<feed xmlns='http://www.w3.org/2005/Atom'>
<title>linux/net/netrom, branch v6.7</title>
<subtitle>Mirror of https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/
</subtitle>
<id>https://git.shady.money/linux/atom?h=v6.7</id>
<link rel='self' href='https://git.shady.money/linux/atom?h=v6.7'/>
<link rel='alternate' type='text/html' href='https://git.shady.money/linux/'/>
<updated>2023-10-01T18:09:54Z</updated>
<entry>
<title>net: implement lockless SO_PRIORITY</title>
<updated>2023-10-01T18:09:54Z</updated>
<author>
<name>Eric Dumazet</name>
<email>edumazet@google.com</email>
</author>
<published>2023-09-21T20:28:11Z</published>
<link rel='alternate' type='text/html' href='https://git.shady.money/linux/commit/?id=10bbf1652c1cca9819e98d56f3432c56d7a2d229'/>
<id>urn:sha1:10bbf1652c1cca9819e98d56f3432c56d7a2d229</id>
<content type='text'>
This is a followup of 8bf43be799d4 ("net: annotate data-races
around sk-&gt;sk_priority").

sk-&gt;sk_priority can be read and written without holding the socket lock.

Signed-off-by: Eric Dumazet &lt;edumazet@google.com&gt;
Reviewed-by: Wenjia Zhang &lt;wenjia@linux.ibm.com&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
</content>
</entry>
<entry>
<title>netrom: Deny concurrent connect().</title>
<updated>2023-08-28T05:58:46Z</updated>
<author>
<name>Kuniyuki Iwashima</name>
<email>kuniyu@amazon.com</email>
</author>
<published>2023-08-24T16:50:59Z</published>
<link rel='alternate' type='text/html' href='https://git.shady.money/linux/commit/?id=c2f8fd7949603efb03908e05abbf7726748c8de3'/>
<id>urn:sha1:c2f8fd7949603efb03908e05abbf7726748c8de3</id>
<content type='text'>
syzkaller reported null-ptr-deref [0] related to AF_NETROM.
This is another self-accept issue from the strace log. [1]

syz-executor creates an AF_NETROM socket and calls connect(), which
is blocked at that time.  Then, sk-&gt;sk_state is TCP_SYN_SENT and
sock-&gt;state is SS_CONNECTING.

  [pid  5059] socket(AF_NETROM, SOCK_SEQPACKET, 0) = 4
  [pid  5059] connect(4, {sa_family=AF_NETROM, sa_data="..." &lt;unfinished ...&gt;

Another thread calls connect() concurrently, which finally fails
with -EINVAL.  However, the problem here is the socket state is
reset even while the first connect() is blocked.

  [pid  5060] connect(4, NULL, 0 &lt;unfinished ...&gt;
  [pid  5060] &lt;... connect resumed&gt;)      = -1 EINVAL (Invalid argument)

As sk-&gt;state is TCP_CLOSE and sock-&gt;state is SS_UNCONNECTED, the
following listen() succeeds.  Then, the first connect() looks up
itself as a listener and puts skb into the queue with skb-&gt;sk itself.
As a result, the next accept() gets another FD of itself as 3, and
the first connect() finishes.

  [pid  5060] listen(4, 0 &lt;unfinished ...&gt;
  [pid  5060] &lt;... listen resumed&gt;)       = 0
  [pid  5060] accept(4, NULL, NULL &lt;unfinished ...&gt;
  [pid  5060] &lt;... accept resumed&gt;)       = 3
  [pid  5059] &lt;... connect resumed&gt;)      = 0

Then, accept4() is called but blocked, which causes the general protection
fault later.

  [pid  5059] accept4(4, NULL, 0x20000400, SOCK_NONBLOCK &lt;unfinished ...&gt;

After that, another self-accept occurs by accept() and writev().

  [pid  5060] accept(4, NULL, NULL &lt;unfinished ...&gt;
  [pid  5061] writev(3, [{iov_base=...}] &lt;unfinished ...&gt;
  [pid  5061] &lt;... writev resumed&gt;)       = 99
  [pid  5060] &lt;... accept resumed&gt;)       = 6

Finally, the leader thread close()s all FDs.  Since the three FDs
reference the same socket, nr_release() does the cleanup for it
three times, and the remaining accept4() causes the following fault.

