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Linus Lüssing 12e407a8ef mac80211: fix potential double free on mesh join
commit 4a2d4496e1 upstream.

While commit 6a01afcf84 ("mac80211: mesh: Free ie data when leaving
mesh") fixed a memory leak on mesh leave / teardown it introduced a
potential memory corruption caused by a double free when rejoining the
mesh:

  ieee80211_leave_mesh()
  -> kfree(sdata->u.mesh.ie);
  ...
  ieee80211_join_mesh()
  -> copy_mesh_setup()
     -> old_ie = ifmsh->ie;
     -> kfree(old_ie);

This double free / kernel panics can be reproduced by using wpa_supplicant
with an encrypted mesh (if set up without encryption via "iw" then
ifmsh->ie is always NULL, which avoids this issue). And then calling:

  $ iw dev mesh0 mesh leave
  $ iw dev mesh0 mesh join my-mesh

Note that typically these commands are not used / working when using
wpa_supplicant. And it seems that wpa_supplicant or wpa_cli are going
through a NETDEV_DOWN/NETDEV_UP cycle between a mesh leave and mesh join
where the NETDEV_UP resets the mesh.ie to NULL via a memcpy of
default_mesh_setup in cfg80211_netdev_notifier_call, which then avoids
the memory corruption, too.

The issue was first observed in an application which was not using
wpa_supplicant but "Senf" instead, which implements its own calls to
nl80211.

Fixing the issue by removing the kfree()'ing of the mesh IE in the mesh
join function and leaving it solely up to the mesh leave to free the
mesh IE.

Cc: stable@vger.kernel.org
Fixes: 6a01afcf84 ("mac80211: mesh: Free ie data when leaving mesh")
Reported-by: Matthias Kretschmer <mathias.kretschmer@fit.fraunhofer.de>
Signed-off-by: Linus Lüssing <ll@simonwunderlich.de>
Tested-by: Mathias Kretschmer <mathias.kretschmer@fit.fraunhofer.de>
Link: https://lore.kernel.org/r/20220310183513.28589-1-linus.luessing@c0d3.blue
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2022-03-28 09:58:45 +02:00
arch uaccess: fix integer overflow on access_ok() 2022-03-28 09:58:45 +02:00
block block: release rq qos structures for queue without disk 2022-03-23 09:16:41 +01:00
certs certs: Add support for using elliptic curve keys for signing modules 2021-08-23 19:55:42 +03:00
crypto crypto: api - Move cryptomgr soft dependency into algapi 2022-02-11 09:10:26 +01:00
Documentation swiotlb: rework "fix info leak with DMA_FROM_DEVICE" 2022-03-16 14:23:43 +01:00
drivers drm/virtio: Ensure that objs is not NULL in virtio_gpu_array_put_free() 2022-03-28 09:58:45 +02:00
fs btrfs: skip reserved bytes warning on unmount after log cleanup failure 2022-03-23 09:16:43 +01:00
include ALSA: pcm: Fix races among concurrent hw_params and hw_free calls 2022-03-28 09:58:43 +02:00
init init: make unknown command line param message clearer 2021-11-18 19:17:11 +01:00
ipc ipc/sem: do not sleep with a spin lock held 2022-02-08 18:34:03 +01:00
kernel rcu: Don't deboost before reporting expedited quiescent state 2022-03-28 09:58:45 +02:00
lib ARM: 9178/1: fix unmet dependency on BITREVERSE for HAVE_ARCH_BITREVERSE 2022-03-19 13:47:48 +01:00
LICENSES LICENSES/dual/CC-BY-4.0: Git rid of "smart quotes" 2021-07-15 06:31:24 -06:00
mm mm: swap: get rid of livelock in swapin readahead 2022-03-23 09:16:41 +01:00
net mac80211: fix potential double free on mesh join 2022-03-28 09:58:45 +02:00
samples samples: bpf: Fix 'unknown warning group' build warning on Clang 2022-01-27 11:03:29 +01:00
scripts kconfig: fix failing to generate auto.conf 2022-02-23 12:03:20 +01:00
security selinux: fix misuse of mutex_is_locked() 2022-03-02 11:47:48 +01:00
sound ALSA: pci: fix reading of swapped values from pcmreg in AC97 codec 2022-03-28 09:58:44 +02:00
tools perf symbols: Fix symbol size calculation condition 2022-03-23 09:16:43 +01:00
usr usr/include/Makefile: add linux/nfc.h to the compile-test coverage 2022-02-01 17:27:15 +01:00
virt KVM: Fix lockdep false negative during host resume 2022-03-16 14:23:40 +01:00
.clang-format clang-format: Update with the latest for_each macro list 2021-05-12 23:32:39 +02:00
.cocciconfig
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.gitattributes
.gitignore .gitignore: ignore only top-level modules.builtin 2021-05-02 00:43:35 +09:00
.mailmap mailmap: add Andrej Shadura 2021-10-18 20:22:03 -10:00
COPYING
CREDITS MAINTAINERS: Move Daniel Drake to credits 2021-09-21 08:34:58 +03:00
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MAINTAINERS MAINTAINERS: adjust file entry for of_net.c after movement 2022-03-08 19:12:53 +01:00
Makefile Linux 5.15.31 2022-03-23 09:16:44 +01:00
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