unix_poll() and unix_dgram_poll() read sk->sk_state locklessly and
calls unix_writable() which also reads sk->sk_state without holding
unix_state_lock().
Let's use READ_ONCE() in unix_poll() and unix_dgram_poll() and pass
it to unix_writable().
While at it, we remove TCP_SYN_SENT check in unix_dgram_poll() as
that state does not exist for AF_UNIX socket since the code was added.
Fixes: 1586a5877d ("af_unix: do not report POLLOUT on listeners")
Fixes: 3c73419c09 ("af_unix: fix 'poll for write'/ connected DGRAM sockets")
Fixes: 1da177e4c3 ("Linux-2.6.12-rc2")
Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
ioctl(SIOCINQ) calls unix_inq_len() that checks sk->sk_state first
and returns -EINVAL if it's TCP_LISTEN.
Then, for SOCK_STREAM sockets, unix_inq_len() returns the number of
bytes in recvq.
However, unix_inq_len() does not hold unix_state_lock(), and the
concurrent listen() might change the state after checking sk->sk_state.
If the race occurs, 0 is returned for the listener, instead of -EINVAL,
because the length of skb with embryo is 0.
We could hold unix_state_lock() in unix_inq_len(), but it's overkill
given the result is true for pre-listen() TCP_CLOSE state.
So, let's use READ_ONCE() for sk->sk_state in unix_inq_len().
Fixes: 1da177e4c3 ("Linux-2.6.12-rc2")
Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
sk->sk_state is changed under unix_state_lock(), but it's read locklessly
in many places.
This patch adds WRITE_ONCE() on the writer side.
We will add READ_ONCE() to the lockless readers in the following patches.
Fixes: 83301b5367 ("af_unix: Set TCP_ESTABLISHED for datagram sockets too")
Fixes: 1da177e4c3 ("Linux-2.6.12-rc2")
Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
When a SOCK_DGRAM socket connect()s to another socket, the both sockets'
sk->sk_state are changed to TCP_ESTABLISHED so that we can register them
to BPF SOCKMAP.
When the socket disconnects from the peer by connect(AF_UNSPEC), the state
is set back to TCP_CLOSE.
Then, the peer's state is also set to TCP_CLOSE, but the update is done
locklessly and unconditionally.
Let's say socket A connect()ed to B, B connect()ed to C, and A disconnects
from B.
After the first two connect()s, all three sockets' sk->sk_state are
TCP_ESTABLISHED:
$ ss -xa
Netid State Recv-Q Send-Q Local Address:Port Peer Address:PortProcess
u_dgr ESTAB 0 0 @A 641 * 642
u_dgr ESTAB 0 0 @B 642 * 643
u_dgr ESTAB 0 0 @C 643 * 0
And after the disconnect, B's state is TCP_CLOSE even though it's still
connected to C and C's state is TCP_ESTABLISHED.
$ ss -xa
Netid State Recv-Q Send-Q Local Address:Port Peer Address:PortProcess
u_dgr UNCONN 0 0 @A 641 * 0
u_dgr UNCONN 0 0 @B 642 * 643
u_dgr ESTAB 0 0 @C 643 * 0
In this case, we cannot register B to SOCKMAP.
So, when a socket disconnects from the peer, we should not set TCP_CLOSE to
the peer if the peer is connected to yet another socket, and this must be
done under unix_state_lock().
Note that we use WRITE_ONCE() for sk->sk_state as there are many lockless
readers. These data-races will be fixed in the following patches.
Fixes: 83301b5367 ("af_unix: Set TCP_ESTABLISHED for datagram sockets too")
Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
When splice() support was added in commit 2b514574f7 ("net:
af_unix: implement splice for stream af_unix sockets"), we had
to release unix_sk(sk)->readlock (current iolock) before calling
splice_to_pipe().
Due to the unlock, commit 73ed5d25dc ("af-unix: fix use-after-free
with concurrent readers while splicing") added a safeguard in
unix_stream_read_generic(); we had to bump the skb refcount before
calling ->recv_actor() and then check if the skb was consumed by a
concurrent reader.
However, the pipe side locking was refactored, and since commit
25869262ef ("skb_splice_bits(): get rid of callback"), we can
call splice_to_pipe() without releasing unix_sk(sk)->iolock.
Now, the skb is always alive after the ->recv_actor() callback,
so let's remove the unnecessary drop_skb logic.
This is mostly the revert of commit 73ed5d25dc ("af-unix: fix
use-after-free with concurrent readers while splicing").
Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Link: https://lore.kernel.org/r/20240529144648.68591-1-kuniyu@amazon.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
syzkaller reported data-race of sk->sk_hash in unix_autobind() [0],
and the same ones exist in unix_bind_bsd() and unix_bind_abstract().
The three bind() functions prefetch sk->sk_hash locklessly and
use it later after validating that unix_sk(sk)->addr is NULL under
unix_sk(sk)->bindlock.
The prefetched sk->sk_hash is the hash value of unbound socket set
in unix_create1() and does not change until bind() completes.
There could be a chance that sk->sk_hash changes after the lockless
read. However, in such a case, non-NULL unix_sk(sk)->addr is visible
under unix_sk(sk)->bindlock, and bind() returns -EINVAL without using
the prefetched value.
The KCSAN splat is false-positive, but let's silence it by reading
sk->sk_hash under unix_sk(sk)->bindlock.
[0]:
BUG: KCSAN: data-race in unix_autobind / unix_autobind
write to 0xffff888034a9fb88 of 4 bytes by task 4468 on cpu 0:
__unix_set_addr_hash net/unix/af_unix.c:331 [inline]
unix_autobind+0x47a/0x7d0 net/unix/af_unix.c:1185
unix_dgram_connect+0x7e3/0x890 net/unix/af_unix.c:1373
__sys_connect_file+0xd7/0xe0 net/socket.c:2048
__sys_connect+0x114/0x140 net/socket.c:2065
__do_sys_connect net/socket.c:2075 [inline]
__se_sys_connect net/socket.c:2072 [inline]
__x64_sys_connect+0x40/0x50 net/socket.c:2072
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0x4f/0x110 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x46/0x4e
read to 0xffff888034a9fb88 of 4 bytes by task 4465 on cpu 1:
unix_autobind+0x28/0x7d0 net/unix/af_unix.c:1134
unix_dgram_connect+0x7e3/0x890 net/unix/af_unix.c:1373
__sys_connect_file+0xd7/0xe0 net/socket.c:2048
__sys_connect+0x114/0x140 net/socket.c:2065
__do_sys_connect net/socket.c:2075 [inline]
__se_sys_connect net/socket.c:2072 [inline]
__x64_sys_connect+0x40/0x50 net/socket.c:2072
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0x4f/0x110 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x46/0x4e
value changed: 0x000000e4 -> 0x000001e3
Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 4465 Comm: syz-executor.0 Not tainted 6.8.0-12822-gcd51db110a7e #12
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.16.0-0-gd239552ce722-prebuilt.qemu.org 04/01/2014
Fixes: afd20b9290 ("af_unix: Replace the big lock with small locks.")
