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This adds API to allow adding per-station GTKs,
updates mac80211 to support it, and also allows
drivers to remove a key from hwaccel again when
this may be necessary due to multiple GTKs.
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
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Instead of using a WARN_ON(!mutex_is_locked())
use lockdep_assert_held() which compiles away
completely when lockdep isn't enabled, and
also is a more accurate assertion since it
checks that the current thread is holding the
mutex.
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
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Allow drivers to specify their own set of cipher
suites to advertise vendor-specific ciphers. The
driver is then required to implement hardware
crypto offload for it.
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Juuso Oikarinen <juuso.oikarinen@nokia.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
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Standardize logging messages from
printk(KERN_<level> "%s: " fmt , wiphy_name(foo), args);
to
wiphy_<level>(foo, fmt, args);
Signed-off-by: Joe Perches <joe@perches.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
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There's no need to keep separate if statements
for setting up the CCMP/AES-CMAC tfm structs;
move that into the existing switch statement.
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
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Currently, mac80211 translates the cfg80211
cipher suite selectors into ALG_* values.
That isn't all too useful, and some drivers
benefit from the distinction between WEP40
and WEP104 as well. Therefore, convert it
all to use the cipher suite selectors.
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Acked-by: Gertjan van Wingerde <gwingerde@gmail.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
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ieee80211_add_key() currently returns -ENOMEM in case of any error,
including a missing crypto algorithm. Change ieee80211_key_alloc()
and ieee80211_aes_{key_setup_encrypt,cmac_key_setup}() to encode
errors with ERR_PTR() rather than returning NULL, and change
ieee80211_add_key() accordingly.
Compile-tested only.
Reported-by: Marcin Owsiany <porridge@debian.org>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
Acked-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
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Key locking simplification removed key->sdata != NULL verification from
ieee80211_key_free(). While that is fine for most use cases, there is one
path where this function can be called with an unlinked key (i.e.,
key->sdata == NULL && key->local == NULL). This results in a NULL pointer
dereference with the current implementation. This is known to happen at
least with FT protocol when wpa_supplicant tries to configure the key
before association.
Avoid the issue by passing in the local pointer to
ieee80211_key_free(). In addition, do not clear the key from hw_accel
or debugfs if it has not yet been added. At least the hw_accel one could
trigger another NULL pointer dereference.
Signed-off-by: Jouni Malinen <j@w1.fi>
Reviewed-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
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When management frame protection (IEEE 802.11w) is used, we must use a
separate counter for tracking received CCMP packet number for the
management frames. The previously used NUM_RX_DATA_QUEUESth queue was
shared with data frames when QoS was not used and that can cause
problems in detecting replays incorrectly for robust management frames.
Add a new counter just for robust management frames to avoid this issue.
Signed-off-by: Jouni Malinen <jouni.malinen@atheros.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
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Since I recently made station management able
to sleep, I can now rework key management as
well; since it will no longer need a spinlock
and can also use a mutex instead, a bunch of
code to allow drivers' set_key to sleep while
key management is protected by a spinlock can
now be removed.
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
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This reverts commit 03ceedea972a82d343fa5c2528b3952fa9e615d5.
This patch was reported to cause a regression in which connectivity is
lost and cannot be reestablished after a suspend/resume cycle.
Signed-off-by: John W. Linville <linville@tuxdriver.com>
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Conflicts:
drivers/net/wireless/ath/ath9k/phy.c
drivers/net/wireless/iwlwifi/iwl-6000.c
drivers/net/wireless/iwlwifi/iwl-debugfs.c
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When I set up multiple VAPs with ath9k, I encountered an issue that
the traffic may be lost after a while.
The detailed phenomenon is
1. After a while the clients connected to one of these VAPs will get
into a state that no broadcast/multicast packets can be transfered
successfully while the unicast packets can be transfered normally.