  [pid  5058] close(3)                    = 0
  [pid  5058] close(4)                    = 0
  [pid  5058] close(5)                    = -1 EBADF (Bad file descriptor)
  [pid  5058] close(6)                    = 0
  [pid  5058] &lt;... exit_group resumed&gt;)   = ?
  [   83.456055][ T5059] general protection fault, probably for non-canonical address 0xdffffc0000000003: 0000 [#1] PREEMPT SMP KASAN

To avoid the issue, we need to return an error for connect() if
another connect() is in progress, as done in __inet_stream_connect().

[0]:
general protection fault, probably for non-canonical address 0xdffffc0000000003: 0000 [#1] PREEMPT SMP KASAN
KASAN: null-ptr-deref in range [0x0000000000000018-0x000000000000001f]
CPU: 0 PID: 5059 Comm: syz-executor.0 Not tainted 6.5.0-rc5-syzkaller-00194-gace0ab3a4b54 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/26/2023
RIP: 0010:__lock_acquire+0x109/0x5de0 kernel/locking/lockdep.c:5012
Code: 45 85 c9 0f 84 cc 0e 00 00 44 8b 05 11 6e 23 0b 45 85 c0 0f 84 be 0d 00 00 48 ba 00 00 00 00 00 fc ff df 4c 89 d1 48 c1 e9 03 &lt;80&gt; 3c 11 00 0f 85 e8 40 00 00 49 81 3a a0 69 48 90 0f 84 96 0d 00
RSP: 0018:ffffc90003d6f9e0 EFLAGS: 00010006
RAX: ffff8880244c8000 RBX: 1ffff920007adf6c RCX: 0000000000000003
RDX: dffffc0000000000 RSI: 0000000000000000 RDI: 0000000000000018
RBP: 0000000000000001 R08: 0000000000000001 R09: 0000000000000001
R10: 0000000000000018 R11: 0000000000000000 R12: 0000000000000000
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
FS:  00007f51d519a6c0(0000) GS:ffff8880b9800000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f51d5158d58 CR3: 000000002943f000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 &lt;TASK&gt;
 lock_acquire kernel/locking/lockdep.c:5761 [inline]
 lock_acquire+0x1ae/0x510 kernel/locking/lockdep.c:5726
 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline]
 _raw_spin_lock_irqsave+0x3a/0x50 kernel/locking/spinlock.c:162
 prepare_to_wait+0x47/0x380 kernel/sched/wait.c:269
 nr_accept+0x20d/0x650 net/netrom/af_netrom.c:798
 do_accept+0x3a6/0x570 net/socket.c:1872
 __sys_accept4_file net/socket.c:1913 [inline]
 __sys_accept4+0x99/0x120 net/socket.c:1943
 __do_sys_accept4 net/socket.c:1954 [inline]
 __se_sys_accept4 net/socket.c:1951 [inline]
 __x64_sys_accept4+0x96/0x100 net/socket.c:1951
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x38/0xb0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x63/0xcd
RIP: 0033:0x7f51d447cae9
Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 e1 20 00 00 90 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 &lt;48&gt; 3d 01 f0 ff ff 73 01 c3 48 c7 c1 b0 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f51d519a0c8 EFLAGS: 00000246 ORIG_RAX: 0000000000000120
RAX: ffffffffffffffda RBX: 00007f51d459bf80 RCX: 00007f51d447cae9
RDX: 0000000020000400 RSI: 0000000000000000 RDI: 0000000000000004
RBP: 00007f51d44c847a R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000800 R11: 0000000000000246 R12: 0000000000000000
R13: 000000000000000b R14: 00007f51d459bf80 R15: 00007ffc25c34e48
 &lt;/TASK&gt;

Link: https://syzkaller.appspot.com/text?tag=CrashLog&amp;x=152cdb63a80000 [1]
Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Reported-by: syzbot+666c97e4686410e79649@syzkaller.appspotmail.com
Closes: https://syzkaller.appspot.com/bug?extid=666c97e4686410e79649
Signed-off-by: Kuniyuki Iwashima &lt;kuniyu@amazon.com&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
</content>
</entry>
<entry>
<title>sock: Remove -&gt;sendpage*() in favour of sendmsg(MSG_SPLICE_PAGES)</title>
<updated>2023-06-24T22:50:13Z</updated>
<author>
<name>David Howells</name>
<email>dhowells@redhat.com</email>
</author>
<published>2023-06-23T22:55:12Z</published>
<link rel='alternate' type='text/html' href='https://git.shady.money/linux/commit/?id=dc97391e661009eab46783030d2404c9b6e6f2e7'/>
<id>urn:sha1:dc97391e661009eab46783030d2404c9b6e6f2e7</id>
<content type='text'>
Remove -&gt;sendpage() and -&gt;sendpage_locked().  sendmsg() with
MSG_SPLICE_PAGES should be used instead.  This allows multiple pages and
multipage folios to be passed through.

