linux.git/net/tipc/net.c, branch v5.10 Linux kernel source tree tipc: fix a deadlock when flushing scheduled work 2020-09-07T19:08:53+00:00 Hoang Huu Le hoang.h.le@dektech.com.au 2020-09-07T06:17:25+00:00 d966ddcc38217a6110a6a0ff37ad2dee7d42e23e In the commit fdeba99b1e58 ("tipc: fix use-after-free in tipc_bcast_get_mode"), we're trying to make sure the tipc_net_finalize_work work item finished if it enqueued. But calling flush_scheduled_work() is not just affecting above work item but either any scheduled work. This has turned out to be overkill and caused to deadlock as syzbot reported: ====================================================== WARNING: possible circular locking dependency detected 5.9.0-rc2-next-20200828-syzkaller #0 Not tainted ------------------------------------------------------ kworker/u4:6/349 is trying to acquire lock: ffff8880aa063d38 ((wq_completion)events){+.+.}-{0:0}, at: flush_workqueue+0xe1/0x13e0 kernel/workqueue.c:2777 but task is already holding lock: ffffffff8a879430 (pernet_ops_rwsem){++++}-{3:3}, at: cleanup_net+0x9b/0xb10 net/core/net_namespace.c:565 [...] Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(pernet_ops_rwsem); lock(&sb->s_type->i_mutex_key#13); lock(pernet_ops_rwsem); lock((wq_completion)events); *** DEADLOCK *** [...] v1: To fix the original issue, we replace above calling by introducing a bit flag. When a namespace cleaned-up, bit flag is set to zero and: - tipc_net_finalize functionial just does return immediately. - tipc_net_finalize_work does not enqueue into the scheduled work queue. v2: Use cancel_work_sync() helper to make sure ONLY the tipc_net_finalize_work() stopped before releasing bcbase object. Reported-by: syzbot+d5aa7e0385f6a5d0f4fd@syzkaller.appspotmail.com Fixes: fdeba99b1e58 ("tipc: fix use-after-free in tipc_bcast_get_mode") Acked-by: Jon Maloy <jmaloy@redhat.com> Signed-off-by: Hoang Huu Le <hoang.h.le@dektech.com.au> Signed-off-by: Jakub Kicinski <kuba@kernel.org> 
In the commit fdeba99b1e58
("tipc: fix use-after-free in tipc_bcast_get_mode"), we're trying
to make sure the tipc_net_finalize_work work item finished if it
enqueued. But calling flush_scheduled_work() is not just affecting
above work item but either any scheduled work. This has turned out
to be overkill and caused to deadlock as syzbot reported:

======================================================
WARNING: possible circular locking dependency detected
5.9.0-rc2-next-20200828-syzkaller #0 Not tainted
------------------------------------------------------
kworker/u4:6/349 is trying to acquire lock:
ffff8880aa063d38 ((wq_completion)events){+.+.}-{0:0}, at: flush_workqueue+0xe1/0x13e0 kernel/workqueue.c:2777

but task is already holding lock:
ffffffff8a879430 (pernet_ops_rwsem){++++}-{3:3}, at: cleanup_net+0x9b/0xb10 net/core/net_namespace.c:565

[...]
 Possible unsafe locking scenario:

       CPU0                    CPU1
       ----                    ----
  lock(pernet_ops_rwsem);
                               lock(&sb->s_type->i_mutex_key#13);
                               lock(pernet_ops_rwsem);
  lock((wq_completion)events);

 *** DEADLOCK ***
[...]

v1:
To fix the original issue, we replace above calling by introducing
a bit flag. When a namespace cleaned-up, bit flag is set to zero and:
- tipc_net_finalize functionial just does return immediately.
- tipc_net_finalize_work does not enqueue into the scheduled work queue.

v2:
Use cancel_work_sync() helper to make sure ONLY the
tipc_net_finalize_work() stopped before releasing bcbase object.

Reported-by: syzbot+d5aa7e0385f6a5d0f4fd@syzkaller.appspotmail.com
Fixes: fdeba99b1e58 ("tipc: fix use-after-free in tipc_bcast_get_mode")
Acked-by: Jon Maloy <jmaloy@redhat.com>
Signed-off-by: Hoang Huu Le <hoang.h.le@dektech.com.au>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
tipc: make legacy address flag readable over netlink 2019-12-21T05:18:42+00:00 John Rutherford john.rutherford@dektech.com.au 2019-12-19T05:03:57+00:00 e1b5e598e5a51b453328879682b178b4acc15105 To enable iproute2/tipc to generate backwards compatible printouts and validate command parameters for nodes using a <z.c.n> node address, it needs to be able to read the legacy address flag from the kernel. The legacy address flag records the way in which the node identity was originally specified. The legacy address flag is requested by the netlink message TIPC_NL_ADDR_LEGACY_GET. If the flag is set the attribute TIPC_NLA_NET_ADDR_LEGACY is set in the return message. Signed-off-by: John Rutherford <john.rutherford@dektech.com.au> Acked-by: Jon Maloy <jon.maloy@ericsson.com> Signed-off-by: David S. Miller <davem@davemloft.net> 
To enable iproute2/tipc to generate backwards compatible
printouts and validate command parameters for nodes using a
<z.c.n> node address, it needs to be able to read the legacy
address flag from the kernel.  The legacy address flag records
the way in which the node identity was originally specified.

