Commit Graph

14 Commits

Author SHA1 Message Date
Kuniyuki Iwashima 409db27e3a netrom: Fix use-after-free of a listening socket.
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)->state = NR_STATE_0
                                        sk->sk_state = TCP_CLOSE
                                        sock_set_flag(sk, SOCK_DEAD)
nr_listen
  if (sk->sk_state != TCP_LISTEN)
    sk->sk_state = TCP_LISTEN
                                    nr_heartbeat_expiry
                                      switch (nr->state)
                                      case NR_STATE_0
                                        if (sk->sk_state == TCP_LISTEN &&
                                            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 517a16b1a8
("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:
 <TASK>
 __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 <48> 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
 </TASK>

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: 517a16b1a8 ("netrom: Decrease sock refcount when sock timers expire")
Reported-by: syzbot+5fafd5cfe1fc91f6b352@syzkaller.appspotmail.com
Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Link: https://lore.kernel.org/r/20230120231927.51711-1-kuniyu@amazon.com
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
2023-01-24 11:54:01 +01:00
Nguyen Dinh Phi 517a16b1a8 netrom: Decrease sock refcount when sock timers expire
Commit 63346650c1 ("netrom: switch to sock timer API") switched to use
sock timer API. It replaces mod_timer() by sk_reset_timer(), and
del_timer() by sk_stop_timer().

Function sk_reset_timer() will increase the refcount of sock if it is
called on an inactive timer, hence, in case the timer expires, we need to
decrease the refcount ourselves in the handler, otherwise, the sock
refcount will be unbalanced and the sock will never be freed.

Signed-off-by: Nguyen Dinh Phi <phind.uet@gmail.com>
Reported-by: syzbot+10f1194569953b72f1ae@syzkaller.appspotmail.com
Fixes: 63346650c1 ("netrom: switch to sock timer API")
Signed-off-by: David S. Miller <davem@davemloft.net>
2021-07-18 09:48:59 -07:00
Thomas Gleixner 2874c5fd28 treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 152
Based on 1 normalized pattern(s):

  this program is free software you can redistribute it and or modify
  it under the terms of the gnu general public license as published by
  the free software foundation either version 2 of the license or at
  your option any later version

extracted by the scancode license scanner the SPDX license identifier

  GPL-2.0-or-later

has been chosen to replace the boilerplate/reference in 3029 file(s).

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Allison Randal <allison@lohutok.net>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190527070032.746973796@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-05-30 11:26:32 -07:00
Cong Wang 63346650c1 netrom: switch to sock timer API
sk_reset_timer() and sk_stop_timer() properly handle
sock refcnt for timer function. Switching to them
could fix a refcounting bug reported by syzbot.

Reported-and-tested-by: syzbot+defa700d16f1bd1b9a05@syzkaller.appspotmail.com
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: linux-hams@vger.kernel.org
Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2019-01-27 10:38:04 -08:00
Kees Cook 841b86f328 treewide: Remove TIMER_FUNC_TYPE and TIMER_DATA_TYPE casts
With all callbacks converted, and the timer callback prototype
switched over, the TIMER_FUNC_TYPE cast is no longer needed,
so remove it. Conversion was done with the following scripts:

    perl -pi -e 's|\(TIMER_FUNC_TYPE\)||g' \
        $(git grep TIMER_FUNC_TYPE | cut -d: -f1 | sort -u)

    perl -pi -e 's|\(TIMER_DATA_TYPE\)||g' \
        $(git grep TIMER_DATA_TYPE | cut -d: -f1 | sort -u)

The now unused macros are also dropped from include/linux/timer.h.

Signed-off-by: Kees Cook <keescook@chromium.org>
2017-11-21 16:35:54 -08:00
Kees Cook 99767f278c net/core: Convert sk_timer users to use timer_setup()
In preparation for unconditionally passing the struct timer_list pointer to
all timer callbacks, switch to using the new timer_setup() and from_timer()
to pass the timer pointer explicitly for all users of sk_timer.

Cc: "David S. Miller" <davem@davemloft.net>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Andrew Hendry <andrew.hendry@gmail.com>
Cc: Eric Dumazet <edumazet@google.com>
Cc: Paolo Abeni <pabeni@redhat.com>
Cc: David Howells <dhowells@redhat.com>
Cc: Julia Lawall <julia.lawall@lip6.fr>
Cc: linzhang <xiaolou4617@gmail.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: netdev@vger.kernel.org
Cc: linux-hams@vger.kernel.org
Cc: linux-x25@vger.kernel.org
Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
2017-10-18 12:40:27 +01:00
Kees Cook 9f12a77e46 net/core: Collapse redundant sk_timer callback data assignments
The core sk_timer initializer can provide the common .data assignment
instead of it being set separately in users.

Cc: "David S. Miller" <davem@davemloft.net>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Andrew Hendry <andrew.hendry@gmail.com>
Cc: Eric Dumazet <edumazet@google.com>
Cc: Paolo Abeni <pabeni@redhat.com>
Cc: David Howells <dhowells@redhat.com>
Cc: Colin Ian King <colin.king@canonical.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: linzhang <xiaolou4617@gmail.com>
Cc: netdev@vger.kernel.org
Cc: linux-hams@vger.kernel.org
Cc: linux-x25@vger.kernel.org
Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
2017-10-18 12:39:55 +01:00
Fabian Frederick dc8e54165f netrom: use linux/uaccess.h
replace asm/uaccess.h by linux/uaccess.h

Signed-off-by: Fabian Frederick <fabf@skynet.be>
Signed-off-by: David S. Miller <davem@davemloft.net>
2014-10-17 23:52:54 -04:00
David Howells 9ffc93f203 Remove all #inclusions of asm/system.h
Remove all #inclusions of asm/system.h preparatory to splitting and killing
it.  Performed with the following command:

perl -p -i -e 's!^#\s*include\s*<asm/system[.]h>.*\n!!' `grep -Irl '^#\s*include\s*<asm/system[.]h>' *`

Signed-off-by: David Howells <dhowells@redhat.com>
2012-03-28 18:30:03 +01:00
Pavel Emelyanov b24b8a247f [NET]: Convert init_timer into setup_timer
Many-many code in the kernel initialized the timer->function
and  timer->data together with calling init_timer(timer). There
is already a helper for this. Use it for networking code.

The patch is HUGE, but makes the code 130 lines shorter
(98 insertions(+), 228 deletions(-)).

Signed-off-by: Pavel Emelyanov <xemul@openvz.org>
Acked-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2008-01-28 14:53:35 -08:00
YOSHIFUJI Hideaki 5f8f59d664 [NET] NETROM: Fix whitespace errors.
Signed-off-by: YOSHIFUJI Hideaki <yoshfuji@linux-ipv6.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
2007-02-10 23:20:00 -08:00
Ralf Baechle 8bf2b7b188 [NETROM]: Drop lock before calling nr_destroy_socket
nr_destroy_socket takes the socket lock itself so it should better be
called with the socket unlocked.

Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
2006-07-12 13:58:45 -07:00
Arnaldo Carvalho de Melo c752f0739f [TCP]: Move the tcp sock states to net/tcp_states.h
Lots of places just needs the states, not even linux/tcp.h, where this
enum was, needs it.

This speeds up development of the refactorings as less sources are
rebuilt when things get moved from net/tcp.h.

Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
2005-08-29 15:41:54 -07:00
Linus Torvalds 1da177e4c3 Linux-2.6.12-rc2
Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.

Let it rip!
2005-04-16 15:20:36 -07:00