Signed-off-by: David Howells &lt;dhowells@redhat.com&gt;
Acked-by: Marc Kleine-Budde &lt;mkl@pengutronix.de&gt; # for net/can
cc: Jens Axboe &lt;axboe@kernel.dk&gt;
cc: Matthew Wilcox &lt;willy@infradead.org&gt;
cc: linux-afs@lists.infradead.org
cc: mptcp@lists.linux.dev
cc: rds-devel@oss.oracle.com
cc: tipc-discussion@lists.sourceforge.net
cc: virtualization@lists.linux-foundation.org
Link: https://lore.kernel.org/r/20230623225513.2732256-16-dhowells@redhat.com
Signed-off-by: Jakub Kicinski &lt;kuba@kernel.org&gt;
</content>
</entry>
<entry>
<title>netrom: fix info-leak in nr_write_internal()</title>
<updated>2023-05-26T04:02:29Z</updated>
<author>
<name>Eric Dumazet</name>
<email>edumazet@google.com</email>
</author>
<published>2023-05-24T14:14:56Z</published>
<link rel='alternate' type='text/html' href='https://git.shady.money/linux/commit/?id=31642e7089df8fd3f54ca7843f7ee2952978cad1'/>
<id>urn:sha1:31642e7089df8fd3f54ca7843f7ee2952978cad1</id>
<content type='text'>
Simon Kapadia reported the following issue:

&lt;quote&gt;

The Online Amateur Radio Community (OARC) has recently been experimenting
with building a nationwide packet network in the UK.
As part of our experimentation, we have been testing out packet on 300bps HF,
and playing with net/rom.  For HF packet at this baud rate you really need
to make sure that your MTU is relatively low; AX.25 suggests a PACLEN of 60,
and a net/rom PACLEN of 40 to go with that.
However the Linux net/rom support didn't work with a low PACLEN;
the mkiss module would truncate packets if you set the PACLEN below about 200 or so, e.g.:

Apr 19 14:00:51 radio kernel: [12985.747310] mkiss: ax1: truncating oversized transmit packet!

This didn't make any sense to me (if the packets are smaller why would they
be truncated?) so I started investigating.
I looked at the packets using ethereal, and found that many were just huge
compared to what I would expect.
A simple net/rom connection request packet had the request and then a bunch
of what appeared to be random data following it:

&lt;/quote&gt;

Simon provided a patch that I slightly revised:
Not only we must not use skb_tailroom(), we also do
not want to count NR_NETWORK_LEN twice.

Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Co-Developed-by: Simon Kapadia &lt;szymon@kapadia.pl&gt;
Signed-off-by: Simon Kapadia &lt;szymon@kapadia.pl&gt;
Signed-off-by: Eric Dumazet &lt;edumazet@google.com&gt;
Tested-by: Simon Kapadia &lt;szymon@kapadia.pl&gt;
Reviewed-by: Simon Horman &lt;simon.horman@corigine.com&gt;
Link: https://lore.kernel.org/r/20230524141456.1045467-1-edumazet@google.com
Signed-off-by: Jakub Kicinski &lt;kuba@kernel.org&gt;
</content>
</entry>
<entry>
<title>netrom: Fix use-after-free caused by accept on already connected socket</title>
<updated>2023-01-30T07:30:47Z</updated>
<author>
<name>Hyunwoo Kim</name>
<email>v4bel@theori.io</email>
</author>
<published>2023-01-27T02:32:50Z</published>
<link rel='alternate' type='text/html' href='https://git.shady.money/linux/commit/?id=611792920925fb088ddccbe2783c7f92fdfb6b64'/>
<id>urn:sha1:611792920925fb088ddccbe2783c7f92fdfb6b64</id>
<content type='text'>
If you call listen() and accept() on an already connect()ed
AF_NETROM socket, accept() can successfully connect.
This is because when the peer socket sends data to sendmsg,
the skb with its own sk stored in the connected socket's
sk-&gt;sk_receive_queue is connected, and nr_accept() dequeues
the skb waiting in the sk-&gt;sk_receive_queue.