2. Minutes latter the unitcast packets transfer will fail as well,
because the ARP entry is expired and it can't be freshed due to the
broadcast trouble.
It's caused by the group key overwritten and someone discussed this
issue in ath9k-devel maillist before, but haven't work out a fix yet.
I referred the method in madwifi, and made a patch for ath9k.
The method is to set the high bit of the sender(AP)'s address, and
associated that mac and the group key. It requires the hardware
supports multicast frame key search. It seems true for AR9160.
Not sure whether it's the correct way to fix this issue. But it seems
to work in my test. The patch is attached, feel free to revise it.
Signed-off-by: Daniel Yingqiang ma <yma.cool@gmail.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
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implicit slab.h inclusion from percpu.h
percpu.h is included by sched.h and module.h and thus ends up being
included when building most .c files. percpu.h includes slab.h which
in turn includes gfp.h making everything defined by the two files
universally available and complicating inclusion dependencies.
percpu.h -> slab.h dependency is about to be removed. Prepare for
this change by updating users of gfp and slab facilities include those
headers directly instead of assuming availability. As this conversion
needs to touch large number of source files, the following script is
used as the basis of conversion.
http://userweb.kernel.org/~tj/misc/slabh-sweep.py
The script does the followings.
* Scan files for gfp and slab usages and update includes such that
only the necessary includes are there. ie. if only gfp is used,
gfp.h, if slab is used, slab.h.
* When the script inserts a new include, it looks at the include
blocks and try to put the new include such that its order conforms
to its surrounding. It's put in the include block which contains
core kernel includes, in the same order that the rest are ordered -
alphabetical, Christmas tree, rev-Xmas-tree or at the end if there
doesn't seem to be any matching order.
* If the script can't find a place to put a new include (mostly
because the file doesn't have fitting include block), it prints out
an error message indicating which .h file needs to be added to the
file.
The conversion was done in the following steps.
1. The initial automatic conversion of all .c files updated slightly
over 4000 files, deleting around 700 includes and adding ~480 gfp.h
and ~3000 slab.h inclusions. The script emitted errors for ~400
files.
2. Each error was manually checked. Some didn't need the inclusion,
some needed manual addition while adding it to implementation .h or
embedding .c file was more appropriate for others. This step added
inclusions to around 150 files.
3. The script was run again and the output was compared to the edits
from #2 to make sure no file was left behind.
4. Several build tests were done and a couple of problems were fixed.
e.g. lib/decompress_*.c used malloc/free() wrappers around slab
APIs requiring slab.h to be added manually.
5. The script was run on all .h files but without automatically
editing them as sprinkling gfp.h and slab.h inclusions around .h
files could easily lead to inclusion dependency hell. Most gfp.h
inclusion directives were ignored as stuff from gfp.h was usually
wildly available and often used in preprocessor macros. Each
slab.h inclusion directive was examined and added manually as
necessary.
6. percpu.h was updated not to include slab.h.
7. Build test were done on the following configurations and failures
were fixed. CONFIG_GCOV_KERNEL was turned off for all tests (as my
distributed build env didn't work with gcov compiles) and a few
more options had to be turned off depending on archs to make things
build (like ipr on powerpc/64 which failed due to missing writeq).
* x86 and x86_64 UP and SMP allmodconfig and a custom test config.
* powerpc and powerpc64 SMP allmodconfig
* sparc and sparc64 SMP allmodconfig
* ia64 SMP allmodconfig
* s390 SMP allmodconfig
* alpha SMP allmodconfig
* um on x86_64 SMP allmodconfig
8. percpu.h modifications were reverted so that it could be applied as
a separate patch and serve as bisection point.
Given the fact that I had only a couple of failures from tests on step
6, I'm fairly confident about the coverage of this conversion patch.
If there is a breakage, it's likely to be something in one of the arch
headers which should be easily discoverable easily on most builds of
the specific arch.
