This simulates the conditions that trigger a free-after-use which was
fixed with:
2c355db7 ("scan: remove periodic scans from queue on abort")
This behavior can be reproduced reliably using this test with the above
patch reverted.
This debug print was before any checks which could bail out prior to
autoconnect starting. This was confusing because debug logs would
contain multiple "station_autoconnect_start()" prints making you think
autoconnect was started several times.
The periodic scan code was refactored to make normal scans and
periodic scans consistent by keeping both in the same queue. But
that change left out the abort path where periodic scans were not
actually removed from the queue.
This fixes a rare crash when a periodic scan has been triggered and
the device goes down. This path never removes the request from the
queue but still frees it. Then when the scan context is removed the
stale request is freed again.
0 0x4bb65b in scan_request_cancel src/scan.c:202
1 0x64313c in l_queue_clear ell/queue.c:107
2 0x643348 in l_queue_destroy ell/queue.c:82
3 0x4bbfb7 in scan_context_free src/scan.c:209
4 0x4c9a78 in scan_wdev_remove src/scan.c:2115
5 0x42fecd in netdev_free src/netdev.c:965
6 0x445827 in netdev_destroy src/netdev.c:6507
7 0x52beb9 in manager_config_notify src/manager.c:765
8 0x67084b in process_multicast ell/genl.c:1029
9 0x67084b in received_data ell/genl.c:1096
10 0x65e790 in io_callback ell/io.c:120
11 0x65aaae in l_main_iterate ell/main.c:478
12 0x65b213 in l_main_run ell/main.c:525
13 0x65b213 in l_main_run ell/main.c:507
14 0x65b72c in l_main_run_with_signal ell/main.c:647
15 0x4124e7 in main src/main.c:532
If netdev_connect_failed is called before netdev_get_oci_cb() the
netdev's handshake will be destroyed and ultimately crash when the
callback is called.
This patch moves the cancelation into netdev_connect_free rather than
netdev_free.
++++++++ backtrace ++++++++
0 0x7f4e1787d320 in /lib64/libc.so.6
1 0x42634c in handshake_state_set_chandef() at src/handshake.c:1057
2 0x40a11b in netdev_get_oci_cb() at src/netdev.c:2387
3 0x483d7b in process_unicast() at ell/genl.c:986
4 0x480d3c in io_callback() at ell/io.c:120
5 0x48004d in l_main_iterate() at ell/main.c:472 (discriminator 2)
6 0x4800fc in l_main_run() at ell/main.c:521
7 0x48032c in l_main_run_with_signal() at ell/main.c:649
8 0x403e95 in main() at src/main.c:532
9 0x7f4e17867b75 in /lib64/libc.so.6
+++++++++++++++++++++++++++
Commit 4d2176df29 ("handshake: Allow event handler to free handshake")
introduced a re-entrancy guard so that handshake_state objects that are
destroyed as a result of the event do not cause a crash. It rightly
used a temporary object to store the passed in handshake. Unfortunately
this caused variable shadowing which resulted in crashes fixed by commit
d22b174a73 ("handshake: use _hs directly in handshake_event").
However, since the temporary was no longer used, this fix itself caused
a crash:
#0 0x00005555f0ba8b3d in eapol_handle_ptk_1_of_4 (sm=sm@entry=0x5555f2b4a920, ek=0x5555f2b62588, ek@entry=0x16, unencrypted=unencrypted@entry=false) at src/eapol.c:1236
1236 handshake_event(sm->handshake,
(gdb) bt
#0 0x00005555f0ba8b3d in eapol_handle_ptk_1_of_4 (sm=sm@entry=0x5555f2b4a920, ek=0x5555f2b62588, ek@entry=0x16, unencrypted=unencrypted@entry=false) at src/eapol.c:1236
#1 0x00005555f0bab118 in eapol_key_handle (unencrypted=<optimized out>, frame=<optimized out>, sm=0x5555f2b4a920) at src/eapol.c:2343
#2 eapol_rx_packet (proto=<optimized out>, from=<optimized out>, frame=<optimized out>, unencrypted=<optimized out>, user_data=0x5555f2b4a920) at src/eapol.c:2665
#3 0x00005555f0bac497 in __eapol_rx_packet (ifindex=62, src=src@entry=0x5555f2b62574 "x\212 J\207\267", proto=proto@entry=34958, frame=frame@entry=0x5555f2b62588 "\002\003",
len=len@entry=121, noencrypt=noencrypt@entry=false) at src/eapol.c:3017
#4 0x00005555f0b8c617 in netdev_control_port_frame_event (netdev=0x5555f2b64450, msg=0x5555f2b62588) at src/netdev.c:5574
#5 netdev_unicast_notify (msg=msg@entry=0x5555f2b619a0, user_data=<optimized out>) at src/netdev.c:5613
#6 0x00007f60084c9a51 in dispatch_unicast_watches (msg=0x5555f2b619a0, id=<optimized out>, genl=0x5555f2b3fc80) at ell/genl.c:954
#7 process_unicast (nlmsg=0x7fff61abeac0, genl=0x5555f2b3fc80) at ell/genl.c:973
#8 received_data (io=<optimized out>, user_data=0x5555f2b3fc80) at ell/genl.c:1098
#9 0x00007f60084c61bd in io_callback (fd=<optimized out>, events=1, user_data=0x5555f2b3fd20) at ell/io.c:120