Reported-by: syzkaller <syzkaller@googlegroups.com>
Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Link: https://lore.kernel.org/r/20240522154218.78088-1-kuniyu@amazon.com
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Once unix_sk(sk)->addr is assigned under net->unx.table.locks and
unix_sk(sk)->bindlock, *(unix_sk(sk)->addr) and unix_sk(sk)->path are
fully set up, and unix_sk(sk)->addr is never changed.
unix_getname() and unix_copy_addr() access the two fields locklessly,
and commit ae3b564179 ("missing barriers in some of unix_sock ->addr
and ->path accesses") added smp_store_release() and smp_load_acquire()
pairs.
In other functions, we still read unix_sk(sk)->addr locklessly to check
if the socket is bound, and KCSAN complains about it. [0]
Given these functions have no dependency for *(unix_sk(sk)->addr) and
unix_sk(sk)->path, READ_ONCE() is enough to annotate the data-race.
Note that it is safe to access unix_sk(sk)->addr locklessly if the socket
is found in the hash table. For example, the lockless read of otheru->addr
in unix_stream_connect() is safe.
Note also that newu->addr there is of the child socket that is still not
accessible from userspace, and smp_store_release() publishes the address
in case the socket is accept()ed and unix_getname() / unix_copy_addr()
is called.
[0]:
BUG: KCSAN: data-race in unix_bind / unix_listen
write (marked) to 0xffff88805f8d1840 of 8 bytes by task 13723 on cpu 0:
__unix_set_addr_hash net/unix/af_unix.c:329 [inline]
unix_bind_bsd net/unix/af_unix.c:1241 [inline]
unix_bind+0x881/0x1000 net/unix/af_unix.c:1319
__sys_bind+0x194/0x1e0 net/socket.c:1847
__do_sys_bind net/socket.c:1858 [inline]
__se_sys_bind net/socket.c:1856 [inline]
__x64_sys_bind+0x40/0x50 net/socket.c:1856
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0x4f/0x110 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x46/0x4e
read to 0xffff88805f8d1840 of 8 bytes by task 13724 on cpu 1:
unix_listen+0x72/0x180 net/unix/af_unix.c:734
__sys_listen+0xdc/0x160 net/socket.c:1881
__do_sys_listen net/socket.c:1890 [inline]
__se_sys_listen net/socket.c:1888 [inline]
__x64_sys_listen+0x2e/0x40 net/socket.c:1888
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0x4f/0x110 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x46/0x4e
value changed: 0x0000000000000000 -> 0xffff88807b5b1b40
Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 13724 Comm: syz-executor.4 Not tainted 6.8.0-12822-gcd51db110a7e #12
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.16.0-0-gd239552ce722-prebuilt.qemu.org 04/01/2014
Fixes: 1da177e4c3 ("Linux-2.6.12-rc2")
Reported-by: syzkaller <syzkaller@googlegroups.com>
Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Link: https://lore.kernel.org/r/20240522154002.77857-1-kuniyu@amazon.com
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
regression you have been notified of in the past weeks.
The TCP window fix will require some follow-up, already queued.
Current release - regressions:
- af_unix: fix garbage collection of embryos
Previous releases - regressions:
- af_unix: fix race between GC and receive path
- ipv6: sr: fix missing sk_buff release in seg6_input_core
- tcp: remove 64 KByte limit for initial tp->rcv_wnd value
- eth: r8169: fix rx hangup
- eth: lan966x: remove ptp traps in case the ptp is not enabled.
- eth: ixgbe: fix link breakage vs cisco switches.
- eth: ice: prevent ethtool from corrupting the channels.
Previous releases - always broken:
- openvswitch: set the skbuff pkt_type for proper pmtud support.
- tcp: Fix shift-out-of-bounds in dctcp_update_alpha().
Misc:
- a bunch of selftests stabilization patches.
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
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Merge tag 'net-6.10-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net
Pull networking fixes from Paolo Abeni:
"Quite smaller than usual. Notably it includes the fix for the unix
regression from the past weeks. The TCP window fix will require some
follow-up, already queued.
Current release - regressions:
- af_unix: fix garbage collection of embryos
Previous releases - regressions:
- af_unix: fix race between GC and receive path
- ipv6: sr: fix missing sk_buff release in seg6_input_core
- tcp: remove 64 KByte limit for initial tp->rcv_wnd value
- eth: r8169: fix rx hangup
- eth: lan966x: remove ptp traps in case the ptp is not enabled
- eth: ixgbe: fix link breakage vs cisco switches
- eth: ice: prevent ethtool from corrupting the channels
Previous releases - always broken:
- openvswitch: set the skbuff pkt_type for proper pmtud support
- tcp: Fix shift-out-of-bounds in dctcp_update_alpha()
Misc:
- a bunch of selftests stabilization patches"
* tag 'net-6.10-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net: (25 commits)
r8169: Fix possible ring buffer corruption on fragmented Tx packets.
idpf: Interpret .set_channels() input differently
ice: Interpret .set_channels() input differently
nfc: nci: Fix handling of zero-length payload packets in nci_rx_work()
net: relax socket state check at accept time.
tcp: remove 64 KByte limit for initial tp->rcv_wnd value
net: ti: icssg_prueth: Fix NULL pointer dereference in prueth_probe()
tls: fix missing memory barrier in tls_init
net: fec: avoid lock evasion when reading pps_enable
Revert "ixgbe: Manual AN-37 for troublesome link partners for X550 SFI"
testing: net-drv: use stats64 for testing
net: mana: Fix the extra HZ in mana_hwc_send_request
net: lan966x: Remove ptp traps in case the ptp is not enabled.
openvswitch: Set the skbuff pkt_type for proper pmtud support.
selftest: af_unix: Make SCM_RIGHTS into OOB data.
af_unix: Fix garbage collection of embryos carrying OOB with SCM_RIGHTS
tcp: Fix shift-out-of-bounds in dctcp_update_alpha().
selftests/net: use tc rule to filter the na packet
ipv6: sr: fix memleak in seg6_hmac_init_algo
af_unix: Update unix_sk(sk)->oob_skb under sk_receive_queue lock.
