Move this API to the canonical timer_*() namespace.
[ tglx: Redone against pre rc1 ]
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/all/aB2X0jCKQO56WdMt@gmail.com
timer_delete[_sync]() replaces del_timer[_sync](). Convert the whole tree
over and remove the historical wrapper inlines.
Conversion was done with coccinelle plus manual fixups where necessary.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Binding AX25 socket by using the autobind feature leads to memory leaks
in ax25_connect() and also refcount leaks in ax25_release(). Memory
leak was detected with kmemleak:
================================================================
unreferenced object 0xffff8880253cd680 (size 96):
backtrace:
__kmalloc_node_track_caller_noprof (./include/linux/kmemleak.h:43)
kmemdup_noprof (mm/util.c:136)
ax25_rt_autobind (net/ax25/ax25_route.c:428)
ax25_connect (net/ax25/af_ax25.c:1282)
__sys_connect_file (net/socket.c:2045)
__sys_connect (net/socket.c:2064)
__x64_sys_connect (net/socket.c:2067)
do_syscall_64 (arch/x86/entry/common.c:52 arch/x86/entry/common.c:83)
entry_SYSCALL_64_after_hwframe (arch/x86/entry/entry_64.S:130)
================================================================
When socket is bound, refcounts must be incremented the way it is done
in ax25_bind() and ax25_setsockopt() (SO_BINDTODEVICE). In case of
autobind, the refcounts are not incremented.
This bug leads to the following issue reported by Syzkaller:
================================================================
ax25_connect(): syz-executor318 uses autobind, please contact jreuter@yaina.de
------------[ cut here ]------------
refcount_t: decrement hit 0; leaking memory.
WARNING: CPU: 0 PID: 5317 at lib/refcount.c:31 refcount_warn_saturate+0xfa/0x1d0 lib/refcount.c:31
Modules linked in:
CPU: 0 UID: 0 PID: 5317 Comm: syz-executor318 Not tainted 6.14.0-rc4-syzkaller-00278-gece144f151ac #0
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2~bpo12+1 04/01/2014
RIP: 0010:refcount_warn_saturate+0xfa/0x1d0 lib/refcount.c:31
...
Call Trace:
<TASK>
__refcount_dec include/linux/refcount.h:336 [inline]
refcount_dec include/linux/refcount.h:351 [inline]
ref_tracker_free+0x6af/0x7e0 lib/ref_tracker.c:236
netdev_tracker_free include/linux/netdevice.h:4302 [inline]
netdev_put include/linux/netdevice.h:4319 [inline]
ax25_release+0x368/0x960 net/ax25/af_ax25.c:1080
__sock_release net/socket.c:647 [inline]
sock_close+0xbc/0x240 net/socket.c:1398
__fput+0x3e9/0x9f0 fs/file_table.c:464
__do_sys_close fs/open.c:1580 [inline]
__se_sys_close fs/open.c:1565 [inline]
__x64_sys_close+0x7f/0x110 fs/open.c:1565
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x77/0x7f
...
</TASK>
================================================================
Considering the issues above and the comments left in the code that say:
"check if we can remove this feature. It is broken."; "autobinding in this
may or may not work"; - it is better to completely remove this feature than
to fix it because it is broken and leads to various kinds of memory bugs.
Now calling connect() without first binding socket will result in an
error (-EINVAL). Userspace software that relies on the autobind feature
might get broken. However, this feature does not seem widely used with
this specific driver as it was not reliable at any point of time, and it
is already broken anyway. E.g. ax25-tools and ax25-apps packages for
popular distributions do not use the autobind feature for AF_AX25.
Found by Linux Verification Center (linuxtesting.org) with Syzkaller.
Fixes: 1da177e4c3 ("Linux-2.6.12-rc2")
Reported-by: syzbot+33841dc6aa3e1d86b78a@syzkaller.appspotmail.com
Closes: https://syzkaller.appspot.com/bug?extid=33841dc6aa3e1d86b78a
Signed-off-by: Murad Masimov <m.masimov@mt-integration.ru>
Signed-off-by: David S. Miller <davem@davemloft.net>
If an AX25 device is bound to a socket by setting the SO_BINDTODEVICE
socket option, a refcount leak will occur in ax25_release().
Commit 9fd75b66b8 ("ax25: Fix refcount leaks caused by ax25_cb_del()")
added decrement of device refcounts in ax25_release(). In order for that
to work correctly the refcounts must already be incremented when the
device is bound to the socket. An AX25 device can be bound to a socket
by either calling ax25_bind() or setting SO_BINDTODEVICE socket option.
In both cases the refcounts should be incremented, but in fact it is done
only in ax25_bind().
This bug leads to the following issue reported by Syzkaller:
================================================================
refcount_t: decrement hit 0; leaking memory.