#10 0x00007f60084c536d in l_main_iterate (timeout=<optimized out>) at ell/main.c:478
#11 0x00007f60084c543e in l_main_run () at ell/main.c:525
#12 l_main_run () at ell/main.c:507
#13 0x00007f60084c5670 in l_main_run_with_signal (callback=callback@entry=0x5555f0b89150 <signal_handler>, user_data=user_data@entry=0x0) at ell/main.c:647
#14 0x00005555f0b886a4 in main (argc=<optimized out>, argv=<optimized out>) at src/main.c:532
This happens when the driver does not support rekeying, which causes iwd to
attempt a disconnect and re-connect. The disconnect action is
taken during the event callback and destroys the underlying eapol state
machine. Since a temporary isn't used, attempting to dereference
sm->handshake results in a crash.
Fix this by introducing a UNIQUE_ID macro which should prevent shadowing
and using a temporary variable as originally intended.
Fixes: d22b174a73 ("handshake: use _hs directly in handshake_event")
Fixes: 4d2176df29 ("handshake: Allow event handler to free handshake")
Reported-By: Toke Høiland-Jørgensen <toke@toke.dk>
Tested-by: Toke Høiland-Jørgensen <toke@toke.dk>
There is no need to punch the holes for netdev/wheel groups to send to
the .Agent interface. This is only done by the iwd daemon itself and
the policy for user 'root' already takes care of this.
A select few drivers send this instead of SIGNAL_MBM. The docs say this
value is the signal 'in unspecified units, scaled to 0..100'. The range
for SIGNAL_MBM is -10000..0 so this can be scaled to the MBM range easy
enough...
Now, this isn't exactly correct because this value ultimately gets
returned from GetOrderedNetworks() and is documented as 100 * dBm where
in reality its just a unit-less signal strength value. Its not ideal, but
this patch at least will fix BSS ranking for these few drivers.
The 'at_console' D-Bus policy setting has been deprecated for more then
10 years and could be ignored at any time in the future. Moreover, while
the intend was to allow locally logged on users to interact with iwd, it
didn't actually do that.
More info at https://www.spinics.net/lists/linux-bluetooth/msg75267.html
and https://gitlab.freedesktop.org/dbus/dbus/-/issues/52
Therefor remove the 'at_console' setting block.
On Debian (based) systems, there is a standard defined group which is
allowed to manage network interfaces, and that is the 'netdev' group.
So add a D-Bus setting block to grant the 'netdev' group that access.
Building on GCC 8 resulted in this compiler error.
src/sae.c:107:25: error: implicit declaration of function 'reallocarray';
did you mean 'realloc'? [-Werror=implicit-function-declaration]
sm->rejected_groups = reallocarray(NULL, 2, sizeof(uint16_t));
src/erp.c:134:10: error: comparison of integer expressions of different
signedness: 'unsigned int' and 'int' [-Werror=sign-compare]
src/eap-ttls.c:378:10: error: comparison of integer expressions of different signedness: 'uint32_t' {aka 'unsigned int'} and 'int' [-Werror=sign-compare]
Fixes the following crash:
#0 0x000211c4 in netdev_connect_event (msg=<optimized out>, netdev=0x2016940) at src/netdev.c:2915
#1 0x76f11220 in process_multicast (nlmsg=0x7e8acafc, group=<optimized out>, genl=<optimized out>) at ell/genl.c:1029
#2 received_data (io=<optimized out>, user_data=<optimized out>) at ell/genl.c:1096
#3 0x76f0da08 in io_callback (fd=<optimized out>, events=1, user_data=0x200a560) at ell/io.c:120
#4 0x76f0ca78 in l_main_iterate (timeout=<optimized out>) at ell/main.c:478
#5 0x76f0cb74 in l_main_run () at ell/main.c:525
#6 l_main_run () at ell/main.c:507
#7 0x76f0cdd4 in l_main_run_with_signal (callback=callback@entry=0x18c94 <signal_handler>, user_data=user_data@entry=0x0)
at ell/main.c:647
#8 0x00018178 in main (argc=<optimized out>, argv=<optimized out>) at src/main.c:532
This crash was introduced in commit:
4d2176df29 ("handshake: Allow event handler to free handshake")
The culprit seems to be that 'hs' is being used both in the caller and
in the macro. Since the macro defines a variable 'hs' in local block
scope, it overrides 'hs' from function scope. Yet (_hs) still evaluates
to 'hs' leading the local variable to be initialized with itself. Only
the 'handshake_event(hs, HANDSHAKE_EVENT_SETTING_KEYS))' is affected
since it is the only macro invocation that uses 'hs' from function
scope. Thus, the crash would only happen on hardware supporting handshake
offload (brcmfmac).