As a result, nr_accept() allocates and returns a sock with
the sk of the parent AF_NETROM socket.

And here use-after-free can happen through complex race conditions:
```
                  cpu0                                                     cpu1
                                                               1. socket_2 = socket(AF_NETROM)
                                                                        .
                                                                        .
                                                                  listen(socket_2)
                                                                  accepted_socket = accept(socket_2)
       2. socket_1 = socket(AF_NETROM)
            nr_create()    // sk refcount : 1
          connect(socket_1)
                                                               3. write(accepted_socket)
                                                                    nr_sendmsg()
                                                                    nr_output()
                                                                    nr_kick()
                                                                    nr_send_iframe()
                                                                    nr_transmit_buffer()
                                                                    nr_route_frame()
                                                                    nr_loopback_queue()
                                                                    nr_loopback_timer()
                                                                    nr_rx_frame()
                                                                    nr_process_rx_frame(sk, skb);    // sk : socket_1's sk
                                                                    nr_state3_machine()
                                                                    nr_queue_rx_frame()
                                                                    sock_queue_rcv_skb()
                                                                    sock_queue_rcv_skb_reason()
                                                                    __sock_queue_rcv_skb()
                                                                    __skb_queue_tail(list, skb);    // list : socket_1's sk-&gt;sk_receive_queue
       4. listen(socket_1)
            nr_listen()
          uaf_socket = accept(socket_1)
            nr_accept()
            skb_dequeue(&amp;sk-&gt;sk_receive_queue);
                                                               5. close(accepted_socket)
                                                                    nr_release()
                                                                    nr_write_internal(sk, NR_DISCREQ)
                                                                    nr_transmit_buffer()    // NR_DISCREQ
                                                                    nr_route_frame()
                                                                    nr_loopback_queue()
                                                                    nr_loopback_timer()
                                                                    nr_rx_frame()    // sk : socket_1's sk
                                                                    nr_process_rx_frame()  // NR_STATE_3
                                                                    nr_state3_machine()    // NR_DISCREQ
                                                                    nr_disconnect()
                                                                    nr_sk(sk)-&gt;state = NR_STATE_0;
       6. close(socket_1)    // sk refcount : 3
            nr_release()    // NR_STATE_0
            sock_put(sk);    // sk refcount : 0
            sk_free(sk);
          close(uaf_socket)
            nr_release()
            sock_hold(sk);    // UAF
```