WARNING: CPU: 1 PID: 5932 at lib/refcount.c:31 refcount_warn_saturate+0x1ed/0x210 lib/refcount.c:31
Modules linked in:
CPU: 1 UID: 0 PID: 5932 Comm: syz-executor424 Not tainted 6.13.0-rc4-syzkaller-00110-g4099a71718b0 #0
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2~bpo12+1 04/01/2014
RIP: 0010:refcount_warn_saturate+0x1ed/0x210 lib/refcount.c:31
Call Trace:
<TASK>
__refcount_dec include/linux/refcount.h:336 [inline]
refcount_dec include/linux/refcount.h:351 [inline]
ref_tracker_free+0x710/0x820 lib/ref_tracker.c:236
netdev_tracker_free include/linux/netdevice.h:4156 [inline]
netdev_put include/linux/netdevice.h:4173 [inline]
netdev_put include/linux/netdevice.h:4169 [inline]
ax25_release+0x33f/0xa10 net/ax25/af_ax25.c:1069
__sock_release+0xb0/0x270 net/socket.c:640
sock_close+0x1c/0x30 net/socket.c:1408
...
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0xcd/0x250 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x77/0x7f
...
</TASK>
================================================================
Fix the implementation of ax25_setsockopt() by adding increment of
refcounts for the new device bound, and decrement of refcounts for
the old unbound device.
Fixes: 9fd75b66b8 ("ax25: Fix refcount leaks caused by ax25_cb_del()")
Reported-by: syzbot+33841dc6aa3e1d86b78a@syzkaller.appspotmail.com
Signed-off-by: Murad Masimov <m.masimov@mt-integration.ru>
Link: https://patch.msgid.link/20250203091203.1744-1-m.masimov@mt-integration.ru
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
When releasing a socket in ax25_release(), we call netdev_put() to
decrease the refcount on the associated ax.25 device. However, the
execution path for accepting an incoming connection never calls
netdev_hold(). This imbalance leads to refcount errors, and ultimately
to kernel crashes.
A typical call trace for the above situation will start with one of the
following errors:
refcount_t: decrement hit 0; leaking memory.
refcount_t: underflow; use-after-free.
And will then have a trace like:
Call Trace:
<TASK>
? show_regs+0x64/0x70
? __warn+0x83/0x120
? refcount_warn_saturate+0xb2/0x100
? report_bug+0x158/0x190
? prb_read_valid+0x20/0x30
? handle_bug+0x3e/0x70
? exc_invalid_op+0x1c/0x70
? asm_exc_invalid_op+0x1f/0x30
? refcount_warn_saturate+0xb2/0x100
? refcount_warn_saturate+0xb2/0x100
ax25_release+0x2ad/0x360
__sock_release+0x35/0xa0
sock_close+0x19/0x20
[...]
On reboot (or any attempt to remove the interface), the kernel gets
stuck in an infinite loop:
unregister_netdevice: waiting for ax0 to become free. Usage count = 0
This patch corrects these issues by ensuring that we call netdev_hold()
and ax25_dev_hold() for new connections in ax25_accept(). This makes the
logic leading to ax25_accept() match the logic for ax25_bind(): in both
cases we increment the refcount, which is ultimately decremented in
ax25_release().
Fixes: 9fd75b66b8 ("ax25: Fix refcount leaks caused by ax25_cb_del()")
Signed-off-by: Lars Kellogg-Stedman <lars@oddbit.com>
Tested-by: Duoming Zhou <duoming@zju.edu.cn>
Tested-by: Dan Cross <crossd@gmail.com>
Tested-by: Chris Maness <christopher.maness@gmail.com>
Reviewed-by: Dan Carpenter <dan.carpenter@linaro.org>
Link: https://lore.kernel.org/r/20240529210242.3346844-2-lars@oddbit.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
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>
This is a followup of 8bf43be799 ("net: annotate data-races
around sk->sk_priority").
sk->sk_priority can be read and written without holding the socket lock.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: Wenjia Zhang <wenjia@linux.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
The valptr pointer is of (void *) type, so other pointers need not be
forced to assign values to it.
Signed-off-by: Li zeming <zeming@nfschina.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
The skb_recv_datagram() in ax25_recvmsg() will hold lock_sock
and block until it receives a packet from the remote. If the client
doesn`t connect to server and calls read() directly, it will not
receive any packets forever. As a result, the deadlock will happen.
The fail log caused by deadlock is shown below:
[ 369.606973] INFO: task ax25_deadlock:157 blocked for more than 245 seconds.
[ 369.608919] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
[ 369.613058] Call Trace:
[ 369.613315] <TASK>
[ 369.614072] __schedule+0x2f9/0xb20
[ 369.615029] schedule+0x49/0xb0
[ 369.615734] __lock_sock+0x92/0x100
[ 369.616763] ? destroy_sched_domains_rcu+0x20/0x20
[ 369.617941] lock_sock_nested+0x6e/0x70
[ 369.618809] ax25_bind+0xaa/0x210
[ 369.619736] __sys_bind+0xca/0xf0
[ 369.620039] ? do_futex+0xae/0x1b0
[ 369.620387] ? __x64_sys_futex+0x7c/0x1c0
[ 369.620601] ? fpregs_assert_state_consistent+0x19/0x40
[ 369.620613] __x64_sys_bind+0x11/0x20
[ 369.621791] do_syscall_64+0x3b/0x90
[ 369.622423] entry_SYSCALL_64_after_hwframe+0x46/0xb0
[ 369.623319] RIP: 0033:0x7f43c8aa8af7
[ 369.624301] RSP: 002b:00007f43c8197ef8 EFLAGS: 00000246 ORIG_RAX: 0000000000000031
[ 369.625756] RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f43c8aa8af7
[ 369.626724] RDX: 0000000000000010 RSI: 000055768e2021d0 RDI: 0000000000000005
[ 369.628569] RBP: 00007f43c8197f00 R08: 0000000000000011 R09: 00007f43c8198700
[ 369.630208] R10: 0000000000000000 R11: 0000000000000246 R12: 00007fff845e6afe
[ 369.632240] R13: 00007fff845e6aff R14: 00007f43c8197fc0 R15: 00007f43c8198700
This patch replaces skb_recv_datagram() with an open-coded variant of it
releasing the socket lock before the __skb_wait_for_more_packets() call
and re-acquiring it after such call in order that other functions that
need socket lock could be executed.