Signed-off-by: Tejun Heo <tj@kernel.org>
Guess-its-ok-by: Christoph Lameter <cl@linux-foundation.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Lee Schermerhorn <Lee.Schermerhorn@hp.com>
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Instead of always using netif_running(sdata->dev)
use ieee80211_sdata_running(sdata) now which is
just an inline containing netif_running() for now.
Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
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It's not all that useful to have the vif/sdata pointer,
we'd rather refer to the interfaces by their name.
Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
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The station management currently uses the virtual
interface, but you cannot add the same station to
multiple virtual interfaces if you're communicating
with it in multiple ways.
This restriction should be lifted so that in the
future we can, for instance, support bluetooth 3
with an access point that mac80211 is already
associated to.
We can do that by requiring all sta_info_get users
to provide the virtual interface and making the RX
code aware that an address may match more than one
station struct. Thanks to the previous patches this
one isn't all that large and except for the RX and
TX status paths changes has low complexity.
Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
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The key todo lock can be taken from different locks
that require it to be _bh to avoid lock inversion
due to (soft)irqs.
This should fix the two problems reported by Bob and
Gabor:
http://mid.gmane.org/20090619113049.GB18956@hash.localnet
http://mid.gmane.org/4A3FA376.8020307@openwrt.org
Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Cc: Bob Copeland <me@bobcopeland.com>
Cc: Gabor Juhos <juhosg@openwrt.org>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
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Validate RSC (NL80211_ATTR_KEY_SEQ) length in nl80211/cfg80211 instead
of having to do this in all the drivers.
Signed-off-by: Jouni Malinen <jouni.malinen@atheros.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
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When setting a key with NL80211_CMD_NEW_KEY, we should allow the key
sequence number (RSC) to be set in order to allow replay protection to
work correctly for group keys. This patch documents this use for
nl80211 and adds the couple of missing pieces in nl80211/cfg80211 and
mac80211 to support this. In addition, WEXT SIOCSIWENCODEEXT compat
processing in cfg80211 is extended to handle the RSC (this was already
specified in WEXT, but just not implemented in cfg80211/mac80211).
Signed-off-by: Jouni Malinen <jouni.malinen@atheros.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
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In order to later add tracing or verifications to the driver
calls mac80211 makes, this patch adds static inline wrappers
for all operations.
All calls are now written as
drv_<op>(local, ...);
instead of
local->ops-><op>(&local->hw, ...);
Where necessary, the wrappers also do existence checking and
return default values as appropriate.
Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
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This patch splits out the ibss code and data from managed (station) mode.
The reason to do this is to better separate the state machines, and have
the code be contained better so it gets easier to determine what exactly
a given change will affect, that in turn makes it easier to understand.
This is quite some churn, especially because I split sdata->u.sta into
sdata->u.mgd and sdata->u.ibss, but I think it's easier to maintain that
way. I've also shuffled around some code -- null function sending is only
applicable to managed interfaces so put that into that file, some other
functions are needed from various places so put them into util, and also
rearranged the prototypes in ieee80211_i.h accordingly.
Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
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Add mechanism for managing BIP keys (IGTK) and integrate BIP into the
TX/RX paths.
Signed-off-by: Jouni Malinen <j@w1.fi>
Acked-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
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The set_key callback now seems rather odd, passing a MAC address
instead of a station struct, and a local address instead of a
vif struct. Change that.
Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Acked-by: Bob Copeland <me@bobcopeland.com> [ath5k]
Acked-by: Ivo van Doorn <ivdoorn@gmail.com> [rt2x00]
Acked-by: Christian Lamparter <chunkeey@web.de> [p54]
Tested-by: Kalle Valo <kalle.valo@nokia.com> [iwl3945]
Tested-by: Samuel Ortiz <samuel@sortiz.org> [iwl3945]
Signed-off-by: John W. Linville <linville@tuxdriver.com>
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Also remove a few stray DECLARE_MAC_BUF that were no longer
used at all.
Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
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Free up 2 bytes in skb->cb to be used for multi-rate retry later.
Move iv_len and icv_len initialization into key alloc.
Signed-off-by: Felix Fietkau <nbd@openwrt.org>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
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This patch changes mac80211 to share some more data about
stations with drivers. Should help iwlwifi and ath9k when
they get around to updating, and might also help with
implementing rate control algorithms without internals.
Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Cc: Sujith Manoharan <Sujith.Manoharan@atheros.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
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There's really no reason for mac80211 to be using its
own interface type defines. Use the nl80211 types and
simplify the configuration code a bit: there's no need
to translate them any more now.
Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
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master.kernel.org:/pub/scm/linux/kernel/git/davem/net-2.6
Conflicts:
drivers/net/wireless/iwlwifi/iwl4965-base.c
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This patch fixes an oops in several failure paths in key allocation. This
Oops occurs when freeing a key that has not been linked yet, so the
key->sdata is not set.
Signed-off-by: Emmanuel Grumbach <emmanuel.grumbach@intel.com>
Signed-off-by: Tomas Winkler <tomas.winkler@intel.com>
Acked-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
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As discussed earlier, we can unify locking in struct sta_info
and use just a single spinlock protecting all members of the
structure that need protection. Many don't, but one of the
especially bad ones is the 'flags' member that can currently
be clobbered when RX and TX is being processed on different
CPUs at the same time.
Because having four spinlocks for different, mostly exclusive
parts of a single structure is overkill, this patch also kills
the ampdu and mesh plink spinlocks and uses just a single one
for everything. Because none of the spinlocks are nested, this
is safe.
It remains to be seen whether or not we should make the sta
flags use atomic bit operations instead, for now though this
is a safe thing and using atomic operations instead will be
very simple using the new static inline functions this patch
introduces for accessing sta->flags.
Since spin_lock_bh() is used with this lock, there shouldn't
be any contention even if aggregation is enabled at around the
same time as both requires frame transmission/reception which
is in a bh context.
Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Cc: Tomas Winkler <tomasw@gmail.com>
Cc: Ron Rindjunsky <ron.rindjunsky@intel.com>
Cc: Luis Carlos Cobo <luisca@cozybit.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
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This adds a new flag to the ieee80211_key_conf structure.
This flag will inform the driver the key is pairwise rather then
a shared key.
This is important for drivers who support both types of keys,
and need to be informed which type of key this is. Alternative
would be drivers checking the address argument of set_key(),
but it will be safer when mac80211 is more explicit.
Signed-off-by: Ivo van Doorn <IvDoorn@gmail.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
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When we add multiple todo entries, we rely on them being executed
mostly in the right order, especially when a key is being replaced.
But when a default key is replaced, the todo list order will differ
from the order when the key being replaced is not a default key, so
problems will happen. Hence, just move each todo item to the end of
the list when it is added so we can in the other code ensure that
hw accel for a key will be disabled before it is enabled for the
replacement.
Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
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When STAs are expired, we need to hold the sta_lock. Using
the same lock for keys too would then mean we'd need another
key free function, and that'll just lead to confusion, so just
use a new spinlock for all key lists.
Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
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The previous key locking patch left a small race: it would be possible
to add a key and take the interface down before the key todo is run so
that hwaccel for that key is enabled on an interface that is down. Avoid
this by running the todo list when an interface is brought up or down.
This patch also fixes a small bug: before this change, a few functions
used the key list without the lock that protects it.
Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
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Up to now, key manipulation is supposed to run under RTNL to
avoid concurrent manipulations and also allow the set_key()
hardware callback to sleep. This is not feasible because STA
structs are rcu-protected and thus a lot of operations there
cannot take the RTNL. Also, key references are rcu-protected
so we cannot do things atomically.