Fix this by removing the local scope variable declaration and evaluate
(_hs) instead.
Fixes: 4d2176df29 ("handshake: Allow event handler to free handshake")
- Ensure that input isn't an empty string
- Ensure that EINVAL errno (which could be optionally returned by
strto{ul|l} is also checked.
- Since strtoul allows '+' and '-' characters in input, ensure that
input which is expected to be an unsigned number doesn't start with
'-'
Given an ASN1 blob of the right form, parse and create
an l_ecc_point object. The form used is specific to DPP
hence why this isn't general purpose and put into dpp-util.
Like in ap.c, allow the event callback to mark the handshake state as
destroyed, without causing invalid accesses after the callback has
returned. In this case the crash was because try_handshake_complete
needed to access members of handshake_state after emitting the event,
as well as access the netdev, which also has been destroyed:
==257707== Invalid read of size 8
==257707== at 0x408C85: try_handshake_complete (netdev.c:1487)
==257707== by 0x408C85: try_handshake_complete (netdev.c:1480)
(...)
==257707== Address 0x4e187e8 is 856 bytes inside a block of size 872 free'd
==257707== at 0x484621F: free (in /usr/libexec/valgrind/vgpreload_memcheck-amd64-linux.so)
==257707== by 0x437887: ap_stop_handshake (ap.c:151)
==257707== by 0x439793: ap_del_station (ap.c:316)
==257707== by 0x43EA92: ap_station_disconnect (ap.c:3411)
==257707== by 0x43EA92: ap_station_disconnect (ap.c:3399)
==257707== by 0x454276: p2p_group_event (p2p.c:1006)
==257707== by 0x439147: ap_event (ap.c:281)
==257707== by 0x4393AB: ap_new_rsna (ap.c:390)
==257707== by 0x4393AB: ap_handshake_event (ap.c:1010)
==257707== by 0x408C7F: try_handshake_complete (netdev.c:1485)
==257707== by 0x408C7F: try_handshake_complete (netdev.c:1480)
(...)
Previously we added logic to defer doing anything in ap_free() to after
the AP event handler has returned so that ap_event() has a chance to
inform whoever called it that the ap_state has been freed. But there's
also a chance that the event handler is destroying both the AP and the
netdev it runs on, so after the handler has returned we can't even use
netdev_get_wdev_id or netdev_get_ifindex. The easiest solution seems to
be to call ap_reset() in ap_free() even if we're within an event handler
to ensure we no longer need any external objects. Also make sure
ap_reset() can be called multiple times.
Another option would be to watch for NETDEV_WATCH_EVENT_DEL and remove
our reference to the netdev (because there's no need actually call
l_rtnl_ifaddr_delete or frame_watch_wdev_remove if the netdev was
destroyed -- frame_watch already tracks netdev removals), or to save
just the ifindex and the wdev id...
The purpose of this was to have a single utility to both cancel an
existing offchannel operation (if one exists) and start a new one.
The problem was the previous offchannel operation was being canceled
first which opened up the radio work queue to other items. This is
not desireable as, for example, a scan would end up breaking the
DPP protocol most likely.
Starting the new offchannel then canceling is the correct order of
operations but to do this required saving the new ID, canceling, then
setting offchannel_id to the new ID so dpp_presence_timeout wouldn't
overwrite the new ID to zero.
This also removes an explicit call to offchannel_cancel which is
already done by dpp_offchannel_start.
Several members are named based on initiator/responder (i/r)
terminology. Eventually both initiator and responder will be
supported so rename these members to use own/peer naming
instead.