...
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Merge tag 'net-accept-more-20240515' of git://git.kernel.dk/linux
Pull more io_uring updates from Jens Axboe:
"This adds support for IORING_CQE_F_SOCK_NONEMPTY for io_uring accept
requests.
This is very similar to previous work that enabled the same hint for
doing receives on sockets. By far the majority of the work here is
refactoring to enable the networking side to pass back whether or not
the socket had more pending requests after accepting the current one,
the last patch just wires it up for io_uring.
Not only does this enable applications to know whether there are more
connections to accept right now, it also enables smarter logic for
io_uring multishot accept on whether to retry immediately or wait for
a poll trigger"
* tag 'net-accept-more-20240515' of git://git.kernel.dk/linux:
io_uring/net: wire up IORING_CQE_F_SOCK_NONEMPTY for accept
net: pass back whether socket was empty post accept
net: have do_accept() take a struct proto_accept_arg argument
net: change proto and proto_ops accept type
Rather than pass in flags, error pointer, and whether this is a kernel
invocation or not, add a struct proto_accept_arg struct as the argument.
This then holds all of these arguments, and prepares accept for being
able to pass back more information.
No functional changes in this patch.
Acked-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
A data-race condition has been identified in af_unix. In one data path,
the write function unix_release_sock() atomically writes to
sk->sk_shutdown using WRITE_ONCE. However, on the reader side,
unix_stream_sendmsg() does not read it atomically. Consequently, this
issue is causing the following KCSAN splat to occur:
BUG: KCSAN: data-race in unix_release_sock / unix_stream_sendmsg
write (marked) to 0xffff88867256ddbb of 1 bytes by task 7270 on cpu 28:
unix_release_sock (net/unix/af_unix.c:640)
unix_release (net/unix/af_unix.c:1050)
sock_close (net/socket.c:659 net/socket.c:1421)
__fput (fs/file_table.c:422)
__fput_sync (fs/file_table.c:508)
__se_sys_close (fs/open.c:1559 fs/open.c:1541)
__x64_sys_close (fs/open.c:1541)
x64_sys_call (arch/x86/entry/syscall_64.c:33)
do_syscall_64 (arch/x86/entry/common.c:?)
entry_SYSCALL_64_after_hwframe (arch/x86/entry/entry_64.S:130)
read to 0xffff88867256ddbb of 1 bytes by task 989 on cpu 14:
unix_stream_sendmsg (net/unix/af_unix.c:2273)
__sock_sendmsg (net/socket.c:730 net/socket.c:745)
____sys_sendmsg (net/socket.c:2584)
__sys_sendmmsg (net/socket.c:2638 net/socket.c:2724)
__x64_sys_sendmmsg (net/socket.c:2753 net/socket.c:2750 net/socket.c:2750)
x64_sys_call (arch/x86/entry/syscall_64.c:33)
do_syscall_64 (arch/x86/entry/common.c:?)
entry_SYSCALL_64_after_hwframe (arch/x86/entry/entry_64.S:130)
value changed: 0x01 -> 0x03
The line numbers are related to commit dd5a440a31 ("Linux 6.9-rc7").
Commit e1d09c2c2f ("af_unix: Fix data races around sk->sk_shutdown.")
addressed a comparable issue in the past regarding sk->sk_shutdown.
However, it overlooked resolving this particular data path.
This patch only offending unix_stream_sendmsg() function, since the
other reads seem to be protected by unix_state_lock() as discussed in
Link: https://lore.kernel.org/all/20240508173324.53565-1-kuniyu@amazon.com/
Fixes: 1da177e4c3 ("Linux-2.6.12-rc2")
Signed-off-by: Breno Leitao <leitao@debian.org>
Reviewed-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Link: https://lore.kernel.org/r/20240509081459.2807828-1-leitao@debian.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Commit dcf70df204 ("af_unix: Fix up unix_edge.successor for embryo
socket.") added spin_lock(&unix_gc_lock) in accept() path, and it
caused regression in a stress test as reported by kernel test robot.
If the embryo socket is not part of the inflight graph, we need not
hold the lock.
To decide that in O(1) time and avoid the regression in the normal
use case,
1. add a new stat unix_sk(sk)->scm_stat.nr_unix_fds
2. count the number of inflight AF_UNIX sockets in the receive
queue under unix_state_lock()
3. move unix_update_edges() call under unix_state_lock()
4. avoid locking if nr_unix_fds is 0 in unix_update_edges()
Reported-by: kernel test robot <oliver.sang@intel.com>
Closes: https://lore.kernel.org/oe-lkp/202404101427.92a08551-oliver.sang@intel.com
Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Link: https://lore.kernel.org/r/20240413021928.20946-1-kuniyu@amazon.com
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Currently, we can read OOB data without MSG_OOB by using MSG_PEEK
when OOB data is sitting on the front row, which is apparently
wrong.
>>> from socket import *
>>> c1, c2 = socketpair(AF_UNIX, SOCK_STREAM)
>>> c1.send(b'a', MSG_OOB)
1
>>> c2.recv(1, MSG_PEEK | MSG_DONTWAIT)
b'a'
If manage_oob() is called when no data has been copied, we only
check if the socket enables SO_OOBINLINE or MSG_PEEK is not used.
Otherwise, the skb is returned as is.
However, here we should return NULL if MSG_PEEK is set and no data
has been copied.
Also, in such a case, we should not jump to the redo label because
we will be caught in the loop and hog the CPU until normal data
comes in.
Then, we need to handle skb == NULL case with the if-clause below
the manage_oob() block.
With this patch:
>>> from socket import *
>>> c1, c2 = socketpair(AF_UNIX, SOCK_STREAM)
>>> c1.send(b'a', MSG_OOB)
1
>>> c2.recv(1, MSG_PEEK | MSG_DONTWAIT)
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
BlockingIOError: [Errno 11] Resource temporarily unavailable
Fixes: 314001f0bf ("af_unix: Add OOB support")
Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Link: https://lore.kernel.org/r/20240410171016.7621-3-kuniyu@amazon.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
When we call recv() for AF_UNIX socket, we first peek one skb and
calls manage_oob() to check if the skb is sent with MSG_OOB.
However, when we fetch the next (and the following) skb, manage_oob()
is not called now, leading a wrong behaviour.