The legacy address flag is requested by the netlink message
TIPC_NL_ADDR_LEGACY_GET.  If the flag is set the attribute
TIPC_NLA_NET_ADDR_LEGACY is set in the return message.

Signed-off-by: John Rutherford <john.rutherford@dektech.com.au>
Acked-by: Jon Maloy <jon.maloy@ericsson.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
tipc: update mon's self addr when node addr generated 2019-11-13T03:45:45+00:00 Hoang Le hoang.h.le@dektech.com.au 2019-11-12T00:40:04+00:00 46cb01eeeb86fca6afe24dda1167b0cb95424e29 In commit 25b0b9c4e835 ("tipc: handle collisions of 32-bit node address hash values"), the 32-bit node address only generated after one second trial period expired. However the self's addr in struct tipc_monitor do not update according to node address generated. This lead to it is always zero as initial value. As result, sorting algorithm using this value does not work as expected, neither neighbor monitoring framework. In this commit, we add a fix to update self's addr when 32-bit node address generated. Fixes: 25b0b9c4e835 ("tipc: handle collisions of 32-bit node address hash values") Acked-by: Jon Maloy <jon.maloy@ericsson.com> Signed-off-by: Hoang Le <hoang.h.le@dektech.com.au> Signed-off-by: David S. Miller <davem@davemloft.net> 
In commit 25b0b9c4e835 ("tipc: handle collisions of 32-bit node address
hash values"), the 32-bit node address only generated after one second
trial period expired. However the self's addr in struct tipc_monitor do
not update according to node address generated. This lead to it is
always zero as initial value. As result, sorting algorithm using this
value does not work as expected, neither neighbor monitoring framework.

In this commit, we add a fix to update self's addr when 32-bit node
address generated.

Fixes: 25b0b9c4e835 ("tipc: handle collisions of 32-bit node address hash values")
Acked-by: Jon Maloy <jon.maloy@ericsson.com>
Signed-off-by: Hoang Le <hoang.h.le@dektech.com.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
netlink: make validation more configurable for future strictness 2019-04-27T21:07:21+00:00 Johannes Berg johannes.berg@intel.com 2019-04-26T12:07:28+00:00 8cb081746c031fb164089322e2336a0bf5b3070c We currently have two levels of strict validation: 1) liberal (default) - undefined (type >= max) & NLA_UNSPEC attributes accepted - attribute length >= expected accepted - garbage at end of message accepted 2) strict (opt-in) - NLA_UNSPEC attributes accepted - attribute length >= expected accepted Split out parsing strictness into four different options: * TRAILING - check that there's no trailing data after parsing attributes (in message or nested) * MAXTYPE - reject attrs > max known type * UNSPEC - reject attributes with NLA_UNSPEC policy entries * STRICT_ATTRS - strictly validate attribute size The default for future things should be *everything*. The current *_strict() is a combination of TRAILING and MAXTYPE, and is renamed to _deprecated_strict(). The current regular parsing has none of this, and is renamed to *_parse_deprecated(). Additionally it allows us to selectively set one of the new flags even on old policies. Notably, the UNSPEC flag could be useful in this case, since it can be arranged (by filling in the policy) to not be an incompatible userspace ABI change, but would then going forward prevent forgetting attribute entries. Similar can apply to the POLICY flag. We end up with the following renames: * nla_parse -> nla_parse_deprecated * nla_parse_strict -> nla_parse_deprecated_strict * nlmsg_parse -> nlmsg_parse_deprecated * nlmsg_parse_strict -> nlmsg_parse_deprecated_strict * nla_parse_nested -> nla_parse_nested_deprecated * nla_validate_nested -> nla_validate_nested_deprecated Using spatch, of course: @@ expression TB, MAX, HEAD, LEN, POL, EXT; @@ -nla_parse(TB, MAX, HEAD, LEN, POL, EXT) +nla_parse_deprecated(TB, MAX, HEAD, LEN, POL, EXT) @@ expression NLH, HDRLEN, TB, MAX, POL, EXT; @@ -nlmsg_parse(NLH, HDRLEN, TB, MAX, POL, EXT) +nlmsg_parse_deprecated(NLH, HDRLEN, TB, MAX, POL, EXT) @@ expression NLH, HDRLEN, TB, MAX, POL, EXT; @@ -nlmsg_parse_strict(NLH, HDRLEN, TB, MAX, POL, EXT) +nlmsg_parse_deprecated_strict(NLH, HDRLEN, TB, MAX, POL, EXT) @@ expression TB, MAX, NLA, POL, EXT; @@ -nla_parse_nested(TB, MAX, NLA, POL, EXT) +nla_parse_nested_deprecated(TB, MAX, NLA, POL, EXT) @@ expression START, MAX, POL, EXT; @@ -nla_validate_nested(START, MAX, POL, EXT) +nla_validate_nested_deprecated(START, MAX, POL, EXT) @@ expression NLH, HDRLEN, MAX, POL, EXT; @@ -nlmsg_validate(NLH, HDRLEN, MAX, POL, EXT) +nlmsg_validate_deprecated(NLH, HDRLEN, MAX, POL, EXT) For this patch, don't actually add the strict, non-renamed versions yet so that it breaks compile if I get it wrong. Also, while at it, make nla_validate and nla_parse go down to a common __nla_validate_parse() function to avoid code duplication. Ultimately, this allows us to have very strict validation for every new caller of nla_parse()/nlmsg_parse() etc as re-introduced in the next patch, while existing things will continue to work as is. In effect then, this adds fully strict validation for any new command. Signed-off-by: Johannes Berg <johannes.berg@intel.com> Signed-off-by: David S. Miller <davem@davemloft.net> 
We currently have two levels of strict validation:

 1) liberal (default)
     - undefined (type >= max) & NLA_UNSPEC attributes accepted
     - attribute length >= expected accepted
     - garbage at end of message accepted
 2) strict (opt-in)
     - NLA_UNSPEC attributes accepted
     - attribute length >= expected accepted

Split out parsing strictness into four different options:
 * TRAILING     - check that there's no trailing data after parsing
                  attributes (in message or nested)
 * MAXTYPE      - reject attrs > max known type
 * UNSPEC       - reject attributes with NLA_UNSPEC policy entries
 * STRICT_ATTRS - strictly validate attribute size

The default for future things should be *everything*.
The current *_strict() is a combination of TRAILING and MAXTYPE,
and is renamed to _deprecated_strict().
The current regular parsing has none of this, and is renamed to
*_parse_deprecated().

Additionally it allows us to selectively set one of the new flags
even on old policies. Notably, the UNSPEC flag could be useful in
this case, since it can be arranged (by filling in the policy) to
not be an incompatible userspace ABI change, but would then going
forward prevent forgetting attribute entries. Similar can apply
to the POLICY flag.

We end up with the following renames:
 * nla_parse           -> nla_parse_deprecated
 * nla_parse_strict    -> nla_parse_deprecated_strict
 * nlmsg_parse         -> nlmsg_parse_deprecated
 * nlmsg_parse_strict  -> nlmsg_parse_deprecated_strict
 * nla_parse_nested    -> nla_parse_nested_deprecated
 * nla_validate_nested -> nla_validate_nested_deprecated

Using spatch, of course:
    @@
    expression TB, MAX, HEAD, LEN, POL, EXT;
    @@
    -nla_parse(TB, MAX, HEAD, LEN, POL, EXT)
    +nla_parse_deprecated(TB, MAX, HEAD, LEN, POL, EXT)

    @@
    expression NLH, HDRLEN, TB, MAX, POL, EXT;
    @@
    -nlmsg_parse(NLH, HDRLEN, TB, MAX, POL, EXT)
    +nlmsg_parse_deprecated(NLH, HDRLEN, TB, MAX, POL, EXT)

    @@
    expression NLH, HDRLEN, TB, MAX, POL, EXT;
    @@
    -nlmsg_parse_strict(NLH, HDRLEN, TB, MAX, POL, EXT)
    +nlmsg_parse_deprecated_strict(NLH, HDRLEN, TB, MAX, POL, EXT)

    @@
    expression TB, MAX, NLA, POL, EXT;
    @@
    -nla_parse_nested(TB, MAX, NLA, POL, EXT)
    +nla_parse_nested_deprecated(TB, MAX, NLA, POL, EXT)

    @@
    expression START, MAX, POL, EXT;
    @@
    -nla_validate_nested(START, MAX, POL, EXT)
    +nla_validate_nested_deprecated(START, MAX, POL, EXT)

    @@
    expression NLH, HDRLEN, MAX, POL, EXT;
    @@
    -nlmsg_validate(NLH, HDRLEN, MAX, POL, EXT)
    +nlmsg_validate_deprecated(NLH, HDRLEN, MAX, POL, EXT)

For this patch, don't actually add the strict, non-renamed versions
yet so that it breaks compile if I get it wrong.

Also, while at it, make nla_validate and nla_parse go down to a
common __nla_validate_parse() function to avoid code duplication.

Ultimately, this allows us to have very strict validation for every
new caller of nla_parse()/nlmsg_parse() etc as re-introduced in the
next patch, while existing things will continue to work as is.