what's more, the socket lock will be released only when recvmsg() will
block and that should produce nicer overall behavior.
Fixes: 1da177e4c3 ("Linux-2.6.12-rc2")
Suggested-by: Thomas Osterried <thomas@osterried.de>
Signed-off-by: Duoming Zhou <duoming@zju.edu.cn>
Reported-by: Thomas Habets <thomas@@habets.se>
Acked-by: Paolo Abeni <pabeni@redhat.com>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Netdev reference helpers have a dev_ prefix for historic
reasons. Renaming the old helpers would be too much churn
but we can rename the tracking ones which are relatively
recent and should be the default for new code.
Rename:
dev_hold_track() -> netdev_hold()
dev_put_track() -> netdev_put()
dev_replace_track() -> netdev_ref_replace()
Link: https://lore.kernel.org/r/20220608043955.919359-1-kuba@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
There are session cleanup problems in ax25_release() and
ax25_disconnect(). If we setup a session and then disconnect,
the disconnected session is still in "LISTENING" state that
is shown below.
Active AX.25 sockets
Dest Source Device State Vr/Vs Send-Q Recv-Q
DL9SAU-4 DL9SAU-3 ??? LISTENING 000/000 0 0
DL9SAU-3 DL9SAU-4 ??? LISTENING 000/000 0 0
The first reason is caused by del_timer_sync() in ax25_release().
The timers of ax25 are used for correct session cleanup. If we use
ax25_release() to close ax25 sessions and ax25_dev is not null,
the del_timer_sync() functions in ax25_release() will execute.
As a result, the sessions could not be cleaned up correctly,
because the timers have stopped.
In order to solve this problem, this patch adds a device_up flag
in ax25_dev in order to judge whether the device is up. If there
are sessions to be cleaned up, the del_timer_sync() in
ax25_release() will not execute. What's more, we add ax25_cb_del()
in ax25_kill_by_device(), because the timers have been stopped
and there are no functions that could delete ax25_cb if we do not
call ax25_release(). Finally, we reorder the position of
ax25_list_lock in ax25_cb_del() in order to synchronize among
different functions that call ax25_cb_del().
The second reason is caused by improper check in ax25_disconnect().
The incoming ax25 sessions which ax25->sk is null will close
heartbeat timer, because the check "if(!ax25->sk || ..)" is
satisfied. As a result, the session could not be cleaned up properly.
In order to solve this problem, this patch changes the improper
check to "if(ax25->sk && ..)" in ax25_disconnect().
What`s more, the ax25_disconnect() may be called twice, which is
not necessary. For example, ax25_kill_by_device() calls
ax25_disconnect() and sets ax25->state to AX25_STATE_0, but
ax25_release() calls ax25_disconnect() again.
In order to solve this problem, this patch add a check in
ax25_release(). If the flag of ax25->sk equals to SOCK_DEAD,
the ax25_disconnect() in ax25_release() should not be executed.
Fixes: 82e31755e5 ("ax25: Fix UAF bugs in ax25 timers")
Fixes: 8a367e74c0 ("ax25: Fix segfault after sock connection timeout")
Reported-and-tested-by: Thomas Osterried <thomas@osterried.de>
Signed-off-by: Duoming Zhou <duoming@zju.edu.cn>
Link: https://lore.kernel.org/r/20220530152158.108619-1-duoming@zju.edu.cn
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
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 & ~MSG_DONTWAIT, flags & MSG_DONTWAIT, &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 <lkp@intel.com>
Signed-off-by: Oliver Hartkopp <socketcan@hartkopp.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
There are race conditions that may lead to UAF bugs in
ax25_heartbeat_expiry(), ax25_t1timer_expiry(), ax25_t2timer_expiry(),
ax25_t3timer_expiry() and ax25_idletimer_expiry(), when we call
ax25_release() to deallocate ax25_dev.
One of the UAF bugs caused by ax25_release() is shown below:
(Thread 1) | (Thread 2)
ax25_dev_device_up() //(1) |
... | ax25_kill_by_device()
ax25_bind() //(2) |
ax25_connect() | ...
ax25_std_establish_data_link() |
ax25_start_t1timer() | ax25_dev_device_down() //(3)
mod_timer(&ax25->t1timer,..) |
| ax25_release()
(wait a time) | ...
| ax25_dev_put(ax25_dev) //(4)FREE
ax25_t1timer_expiry() |
ax25->ax25_dev->values[..] //USE| ...