Let's say a socket send()s "hello" with MSG_OOB and the peer tries
to recv() 5 bytes with MSG_PEEK. Here, we should get only "hell"
without 'o', but actually not:
>>> from socket import *
>>> c1, c2 = socketpair(AF_UNIX, SOCK_STREAM)
>>> c1.send(b'hello', MSG_OOB)
5
>>> c2.recv(5, MSG_PEEK)
b'hello'
The first skb fills 4 bytes, and the next skb is peeked but not
properly checked by manage_oob().
Let's move up the again label to call manage_oob() for evry skb.
With this patch:
>>> from socket import *
>>> c1, c2 = socketpair(AF_UNIX, SOCK_STREAM)
>>> c1.send(b'hello', MSG_OOB)
5
>>> c2.recv(5, MSG_PEEK)
b'hell'
Fixes: 314001f0bf ("af_unix: Add OOB support")
Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Link: https://lore.kernel.org/r/20240410171016.7621-2-kuniyu@amazon.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
syzkaller started to report deadlock of unix_gc_lock after commit
4090fa373f ("af_unix: Replace garbage collection algorithm."), but
it just uncovers the bug that has been there since commit 314001f0bf
("af_unix: Add OOB support").
The repro basically does the following.
from socket import *
from array import array
c1, c2 = socketpair(AF_UNIX, SOCK_STREAM)
c1.sendmsg([b'a'], [(SOL_SOCKET, SCM_RIGHTS, array("i", [c2.fileno()]))], MSG_OOB)
c2.recv(1) # blocked as no normal data in recv queue
c2.close() # done async and unblock recv()
c1.close() # done async and trigger GC
A socket sends its file descriptor to itself as OOB data and tries to
receive normal data, but finally recv() fails due to async close().
The problem here is wrong handling of OOB skb in manage_oob(). When
recvmsg() is called without MSG_OOB, manage_oob() is called to check
if the peeked skb is OOB skb. In such a case, manage_oob() pops it
out of the receive queue but does not clear unix_sock(sk)->oob_skb.
This is wrong in terms of uAPI.
Let's say we send "hello" with MSG_OOB, and "world" without MSG_OOB.
The 'o' is handled as OOB data. When recv() is called twice without
MSG_OOB, the OOB data should be lost.
>>> from socket import *
>>> c1, c2 = socketpair(AF_UNIX, SOCK_STREAM, 0)
>>> c1.send(b'hello', MSG_OOB) # 'o' is OOB data
5
>>> c1.send(b'world')
5
>>> c2.recv(5) # OOB data is not received
b'hell'
>>> c2.recv(5) # OOB date is skipped
b'world'
>>> c2.recv(5, MSG_OOB) # This should return an error
b'o'
In the same situation, TCP actually returns -EINVAL for the last
recv().
Also, if we do not clear unix_sk(sk)->oob_skb, unix_poll() always set
EPOLLPRI even though the data has passed through by previous recv().
To avoid these issues, we must clear unix_sk(sk)->oob_skb when dequeuing
it from recv queue.
The reason why the old GC did not trigger the deadlock is because the
old GC relied on the receive queue to detect the loop.
When it is triggered, the socket with OOB data is marked as GC candidate
because file refcount == inflight count (1). However, after traversing
all inflight sockets, the socket still has a positive inflight count (1),
thus the socket is excluded from candidates. Then, the old GC lose the
chance to garbage-collect the socket.
With the old GC, the repro continues to create true garbage that will
never be freed nor detected by kmemleak as it's linked to the global
inflight list. That's why we couldn't even notice the issue.
Fixes: 314001f0bf ("af_unix: Add OOB support")
Reported-by: syzbot+7f7f201cc2668a8fd169@syzkaller.appspotmail.com
Closes: https://syzkaller.appspot.com/bug?extid=7f7f201cc2668a8fd169
Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Link: https://lore.kernel.org/r/20240405221057.2406-1-kuniyu@amazon.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
In the previous GC implementation, the shape of the inflight socket
graph was not expected to change while GC was in progress.
MSG_PEEK was tricky because it could install inflight fd silently
and transform the graph.
Let's say we peeked a fd, which was a listening socket, and accept()ed
some embryo sockets from it. The garbage collection algorithm would
have been confused because the set of sockets visited in scan_inflight()
would change within the same GC invocation.
That's why we placed spin_lock(&unix_gc_lock) and spin_unlock() in
unix_peek_fds() with a fat comment.
In the new GC implementation, we no longer garbage-collect the socket
if it exists in another queue, that is, if it has a bridge to another
SCC. Also, accept() will require the lock if it has edges.
Thus, we need not do the complicated lock dance.
Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Link: https://lore.kernel.org/r/20240401173125.92184-3-kuniyu@amazon.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
When we passed fds, we used to bump each file's refcount twice
in scm_fp_copy() and scm_fp_dup() before linking the socket to
gc_inflight_list.
This is because we incremented the inflight count of the socket
and linked it to the list in advance before passing skb to the
destination socket.
Otherwise, the inflight socket could have been garbage-collected
in a small race window between linking the socket to the list and
queuing skb:
CPU 1 : sendmsg(X) w/ A's fd CPU 2 : close(A)
----- -----
/* Here A's refcount is 1, and inflight count is 0 */
bump A's refcount to 2 in scm_fp_copy()
bump A's inflight count to 1
link A to gc_inflight_list
decrement A's refcount to 1
/* A's refcount == inflight count, thus A could be GC candidate */
start GC
mark A as candidate
purge A's receive queue
queue skb w/ A's fd to X
/* A is queued, but all data has been lost */
After commit 4090fa373f ("af_unix: Replace garbage collection
algorithm."), we increment the inflight count and link the socket
to the global list only when queuing the skb.
The race no longer exists, so let's not clone the fd nor bump
the count in unix_attach_fds().
Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Link: https://lore.kernel.org/r/20240401173125.92184-2-kuniyu@amazon.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
While looking at UDP receive performance, I saw sk_wake_async()
was no longer inlined.
This matters at least on AMD Zen1-4 platforms (see SRSO)
This might be because rcu_read_lock() and rcu_read_unlock()
are no longer nops in recent kernels ?
Add sk_wake_async_rcu() variant, which must be called from
contexts already holding rcu lock.
As SOCK_FASYNC is deprecated in modern days, use unlikely()
to give a hint to the compiler.
sk_wake_async_rcu() is properly inlined from
__udp_enqueue_schedule_skb() and sock_def_readable().
Signed-off-by: Eric Dumazet <edumazet@google.com>
Link: https://lore.kernel.org/r/20240328144032.1864988-5-edumazet@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
If we find a dead SCC during iteration, we call unix_collect_skb()
to splice all skb in the SCC to the global sk_buff_head, hitlist.