This patch changes key locking completely:
* key operations are now atomic
* hardware crypto offload is enabled and disabled from
a workqueue, due to that key freeing is also delayed
* debugfs code is also run from a workqueue
* keys reference STAs (and vice versa!) so during STA
unlink the STAs key reference is removed but not the
keys STA reference, to avoid races key todo work is
run before STA destruction.
* fewer STA operations now need the RTNL which was
required due to key operations
This fixes the locking problems lockdep pointed out and also
makes things more light-weight because the rtnl isn't required
as much.
Note that the key todo lock/key mutex are global locks, this
is not required, of course, they could be per-hardware instead.
Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
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When the IBSS code tries to flush the STA list, it does so in
an atomic context. Flushing isn't safe there, however, and
requires the RTNL, so we need to defer it to a workqueue.
Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
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Today I hit one of my new WARN_ONs in the mac80211 code because
a key wasn't being freed correctly. After wondering for a while
I finally tracked it to the fact that STA keys aren't added to
the per-sdata key list correctly, they are supposed to always be
on that list, not just for default keys. This patch fixes that.
Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
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Quite a while ago I started this book. The required kernel-doc
patches have since gone into the tree so it is now possible to
build the book in mainline.
The actual documentation is still rather incomplete and not all
things are linked into the book, but this enables us to edit
the documentation collaboratively, hopefully driver authors can
add documentation based on their experience with mac80211.
Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
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This makes access to the STA hash table/list use RCU to protect
against freeing of items. However, it's not a true RCU, the
copy step is missing: whenever somebody changes a STA item it
is simply updated. This is an existing race condition that is
now somewhat understandable.
This patch also fixes the race key freeing vs. STA destruction
by making sure that sta_info_destroy() is always called under
RTNL and frees the key.
Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
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Even though I thought about it a lot and had also tested it, some
of my recent changes in the key code broke replacing keys, making
the kernel oops because a key is removed from a list while not on
it.
This patch fixes that using the list as an indication whether or
not the key is on it (an empty list means it's not on any list.)
Also, this patch fixes hw accel enabling, the check for not doing
hw accel when the interface is down was lost and is restored by
this.
Additionally, move adding the key to the list into the function
__ieee80211_key_replace() for more consistency.
Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
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In order to RCU-ify sta_info, we need to be able to allocate
a key without linking it to an sdata/sta structure (because
allocation cannot be done in an rcu critical section). This
patch splits up ieee80211_key_alloc() and updates all users
appropriately.
While at it, this patch fixes a number of race conditions
such as finally making key replacement atomic, unfortunately
at the expense of more complex code.
Note that this patch documents /existing/ bugs with sta info
and key interaction, there is currently a race condition
when a sta info is freed without holding the RTNL. This will
finally be fixed by a followup patch.
Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
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Drivers that support mixed AP/STA operation may well need to
know the type of a virtual interface when iterating over them.
The easiest way to support that is to move the interface type
variable into the vif structure.
Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
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This "algorithm" is used only internally and is not useful.
Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Cc: Michael Buesch <mb@bu3sch.de>
Acked-by: Zhu Yi <yi.zhu@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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The typedef is not required, we can just use "enum ieee80211_key_alg"
instead of "ieee80211_key_alg"
Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: Michael Wu <flamingice@sourmilk.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
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This is nicer than the MAC_FMT stuff.
Signed-off-by: Joe Perches <joe@perches.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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This patch makes the mac80211/driver interface rely only on the
IEEE80211_TXCTL_DO_NOT_ENCRYPT flag to signal to the driver whether
a frame should be encrypted or not, since mac80211 internally no
longer relies on HW_KEY_IDX_INVALID either this removes it, changes
the key index to be a u8 in all places and makes the full range of
the value available to drivers.
Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Acked-by: Michael Wu <flamingice@sourmilk.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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No existing drivers use this callback, hence there's no telling
how it might be used. In fact, it is unlikely to be of much use
as-is because the default key index isn't something that the
driver can do much with without knowing which interface it was
for etc. And if it needs the key index for the transmitted frame,
it can get it by keeping a reference to the key_conf structure
and looking it up by hw_key_idx.
Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Acked-by: Michael Wu <flamingice@sourmilk.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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During receive processing, we select the key long before using it and
because there's no locking it is possible that we kfree() the key
after having selected it but before using it for crypto operations.
Obviously, this is bad.
Secondly, during transmit processing, there are two possible races: We
have a similar race between select_key() and using it for encryption,
but we also have a race here between select_key() and hardware
encryption (both when a key is removed.)
This patch solves these issues by using RCU: when a key is to be freed,
we first remove the pointer from the appropriate places (sdata->keys,
sdata->default_key, sta->key) using rcu_assign_pointer() and then
synchronize_rcu(). Then, we can safely kfree() the key and remove it
from the hardware. There's a window here where the hardware may still
be using it for decryption, but we can't work around that without having
two hardware callbacks, one to disable the key for RX and one to disable
it for TX; but the worst thing that will happen is that we receive a
packet decrypted that we don't find a key for any more and then drop it.
When we add a key, we first need to upload it to the hardware and then,
using rcu_assign_pointer() again, link it into our structures.
In the code using keys (TX/RX paths) we use rcu_dereference() to get the
key and enclose the whole tx/rx section in a rcu_read_lock() ...
rcu_read_unlock() block. Because we've uploaded the key to hardware
before linking it into internal structures, we can guarantee that it is
valid once get to into tx().
One possible race condition remains, however: when we have hardware
acceleration enabled and the driver shuts down the queues, we end up
queueing the frame. If now somebody removes the key, the key will be
removed from hwaccel and then then driver will be asked to encrypt the
frame with a key index that has been removed. Hence, drivers will need
to be aware that the hw_key_index they are passed might not be under
all circumstances. Most drivers will, however, simply ignore that
condition and encrypt the frame with the selected key anyway, this
only results in a frame being encrypted with a wrong key or dropped
(rightfully) because the key was not valid. There isn't much we can
do about it unless we want to walk the pending frame queue every time
a key is removed and remove all frames that used it.
This race condition, however, will most likely be solved once we add
multiqueue support to mac80211 because then frames will be queued
further up the stack instead of after being processed.
Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Acked-by: Michael Wu <flamingice@sourmilk.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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This moves all the key handling code out from ieee80211_ioctl.c
into key.c and also does the following changes including documentation
updates in mac80211.h:
1) Turn off hardware acceleration for keys when the interface
is down. This is necessary because otherwise monitor
interfaces could be decrypting frames for other interfaces
that are down at the moment. Also, it should go some way
towards better suspend/resume support, in any case the
routines used here could be used for that as well.
Additionally, this makes the driver interface nicer, keys
for a specific local MAC address are only ever present
while an interface with that MAC address is enabled.
2) Change driver set_key() callback interface to allow only
return values of -ENOSPC, -EOPNOTSUPP and 0, warn on all
other return values. This allows debugging the stack when
a driver notices it's handed a key while it is down.
3) Invert the flag meaning to KEY_FLAG_UPLOADED_TO_HARDWARE.
4) Remove REMOVE_ALL_KEYS command as it isn't used nor do we
want to use it, we'll use DISABLE_KEY for each key. It is
hard to use REMOVE_ALL_KEYS because we can handle multiple
virtual interfaces with different key configuration, so we'd
have to keep track of a lot of state for this and that isn't
worth it.
5) Warn when disabling a key fails, it musn't.
6) Remove IEEE80211_HW_NO_TKIP_WMM_HWACCEL in favour of per-key
IEEE80211_KEY_FLAG_WMM_STA to let driver sort it out itself.
7) Tell driver that a (non-WEP) key is used only for transmission
by using an all-zeroes station MAC address when configuring.
8) Change the set_key() callback to have access to the local MAC
address the key is being added for.
Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Acked-by: Michael Wu <flamingice@sourmilk.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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