.
Fix the problem by removing the space check in sbappendcontrol(),
whose only consumer is the unix sockets code. The stream sockets code
uses the SB_STOP mechanism to ensure that senders will block if the
receive buffer fills up.
PR: 181741
MFC after: 1 month
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D16515
Enable the LOCAL_PEERCRED socket option for unix domain stream sockets
created with socketpair(2). Previously, it only worked with unix domain
stream sockets created with socket(2)/listen(2)/connect(2)/accept(2).
PR: 176419
Reported by: Nicholas Wilson <nicholas@nicholaswilson.me.uk>
MFC after: 2 weeks
Differential Revision: https://reviews.freebsd.org/D16350
Replace size_t members with ksize_t (uint64_t) and pointer members
(never used as pointers in userspace, but instead as unique
idenitifiers) with kvaddr_t (uint64_t). This makes the structs
identical between 32-bit and 64-bit ABIs.
On 64-bit bit systems, the ABI is maintained. On 32-bit systems,
this is an ABI breaking change. The ABI of most of these structs
was previously broken in r315662. This also imposes a small API
change on userspace consumers who must handle kernel pointers
becoming virtual addresses.
PR: 228301 (exp-run by antoine)
Reviewed by: jtl, kib, rwatson (various versions)
Sponsored by: DARPA, AFRL
Differential Revision: https://reviews.freebsd.org/D15386
to themselves. The updated code assumed that that could not happen
and would try to lock the unp mutex twice.
There may be a lingering issue here but this fixes it for the
reporter.
PR: 228458
Reported by: marieheleneka at gmail.com
two copyrights. The line originated with the Berkeely Regents, who
we have not approached about removing it (it's honestly too trivial
to be worth that fight). Restore it to rwatson's line as well. He
can decide if he wants it or not on his own. Matt clearly doesn't
want it, per project preference and his own statements on IRC.
Noticed by: rgrimes@
This change moves to using a reference count across lock drop / reacquire
to guarantee liveness.
Currently sends on unix sockets contend heavily on read locking the list lock.
unix1_processes in will-it-scale peaks at 6 processes and then declines.
With this change I get a substantial improvement in number of operations per second
with 96 processes:
x before
+ after
N Min Max Median Avg Stddev
x 11 1688420 1696389 1693578 1692766.3 2971.1702
+ 10 63417955 71030114 70662504 69576423 2374684.6
Difference at 95.0% confidence
6.78837e+07 +/- 1.49463e+06
4010.22% +/- 88.4246%
(Student's t, pooled s = 1.63437e+06)
And even for 2 processes shows a ~18% improvement.
"Small" iron changes (1, 2, and 4 processes):
x before1
+ after1.2
+------------------------------------------------------------------------+
| + |
| x + |
| x + |
| x + |
| x ++ |
| xx ++ |
|x x xx ++ |
| |__________________A_____M_____AM____||
+------------------------------------------------------------------------+
N Min Max Median Avg Stddev
x 10 1131648 1197750 1197138.5 1190369.3 20651.839
+ 10 1203840 1205056 1204919 1204827.9 353.27404
Difference at 95.0% confidence
14458.6 +/- 13723
1.21463% +/- 1.16683%
(Student's t, pooled s = 14605.2)
x before2
+ after2.2
+------------------------------------------------------------------------+
| +|
| +|
| +|
| +|
| +|
| +|
| x +|
| x +|
| x xx +|
|x xxxx +|
| |___AM_| A|
+------------------------------------------------------------------------+
N Min Max Median Avg Stddev
x 10 1972843 2045866 2038186.5 2030443.8 21367.694
+ 10 2400853 2402196 2401043.5 2401172.7 385.40024
Difference at 95.0% confidence
370729 +/- 14198.9
18.2585% +/- 0.826943%
(Student's t, pooled s = 15111.7)
x before4
+ after4.2
N Min Max Median Avg Stddev
x 10 3986994 3991728 3990137.5 3989985.2 1300.0164
+ 10 4799990 4806664 4806116.5 4805194 1990.6625
Difference at 95.0% confidence
815209 +/- 1579.64
20.4314% +/- 0.0421713%
(Student's t, pooled s = 1681.19)
Tested by: pho
Reported by: mjg
Approved by: sbruno
Sponsored by: Limelight Networks
Differential Revision: https://reviews.freebsd.org/D15430
When allocating memory through malloc(9), we always expect the amount of
memory requested to be unsigned as a negative value would either stand for
an error or an overflow.