After iterating all SCC, we unlock unix_gc_lock and purge the queue.
Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Acked-by: Paolo Abeni <pabeni@redhat.com>
Link: https://lore.kernel.org/r/20240325202425.60930-15-kuniyu@amazon.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
To garbage collect inflight AF_UNIX sockets, we must define the
cyclic reference appropriately. This is a bit tricky if the loop
consists of embryo sockets.
Suppose that the fd of AF_UNIX socket A is passed to D and the fd B
to C and that C and D are embryo sockets of A and B, respectively.
It may appear that there are two separate graphs, A (-> D) and
B (-> C), but this is not correct.
A --. .-- B
X
C <-' `-> D
Now, D holds A's refcount, and C has B's refcount, so unix_release()
will never be called for A and B when we close() them. However, no
one can call close() for D and C to free skbs holding refcounts of A
and B because C/D is in A/B's receive queue, which should have been
purged by unix_release() for A and B.
So, here's another type of cyclic reference. When a fd of an AF_UNIX
socket is passed to an embryo socket, the reference is indirectly held
by its parent listening socket.
.-> A .-> B
| `- sk_receive_queue | `- sk_receive_queue
| `- skb | `- skb
| `- sk == C | `- sk == D
| `- sk_receive_queue | `- sk_receive_queue
| `- skb +---------' `- skb +-.
| |
`---------------------------------------------------------'
Technically, the graph must be denoted as A <-> B instead of A (-> D)
and B (-> C) to find such a cyclic reference without touching each
socket's receive queue.
.-> A --. .-- B <-.
| X | == A <-> B
`-- C <-' `-> D --'
We apply this fixup during GC by fetching the real successor by
unix_edge_successor().
When we call accept(), we clear unix_sock.listener under unix_gc_lock
not to confuse GC.
Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Acked-by: Paolo Abeni <pabeni@redhat.com>
Link: https://lore.kernel.org/r/20240325202425.60930-9-kuniyu@amazon.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
This is a prep patch for the following change, where we need to
fetch the listening socket from the successor embryo socket
during GC.
We add a new field to struct unix_sock to save a pointer to a
listening socket.
We set it when connect() creates a new socket, and clear it when
accept() is called.
Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Acked-by: Paolo Abeni <pabeni@redhat.com>
Link: https://lore.kernel.org/r/20240325202425.60930-8-kuniyu@amazon.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
We will replace the garbage collection algorithm for AF_UNIX, where
we will consider each inflight AF_UNIX socket as a vertex and its file
descriptor as an edge in a directed graph.
This patch introduces a new struct unix_vertex representing a vertex
in the graph and adds its pointer to struct unix_sock.
When we send a fd using the SCM_RIGHTS message, we allocate struct
scm_fp_list to struct scm_cookie in scm_fp_copy(). Then, we bump
each refcount of the inflight fds' struct file and save them in
scm_fp_list.fp.
After that, unix_attach_fds() inexplicably clones scm_fp_list of
scm_cookie and sets it to skb. (We will remove this part after
replacing GC.)
Here, we add a new function call in unix_attach_fds() to preallocate
struct unix_vertex per inflight AF_UNIX fd and link each vertex to
skb's scm_fp_list.vertices.
When sendmsg() succeeds later, if the socket of the inflight fd is
still not inflight yet, we will set the preallocated vertex to struct
unix_sock.vertex and link it to a global list unix_unvisited_vertices
under spin_lock(&unix_gc_lock).
If the socket is already inflight, we free the preallocated vertex.
This is to avoid taking the lock unnecessarily when sendmsg() could
fail later.
In the following patch, we will similarly allocate another struct
per edge, which will finally be linked to the inflight socket's
unix_vertex.edges.
And then, we will count the number of edges as unix_vertex.out_degree.
Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Acked-by: Paolo Abeni <pabeni@redhat.com>
Link: https://lore.kernel.org/r/20240325202425.60930-2-kuniyu@amazon.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Originally, the code related to garbage collection was all in garbage.c.
Commit f4e65870e5 ("net: split out functions related to registering
inflight socket files") moved some functions to scm.c for io_uring and
added CONFIG_UNIX_SCM just in case AF_UNIX was built as module.
However, since commit 97154bcf4d ("af_unix: Kconfig: make CONFIG_UNIX
bool"), AF_UNIX is no longer built separately. Also, io_uring does not
support SCM_RIGHTS now.
Let's move the functions back to garbage.c
Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Acked-by: Jens Axboe <axboe@kernel.dk>
Link: https://lore.kernel.org/r/20240129190435.57228-4-kuniyu@amazon.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
If more than 16000 inflight AF_UNIX sockets exist and the garbage
collector is not running, unix_(dgram|stream)_sendmsg() call unix_gc().
Also, they wait for unix_gc() to complete.
In unix_gc(), all inflight AF_UNIX sockets are traversed at least once,
and more if they are the GC candidate. Thus, sendmsg() significantly
slows down with too many inflight AF_UNIX sockets.
However, if a process sends data with no AF_UNIX FD, the sendmsg() call
does not need to wait for GC. After this change, only the process that
meets the condition below will be blocked under such a situation.
1) cmsg contains AF_UNIX socket
2) more than 32 AF_UNIX sent by the same user are still inflight
Note that even a sendmsg() call that does not meet the condition but has
AF_UNIX FD will be blocked later in unix_scm_to_skb() by the spinlock,
but we allow that as a bonus for sane users.
The results below are the time spent in unix_dgram_sendmsg() sending 1
byte of data with no FD 4096 times on a host where 32K inflight AF_UNIX
sockets exist.
Without series: the sane sendmsg() needs to wait gc unreasonably.
$ sudo /usr/share/bcc/tools/funclatency -p 11165 unix_dgram_sendmsg
Tracing 1 functions for "unix_dgram_sendmsg"... Hit Ctrl-C to end.
^C
nsecs : count distribution
[...]
524288 -> 1048575 : 0 | |
1048576 -> 2097151 : 3881 |****************************************|
2097152 -> 4194303 : 214 |** |
4194304 -> 8388607 : 1 | |
avg = 1825567 nsecs, total: 7477526027 nsecs, count: 4096
With series: the sane sendmsg() can finish much faster.
$ sudo /usr/share/bcc/tools/funclatency -p 8702 unix_dgram_sendmsg
Tracing 1 functions for "unix_dgram_sendmsg"... Hit Ctrl-C to end.
^C
nsecs : count distribution
[...]