KASAN report by syzbot:
```
BUG: KASAN: use-after-free in nr_release+0x66/0x460 net/netrom/af_netrom.c:520
Write of size 4 at addr ffff8880235d8080 by task syz-executor564/5128

Call Trace:
 &lt;TASK&gt;
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0xd1/0x138 lib/dump_stack.c:106
 print_address_description mm/kasan/report.c:306 [inline]
 print_report+0x15e/0x461 mm/kasan/report.c:417
 kasan_report+0xbf/0x1f0 mm/kasan/report.c:517
 check_region_inline mm/kasan/generic.c:183 [inline]
 kasan_check_range+0x141/0x190 mm/kasan/generic.c:189
 instrument_atomic_read_write include/linux/instrumented.h:102 [inline]
 atomic_fetch_add_relaxed include/linux/atomic/atomic-instrumented.h:116 [inline]
 __refcount_add include/linux/refcount.h:193 [inline]
 __refcount_inc include/linux/refcount.h:250 [inline]
 refcount_inc include/linux/refcount.h:267 [inline]
 sock_hold include/net/sock.h:775 [inline]
 nr_release+0x66/0x460 net/netrom/af_netrom.c:520
 __sock_release+0xcd/0x280 net/socket.c:650
 sock_close+0x1c/0x20 net/socket.c:1365
 __fput+0x27c/0xa90 fs/file_table.c:320
 task_work_run+0x16f/0x270 kernel/task_work.c:179
 exit_task_work include/linux/task_work.h:38 [inline]
 do_exit+0xaa8/0x2950 kernel/exit.c:867
 do_group_exit+0xd4/0x2a0 kernel/exit.c:1012
 get_signal+0x21c3/0x2450 kernel/signal.c:2859
 arch_do_signal_or_restart+0x79/0x5c0 arch/x86/kernel/signal.c:306
 exit_to_user_mode_loop kernel/entry/common.c:168 [inline]
 exit_to_user_mode_prepare+0x15f/0x250 kernel/entry/common.c:203
 __syscall_exit_to_user_mode_work kernel/entry/common.c:285 [inline]
 syscall_exit_to_user_mode+0x1d/0x50 kernel/entry/common.c:296
 do_syscall_64+0x46/0xb0 arch/x86/entry/common.c:86
 entry_SYSCALL_64_after_hwframe+0x63/0xcd
RIP: 0033:0x7f6c19e3c9b9
Code: Unable to access opcode bytes at 0x7f6c19e3c98f.
RSP: 002b:00007fffd4ba2ce8 EFLAGS: 00000246 ORIG_RAX: 0000000000000133
RAX: 0000000000000116 RBX: 0000000000000003 RCX: 00007f6c19e3c9b9
RDX: 0000000000000318 RSI: 00000000200bd000 RDI: 0000000000000006
RBP: 0000000000000003 R08: 000000000000000d R09: 000000000000000d
R10: 0000000000000000 R11: 0000000000000246 R12: 000055555566a2c0
R13: 0000000000000011 R14: 0000000000000000 R15: 0000000000000000
 &lt;/TASK&gt;

Allocated by task 5128:
 kasan_save_stack+0x22/0x40 mm/kasan/common.c:45
 kasan_set_track+0x25/0x30 mm/kasan/common.c:52
 ____kasan_kmalloc mm/kasan/common.c:371 [inline]
 ____kasan_kmalloc mm/kasan/common.c:330 [inline]
 __kasan_kmalloc+0xa3/0xb0 mm/kasan/common.c:380
 kasan_kmalloc include/linux/kasan.h:211 [inline]
 __do_kmalloc_node mm/slab_common.c:968 [inline]
 __kmalloc+0x5a/0xd0 mm/slab_common.c:981
 kmalloc include/linux/slab.h:584 [inline]
 sk_prot_alloc+0x140/0x290 net/core/sock.c:2038
 sk_alloc+0x3a/0x7a0 net/core/sock.c:2091
 nr_create+0xb6/0x5f0 net/netrom/af_netrom.c:433
 __sock_create+0x359/0x790 net/socket.c:1515
 sock_create net/socket.c:1566 [inline]
 __sys_socket_create net/socket.c:1603 [inline]
 __sys_socket_create net/socket.c:1588 [inline]
 __sys_socket+0x133/0x250 net/socket.c:1636
 __do_sys_socket net/socket.c:1649 [inline]
 __se_sys_socket net/socket.c:1647 [inline]
 __x64_sys_socket+0x73/0xb0 net/socket.c:1647
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x39/0xb0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x63/0xcd

Freed by task 5128:
 kasan_save_stack+0x22/0x40 mm/kasan/common.c:45
 kasan_set_track+0x25/0x30 mm/kasan/common.c:52
 kasan_save_free_info+0x2b/0x40 mm/kasan/generic.c:518
 ____kasan_slab_free mm/kasan/common.c:236 [inline]
 ____kasan_slab_free+0x13b/0x1a0 mm/kasan/common.c:200
 kasan_slab_free include/linux/kasan.h:177 [inline]
 __cache_free mm/slab.c:3394 [inline]
 __do_kmem_cache_free mm/slab.c:3580 [inline]
 __kmem_cache_free+0xcd/0x3b0 mm/slab.c:3587
 sk_prot_free net/core/sock.c:2074 [inline]
 __sk_destruct+0x5df/0x750 net/core/sock.c:2166
 sk_destruct net/core/sock.c:2181 [inline]
 __sk_free+0x175/0x460 net/core/sock.c:2192
 sk_free+0x7c/0xa0 net/core/sock.c:2203
 sock_put include/net/sock.h:1991 [inline]
 nr_release+0x39e/0x460 net/netrom/af_netrom.c:554
 __sock_release+0xcd/0x280 net/socket.c:650
 sock_close+0x1c/0x20 net/socket.c:1365
 __fput+0x27c/0xa90 fs/file_table.c:320
 task_work_run+0x16f/0x270 kernel/task_work.c:179
 exit_task_work include/linux/task_work.h:38 [inline]
 do_exit+0xaa8/0x2950 kernel/exit.c:867
 do_group_exit+0xd4/0x2a0 kernel/exit.c:1012
 get_signal+0x21c3/0x2450 kernel/signal.c:2859
 arch_do_signal_or_restart+0x79/0x5c0 arch/x86/kernel/signal.c:306
 exit_to_user_mode_loop kernel/entry/common.c:168 [inline]
 exit_to_user_mode_prepare+0x15f/0x250 kernel/entry/common.c:203
 __syscall_exit_to_user_mode_work kernel/entry/common.c:285 [inline]
 syscall_exit_to_user_mode+0x1d/0x50 kernel/entry/common.c:296
 do_syscall_64+0x46/0xb0 arch/x86/entry/common.c:86
 entry_SYSCALL_64_after_hwframe+0x63/0xcd
```

To fix this issue, nr_listen() returns -EINVAL for sockets that
successfully nr_connect().