... |
We increase the refcount of ax25_dev in position (1) and (2), and
decrease the refcount of ax25_dev in position (3) and (4).
The ax25_dev will be freed in position (4) and be used in
ax25_t1timer_expiry().
The fail log is shown below:
==============================================================
[ 106.116942] BUG: KASAN: use-after-free in ax25_t1timer_expiry+0x1c/0x60
[ 106.116942] Read of size 8 at addr ffff88800bda9028 by task swapper/0/0
[ 106.116942] CPU: 0 PID: 0 Comm: swapper/0 Not tainted 5.17.0-06123-g0905eec574
[ 106.116942] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-14
[ 106.116942] Call Trace:
...
[ 106.116942] ax25_t1timer_expiry+0x1c/0x60
[ 106.116942] call_timer_fn+0x122/0x3d0
[ 106.116942] __run_timers.part.0+0x3f6/0x520
[ 106.116942] run_timer_softirq+0x4f/0xb0
[ 106.116942] __do_softirq+0x1c2/0x651
...
This patch adds del_timer_sync() in ax25_release(), which could ensure
that all timers stop before we deallocate ax25_dev.
Signed-off-by: Duoming Zhou <duoming@zju.edu.cn>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
There are UAF bugs in ax25_send_control(), when we call ax25_release()
to deallocate ax25_dev. The possible race condition is shown below:
(Thread 1) | (Thread 2)
ax25_dev_device_up() //(1) |
| ax25_kill_by_device()
ax25_bind() //(2) |
ax25_connect() | ...
ax25->state = AX25_STATE_1 |
... | ax25_dev_device_down() //(3)
(Thread 3)
ax25_release() |
ax25_dev_put() //(4) FREE |
case AX25_STATE_1: |
ax25_send_control() |
alloc_skb() //USE |
The refcount of ax25_dev increases in position (1) and (2), and
decreases in position (3) and (4). The ax25_dev will be freed
before dereference sites in ax25_send_control().
The following is part of the report:
[ 102.297448] BUG: KASAN: use-after-free in ax25_send_control+0x33/0x210
[ 102.297448] Read of size 8 at addr ffff888009e6e408 by task ax25_close/602
[ 102.297448] Call Trace:
[ 102.303751] ax25_send_control+0x33/0x210
[ 102.303751] ax25_release+0x356/0x450
[ 102.305431] __sock_release+0x6d/0x120
[ 102.305431] sock_close+0xf/0x20
[ 102.305431] __fput+0x11f/0x420
[ 102.305431] task_work_run+0x86/0xd0
[ 102.307130] get_signal+0x1075/0x1220
[ 102.308253] arch_do_signal_or_restart+0x1df/0xc00
[ 102.308253] exit_to_user_mode_prepare+0x150/0x1e0
[ 102.308253] syscall_exit_to_user_mode+0x19/0x50
[ 102.308253] do_syscall_64+0x48/0x90
[ 102.308253] entry_SYSCALL_64_after_hwframe+0x44/0xae
[ 102.308253] RIP: 0033:0x405ae7
This patch defers the free operation of ax25_dev and net_device after
all corresponding dereference sites in ax25_release() to avoid UAF.
Fixes: 9fd75b66b8 ("ax25: Fix refcount leaks caused by ax25_cb_del()")
Signed-off-by: Duoming Zhou <duoming@zju.edu.cn>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
The previous commit 7ec02f5ac8 ("ax25: fix NPD bug in ax25_disconnect")
move ax25_disconnect into lock_sock() in order to prevent NPD bugs. But
there are race conditions that may lead to null pointer dereferences in
ax25_heartbeat_expiry(), ax25_t1timer_expiry(), ax25_t2timer_expiry(),
ax25_t3timer_expiry() and ax25_idletimer_expiry(), when we use
ax25_kill_by_device() to detach the ax25 device.
One of the race conditions that cause null pointer dereferences can be
shown as below:
(Thread 1) | (Thread 2)
ax25_connect() |
ax25_std_establish_data_link() |
ax25_start_t1timer() |
mod_timer(&ax25->t1timer,..) |
| ax25_kill_by_device()
(wait a time) | ...
| s->ax25_dev = NULL; //(1)
ax25_t1timer_expiry() |
ax25->ax25_dev->values[..] //(2)| ...
... |
We set null to ax25_cb->ax25_dev in position (1) and dereference
the null pointer in position (2).
The corresponding fail log is shown below:
===============================================================
BUG: kernel NULL pointer dereference, address: 0000000000000050
CPU: 1 PID: 0 Comm: swapper/1 Not tainted 5.17.0-rc6-00794-g45690b7d0
RIP: 0010:ax25_t1timer_expiry+0x12/0x40
...
Call Trace:
call_timer_fn+0x21/0x120
__run_timers.part.0+0x1ca/0x250
run_timer_softirq+0x2c/0x60
__do_softirq+0xef/0x2f3
irq_exit_rcu+0xb6/0x100
sysvec_apic_timer_interrupt+0xa2/0xd0
...