ASN1 parsing will soon be required which will need some utilities in
asn1-private.h. To avoid duplication include this private header and
replace the OID's with the defined structures as well as remove the
duplicated macros.
station_set_scan_results takes an autoconnect flag which was being
set true in both regular/quick autoconnect scans. Since OWE networks
are processed after setting the scan results IWD could end up
connecting to a network before all the OWE hidden networks are
populated.
To fix this regular/quick autoconnect results will set the flag to
false, then process OWE networks, then start autoconnect. If any
OWE network scans are pending station_autoconnect_start will fail
but will pick back up after the hidden OWE scan.
During investigation another separate crash was found. The original is
caused by a disconnect event coming in after a neighbor report scan
was completed (roam failed) during the full roam scan.
The second crash is caused by a disconnect coming in during a full
roam scan when no neighbor report scan was ever issued.
scan_request_failed and scan_finished remove the finished scan_request
from the request queue right away, before calling the callback. This
breaks those clients that rely on scan_cancel working on such requests
(i.e. to force the destroy callback to be invoked synchronously, see
a0911ca778 ("station: Make sure roam_scan_id is always canceled").
Fix this by removing the scan_request from the request queue after
invoking the callback. Also provide a re-entrancy guard that will make
sure that the scan_request isn't removed in scan_cancel itself.
There are similar operations being performed but with different
callbacks and userdata, depending on whether 'sr' is NULL or not.
Optimize the function flow slightly to make if-else unnecessary.
While here, update the comment. periodic scans are now scheduled only
based on the periodic timeout timer.
If periodic scan is active and we receive a SCAN_ABORTED event, we would
still invoke the periodic scan callback with an error. This is rather
pointless since the periodic scan callback cannot do anything useful
with this information. Fix that.
We should never reach a point where NEW_SCAN_RESULTS or SCAN_ABORTED are
received before a corresponding TRIGGER_SCAN is received. Even if this
does happen, there's no harm from processing the commands anyway.
This makes it a little easier to book-keep the started variable. Since
scan_request already has a 'passive' bit-field, there should be no
storage penalty.
If scan_cancel is called on a scan_request that is 'finished' but with
the GET_SCAN command still in flight, it will trigger a crash as
follows:
Received Deauthentication event, reason: 2, from_ap: true
src/station.c:station_disconnect_event() 11
src/station.c:station_disassociated() 11
src/station.c:station_reset_connection_state() 11
src/station.c:station_roam_state_clear() 11
src/scan.c:scan_cancel() Trying to cancel scan id 6 for wdev 200000002
src/scan.c:scan_cancel() Scan is at the top of the queue, but not triggered
src/scan.c:get_scan_done() get_scan_done
Aborting (signal 11) [/home/denkenz/iwd-master/src/iwd]
++++++++ backtrace ++++++++
#0 0x7f9871aef3f0 in /lib64/libc.so.6
#1 0x41f470 in station_roam_scan_notify() at /home/denkenz/iwd-master/src/station.c:2285
#2 0x43936a in scan_finished() at /home/denkenz/iwd-master/src/scan.c:1709
#3 0x439495 in get_scan_done() at /home/denkenz/iwd-master/src/scan.c:1739
#4 0x4bdef5 in destroy_request() at /home/denkenz/iwd-master/ell/genl.c:676
#5 0x4c070b in l_genl_family_cancel() at /home/denkenz/iwd-master/ell/genl.c:1960
#6 0x437069 in scan_cancel() at /home/denkenz/iwd-master/src/scan.c:842
#7 0x41dc2e in station_roam_state_clear() at /home/denkenz/iwd-master/src/station.c:1594
#8 0x41dd2b in station_reset_connection_state() at /home/denkenz/iwd-master/src/station.c:1619
#9 0x41dea4 in station_disassociated() at /home/denkenz/iwd-master/src/station.c:1644
The happens because get_scan_done callback is still called as a result of
l_genl_cancel. Add a re-entrancy guard in the form of 'canceled'
variable in struct scan_request. If set, get_scan_done will skip invoking
scan_finished.
It isn't clear what 'l_queue_peek_head() == results->sr' check was trying
to accomplish. If GET_SCAN dump was scheduled, then it should be
reported. Drop it.
results->sr is set to NULL for 'opportunistic' scans which were
triggered externally. See scan_notify() for details. However,
get_scan_done would only invoke scan_finished (and thus the periodic
scan callback sc->sp.callback) only if the scan queue was empty. It
should do so in all cases.
The point type was being hard coded to 0x3 (BIT1) which may have resulted
in the peer subtracting Y from P when reading in the point (depending on
if Y was odd or not).
Instead set the compressed type to whatever avoids the subtraction which
both saves IWD from needing to do it, as well as the peer.