In effect then, this adds fully strict validation for any new command.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
netlink: make nla_nest_start() add NLA_F_NESTED flag 2019-04-27T21:03:44+00:00 Michal Kubecek mkubecek@suse.cz 2019-04-26T09:13:06+00:00 ae0be8de9a53cda3505865c11826d8ff0640237c Even if the NLA_F_NESTED flag was introduced more than 11 years ago, most netlink based interfaces (including recently added ones) are still not setting it in kernel generated messages. Without the flag, message parsers not aware of attribute semantics (e.g. wireshark dissector or libmnl's mnl_nlmsg_fprintf()) cannot recognize nested attributes and won't display the structure of their contents. Unfortunately we cannot just add the flag everywhere as there may be userspace applications which check nlattr::nla_type directly rather than through a helper masking out the flags. Therefore the patch renames nla_nest_start() to nla_nest_start_noflag() and introduces nla_nest_start() as a wrapper adding NLA_F_NESTED. The calls which add NLA_F_NESTED manually are rewritten to use nla_nest_start(). Except for changes in include/net/netlink.h, the patch was generated using this semantic patch: @@ expression E1, E2; @@ -nla_nest_start(E1, E2) +nla_nest_start_noflag(E1, E2) @@ expression E1, E2; @@ -nla_nest_start_noflag(E1, E2 | NLA_F_NESTED) +nla_nest_start(E1, E2) Signed-off-by: Michal Kubecek <mkubecek@suse.cz> Acked-by: Jiri Pirko <jiri@mellanox.com> Acked-by: David Ahern <dsahern@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net> 
Even if the NLA_F_NESTED flag was introduced more than 11 years ago, most
netlink based interfaces (including recently added ones) are still not
setting it in kernel generated messages. Without the flag, message parsers
not aware of attribute semantics (e.g. wireshark dissector or libmnl's
mnl_nlmsg_fprintf()) cannot recognize nested attributes and won't display
the structure of their contents.

Unfortunately we cannot just add the flag everywhere as there may be
userspace applications which check nlattr::nla_type directly rather than
through a helper masking out the flags. Therefore the patch renames
nla_nest_start() to nla_nest_start_noflag() and introduces nla_nest_start()
as a wrapper adding NLA_F_NESTED. The calls which add NLA_F_NESTED manually
are rewritten to use nla_nest_start().

Except for changes in include/net/netlink.h, the patch was generated using
this semantic patch:

@@ expression E1, E2; @@
-nla_nest_start(E1, E2)
+nla_nest_start_noflag(E1, E2)

@@ expression E1, E2; @@
-nla_nest_start_noflag(E1, E2 | NLA_F_NESTED)
+nla_nest_start(E1, E2)

Signed-off-by: Michal Kubecek <mkubecek@suse.cz>
Acked-by: Jiri Pirko <jiri@mellanox.com>
Acked-by: David Ahern <dsahern@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
tipc: change to check tipc_own_id to return in tipc_net_stop 2019-03-26T18:21:20+00:00 Xin Long lucien.xin@gmail.com 2019-03-23T16:48:22+00:00 9926cb5f8b0f0aea535735185600d74db7608550 When running a syz script, a panic occurred: [ 156.088228] BUG: KASAN: use-after-free in tipc_disc_timeout+0x9c9/0xb20 [tipc] [ 156.094315] Call Trace: [ 156.094844] <IRQ> [ 156.095306] dump_stack+0x7c/0xc0 [ 156.097346] print_address_description+0x65/0x22e [ 156.100445] kasan_report.cold.3+0x37/0x7a [ 156.102402] tipc_disc_timeout+0x9c9/0xb20 [tipc] [ 156.106517] call_timer_fn+0x19a/0x610 [ 156.112749] run_timer_softirq+0xb51/0x1090 It was caused by the netns freed without deleting the discoverer timer, while later on the netns would be accessed in the timer handler. The timer should have been deleted by tipc_net_stop() when cleaning up a netns. However, tipc has been able to enable a bearer and start d->timer without the local node_addr set since Commit 52dfae5c85a4 ("tipc: obtain node identity from interface by default"), which caused the timer not to be deleted in tipc_net_stop() then. So fix it in tipc_net_stop() by changing to check local node_id instead of local node_addr, as Jon suggested. While at it, remove the calling of tipc_nametbl_withdraw() there, since tipc_nametbl_stop() will take of the nametbl's freeing after. Fixes: 52dfae5c85a4 ("tipc: obtain node identity from interface by default") Reported-by: syzbot+a25307ad099309f1c2b9@syzkaller.appspotmail.com Signed-off-by: Xin Long <lucien.xin@gmail.com> Acked-by: Ying Xue <ying.xue@windriver.com> Acked-by: Jon Maloy <jon.maloy@ericsson.com> Signed-off-by: David S. Miller <davem@davemloft.net> 
When running a syz script, a panic occurred:

[  156.088228] BUG: KASAN: use-after-free in tipc_disc_timeout+0x9c9/0xb20 [tipc]
[  156.094315] Call Trace:
[  156.094844]  <IRQ>
[  156.095306]  dump_stack+0x7c/0xc0
[  156.097346]  print_address_description+0x65/0x22e
[  156.100445]  kasan_report.cold.3+0x37/0x7a
[  156.102402]  tipc_disc_timeout+0x9c9/0xb20 [tipc]
[  156.106517]  call_timer_fn+0x19a/0x610
[  156.112749]  run_timer_softirq+0xb51/0x1090

It was caused by the netns freed without deleting the discoverer timer,
while later on the netns would be accessed in the timer handler.

The timer should have been deleted by tipc_net_stop() when cleaning up a
netns. However, tipc has been able to enable a bearer and start d->timer
without the local node_addr set since Commit 52dfae5c85a4 ("tipc: obtain
node identity from interface by default"), which caused the timer not to
be deleted in tipc_net_stop() then.