This patch moves ax25_disconnect() before s->ax25_dev = NULL
and uses del_timer_sync() to delete timers in ax25_disconnect().
If ax25_disconnect() is called by ax25_kill_by_device() or
ax25->ax25_dev is NULL, the reason in ax25_disconnect() will be
equal to ENETUNREACH, it will wait all timers to stop before we
set null to s->ax25_dev in ax25_kill_by_device().
Fixes: 7ec02f5ac8 ("ax25: fix NPD bug in ax25_disconnect")
Signed-off-by: Duoming Zhou <duoming@zju.edu.cn>
Signed-off-by: David S. Miller <davem@davemloft.net>
The previous commit d01ffb9eee ("ax25: add refcount in ax25_dev to
avoid UAF bugs") and commit feef318c85 ("ax25: fix UAF bugs of
net_device caused by rebinding operation") increase the refcounts of
ax25_dev and net_device in ax25_bind() and decrease the matching refcounts
in ax25_kill_by_device() in order to prevent UAF bugs, but there are
reference count leaks.
The root cause of refcount leaks is shown below:
(Thread 1) | (Thread 2)
ax25_bind() |
... |
ax25_addr_ax25dev() |
ax25_dev_hold() //(1) |
... |
dev_hold_track() //(2) |
... | ax25_destroy_socket()
| ax25_cb_del()
| ...
| hlist_del_init() //(3)
|
|
(Thread 3) |
ax25_kill_by_device() |
... |
ax25_for_each(s, &ax25_list) { |
if (s->ax25_dev == ax25_dev) //(4) |
... |
Firstly, we use ax25_bind() to increase the refcount of ax25_dev in
position (1) and increase the refcount of net_device in position (2).
Then, we use ax25_cb_del() invoked by ax25_destroy_socket() to delete
ax25_cb in hlist in position (3) before calling ax25_kill_by_device().
Finally, the decrements of refcounts in ax25_kill_by_device() will not
be executed, because no s->ax25_dev equals to ax25_dev in position (4).
This patch adds decrements of refcounts in ax25_release() and use
lock_sock() to do synchronization. If refcounts decrease in ax25_release(),
the decrements of refcounts in ax25_kill_by_device() will not be
executed and vice versa.
Fixes: d01ffb9eee ("ax25: add refcount in ax25_dev to avoid UAF bugs")
Fixes: 87563a043c ("ax25: fix reference count leaks of ax25_dev")
Fixes: feef318c85 ("ax25: fix UAF bugs of net_device caused by rebinding operation")
Reported-by: Thomas Osterried <thomas@osterried.de>
Signed-off-by: Duoming Zhou <duoming@zju.edu.cn>
Signed-off-by: David S. Miller <davem@davemloft.net>
When two ax25 devices attempted to establish connection, the requester use ax25_create(),
ax25_bind() and ax25_connect() to initiate connection. The receiver use ax25_rcv() to
accept connection and use ax25_create_cb() in ax25_rcv() to create ax25_cb, but the
ax25_cb->sk is NULL. When the receiver is detaching, a NULL pointer dereference bug
caused by sock_hold(sk) in ax25_kill_by_device() will happen. The corresponding
fail log is shown below:
===============================================================
BUG: KASAN: null-ptr-deref in ax25_device_event+0xfd/0x290
Call Trace:
...
ax25_device_event+0xfd/0x290
raw_notifier_call_chain+0x5e/0x70
dev_close_many+0x174/0x220
unregister_netdevice_many+0x1f7/0xa60
unregister_netdevice_queue+0x12f/0x170
unregister_netdev+0x13/0x20
mkiss_close+0xcd/0x140
tty_ldisc_release+0xc0/0x220
tty_release_struct+0x17/0xa0
tty_release+0x62d/0x670
...
This patch add condition check in ax25_kill_by_device(). If s->sk is
NULL, it will goto if branch to kill device.
Fixes: 4e0f718daf ("ax25: improve the incomplete fix to avoid UAF and NPD bugs")
Reported-by: Thomas Osterried <thomas@osterried.de>
Signed-off-by: Duoming Zhou <duoming@zju.edu.cn>
Signed-off-by: David S. Miller <davem@davemloft.net>
The ax25_kill_by_device() will set s->ax25_dev = NULL and
call ax25_disconnect() to change states of ax25_cb and
sock, if we call ax25_bind() before ax25_kill_by_device().
However, if we call ax25_bind() again between the window of
ax25_kill_by_device() and ax25_dev_device_down(), the values
and states changed by ax25_kill_by_device() will be reassigned.
Finally, ax25_dev_device_down() will deallocate net_device.
If we dereference net_device in syscall functions such as
ax25_release(), ax25_sendmsg(), ax25_getsockopt(), ax25_getname()
and ax25_info_show(), a UAF bug will occur.
One of the possible race conditions is shown below:
(USE) | (FREE)
ax25_bind() |
| ax25_kill_by_device()
ax25_bind() |
ax25_connect() | ...
| ax25_dev_device_down()
| ...
| dev_put_track(dev, ...) //FREE
ax25_release() | ...
ax25_send_control() |
alloc_skb() //USE |
the corresponding fail log is shown below:
===============================================================
BUG: KASAN: use-after-free in ax25_send_control+0x43/0x210
...