Reported-by: syzbot+caa188bdfc1eeafeb418@syzkaller.appspotmail.com
Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Signed-off-by: Hyunwoo Kim &lt;v4bel@theori.io&gt;
Reviewed-by: Kuniyuki Iwashima &lt;kuniyu@amazon.com&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
</content>
</entry>
<entry>
<title>netrom: Fix use-after-free of a listening socket.</title>
<updated>2023-01-24T10:54:01Z</updated>
<author>
<name>Kuniyuki Iwashima</name>
<email>kuniyu@amazon.com</email>
</author>
<published>2023-01-20T23:19:27Z</published>
<link rel='alternate' type='text/html' href='https://git.shady.money/linux/commit/?id=409db27e3a2eb5e8ef7226ca33be33361b3ed1c9'/>
<id>urn:sha1:409db27e3a2eb5e8ef7226ca33be33361b3ed1c9</id>
<content type='text'>
syzbot reported a use-after-free in do_accept(), precisely nr_accept()
as sk_prot_alloc() allocated the memory and sock_put() frees it. [0]

The issue could happen if the heartbeat timer is fired and
nr_heartbeat_expiry() calls nr_destroy_socket(), where a socket
has SOCK_DESTROY or a listening socket has SOCK_DEAD.

In this case, the first condition cannot be true.  SOCK_DESTROY is
flagged in nr_release() only when the file descriptor is close()d,
but accept() is being called for the listening socket, so the second
condition must be true.

Usually, the AF_NETROM listener neither starts timers nor sets
SOCK_DEAD.  However, the condition is met if connect() fails before
listen().  connect() starts the t1 timer and heartbeat timer, and
t1timer calls nr_disconnect() when timeout happens.  Then, SOCK_DEAD
is set, and if we call listen(), the heartbeat timer calls
nr_destroy_socket().

  nr_connect
    nr_establish_data_link(sk)
      nr_start_t1timer(sk)
    nr_start_heartbeat(sk)
                                    nr_t1timer_expiry
                                      nr_disconnect(sk, ETIMEDOUT)
                                        nr_sk(sk)-&gt;state = NR_STATE_0
                                        sk-&gt;sk_state = TCP_CLOSE
                                        sock_set_flag(sk, SOCK_DEAD)
nr_listen
  if (sk-&gt;sk_state != TCP_LISTEN)
    sk-&gt;sk_state = TCP_LISTEN
                                    nr_heartbeat_expiry
                                      switch (nr-&gt;state)
                                      case NR_STATE_0
                                        if (sk-&gt;sk_state == TCP_LISTEN &amp;&amp;
                                            sock_flag(sk, SOCK_DEAD))
                                          nr_destroy_socket(sk)

This path seems expected, and nr_destroy_socket() is called to clean
up resources.  Initially, there was sock_hold() before nr_destroy_socket()
so that the socket would not be freed, but the commit 517a16b1a88b
("netrom: Decrease sock refcount when sock timers expire") accidentally
removed it.

To fix use-after-free, let's add sock_hold().

[0]:
BUG: KASAN: use-after-free in do_accept+0x483/0x510 net/socket.c:1848
Read of size 8 at addr ffff88807978d398 by task syz-executor.3/5315