So fix it in tipc_net_stop() by changing to check local node_id instead
of local node_addr, as Jon suggested.

While at it, remove the calling of tipc_nametbl_withdraw() there, since
tipc_nametbl_stop() will take of the nametbl's freeing after.

Fixes: 52dfae5c85a4 ("tipc: obtain node identity from interface by default")
Reported-by: syzbot+a25307ad099309f1c2b9@syzkaller.appspotmail.com
Signed-off-by: Xin Long <lucien.xin@gmail.com>
Acked-by: Ying Xue <ying.xue@windriver.com>
Acked-by: Jon Maloy <jon.maloy@ericsson.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
tipc: fix lockdep warning when reinitilaizing sockets 2018-11-18T06:01:31+00:00 Jon Maloy donmalo99@gmail.com 2018-11-16T21:55:04+00:00 adba75be0d23cca92a028749d92c60c8909bbdb3 We get the following warning: [ 47.926140] 32-bit node address hash set to 2010a0a [ 47.927202] [ 47.927433] ================================ [ 47.928050] WARNING: inconsistent lock state [ 47.928661] 4.19.0+ #37 Tainted: G E [ 47.929346] -------------------------------- [ 47.929954] inconsistent {SOFTIRQ-ON-W} -> {IN-SOFTIRQ-W} usage. [ 47.930116] swapper/3/0 [HC0[0]:SC1[3]:HE1:SE0] takes: [ 47.930116] 00000000af8bc31e (&(&ht->lock)->rlock){+.?.}, at: rhashtable_walk_enter+0x36/0xb0 [ 47.930116] {SOFTIRQ-ON-W} state was registered at: [ 47.930116] _raw_spin_lock+0x29/0x60 [ 47.930116] rht_deferred_worker+0x556/0x810 [ 47.930116] process_one_work+0x1f5/0x540 [ 47.930116] worker_thread+0x64/0x3e0 [ 47.930116] kthread+0x112/0x150 [ 47.930116] ret_from_fork+0x3a/0x50 [ 47.930116] irq event stamp: 14044 [ 47.930116] hardirqs last enabled at (14044): [<ffffffff9a07fbba>] __local_bh_enable_ip+0x7a/0xf0 [ 47.938117] hardirqs last disabled at (14043): [<ffffffff9a07fb81>] __local_bh_enable_ip+0x41/0xf0 [ 47.938117] softirqs last enabled at (14028): [<ffffffff9a0803ee>] irq_enter+0x5e/0x60 [ 47.938117] softirqs last disabled at (14029): [<ffffffff9a0804a5>] irq_exit+0xb5/0xc0 [ 47.938117] [ 47.938117] other info that might help us debug this: [ 47.938117] Possible unsafe locking scenario: [ 47.938117] [ 47.938117] CPU0 [ 47.938117] ---- [ 47.938117] lock(&(&ht->lock)->rlock); [ 47.938117] <Interrupt> [ 47.938117] lock(&(&ht->lock)->rlock); [ 47.938117] [ 47.938117] *** DEADLOCK *** [ 47.938117] [ 47.938117] 2 locks held by swapper/3/0: [ 47.938117] #0: 0000000062c64f90 ((&d->timer)){+.-.}, at: call_timer_fn+0x5/0x280 [ 47.938117] #1: 00000000ee39619c (&(&d->lock)->rlock){+.-.