Call Trace:
...
ax25_send_control+0x43/0x210
ax25_release+0x2db/0x3b0
__sock_release+0x6d/0x120
sock_close+0xf/0x20
__fput+0x11f/0x420
...
Allocated by task 1283:
...
__kasan_kmalloc+0x81/0xa0
alloc_netdev_mqs+0x5a/0x680
mkiss_open+0x6c/0x380
tty_ldisc_open+0x55/0x90
...
Freed by task 1969:
...
kfree+0xa3/0x2c0
device_release+0x54/0xe0
kobject_put+0xa5/0x120
tty_ldisc_kill+0x3e/0x80
...
In order to fix these UAF bugs caused by rebinding operation,
this patch adds dev_hold_track() into ax25_bind() and
corresponding dev_put_track() into ax25_kill_by_device().
Signed-off-by: Duoming Zhou <duoming@zju.edu.cn>
Signed-off-by: David S. Miller <davem@davemloft.net>
The ax25_disconnect() in ax25_kill_by_device() is not
protected by any locks, thus there is a race condition
between ax25_disconnect() and ax25_destroy_socket().
when ax25->sk is assigned as NULL by ax25_destroy_socket(),
a NULL pointer dereference bug will occur if site (1) or (2)
dereferences ax25->sk.
ax25_kill_by_device() | ax25_release()
ax25_disconnect() | ax25_destroy_socket()
... |
if(ax25->sk != NULL) | ...
... | ax25->sk = NULL;
bh_lock_sock(ax25->sk); //(1) | ...
... |
bh_unlock_sock(ax25->sk); //(2)|
This patch moves ax25_disconnect() into lock_sock(), which can
synchronize with ax25_destroy_socket() in ax25_release().
Fail log:
===============================================================
BUG: kernel NULL pointer dereference, address: 0000000000000088
...
RIP: 0010:_raw_spin_lock+0x7e/0xd0
...
Call Trace:
ax25_disconnect+0xf6/0x220
ax25_device_event+0x187/0x250
raw_notifier_call_chain+0x5e/0x70
dev_close_many+0x17d/0x230
rollback_registered_many+0x1f1/0x950
unregister_netdevice_queue+0x133/0x200
unregister_netdev+0x13/0x20
...
Signed-off-by: Duoming Zhou <duoming@zju.edu.cn>
Signed-off-by: David S. Miller <davem@davemloft.net>
The previous commit d01ffb9eee ("ax25: add refcount in ax25_dev
to avoid UAF bugs") introduces refcount into ax25_dev, but there
are reference leak paths in ax25_ctl_ioctl(), ax25_fwd_ioctl(),
ax25_rt_add(), ax25_rt_del() and ax25_rt_opt().
This patch uses ax25_dev_put() and adjusts the position of
ax25_addr_ax25dev() to fix reference cout leaks of ax25_dev.
Fixes: d01ffb9eee ("ax25: add refcount in ax25_dev to avoid UAF bugs")
Signed-off-by: Duoming Zhou <duoming@zju.edu.cn>
Reviewed-by: Dan Carpenter <dan.carpenter@oracle.com>
Link: https://lore.kernel.org/r/20220203150811.42256-1-duoming@zju.edu.cn
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
If we dereference ax25_dev after we call kfree(ax25_dev) in
ax25_dev_device_down(), it will lead to concurrency UAF bugs.
There are eight syscall functions suffer from UAF bugs, include
ax25_bind(), ax25_release(), ax25_connect(), ax25_ioctl(),
ax25_getname(), ax25_sendmsg(), ax25_getsockopt() and
ax25_info_show().
One of the concurrency UAF can be shown as below:
(USE) | (FREE)
| ax25_device_event
| ax25_dev_device_down
ax25_bind | ...
... | kfree(ax25_dev)
ax25_fillin_cb() | ...
ax25_fillin_cb_from_dev() |
... |
The root cause of UAF bugs is that kfree(ax25_dev) in
ax25_dev_device_down() is not protected by any locks.
When ax25_dev, which there are still pointers point to,
is released, the concurrency UAF bug will happen.
This patch introduces refcount into ax25_dev in order to
guarantee that there are no pointers point to it when ax25_dev
is released.
Signed-off-by: Duoming Zhou <duoming@zju.edu.cn>
Signed-off-by: David S. Miller <davem@davemloft.net>
The previous commit 1ade48d0c2 ("ax25: NPD bug when detaching
AX25 device") introduce lock_sock() into ax25_kill_by_device to
prevent NPD bug. But the concurrency NPD or UAF bug will occur,
when lock_sock() or release_sock() dereferences the ax25_cb->sock.
The NULL pointer dereference bug can be shown as below:
ax25_kill_by_device() | ax25_release()
| ax25_destroy_socket()
| ax25_cb_del()
... | ...
| ax25->sk=NULL;
lock_sock(s->sk); //(1) |
s->ax25_dev = NULL; | ...
release_sock(s->sk); //(2) |
... |
The root cause is that the sock is set to null before dereference
site (1) or (2). Therefore, this patch extracts the ax25_cb->sock
in advance, and uses ax25_list_lock to protect it, which can synchronize
with ax25_cb_del() and ensure the value of sock is not null before
dereference sites.