CPU: 0 PID: 5315 Comm: syz-executor.3 Not tainted 6.2.0-rc3-syzkaller-00165-gd9fc1511728c #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/26/2022
Call Trace:
 &lt;TASK&gt;
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0xd1/0x138 lib/dump_stack.c:106
 print_address_description mm/kasan/report.c:306 [inline]
 print_report+0x15e/0x461 mm/kasan/report.c:417
 kasan_report+0xbf/0x1f0 mm/kasan/report.c:517
 do_accept+0x483/0x510 net/socket.c:1848
 __sys_accept4_file net/socket.c:1897 [inline]
 __sys_accept4+0x9a/0x120 net/socket.c:1927
 __do_sys_accept net/socket.c:1944 [inline]
 __se_sys_accept net/socket.c:1941 [inline]
 __x64_sys_accept+0x75/0xb0 net/socket.c:1941
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x39/0xb0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x63/0xcd
RIP: 0033:0x7fa436a8c0c9
Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 f1 19 00 00 90 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 &lt;48&gt; 3d 01 f0 ff ff 73 01 c3 48 c7 c1 b8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007fa437784168 EFLAGS: 00000246 ORIG_RAX: 000000000000002b
RAX: ffffffffffffffda RBX: 00007fa436bac050 RCX: 00007fa436a8c0c9
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000005
RBP: 00007fa436ae7ae9 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007ffebc6700df R14: 00007fa437784300 R15: 0000000000022000
 &lt;/TASK&gt;

Allocated by task 5294:
 kasan_save_stack+0x22/0x40 mm/kasan/common.c:45
 kasan_set_track+0x25/0x30 mm/kasan/common.c:52
 ____kasan_kmalloc mm/kasan/common.c:371 [inline]
 ____kasan_kmalloc mm/kasan/common.c:330 [inline]
 __kasan_kmalloc+0xa3/0xb0 mm/kasan/common.c:380
 kasan_kmalloc include/linux/kasan.h:211 [inline]
 __do_kmalloc_node mm/slab_common.c:968 [inline]
 __kmalloc+0x5a/0xd0 mm/slab_common.c:981
 kmalloc include/linux/slab.h:584 [inline]
 sk_prot_alloc+0x140/0x290 net/core/sock.c:2038
 sk_alloc+0x3a/0x7a0 net/core/sock.c:2091
 nr_create+0xb6/0x5f0 net/netrom/af_netrom.c:433
 __sock_create+0x359/0x790 net/socket.c:1515
 sock_create net/socket.c:1566 [inline]
 __sys_socket_create net/socket.c:1603 [inline]
 __sys_socket_create net/socket.c:1588 [inline]
 __sys_socket+0x133/0x250 net/socket.c:1636
 __do_sys_socket net/socket.c:1649 [inline]
 __se_sys_socket net/socket.c:1647 [inline]
 __x64_sys_socket+0x73/0xb0 net/socket.c:1647
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x39/0xb0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x63/0xcd

Freed by task 14:
 kasan_save_stack+0x22/0x40 mm/kasan/common.c:45
 kasan_set_track+0x25/0x30 mm/kasan/common.c:52
 kasan_save_free_info+0x2b/0x40 mm/kasan/generic.c:518
 ____kasan_slab_free mm/kasan/common.c:236 [inline]
 ____kasan_slab_free+0x13b/0x1a0 mm/kasan/common.c:200
 kasan_slab_free include/linux/kasan.h:177 [inline]
 __cache_free mm/slab.c:3394 [inline]
 __do_kmem_cache_free mm/slab.c:3580 [inline]
 __kmem_cache_free+0xcd/0x3b0 mm/slab.c:3587
 sk_prot_free net/core/sock.c:2074 [inline]
 __sk_destruct+0x5df/0x750 net/core/sock.c:2166
 sk_destruct net/core/sock.c:2181 [inline]
 __sk_free+0x175/0x460 net/core/sock.c:2192
 sk_free+0x7c/0xa0 net/core/sock.c:2203
 sock_put include/net/sock.h:1991 [inline]
 nr_heartbeat_expiry+0x1d7/0x460 net/netrom/nr_timer.c:148
 call_timer_fn+0x1da/0x7c0 kernel/time/timer.c:1700
 expire_timers+0x2c6/0x5c0 kernel/time/timer.c:1751
 __run_timers kernel/time/timer.c:2022 [inline]
 __run_timers kernel/time/timer.c:1995 [inline]
 run_timer_softirq+0x326/0x910 kernel/time/timer.c:2035
 __do_softirq+0x1fb/0xadc kernel/softirq.c:571