128 -> 255 : 0 | |
256 -> 511 : 4092 |****************************************|
512 -> 1023 : 2 | |
1024 -> 2047 : 0 | |
2048 -> 4095 : 0 | |
4096 -> 8191 : 1 | |
8192 -> 16383 : 1 | |
avg = 410 nsecs, total: 1680510 nsecs, count: 4096
Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Link: https://lore.kernel.org/r/20240123170856.41348-6-kuniyu@amazon.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
When touching unix_sk(sk)->inflight, we are always under
spin_lock(&unix_gc_lock).
Let's convert unix_sk(sk)->inflight to the normal unsigned long.
Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Reviewed-by: Simon Horman <horms@kernel.org>
Link: https://lore.kernel.org/r/20240123170856.41348-3-kuniyu@amazon.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
AF_UNIX stream sockets are a paired socket. So sending on one of the pairs
will lookup the paired socket as part of the send operation. It is possible
however to put just one of the pairs in a BPF map. This currently increments
the refcnt on the sock in the sockmap to ensure it is not free'd by the
stack before sockmap cleans up its state and stops any skbs being sent/recv'd
to that socket.
But we missed a case. If the peer socket is closed it will be free'd by the
stack. However, the paired socket can still be referenced from BPF sockmap
side because we hold a reference there. Then if we are sending traffic through
BPF sockmap to that socket it will try to dereference the free'd pair in its
send logic creating a use after free. And following splat:
[59.900375] BUG: KASAN: slab-use-after-free in sk_wake_async+0x31/0x1b0
[59.901211] Read of size 8 at addr ffff88811acbf060 by task kworker/1:2/954
[...]
[59.905468] Call Trace:
[59.905787] <TASK>
[59.906066] dump_stack_lvl+0x130/0x1d0
[59.908877] print_report+0x16f/0x740
[59.910629] kasan_report+0x118/0x160
[59.912576] sk_wake_async+0x31/0x1b0
[59.913554] sock_def_readable+0x156/0x2a0
[59.914060] unix_stream_sendmsg+0x3f9/0x12a0
[59.916398] sock_sendmsg+0x20e/0x250
[59.916854] skb_send_sock+0x236/0xac0
[59.920527] sk_psock_backlog+0x287/0xaa0
To fix let BPF sockmap hold a refcnt on both the socket in the sockmap and its
paired socket. It wasn't obvious how to contain the fix to bpf_unix logic. The
primarily problem with keeping this logic in bpf_unix was: In the sock close()
we could handle the deref by having a close handler. But, when we are destroying
the psock through a map delete operation we wouldn't have gotten any signal
thorugh the proto struct other than it being replaced. If we do the deref from
the proto replace its too early because we need to deref the sk_pair after the
backlog worker has been stopped.
Given all this it seems best to just cache it at the end of the psock and eat 8B
for the af_unix and vsock users. Notice dgram sockets are OK because they handle
locking already.
Fixes: 94531cfcbe ("af_unix: Add unix_stream_proto for sockmap")
Signed-off-by: John Fastabend <john.fastabend@gmail.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Reviewed-by: Jakub Sitnicki <jakub@cloudflare.com>
Link: https://lore.kernel.org/bpf/20231129012557.95371-2-john.fastabend@gmail.com
Since commit 97154bcf4d ("af_unix: Kconfig: make CONFIG_UNIX bool"),
af_unix.c is no longer built as module.
Let's remove unnecessary #if condition, exitcall, and module macros.
Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Link: https://lore.kernel.org/r/20231026212305.45545-1-kuniyu@amazon.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
These hooks allows intercepting connect(), getsockname(),
getpeername(), sendmsg() and recvmsg() for unix sockets. The unix
socket hooks get write access to the address length because the
address length is not fixed when dealing with unix sockets and
needs to be modified when a unix socket address is modified by
the hook. Because abstract socket unix addresses start with a
NUL byte, we cannot recalculate the socket address in kernelspace
after running the hook by calculating the length of the unix socket
path using strlen().
These hooks can be used when users want to multiplex syscall to a
single unix socket to multiple different processes behind the scenes
by redirecting the connect() and other syscalls to process specific
sockets.
We do not implement support for intercepting bind() because when
using bind() with unix sockets with a pathname address, this creates
an inode in the filesystem which must be cleaned up. If we rewrite
the address, the user might try to clean up the wrong file, leaking
the socket in the filesystem where it is never cleaned up. Until we
figure out a solution for this (and a use case for intercepting bind()),
we opt to not allow rewriting the sockaddr in bind() calls.
We also implement recvmsg() support for connected streams so that
after a connect() that is modified by a sockaddr hook, any corresponding
recmvsg() on the connected socket can also be modified to make the
connected program think it is connected to the "intended" remote.
Reviewed-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Signed-off-by: Daan De Meyer <daan.j.demeyer@gmail.com>
Link: https://lore.kernel.org/r/20231011185113.140426-5-daan.j.demeyer@gmail.com
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
sk_getsockopt() runs locklessly, thus we need to annotate the read
of sk->sk_peek_off.
While we are at it, add corresponding annotations to sk_set_peek_off()
and unix_set_peek_off().
Fixes: b9bb53f383 ("sock: convert sk_peek_offset functions to WRITE_ONCE")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Willem de Bruijn <willemb@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
kernel test robot reported slab-out-of-bounds access in strlen(). [0]
Commit 06d4c8a808 ("af_unix: Fix fortify_panic() in unix_bind_bsd().")
removed unix_mkname_bsd() call in unix_bind_bsd().
If sunaddr->sun_path is not terminated by user and we don't enable
CONFIG_INIT_STACK_ALL_ZERO=y, strlen() will do the out-of-bounds access
during file creation.
Let's go back to strlen()-with-sockaddr_storage way and pack all 108
trickiness into unix_mkname_bsd() with bold comments.
[0]:
BUG: KASAN: slab-out-of-bounds in strlen (lib/string.c:?)