}, at: tipc_disc_timeout+0xc8/0x540 [tipc] [ 47.938117] [ 47.938117] stack backtrace: [ 47.938117] CPU: 3 PID: 0 Comm: swapper/3 Tainted: G E 4.19.0+ #37 [ 47.938117] Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011 [ 47.938117] Call Trace: [ 47.938117] <IRQ> [ 47.938117] dump_stack+0x5e/0x8b [ 47.938117] print_usage_bug+0x1ed/0x1ff [ 47.938117] mark_lock+0x5b5/0x630 [ 47.938117] __lock_acquire+0x4c0/0x18f0 [ 47.938117] ? lock_acquire+0xa6/0x180 [ 47.938117] lock_acquire+0xa6/0x180 [ 47.938117] ? rhashtable_walk_enter+0x36/0xb0 [ 47.938117] _raw_spin_lock+0x29/0x60 [ 47.938117] ? rhashtable_walk_enter+0x36/0xb0 [ 47.938117] rhashtable_walk_enter+0x36/0xb0 [ 47.938117] tipc_sk_reinit+0xb0/0x410 [tipc] [ 47.938117] ? mark_held_locks+0x6f/0x90 [ 47.938117] ? __local_bh_enable_ip+0x7a/0xf0 [ 47.938117] ? lockdep_hardirqs_on+0x20/0x1a0 [ 47.938117] tipc_net_finalize+0xbf/0x180 [tipc] [ 47.938117] tipc_disc_timeout+0x509/0x540 [tipc] [ 47.938117] ? call_timer_fn+0x5/0x280 [ 47.938117] ? tipc_disc_msg_xmit.isra.19+0xa0/0xa0 [tipc] [ 47.938117] ? tipc_disc_msg_xmit.isra.19+0xa0/0xa0 [tipc] [ 47.938117] call_timer_fn+0xa1/0x280 [ 47.938117] ? tipc_disc_msg_xmit.isra.19+0xa0/0xa0 [tipc] [ 47.938117] run_timer_softirq+0x1f2/0x4d0 [ 47.938117] __do_softirq+0xfc/0x413 [ 47.938117] irq_exit+0xb5/0xc0 [ 47.938117] smp_apic_timer_interrupt+0xac/0x210 [ 47.938117] apic_timer_interrupt+0xf/0x20 [ 47.938117] </IRQ> [ 47.938117] RIP: 0010:default_idle+0x1c/0x140 [ 47.938117] Code: 90 90 90 90 90 90 90 90 90 90 90 90 90 90 0f 1f 44 00 00 41 54 55 53 65 8b 2d d8 2b 74 65 0f 1f 44 00 00 e8 c6 2c 8b ff fb f4 <65> 8b 2d c5 2b 74 65 0f 1f 44 00 00 5b 5d 41 5c c3 65 8b 05 b4 2b [ 47.938117] RSP: 0018:ffffaf6ac0207ec8 EFLAGS: 00000206 ORIG_RAX: ffffffffffffff13 [ 47.938117] RAX: ffff8f5b3735e200 RBX: 0000000000000003 RCX: 0000000000000001 [ 47.938117] RDX: 0000000000000001 RSI: 0000000000000001 RDI: ffff8f5b3735e200 [ 47.938117] RBP: 0000000000000003 R08: 0000000000000001 R09: 0000000000000000 [ 47.938117] R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000 [ 47.938117] R13: 0000000000000000 R14: ffff8f5b3735e200 R15: ffff8f5b3735e200 [ 47.938117] ? default_idle+0x1a/0x140 [ 47.938117] do_idle+0x1bc/0x280 [ 47.938117] cpu_startup_entry+0x19/0x20 [ 47.938117] start_secondary+0x187/0x1c0 [ 47.938117] secondary_startup_64+0xa4/0xb0 The reason seems to be that tipc_net_finalize()->tipc_sk_reinit() is calling the function rhashtable_walk_enter() within a timer interrupt. We fix this by executing tipc_net_finalize() in work queue context. Acked-by: Ying Xue <ying.xue@windriver.com> Signed-off-by: Jon Maloy <jon.maloy@ericsson.com> Signed-off-by: David S. Miller <davem@davemloft.net> 
We get the following warning:

[   47.926140] 32-bit node address hash set to 2010a0a
[   47.927202]
[   47.927433] ================================
[   47.928050] WARNING: inconsistent lock state
[   47.928661] 4.19.0+ #37 Tainted: G            E
[   47.929346] --------------------------------
[   47.929954] inconsistent {SOFTIRQ-ON-W} -> {IN-SOFTIRQ-W} usage.
[   47.930116] swapper/3/0 [HC0[0]:SC1[3]:HE1:SE0] takes:
[   47.930116] 00000000af8bc31e (&(&ht->lock)->rlock){+.?.}, at: rhashtable_walk_enter+0x36/0xb0
[   47.930116] {SOFTIRQ-ON-W} state was registered at:
[   47.930116]   _raw_spin_lock+0x29/0x60
[   47.930116]   rht_deferred_worker+0x556/0x810
[   47.930116]   process_one_work+0x1f5/0x540
[   47.930116]   worker_thread+0x64/0x3e0
[   47.930116]   kthread+0x112/0x150
[   47.930116]   ret_from_fork+0x3a/0x50
[   47.930116] irq event stamp: 14044
[   47.930116] hardirqs last  enabled at (14044): [<ffffffff9a07fbba>] __local_bh_enable_ip+0x7a/0xf0
[   47.938117] hardirqs last disabled at (14043): [<ffffffff9a07fb81>] __local_bh_enable_ip+0x41/0xf0
[   47.938117] softirqs last  enabled at (14028): [<ffffffff9a0803ee>] irq_enter+0x5e/0x60
[   47.938117] softirqs last disabled at (14029): [<ffffffff9a0804a5>] irq_exit+0xb5/0xc0
[   47.938117]
[   47.938117] other info that might help us debug this:
[   47.938117]  Possible unsafe locking scenario:
[   47.938117]
[   47.938117]        CPU0
[   47.938117]        ----
[   47.938117]   lock(&(&ht->lock)->rlock);
[   47.938117]   <Interrupt>
[   47.938117]     lock(&(&ht->lock)->rlock);
[   47.938117]
[   47.938117]  *** DEADLOCK ***
[   47.938117]
[   47.938117] 2 locks held by swapper/3/0:
[   47.938117]  #0: 0000000062c64f90 ((&d->timer)){+.-.}, at: call_timer_fn+0x5/0x280
[   47.938117]  #1: 00000000ee39619c (&(&d->lock)->rlock){+.-.}, at: tipc_disc_timeout+0xc8/0x540 [tipc]
[   47.938117]
[   47.938117] stack backtrace:
[   47.938117] CPU: 3 PID: 0 Comm: swapper/3 Tainted: G            E     4.19.0+ #37
[   47.938117] Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011
[   47.938117] Call Trace:
[   47.938117]  <IRQ>
[   47.938117]  dump_stack+0x5e/0x8b
[   47.938117]  print_usage_bug+0x1ed/0x1ff
[   47.938117]  mark_lock+0x5b5/0x630
[   47.938117]  __lock_acquire+0x4c0/0x18f0
[   47.938117]  ? lock_acquire+0xa6/0x180
[   47.938117]  lock_acquire+0xa6/0x180
[   47.938117]  ? rhashtable_walk_enter+0x36/0xb0
[   47.938117]  _raw_spin_lock+0x29/0x60
[   47.938117]  ? rhashtable_walk_enter+0x36/0xb0
[   47.938117]  rhashtable_walk_enter+0x36/0xb0
[   47.938117]  tipc_sk_reinit+0xb0/0x410 [tipc]
[   47.938117]  ? mark_held_locks+0x6f/0x90
[   47.938117]  ? __local_bh_enable_ip+0x7a/0xf0
[   47.938117]  ? lockdep_hardirqs_on+0x20/0x1a0
[   47.938117]  tipc_net_finalize+0xbf/0x180 [tipc]
[   47.938117]  tipc_disc_timeout+0x509/0x540 [tipc]
[   47.938117]  ? call_timer_fn+0x5/0x280
[   47.938117]  ? tipc_disc_msg_xmit.isra.19+0xa0/0xa0 [tipc]
[   47.938117]  ? tipc_disc_msg_xmit.isra.19+0xa0/0xa0 [tipc]
[   47.938117]  call_timer_fn+0xa1/0x280
[   47.938117]  ? tipc_disc_msg_xmit.isra.19+0xa0/0xa0 [tipc]
[   47.938117]  run_timer_softirq+0x1f2/0x4d0
[   47.938117]  __do_softirq+0xfc/0x413
[   47.938117]  irq_exit+0xb5/0xc0
[   47.938117]  smp_apic_timer_interrupt+0xac/0x210
[   47.938117]  apic_timer_interrupt+0xf/0x20
[   47.938117]  </IRQ>
[   47.938117] RIP: 0010:default_idle+0x1c/0x140
[   47.938117] Code: 90 90 90 90 90 90 90 90 90 90 90 90 90 90 0f 1f 44 00 00 41 54 55 53 65 8b 2d d8 2b 74 65 0f 1f 44 00 00 e8 c6 2c 8b ff fb f4 <65> 8b 2d c5 2b 74 65 0f 1f 44 00 00 5b 5d 41 5c c3 65 8b 05 b4 2b
[   47.938117] RSP: 0018:ffffaf6ac0207ec8 EFLAGS: 00000206 ORIG_RAX: ffffffffffffff13
[   47.938117] RAX: ffff8f5b3735e200 RBX: 0000000000000003 RCX: 0000000000000001
[   47.938117] RDX: 0000000000000001 RSI: 0000000000000001 RDI: ffff8f5b3735e200
[   47.938117] RBP: 0000000000000003 R08: 0000000000000001 R09: 0000000000000000
[   47.938117] R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000
[   47.938117] R13: 0000000000000000 R14: ffff8f5b3735e200 R15: ffff8f5b3735e200
[   47.938117]  ? default_idle+0x1a/0x140
[   47.938117]  do_idle+0x1bc/0x280
[   47.938117]  cpu_startup_entry+0x19/0x20
[   47.938117]  start_secondary+0x187/0x1c0
[   47.938117]  secondary_startup_64+0xa4/0xb0