The concurrency UAF bug can be shown as below:
ax25_kill_by_device() | ax25_release()
| ax25_destroy_socket()
... | ...
| sock_put(sk); //FREE
lock_sock(s->sk); //(1) |
s->ax25_dev = NULL; | ...
release_sock(s->sk); //(2) |
... |
The root cause is that the sock is released before dereference
site (1) or (2). Therefore, this patch uses sock_hold() to increase
the refcount of sock and uses ax25_list_lock to protect it, which
can synchronize with ax25_cb_del() in ax25_destroy_socket() and
ensure the sock wil not be released before dereference sites.
Signed-off-by: Duoming Zhou <duoming@zju.edu.cn>
Signed-off-by: David S. Miller <davem@davemloft.net>
The "opt" variable is unsigned long but we only copy 4 bytes from
the user so the lower 4 bytes are uninitialized.
I have changed the integer overflow checks from ULONG to UINT as well.
This is a slight API change but I don't expect it to break anything.
Fixes: a7b75c5a8c ("net: pass a sockptr_t into ->setsockopt")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
The existing cleanup routine implementation is not well synchronized
with the syscall routine. When a device is detaching, below race could
occur.
static int ax25_sendmsg(...) {
...
lock_sock()
ax25 = sk_to_ax25(sk);
if (ax25->ax25_dev == NULL) // CHECK
...
ax25_queue_xmit(skb, ax25->ax25_dev->dev); // USE
...
}
static void ax25_kill_by_device(...) {
...
if (s->ax25_dev == ax25_dev) {
s->ax25_dev = NULL;
...
}
Other syscall functions like ax25_getsockopt, ax25_getname,
ax25_info_show also suffer from similar races. To fix them, this patch
introduce lock_sock() into ax25_kill_by_device in order to guarantee
that the nullify action in cleanup routine cannot proceed when another
socket request is pending.
Signed-off-by: Hanjie Wu <nagi@zju.edu.cn>
Signed-off-by: Lin Ma <linma@zju.edu.cn>
Signed-off-by: David S. Miller <davem@davemloft.net>
In preparation for netdev->dev_addr being constant
make all relevant arguments in AX25 constant.
Modify callers as well (netrom, rose).
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
In preparation to enable -Wimplicit-fallthrough for Clang, fix a warning
by explicitly adding a break statement instead of letting the code fall
through to the next case.
Link: https://github.com/KSPP/linux/issues/115
Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
The UDP reuseport conflict was a little bit tricky.
The net-next code, via bpf-next, extracted the reuseport handling
into a helper so that the BPF sk lookup code could invoke it.
At the same time, the logic for reuseport handling of unconnected
sockets changed via commit efc6b6f6c3
which changed the logic to carry on the reuseport result into the
rest of the lookup loop if we do not return immediately.
This requires moving the reuseport_has_conns() logic into the callers.
While we are here, get rid of inline directives as they do not belong
in foo.c files.
The other changes were cases of more straightforward overlapping
modifications.
Signed-off-by: David S. Miller <davem@davemloft.net>
Rework the remaining setsockopt code to pass a sockptr_t instead of a
plain user pointer. This removes the last remaining set_fs(KERNEL_DS)
outside of architecture specific code.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Acked-by: Stefan Schmidt <stefan@datenfreihafen.org> [ieee802154]
Acked-by: Matthieu Baerts <matthieu.baerts@tessares.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
We recently added some bounds checking in ax25_connect() and
ax25_sendmsg() and we so we removed the AX25_MAX_DIGIS checks because
they were no longer required.
Unfortunately, I believe they are required to prevent integer overflows
so I have added them back.
Fixes: 8885bb0621 ("AX.25: Prevent out-of-bounds read in ax25_sendmsg()")
Fixes: 2f2a7ffad5 ("AX.25: Fix out-of-bounds read in ax25_connect()")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Checks on `addr_len` and `usax->sax25_ndigis` are insufficient.
ax25_sendmsg() can go out of bounds when `usax->sax25_ndigis` equals to 7
or 8. Fix it.
It is safe to remove `usax->sax25_ndigis > AX25_MAX_DIGIS`, since
`addr_len` is guaranteed to be less than or equal to
`sizeof(struct full_sockaddr_ax25)`
Signed-off-by: Peilin Ye <yepeilin.cs@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Checks on `addr_len` and `fsa->fsa_ax25.sax25_ndigis` are insufficient.
ax25_connect() can go out of bounds when `fsa->fsa_ax25.sax25_ndigis`
equals to 7 or 8. Fix it.
This issue has been reported as a KMSAN uninit-value bug, because in such
a case, ax25_connect() reaches into the uninitialized portion of the
`struct sockaddr_storage` statically allocated in __sys_connect().
It is safe to remove `fsa->fsa_ax25.sax25_ndigis > AX25_MAX_DIGIS` because
`addr_len` is guaranteed to be less than or equal to
`sizeof(struct full_sockaddr_ax25)`.