Read of size 1 at addr ffff000015492777 by task fortify_strlen_/168
CPU: 0 PID: 168 Comm: fortify_strlen_ Not tainted 6.5.0-rc1-00333-g3329b603ebba #16
Hardware name: linux,dummy-virt (DT)
Call trace:
dump_backtrace (arch/arm64/kernel/stacktrace.c:235)
show_stack (arch/arm64/kernel/stacktrace.c:242)
dump_stack_lvl (lib/dump_stack.c:107)
print_report (mm/kasan/report.c:365 mm/kasan/report.c:475)
kasan_report (mm/kasan/report.c:590)
__asan_report_load1_noabort (mm/kasan/report_generic.c:378)
strlen (lib/string.c:?)
getname_kernel (./include/linux/fortify-string.h:? fs/namei.c:226)
kern_path_create (fs/namei.c:3926)
unix_bind (net/unix/af_unix.c:1221 net/unix/af_unix.c:1324)
__sys_bind (net/socket.c:1792)
__arm64_sys_bind (net/socket.c:1801)
invoke_syscall (arch/arm64/kernel/syscall.c:? arch/arm64/kernel/syscall.c:52)
el0_svc_common (./include/linux/thread_info.h:127 arch/arm64/kernel/syscall.c:147)
do_el0_svc (arch/arm64/kernel/syscall.c:189)
el0_svc (./arch/arm64/include/asm/daifflags.h:28 arch/arm64/kernel/entry-common.c:133 arch/arm64/kernel/entry-common.c:144 arch/arm64/kernel/entry-common.c:648)
el0t_64_sync_handler (arch/arm64/kernel/entry-common.c:?)
el0t_64_sync (arch/arm64/kernel/entry.S:591)
Allocated by task 168:
kasan_set_track (mm/kasan/common.c:45 mm/kasan/common.c:52)
kasan_save_alloc_info (mm/kasan/generic.c:512)
__kasan_kmalloc (mm/kasan/common.c:383)
__kmalloc (mm/slab_common.c:? mm/slab_common.c:998)
unix_bind (net/unix/af_unix.c:257 net/unix/af_unix.c:1213 net/unix/af_unix.c:1324)
__sys_bind (net/socket.c:1792)
__arm64_sys_bind (net/socket.c:1801)
invoke_syscall (arch/arm64/kernel/syscall.c:? arch/arm64/kernel/syscall.c:52)
el0_svc_common (./include/linux/thread_info.h:127 arch/arm64/kernel/syscall.c:147)
do_el0_svc (arch/arm64/kernel/syscall.c:189)
el0_svc (./arch/arm64/include/asm/daifflags.h:28 arch/arm64/kernel/entry-common.c:133 arch/arm64/kernel/entry-common.c:144 arch/arm64/kernel/entry-common.c:648)
el0t_64_sync_handler (arch/arm64/kernel/entry-common.c:?)
el0t_64_sync (arch/arm64/kernel/entry.S:591)
The buggy address belongs to the object at ffff000015492700
which belongs to the cache kmalloc-128 of size 128
The buggy address is located 0 bytes to the right of
allocated 119-byte region [ffff000015492700, ffff000015492777)
The buggy address belongs to the physical page:
page:00000000aeab52ba refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x55492
anon flags: 0x3fffc0000000200(slab|node=0|zone=0|lastcpupid=0xffff)
page_type: 0xffffffff()
raw: 03fffc0000000200 ffff0000084018c0 fffffc00003d0e00 0000000000000005
raw: 0000000000000000 0000000080100010 00000001ffffffff 0000000000000000
page dumped because: kasan: bad access detected
Memory state around the buggy address:
ffff000015492600: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff000015492680: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>ffff000015492700: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 07 fc
^
ffff000015492780: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
ffff000015492800: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
Fixes: 06d4c8a808 ("af_unix: Fix fortify_panic() in unix_bind_bsd().")
Reported-by: kernel test robot <oliver.sang@intel.com>
Closes: https://lore.kernel.org/netdev/202307262110.659e5e8-oliver.sang@intel.com/
Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Link: https://lore.kernel.org/r/20230726190828.47874-1-kuniyu@amazon.com
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
syzkaller found a bug in unix_bind_bsd() [0]. We can reproduce it
by bind()ing a socket on a path with length 108.
108 is the size of sun_addr of struct sockaddr_un and is the maximum
valid length for the pathname socket. When calling bind(), we use
struct sockaddr_storage as the actual buffer size, so terminating
sun_addr[108] with null is legitimate as done in unix_mkname_bsd().
However, strlen(sunaddr) for such a case causes fortify_panic() if
CONFIG_FORTIFY_SOURCE=y. __fortify_strlen() has no idea about the
actual buffer size and see the string as unterminated.
Let's use strnlen() to allow sun_addr to be unterminated at 107.
[0]:
detected buffer overflow in __fortify_strlen
kernel BUG at lib/string_helpers.c:1031!
Internal error: Oops - BUG: 00000000f2000800 [#1] PREEMPT SMP
Modules linked in:
CPU: 0 PID: 255 Comm: syz-executor296 Not tainted 6.5.0-rc1-00330-g60cc1f7d0605 #4
Hardware name: linux,dummy-virt (DT)
pstate: 60400005 (nZCv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--)
pc : fortify_panic+0x1c/0x20 lib/string_helpers.c:1030
lr : fortify_panic+0x1c/0x20 lib/string_helpers.c:1030
sp : ffff800089817af0
x29: ffff800089817af0 x28: ffff800089817b40 x27: 1ffff00011302f68
x26: 000000000000006e x25: 0000000000000012 x24: ffff800087e60140
x23: dfff800000000000 x22: ffff800089817c20 x21: ffff800089817c8e
x20: 000000000000006c x19: ffff00000c323900 x18: ffff800086ab1630
x17: 0000000000000000 x16: 0000000000000000 x15: 0000000000000001
x14: 1ffff00011302eb8 x13: 0000000000000000 x12: 0000000000000000
x11: 0000000000000000 x10: 0000000000000000 x9 : 64a26b65474d2a00
x8 : 64a26b65474d2a00 x7 : 0000000000000001 x6 : 0000000000000001
x5 : ffff800089817438 x4 : ffff800086ac99e0 x3 : ffff800080f19e8c
x2 : 0000000000000001 x1 : 0000000100000000 x0 : 000000000000002c
Call trace:
fortify_panic+0x1c/0x20 lib/string_helpers.c:1030
_Z16__fortify_strlenPKcU25pass_dynamic_object_size1 include/linux/fortify-string.h:217 [inline]
unix_bind_bsd net/unix/af_unix.c:1212 [inline]
unix_bind+0xba8/0xc58 net/unix/af_unix.c:1326
__sys_bind+0x1ac/0x248 net/socket.c:1792
__do_sys_bind net/socket.c:1803 [inline]
__se_sys_bind net/socket.c:1801 [inline]
__arm64_sys_bind+0x7c/0x94 net/socket.c:1801
__invoke_syscall arch/arm64/kernel/syscall.c:38 [inline]
invoke_syscall+0x98/0x2c0 arch/arm64/kernel/syscall.c:52
el0_svc_common+0x134/0x240 arch/arm64/kernel/syscall.c:139
do_el0_svc+0x64/0x198 arch/arm64/kernel/syscall.c:188
el0_svc+0x2c/0x7c arch/arm64/kernel/entry-common.c:647
el0t_64_sync_handler+0x84/0xfc arch/arm64/kernel/entry-common.c:665
el0t_64_sync+0x190/0x194 arch/arm64/kernel/entry.S:591
Code: aa0003e1 d0000e80 91030000 97ffc91a (d4210000)
Fixes: df8fc4e934 ("kbuild: Enable -fstrict-flex-arrays=3")
Reported-by: syzkaller <syzkaller@googlegroups.com>
Suggested-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Link: https://lore.kernel.org/r/20230724213425.22920-2-kuniyu@amazon.com
Reviewed-by: Simon Horman <simon.horman@corigine.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Recently, our friends from bluetooth subsystem reported [1] that after
commit 5e2ff6704a ("scm: add SO_PASSPIDFD and SCM_PIDFD") scm_recv()
helper become unusable in kernel modules (because it uses unexported
pidfd_prepare() API).