Fixes: 517a16b1a88b ("netrom: Decrease sock refcount when sock timers expire")
Reported-by: syzbot+5fafd5cfe1fc91f6b352@syzkaller.appspotmail.com
Signed-off-by: Kuniyuki Iwashima &lt;kuniyu@amazon.com&gt;
Link: https://lore.kernel.org/r/20230120231927.51711-1-kuniyu@amazon.com
Signed-off-by: Paolo Abeni &lt;pabeni@redhat.com&gt;
</content>
</entry>
<entry>
<title>net: remove noblock parameter from skb_recv_datagram()</title>
<updated>2022-04-06T12:45:26Z</updated>
<author>
<name>Oliver Hartkopp</name>
<email>socketcan@hartkopp.net</email>
</author>
<published>2022-04-04T16:30:22Z</published>
<link rel='alternate' type='text/html' href='https://git.shady.money/linux/commit/?id=f4b41f062c424209e3939a81e6da022e049a45f2'/>
<id>urn:sha1:f4b41f062c424209e3939a81e6da022e049a45f2</id>
<content type='text'>
skb_recv_datagram() has two parameters 'flags' and 'noblock' that are
merged inside skb_recv_datagram() by 'flags | (noblock ? MSG_DONTWAIT : 0)'

As 'flags' may contain MSG_DONTWAIT as value most callers split the 'flags'
into 'flags' and 'noblock' with finally obsolete bit operations like this:

skb_recv_datagram(sk, flags &amp; ~MSG_DONTWAIT, flags &amp; MSG_DONTWAIT, &amp;rc);

And this is not even done consistently with the 'flags' parameter.

This patch removes the obsolete and costly splitting into two parameters
and only performs bit operations when really needed on the caller side.

One missing conversion thankfully reported by kernel test robot. I missed
to enable kunit tests to build the mctp code.

Reported-by: kernel test robot &lt;lkp@intel.com&gt;
Signed-off-by: Oliver Hartkopp &lt;socketcan@hartkopp.net&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
</content>
</entry>
<entry>
<title>netrom: fix api breakage in nr_setsockopt()</title>
<updated>2022-01-07T14:11:05Z</updated>
<author>
<name>Dan Carpenter</name>
<email>dan.carpenter@oracle.com</email>
</author>
<published>2022-01-07T07:12:10Z</published>
<link rel='alternate' type='text/html' href='https://git.shady.money/linux/commit/?id=dc35616e6c2907b0c0c391a205802d8880f7fd85'/>
<id>urn:sha1:dc35616e6c2907b0c0c391a205802d8880f7fd85</id>
<content type='text'>
This needs to copy an unsigned int from user space instead of a long to
avoid breaking user space with an API change.

I have updated all the integer overflow checks from ULONG to UINT as
well.  This is a slight API change but I do not expect it to affect
anything in real life.

Fixes: 3087a6f36ee0 ("netrom: fix copying in user data in nr_setsockopt")
Signed-off-by: Dan Carpenter &lt;dan.carpenter@oracle.com&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
</content>
</entry>
<entry>
<title>netrom: fix copying in user data in nr_setsockopt</title>
<updated>2022-01-04T12:36:01Z</updated>
<author>
<name>Christoph Hellwig</name>
<email>hch@lst.de</email>
</author>
<published>2022-01-04T09:21:26Z</published>
<link rel='alternate' type='text/html' href='https://git.shady.money/linux/commit/?id=3087a6f36ee028ec095c04a8531d7d33899b7fed'/>
<id>urn:sha1:3087a6f36ee028ec095c04a8531d7d33899b7fed</id>
<content type='text'>
This code used to copy in an unsigned long worth of data before
the sockptr_t conversion, so restore that.

Fixes: a7b75c5a8c41 ("net: pass a sockptr_t into -&gt;setsockopt")
Reported-by: Dan Carpenter &lt;dan.carpenter@oracle.com&gt;
Signed-off-by: Christoph Hellwig &lt;hch@lst.de&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
</content>
</entry>
<entry>
<title>ax25: constify dev_addr passing</title>
<updated>2021-10-13T16:40:45Z</updated>
<author>
<name>Jakub Kicinski</name>
<email>kuba@kernel.org</email>
</author>
<published>2021-10-12T15:58:35Z</published>
<link rel='alternate' type='text/html' href='https://git.shady.money/linux/commit/?id=c045ad2cc01e473b98771379eb58fe13560b7f70'/>
<id>urn:sha1:c045ad2cc01e473b98771379eb58fe13560b7f70</id>
<content type='text'>
In preparation for netdev-&gt;dev_addr being constant
make all relevant arguments in AX25 constant.

Modify callers as well (netrom, rose).

Signed-off-by: Jakub Kicinski &lt;kuba@kernel.org&gt;
</content>
</entry>
</feed>