Reported-by: syzbot+c82752228ed975b0a623@syzkaller.appspotmail.com
Link: https://syzkaller.appspot.com/bug?id=55ef9d629f3b3d7d70b69558015b63b48d01af66
Signed-off-by: Peilin Ye <yepeilin.cs@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
SK_PROTOCOL_MAX is only used in two places, for DECNet and AX.25. The
limits have more to do with the those protocol definitions than they do
with the data type of sk_protocol, so remove SK_PROTOCOL_MAX and use
U8_MAX directly.
Reviewed-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: Mat Martineau <mathew.j.martineau@linux.intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Writers are holding a lock, but many readers do not.
Following patch will add appropriate barriers in
sk_acceptq_removed() and sk_acceptq_added().
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
When creating a raw AF_AX25 socket, CAP_NET_RAW needs to be checked
first.
Signed-off-by: Ori Nimron <orinimron123@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
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>
Pointers should be printed with %p or %px rather than
cast to long type and printed with %8.8lx.
Change %8.8lx to %p to print the pointer.
Signed-off-by: Fuqian Huang <huangfq.daxian@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
The SIOCGSTAMP/SIOCGSTAMPNS ioctl commands are implemented by many
socket protocol handlers, and all of those end up calling the same
sock_get_timestamp()/sock_get_timestampns() helper functions, which
results in a lot of duplicate code.
With the introduction of 64-bit time_t on 32-bit architectures, this
gets worse, as we then need four different ioctl commands in each
socket protocol implementation.
To simplify that, let's add a new .gettstamp() operation in
struct proto_ops, and move ioctl implementation into the common
sock_ioctl()/compat_sock_ioctl_trans() functions that these all go
through.
We can reuse the sock_get_timestamp() implementation, but generalize
it so it can deal with both native and compat mode, as well as
timeval and timespec structures.
Acked-by: Stefan Schmidt <stefan@datenfreihafen.org>
Acked-by: Neil Horman <nhorman@tuxdriver.com>
Acked-by: Marc Kleine-Budde <mkl@pengutronix.de>
Link: https://lore.kernel.org/lkml/CAK8P3a038aDQQotzua_QtKGhq8O9n+rdiz2=WDCp82ys8eUT+A@mail.gmail.com/
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Willem de Bruijn <willemb@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
There are multiple issues here:
1. After freeing dev->ax25_ptr, we need to set it to NULL otherwise
we may use a dangling pointer.
2. There is a race between ax25_setsockopt() and device notifier as
reported by syzbot. Close it by holding RTNL lock.
3. We need to test if dev->ax25_ptr is NULL before using it.
Reported-and-tested-by: syzbot+ae6bb869cbed29b29040@syzkaller.appspotmail.com
Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
The poll() changes were not well thought out, and completely
unexplained. They also caused a huge performance regression, because
"->poll()" was no longer a trivial file operation that just called down
to the underlying file operations, but instead did at least two indirect
calls.
Indirect calls are sadly slow now with the Spectre mitigation, but the
performance problem could at least be largely mitigated by changing the
"->get_poll_head()" operation to just have a per-file-descriptor pointer
to the poll head instead. That gets rid of one of the new indirections.
But that doesn't fix the new complexity that is completely unwarranted
for the regular case. The (undocumented) reason for the poll() changes
was some alleged AIO poll race fixing, but we don't make the common case
slower and more complex for some uncommon special case, so this all
really needs way more explanations and most likely a fundamental
redesign.
[ This revert is a revert of about 30 different commits, not reverted
individually because that would just be unnecessarily messy - Linus ]
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Christoph Hellwig <hch@lst.de>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Pull aio updates from Al Viro:
"Majority of AIO stuff this cycle. aio-fsync and aio-poll, mostly.
The only thing I'm holding back for a day or so is Adam's aio ioprio -
his last-minute fixup is trivial (missing stub in !CONFIG_BLOCK case),
but let it sit in -next for decency sake..."
* 'work.aio-1' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: (46 commits)
aio: sanitize the limit checking in io_submit(2)
aio: fold do_io_submit() into callers
aio: shift copyin of iocb into io_submit_one()
aio_read_events_ring(): make a bit more readable
aio: all callers of aio_{read,write,fsync,poll} treat 0 and -EIOCBQUEUED the same way
aio: take list removal to (some) callers of aio_complete()
aio: add missing break for the IOCB_CMD_FDSYNC case
random: convert to ->poll_mask
timerfd: convert to ->poll_mask
eventfd: switch to ->poll_mask
pipe: convert to ->poll_mask
crypto: af_alg: convert to ->poll_mask
net/rxrpc: convert to ->poll_mask
net/iucv: convert to ->poll_mask
net/phonet: convert to ->poll_mask
net/nfc: convert to ->poll_mask
net/caif: convert to ->poll_mask
net/bluetooth: convert to ->poll_mask
net/sctp: convert to ->poll_mask
net/tipc: convert to ->poll_mask
...
Variants of proc_create{,_data} that directly take a struct seq_operations
argument and drastically reduces the boilerplate code in the callers.
All trivial callers converted over.
Signed-off-by: Christoph Hellwig <hch@lst.de>
