When the BSS table is being updated based on new scan results, a BSS
entry could end up getting added into last_scan_res list multiple times
if the scan results from the driver includes duplicated values. This
should not happen with driver_nl80211.c since it filter outs duplicates,
but in theory, other driver wrappers could indicate such scan results.
Anyway, it is safer to make sure this cannot happen by explicitly
verifying the last_scan_res list before adding an updated BSS entry
there. A duplicated entry in the list could potentially result in freed
memory being used if there is large enough number of BSSes in the scan
results to cause removal of old BSS entries.
Signed-hostap: Jouni Malinen <jouni@qca.qualcomm.com>
If there are large number of BSSes in the scan results, BSS table update
could have added a BSS entry to the last_scan_res in a case where that
BSS entry got just deleted. This would happen only if there are more
than bss_max_count (by default 200) BSSes and if at least bss_max_count
of those BSSes are known (match a configured network). In such a case,
wpa_bss_add() could end up allocating a new BSS entry and return a
pointer to that entry even if it was the one that ended up getting freed
to keep the BSS table length within the limit. This could result in
freed memory being used and the process crashing (likely with segfault)
when trying to access information from that BSS entry.
Fix the issue by removing the oldest BSS entry before linking the new
entry to the table. This makes sure the newly added entry will never get
picked up as the one to be deleted immediately.
Signed-hostap: Jouni Malinen <jouni@qca.qualcomm.com>
This can be used to configure wpa_supplicant to ignore old scan results
from the driver cache in cases where such results were not updated after
the scan trigger from wpa_supplicant. This can be useful in some cases
where the driver may cache information for a significant time and the AP
configuration is changing. Many such cases are for testing scripts, but
this could potentially be useful for some WPS use cases, too.
Signed-hostap: Jouni Malinen <j@w1.fi>
If the AP (P2P GO) has changes its channel of SSID recently, the BSS
table may have multiple entries for a BSSID. Select the one which was
most recently updated for WPS/P2P operations in such case to increase
the likelihood of using current information.
Signed-hostap: Jouni Malinen <j@w1.fi>
For various P2P use cases, it is useful to have more accurate timestamp
for the peer information update. This commit improves scan result
handling by using a single timestamp that is taken immediately after
fetching the results from the driver and then using that value to
calculate the time when the driver last updated the BSS entry. In
addition, more debug information is added for P2P peer updates to be
able to clearly see how old information is being used here.
Signed-hostap: Jouni Malinen <jouni@qca.qualcomm.com>
The RANGE=N1-N2 command did not return any entries in some cases where
N1 does not match with any BSS entry. Fix this by allow entries to be
fetched even without knowing the exact id values.
Signed-hostap: Jouni Malinen <jouni@qca.qualcomm.com>
When ANQP_GET or HS20_ANQP_GET is used to request ANQP information,
unshare the ANQP information (i.e., create a per-BSS copy of it) to
make sure the information from the specified BSS is available in case
the APs provide different information within HESSID.
Signed-hostap: Jouni Malinen <jouni@qca.qualcomm.com>
The BSS pointer may change if the entry needs to be reallocated
and the new pointer has to be added to the last_scan_res array
to avoid using pointers to freed memory.
Signed-hostap: Jouni Malinen <j@w1.fi>
This is an initial step in allowing the ANQP responses to be shared
among multiple BSSes if the BSSes are determined to be operating under
identical configuration.
Signed-hostap: Jouni Malinen <jouni@qca.qualcomm.com>
This allows last results to be used even after they have been freed
since the information is copied to the BSS entries anyway and this new
array provides the order in which scan results were processed.
Signed-hostap: Jouni Malinen <j@w1.fi>
When looking for a BSS to eject due to too many entries, never
pick one that is in use. Otherwise, we run the risk of having
pointers to freed data.
Signed-hostap: Paul Stewart <pstew@chromium.org>
For concurrency scenarios we should not update the scan results without
P2P IE to P2P group interfaces. This patch is to take care if a scan has
been requested on STA interface and scan results are getting updated
from sibling to P2P group interface. A P2P GO Probe Response for a
legacy STA scan would be without P2P IE. So it will wrongly update the
BSS list of P2P group interface too when results are updated from
sibling.
Since P2P group interfaces are used only for connecting to a P2P group,
it is fine to filter out all non-P2P entries from their BSS table.
Signed-off-by: Neeraj Garg <neerajkg@broadcom.com>
After reallocation of the bss struct, current_bss wasn't updated and
could hold an invalid pointer (which might get dereferenced later).
Update current_bss if the pointer was changed.