Unsign some values, found when considering the use of mallocarray(9), to
avoid unnecessary casting. Also consider that indexes should be of
at least the same size/type as the upper limit they pretend to index.
MFC after: 3 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.
Violators may define _WANT_SOCKET and _WANT_UNPCB respectively and
are not guaranteed for stability of the structures. The violators
list is the the usual one: libprocstat(3) and netstat(1) internally
and lsof in ports.
In struct xunpcb remove the inclusion of kernel structure and add
a bunch of spare fields. The xsocket already has socket not included,
but add there spares as well. Embed xsockbuf into xsocket.
Sort declarations in sys/socketvar.h to separate kernel only from
userland available ones.
PR: 221820 (exp-run)
in UNIX sockets.
o Check that socket is still connected in uipc_ready(). If not
we are responsible to free mbufs.
o In uipc_send() if socket appears to be disconnected, but we
are sending data with pending I/Os, don't free mbufs.
Reported by: Kevin Bowling <kbowling llnw.com>
Tested by: Kevin Bowling <kbowling llnw.com>
PR: 222259
Reported by: Mark Martinec <Mark.Martinec ijs.si>
MFC after: 3 days
o Separate fields of struct socket that belong to listening from
fields that belong to normal dataflow, and unionize them. This
shrinks the structure a bit.
- Take out selinfo's from the socket buffers into the socket. The
first reason is to support braindamaged scenario when a socket is
added to kevent(2) and then listen(2) is cast on it. The second
reason is that there is future plan to make socket buffers pluggable,
so that for a dataflow socket a socket buffer can be changed, and
in this case we also want to keep same selinfos through the lifetime
of a socket.
- Remove struct struct so_accf. Since now listening stuff no longer
affects struct socket size, just move its fields into listening part
of the union.
- Provide sol_upcall field and enforce that so_upcall_set() may be called
only on a dataflow socket, which has buffers, and for listening sockets
provide solisten_upcall_set().
o Remove ACCEPT_LOCK() global.
- Add a mutex to socket, to be used instead of socket buffer lock to lock
fields of struct socket that don't belong to a socket buffer.
- Allow to acquire two socket locks, but the first one must belong to a
listening socket.
- Make soref()/sorele() to use atomic(9). This allows in some situations
to do soref() without owning socket lock. There is place for improvement
here, it is possible to make sorele() also to lock optionally.
- Most protocols aren't touched by this change, except UNIX local sockets.
See below for more information.
o Reduce copy-and-paste in kernel modules that accept connections from
listening sockets: provide function solisten_dequeue(), and use it in
the following modules: ctl(4), iscsi(4), ng_btsocket(4), ng_ksocket(4),
infiniband, rpc.
o UNIX local sockets.
- Removal of ACCEPT_LOCK() global uncovered several races in the UNIX
local sockets. Most races exist around spawning a new socket, when we
are connecting to a local listening socket. To cover them, we need to
hold locks on both PCBs when spawning a third one. This means holding
them across sonewconn(). This creates a LOR between pcb locks and
unp_list_lock.
- To fix the new LOR, abandon the global unp_list_lock in favor of global
unp_link_lock. Indeed, separating these two locks didn't provide us any
extra parralelism in the UNIX sockets.
- Now call into uipc_attach() may happen with unp_link_lock hold if, we
are accepting, or without unp_link_lock in case if we are just creating
a socket.
- Another problem in UNIX sockets is that uipc_close() basicly did nothing
for a listening socket. The vnode remained opened for connections. This
is fixed by removing vnode in uipc_close(). Maybe the right way would be
to do it for all sockets (not only listening), simply move the vnode
teardown from uipc_detach() to uipc_close()?
