linux.git/net/wireless/scan.c, branch v2.6.39

cfg80211: fix BSS double-unlinking (continued)

2011-03-28T19:42:02+00:00

This patch adds to the fix "fix BSS double-unlinking"
(commit 3207390a8b58bfc1335750f91cf6783c48ca19ca) by Johannes Berg.

It turns out, that the double-unlinking scenario can also occur if expired
BSS elements are removed whilst an interface is performing association.

To work around that, replace list_del with list_del_init also in the
"cfg80211_bss_expire" function, so that the check for whether the BSS still is
in the list works correctly in cfg80211_unlink_bss.

Signed-off-by: Juuso Oikarinen 
Reviewed-by: Johannes Berg 
Signed-off-by: John W. Linville

cfg80211:: fix possible NULL pointer dereference

2011-03-28T19:42:02+00:00

In cfg80211_inform_bss_frame() wiphy is first dereferenced on privsz
initialisation and then it is checked for NULL. This patch fixes that.

Signed-off-by: Mariusz Kozlowski 
Acked-by: Johannes Berg 
Signed-off-by: John W. Linville

cfg80211: update information elements in cached BSS struct

2010-12-13T20:23:28+00:00

When a cached BSS struct is updated because a new beacon was received,
the code replaces the cached information elements by the IEs from the
new beacon. However it did not update the pub.information_elements
and pub.len_information_elements fields leaving them either pointing
to the old beacon IEs or in an inconsistent state where the data is
replaced by the new beacon IEs but len_information_elements still has
its value from the first beacon.

Fix this by updating the information elements fields if they are
pointing to beacon IEs.

Signed-off-by: Sven Neumann 
Reviewed-by: Johannes Berg 
Signed-off-by: John W. Linville

cfg80211: fix BSS double-unlinking

2010-10-06T20:30:43+00:00

When multiple interfaces are actively trying
to associate with the same BSS, they may both
find that the BSS isn't there and then try to
unlink it. This can cause errors since the
unlinking code can't currently deal with items
that have already been unlinked.

Normally this doesn't happen as most people
don't try to use multiple station interfaces
that associate at the same time too.

Fix this by using the list entry as a flag to
see if the item is still on a list.

Cc: stable@kernel.org
Reported-by: Ben Greear 
Tested-by: Hun-Kyi Wynn 
Signed-off-by: Johannes Berg 
Signed-off-by: John W. Linville

cfg80211: don't get expired BSSes

2010-07-14T17:52:45+00:00

When kernel-internal users use cfg80211_get_bss()
to get a reference to a BSS struct, they may end
up getting one that would have been removed from
the list if there had been any userspace access
to the list. This leads to inconsistencies and
problems.

Fix it by making cfg80211_get_bss() ignore BSSes
that cfg80211_bss_expire() would remove.

Fixes http://bugzilla.intellinuxwireless.org/show_bug.cgi?id=2180

Cc: stable@kernel.org
Reported-by: Jiajia Zheng 
Tested-by: Jiajia Zheng 
Signed-off-by: Johannes Berg 
Signed-off-by: John W. Linville

cfg80211: Fix signal_type comparison

2010-05-21T18:39:59+00:00

signal_type is enum cfg80211_signal_type.

This fixes the gcc warning:

scan.c: In function `cfg80211_inform_bss':
scan.c:518:6: warning: comparison between `enum cfg80211_signal_type' and `enum nl80211_bss'
scan.c: In function `cfg80211_inform_bss_frame':
scan.c:574:6: warning: comparison between `enum cfg80211_signal_type' and `enum nl80211_bss'

Signed-off-by: Sujith 
Signed-off-by: John W. Linville

include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h

2010-03-30T13:02:32+00:00

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 
Guess-its-ok-by: Christoph Lameter 
Cc: Ingo Molnar 
Cc: Lee Schermerhorn

cfg80211: export cfg80211_find_ie

2010-01-26T16:53:20+00:00

This new function (previously a static function
called just "find_ie" can be used to find a
specific IE in a buffer of IEs.

Signed-off-by: Johannes Berg 
Signed-off-by: John W. Linville

cfg80211: Store IEs from both Beacon and Probe Response frames

2010-01-12T18:51:28+00:00

Store information elements from Beacon and Probe Response frames in
separate buffers to allow both sets to be made available through
nl80211. This allows user space applications to get access to IEs from
Beacon frames even if we have received Probe Response frames from the
BSS. Previously, the IEs from Probe Response frames would have
overridden the IEs from Beacon frames.

This feature is of somewhat limited use since most protocols include
the same (or extended) information in Probe Response frames. However,
there are couple of exceptions where the IEs from Beacon frames could
be of some use: TIM IE is only included in Beacon frames (and it would
be needed to figure out the DTIM period used in the BSS) and at least
some implementations of Wireless Provisioning Services seem to include
the full IE only in Beacon frames).

The new BSS attribute for scan results is added to allow both the IE
sets to be delivered. This is done in a way that maintains the
previously used behavior for applications that are not aware of the
new NL80211_BSS_BEACON_IES attribute.

Signed-off-by: Jouni Malinen 
Acked-by: Johannes Berg 
Signed-off-by: John W. Linville

cfg80211: fix error path in cfg80211_wext_siwscan

2009-12-28T21:19:58+00:00

If there's an invalid channel or SSID, the code leaks
the scan request. Always free the scan request, unless
it was successfully given to the driver.

Reported-by: Dan Carpenter 
Signed-off-by: Johannes Berg 
Acked-by: Dan Carpenter 
Signed-off-by: John W. Linville