We were aware of this issue and workarounded it in a hard way
by commit 97154bcf4d ("af_unix: Kconfig: make CONFIG_UNIX bool").
But recently a new functionality was added in the scope of commit
817efd3cad74 ("Bluetooth: hci_sock: Forward credentials to monitor")
and after that bluetooth can't be compiled as a kernel module.
After some discussion in [1] we decided to split scm_recv() into
two helpers, one won't support SCM_PIDFD (used for unix sockets),
and another one will be completely the same as it was before commit
5e2ff6704a ("scm: add SO_PASSPIDFD and SCM_PIDFD").
Link: https://lore.kernel.org/lkml/CAJqdLrpFcga4n7wxBhsFqPQiN8PKFVr6U10fKcJ9W7AcZn+o6Q@mail.gmail.com/ [1]
Fixes: 5e2ff6704a ("scm: add SO_PASSPIDFD and SCM_PIDFD")
Signed-off-by: Alexander Mikhalitsyn <aleksandr.mikhalitsyn@canonical.com>
Reviewed-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Link: https://lore.kernel.org/r/20230627174314.67688-3-kuniyu@amazon.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
This reverts commit 3f5f118bb6.
Konrad reported that desktop environment below cannot be reached after
commit 3f5f118bb6 ("af_unix: Call scm_recv() only after scm_set_cred().")
- postmarketOS (Alpine Linux w/ musl 1.2.4)
- busybox 1.36.1
- GNOME 44.1
- networkmanager 1.42.6
- openrc 0.47
Regarding to the warning of SO_PASSPIDFD, I'll post another patch to
suppress it by skipping SCM_PIDFD if scm->pid == NULL in scm_pidfd_recv().
Reported-by: Konrad Dybcio <konradybcio@kernel.org>
Link: https://lore.kernel.org/netdev/8c7f9abd-4f84-7296-2788-1e130d6304a0@kernel.org/
Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Tested-by: Ido Schimmel <idosch@nvidia.com>
Tested-by: Gal Pressman <gal@nvidia.com>
Link: https://lore.kernel.org/r/20230626205837.82086-1-kuniyu@amazon.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Add SO_PEERPIDFD which allows to get pidfd of peer socket holder pidfd.
This thing is direct analog of SO_PEERCRED which allows to get plain PID.
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Eric Dumazet <edumazet@google.com>
Cc: Jakub Kicinski <kuba@kernel.org>
Cc: Paolo Abeni <pabeni@redhat.com>
Cc: Leon Romanovsky <leon@kernel.org>
Cc: David Ahern <dsahern@kernel.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Kees Cook <keescook@chromium.org>
Cc: Christian Brauner <brauner@kernel.org>
Cc: Kuniyuki Iwashima <kuniyu@amazon.com>
Cc: Lennart Poettering <mzxreary@0pointer.de>
Cc: Luca Boccassi <bluca@debian.org>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: Stanislav Fomichev <sdf@google.com>
Cc: bpf@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Cc: netdev@vger.kernel.org
Cc: linux-arch@vger.kernel.org
Reviewed-by: Christian Brauner <brauner@kernel.org>
Acked-by: Stanislav Fomichev <sdf@google.com>
Tested-by: Luca Boccassi <bluca@debian.org>
Signed-off-by: Alexander Mikhalitsyn <aleksandr.mikhalitsyn@canonical.com>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Implement SCM_PIDFD, a new type of CMSG type analogical to SCM_CREDENTIALS,
but it contains pidfd instead of plain pid, which allows programmers not
to care about PID reuse problem.
We mask SO_PASSPIDFD feature if CONFIG_UNIX is not builtin because
it depends on a pidfd_prepare() API which is not exported to the kernel
modules.
Idea comes from UAPI kernel group:
https://uapi-group.org/kernel-features/
Big thanks to Christian Brauner and Lennart Poettering for productive
discussions about this.
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Eric Dumazet <edumazet@google.com>
Cc: Jakub Kicinski <kuba@kernel.org>
Cc: Paolo Abeni <pabeni@redhat.com>
Cc: Leon Romanovsky <leon@kernel.org>
Cc: David Ahern <dsahern@kernel.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Kees Cook <keescook@chromium.org>
Cc: Christian Brauner <brauner@kernel.org>
Cc: Kuniyuki Iwashima <kuniyu@amazon.com>
Cc: Lennart Poettering <mzxreary@0pointer.de>
Cc: Luca Boccassi <bluca@debian.org>
Cc: linux-kernel@vger.kernel.org
Cc: netdev@vger.kernel.org
Cc: linux-arch@vger.kernel.org
Tested-by: Luca Boccassi <bluca@debian.org>
Reviewed-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Reviewed-by: Christian Brauner <brauner@kernel.org>
Signed-off-by: Alexander Mikhalitsyn <aleksandr.mikhalitsyn@canonical.com>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Convert unix_stream_sendpage() to use sendmsg() with MSG_SPLICE_PAGES
rather than directly splicing in the pages itself.
This allows ->sendpage() to be replaced by something that can handle
multiple multipage folios in a single transaction.
Signed-off-by: David Howells <dhowells@redhat.com>
cc: Kuniyuki Iwashima <kuniyu@amazon.com>
cc: Jens Axboe <axboe@kernel.dk>
cc: Matthew Wilcox <willy@infradead.org>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Kuniyuki Iwashima
Linus Torvalds
Jakub Kicinski
Jens Axboe
Breno Leitao
Eric Dumazet
John Fastabend
Daan De Meyer
Alexander Mikhalitsyn
David Howells