The reason seems to be that tipc_net_finalize()->tipc_sk_reinit() is
calling the function rhashtable_walk_enter() within a timer interrupt.
We fix this by executing tipc_net_finalize() in work queue context.

Acked-by: Ying Xue <ying.xue@windriver.com>
Signed-off-by: Jon Maloy <jon.maloy@ericsson.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
tipc: fix an interrupt unsafe locking scenario 2018-08-07T20:15:35+00:00 Ying Xue ying.xue@windriver.com 2018-08-07T07:52:32+00:00 37436d9c0e8f62c3eebe204ff5776ff31fd64658 Commit 9faa89d4ed9d ("tipc: make function tipc_net_finalize() thread safe") tries to make it thread safe to set node address, so it uses node_list_lock lock to serialize the whole process of setting node address in tipc_net_finalize(). But it causes the following interrupt unsafe locking scenario: CPU0 CPU1 ---- ---- rht_deferred_worker() rhashtable_rehash_table() lock(&(&ht->lock)->rlock) tipc_nl_compat_doit() tipc_net_finalize() local_irq_disable(); lock(&(&tn->node_list_lock)->rlock); tipc_sk_reinit() rhashtable_walk_enter() lock(&(&ht->lock)->rlock); <Interrupt> tipc_disc_rcv() tipc_node_check_dest() tipc_node_create() lock(&(&tn->node_list_lock)->rlock); *** DEADLOCK *** When rhashtable_rehash_table() holds ht->lock on CPU0, it doesn't disable BH. So if an interrupt happens after the lock, it can create an inverse lock ordering between ht->lock and tn->node_list_lock. As a consequence, deadlock might happen. The reason causing the inverse lock ordering scenario above is because the initial purpose of node_list_lock is not designed to do the serialization of node address setting. As cmpxchg() can guarantee CAS (compare-and-swap) process is atomic, we use it to replace node_list_lock to ensure setting node address can be atomically finished. It turns out the potential deadlock can be avoided as well. Fixes: 9faa89d4ed9d ("tipc: make function tipc_net_finalize() thread safe") Signed-off-by: Ying Xue <ying.xue@windriver.com> Acked-by: Jon Maloy <maloy@donjonn.com> Signed-off-by: David S. Miller <davem@davemloft.net> 
Commit 9faa89d4ed9d ("tipc: make function tipc_net_finalize() thread
safe") tries to make it thread safe to set node address, so it uses
node_list_lock lock to serialize the whole process of setting node
address in tipc_net_finalize(). But it causes the following interrupt
unsafe locking scenario:

       CPU0                    CPU1
       ----                    ----
  rht_deferred_worker()
  rhashtable_rehash_table()
  lock(&(&ht->lock)->rlock)
			       tipc_nl_compat_doit()
                               tipc_net_finalize()
                               local_irq_disable();
                               lock(&(&tn->node_list_lock)->rlock);
                               tipc_sk_reinit()
                               rhashtable_walk_enter()
                               lock(&(&ht->lock)->rlock);
  <Interrupt>
  tipc_disc_rcv()
  tipc_node_check_dest()
  tipc_node_create()
  lock(&(&tn->node_list_lock)->rlock);

 *** DEADLOCK ***

When rhashtable_rehash_table() holds ht->lock on CPU0, it doesn't
disable BH. So if an interrupt happens after the lock, it can create
an inverse lock ordering between ht->lock and tn->node_list_lock. As
a consequence, deadlock might happen.

The reason causing the inverse lock ordering scenario above is because
the initial purpose of node_list_lock is not designed to do the
serialization of node address setting.

As cmpxchg() can guarantee CAS (compare-and-swap) process is atomic,
we use it to replace node_list_lock to ensure setting node address can
be atomically finished. It turns out the potential deadlock can be
avoided as well.

Fixes: 9faa89d4ed9d ("tipc: make function tipc_net_finalize() thread safe")
Signed-off-by: Ying Xue <ying.xue@windriver.com>
Acked-by: Jon Maloy <maloy@donjonn.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
tipc: make function tipc_net_finalize() thread safe 2018-07-07T10:49:02+00:00 Jon Maloy jon.maloy@ericsson.com 2018-07-06T18:10:06+00:00 9faa89d4ed9d7d326f4763d262842270450f9b1f The setting of the node address is not thread safe, meaning that two discoverers may decide to set it simultanously, with a duplicate entry in the name table as result. We fix that with this commit. Fixes: 25b0b9c4e835 ("tipc: handle collisions of 32-bit node address hash values") Signed-off-by: Jon Maloy <jon.maloy@ericsson.com> Signed-off-by: David S. Miller <davem@davemloft.net> 
The setting of the node address is not thread safe, meaning that
two discoverers may decide to set it simultanously, with a duplicate
entry in the name table as result. We fix that with this commit.

Fixes: 25b0b9c4e835 ("tipc: handle collisions of 32-bit node address hash values")
Signed-off-by: Jon Maloy <jon.maloy@ericsson.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
tipc: fix possible crash in __tipc_nl_net_set() 2018-04-16T22:08:18+00:00 Eric Dumazet edumazet@google.com 2018-04-16T15:29:43+00:00 c6404122cb18f1fbd2a6dc85ab687f6fa2e454cf syzbot reported a crash in __tipc_nl_net_set() caused by NULL dereference. We need to check that both TIPC_NLA_NET_NODEID and TIPC_NLA_NET_NODEID_W1 are present. We also need to make sure userland provided u64 attributes. Fixes: d50ccc2d3909 ("tipc: add 128-bit node identifier") Signed-off-by: Eric Dumazet <edumazet@google.com> Cc: Jon Maloy <jon.maloy@ericsson.com> Cc: Ying Xue <ying.xue@windriver.com> Reported-by: syzbot <syzkaller@googlegroups.com> Signed-off-by: David S. Miller <davem@davemloft.net> 
syzbot reported a crash in __tipc_nl_net_set() caused by NULL dereference.

We need to check that both TIPC_NLA_NET_NODEID and TIPC_NLA_NET_NODEID_W1
are present.

We also need to make sure userland provided u64 attributes.

Fixes: d50ccc2d3909 ("tipc: add 128-bit node identifier")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Jon Maloy <jon.maloy@ericsson.com>
Cc: Ying Xue <ying.xue@windriver.com>
Reported-by: syzbot <syzkaller@googlegroups.com>
Signed-off-by: David S. Miller <davem@davemloft.net>