Signed-hostap: Eliad Peller <eliad@wizery.com>
intended-for: hostap-1
wpa_supplicant can now be configured to filter out scan results based
on a BSSID filter. Space-separated set of allowed BSSIDs can be set
with wpa_cli set bssid_filter command. Filtering mechanism can be
disabled by setting this variable to an empty list. When set, only
the BSSes that have a matching entry in this list will be accepted
from scan results.
Signed-hostap: Jouni Malinen <jouni@qca.qualcomm.com>
"BSS p2p_dev_addr=<P2P Device Address>" can now be used to fetch a
specific BSS entry based on the P2P Device Address of the GO to avoid
having to iterate through the full BSS table when an external program
needs to figure out whether a specific peer is currently operating as
a GO.
Signed-hostap: Jouni Malinen <jouni@qca.qualcomm.com>
Add mechanism for using GAS/ANQP to query Interworking related
information from APs. The received information is stored in the BSS
table and can be viewed with ctrl_iface BSS command.
New ctrl_iface command ANQP_GET can be used to fetch ANQP elements from
a specific AP. Additional commands FETCH_ANQP and STOP_FETCH_ANQP can be
used to initiate and stop an iteration through all APs in the BSS table
that indicate support Interworking to fetch ANQP elements from them.
When the BSS table size limit has been reached, drop first the oldest
BSS entries for which there is not a matching network in the
configuration based on SSID (wildcards are ignored). This makes it
less likely to hit connection issues in environments with huge number
of visible APs.
When comparing BSS table entries, handle empty concatenated
vendor-specific IE differently from completely missing IE. This
does not change anything for the only currently compared IE that
can be fragmented (WPS IE), but it is better to have the generic
code here ready for any possible new IE that could be used in
with zero-length data.
Replace compile-time BSS cache expiration age and scan count by config
parameters that can be set via wpa_cli and the new D-Bus API. The latter
is done with interface properties BSSExpireAge and BSSExpireCount.
This fixes an issue seen in our wifi testbed, where we frequently
switch the SSID of the AP. wpa_supplicant's BSS list will have, for
example both <bssid, "Check11b"> (from the previous test) and <bssid,
"Check11g"> (from the current test) - note that the bssid is the same for
both. The (old) D-Bus API for fetching scan responses from wpa_supplicant
is fetch-by-bssid, so the caller (flimflam) incorrectly believes we're
associated with <bssid, "Check11b">.
Add an "Interface.FlushBSS" method to the new D-Bus API and a "flush"
method to the old API. Both take an age parameter that is a threshold
(in seconds) for selecting entries to evict. Setting this parameter
to zero flushes all entries from the cache.
This mechanism is useful for a connection manager to clear state at
startup and on resume (where the age parameter may be used to hold
onto recent/valid data).
This converts number of debugging messages to use wpa_msg() in order
to allow the interface name to be shown with the messages.
A new function, wpa_dbg(), is introduced to allow
CONFIG_NO_STDOUT_DEBUG=y builds to remove the debug strings. This is
otherwise identical with wpa_msg(), but it gets compiled out if stdout
debugging is disabled.
New global configuration parameter bss_max_count can now be used to
change the maximum BSS table size. The old fixed size limit (200) is
used as the default value for this parameter.
Expose RSN and WPA properties for BSS objects containing information
about key management and cipher suites. Get rid of WPA/RSN/WPSIE
byte array properties and add IEs byte array property with all IE data
instead.
This allows the driver wrappers to return two sets of IEs, so that
the BSS code can use information from both Beacon and Probe Response
frames if needed. For example, some Cisco APs seem to include more
information in Wireless Provisioning Services IE when it is in the
Beacon frame.
Most of this file was already moved into wpa_supplicant/scan.c and
we can remove the file completely by having couple of small helper
functions copied to the remaining users outside core wpa_supplicant
code.
The wpa_s->bss_id list was being corrupted when the BSS entry needed
to be reallocated due to longer IE data. The entry has to be removed
from all lists before reallocation to avoid this (it was only removed
from the wpa_s->bss list).
Get more information about scans when updating BSS table information.
This allows the missing-from-scans expiration rule to work properly
when only partial set of channels or SSIDs are being scanned.
This allows the BSS list to be iterated in order of increasing id
to avoid problems with new scans reordering entries. The order on the
wpa_s->bss list changes with most recently updated entries being moved
to the tail of the list while wpa_s->bss_id list maintains its order
with new entries being added to the tail and old entries being removed
when they expire.
Collect information from scan results into a BSS table that will not
expire information as quickly as scan results where every new scan,
no matter for how limited set of channels/SSIDs, clears all old
information.
For now, this is only used for D-Bus BSS added/removed notifications,
but this will likely be extended to be used internally instead of the
scan results to better support partial scans.