Sponsored by: Netflix
Differential Revision: https://reviews.freebsd.org/D9770
sources to return timestamps when SO_TIMESTAMP is enabled. Two additional
clock sources are:
o nanosecond resolution realtime clock (equivalent of CLOCK_REALTIME);
o nanosecond resolution monotonic clock (equivalent of CLOCK_MONOTONIC).
In addition to this, this option provides unified interface to get bintime
(equivalent of using SO_BINTIME), except it also supported with IPv6 where
SO_BINTIME has never been supported. The long term plan is to depreciate
SO_BINTIME and move everything to using SO_TS_CLOCK.
Idea for this enhancement has been briefly discussed on the Net session
during dev summit in Ottawa last June and the general input was positive.
This change is believed to benefit network benchmarks/profiling as well
as other scenarios where precise time of arrival measurement is necessary.
There are two regression test cases as part of this commit: one extends unix
domain test code (unix_cmsg) to test new SCM_XXX types and another one
implementis totally new test case which exchanges UDP packets between two
processes using both conventional methods (i.e. calling clock_gettime(2)
before recv(2) and after send(2)), as well as using setsockopt()+recv() in
receive path. The resulting delays are checked for sanity for all supported
clock types.
Reviewed by: adrian, gnn
Differential Revision: https://reviews.freebsd.org/D9171
If the listening socket is closed while sonewconn() is executing, the
nascent child socket is aborted, which results in recursion on the
unp_link lock when the child's pru_detach method is invoked. Fix this
by using a flag to mark such sockets, and skip a part of the socket's
teardown during detach.
Reported by: Raviprakash Darbha <rdarbha@juniper.net>
Tested by: pho
MFC after: 2 weeks
Differential Revision: https://reviews.freebsd.org/D7398
While making CloudABI work well on Linux, I discovered that I had a
FreeBSD-ism in one of my unit tests. The test did the following:
- Create UNIX socket 1, bind it, make it listen.
- Create UNIX socket 2, connect it to UNIX socket 1.
- Close UNIX socket 1.
- Obtain SO_ERROR from socket 2.
On FreeBSD this returns ECONNABORTED, while on Linux it returns
ECONNRESET. I dug through some of the relevant specifications[1] and it
looks like Linux is all right here. ECONNABORTED should only be returned
when the local connection (socket 2) is aborted; not the peer (socket 1).
It is of course slightly misleading: the function in which we set this
error is called uipc_abort(), but keep in mind that we're aborting the
peer, thus resetting the local socket.
[1] http://pubs.opengroup.org/onlinepubs/9699919799/functions/connect.html
Reviewed by: cem
Sponsored by: Nuxi, the Netherlands
Differential Revision: https://reviews.freebsd.org/D5419
sbappendstream() does. Although, M_NOTREADY may appear only on SOCK_STREAM
sockets, due to sendfile(2) supporting only the latter, there is a corner
case of AF_UNIX/SOCK_STREAM socket, that still uses records for the sake
of control data, albeit being stream socket.
Provide private version of m_clrprotoflags(), which understands PRUS_NOTREADY,
similar to m_demote().
The filedesc lock is only needed if ioctls caps are present, which is a
rare situation. This is a step towards reducing the scope of the filedesc
lock.
unp_dispose and unp_gc could race to teardown the same mbuf chains, which
can lead to dereferencing freed filedesc pointers.
This patch adds an IGNORE_RIGHTS flag on unpcbs marking the unpcb's RIGHTS
as invalid/freed. The flag is protected by UNP_LIST_LOCK.
To serialize against unp_gc, unp_dispose needs the socket object. Change the
dom_dispose() KPI to take a socket object instead of an mbuf chain directly.
PR: 194264
Differential Revision: https://reviews.freebsd.org/D3044
Reviewed by: mjg (earlier version)
Approved by: markj (mentor)
Obtained from: mjg
MFC after: 1 month
Sponsored by: EMC / Isilon Storage Division
