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| author | Xiang Mei <xmei5@asu.edu> | 2026-03-18 06:42:44 +0300 |
|---|---|---|
| committer | Johannes Berg <johannes.berg@intel.com> | 2026-03-18 11:01:16 +0300 |
| commit | c73bb9a2d33bf81f6eecaa0f474b6c6dbe9855bd (patch) | |
| tree | b5cafb7a304d9c38ce1de70507dba6be65d6b27b | |
| parent | 7d73872d949c488a1d7c308031d6a9d89b5e0a8b (diff) | |
| download | linux-c73bb9a2d33bf81f6eecaa0f474b6c6dbe9855bd.tar.xz | |
wifi: mac80211: fix NULL deref in mesh_matches_local()
mesh_matches_local() unconditionally dereferences ie->mesh_config to
compare mesh configuration parameters. When called from
mesh_rx_csa_frame(), the parsed action-frame elements may not contain a
Mesh Configuration IE, leaving ie->mesh_config NULL and triggering a
kernel NULL pointer dereference.
The other two callers are already safe:
- ieee80211_mesh_rx_bcn_presp() checks !elems->mesh_config before
calling mesh_matches_local()
- mesh_plink_get_event() is only reached through
mesh_process_plink_frame(), which checks !elems->mesh_config, too
mesh_rx_csa_frame() is the only caller that passes raw parsed elements
to mesh_matches_local() without guarding mesh_config. An adjacent
attacker can exploit this by sending a crafted CSA action frame that
includes a valid Mesh ID IE but omits the Mesh Configuration IE,
crashing the kernel.
The captured crash log:
Oops: general protection fault, probably for non-canonical address ...
KASAN: null-ptr-deref in range [0x0000000000000000-0x0000000000000007]
Workqueue: events_unbound cfg80211_wiphy_work
[...]
Call Trace:
<TASK>
? __pfx_mesh_matches_local (net/mac80211/mesh.c:65)
ieee80211_mesh_rx_queued_mgmt (net/mac80211/mesh.c:1686)
[...]
ieee80211_iface_work (net/mac80211/iface.c:1754 net/mac80211/iface.c:1802)
[...]
cfg80211_wiphy_work (net/wireless/core.c:426)
process_one_work (net/kernel/workqueue.c:3280)
? assign_work (net/kernel/workqueue.c:1219)
worker_thread (net/kernel/workqueue.c:3352)
? __pfx_worker_thread (net/kernel/workqueue.c:3385)
kthread (net/kernel/kthread.c:436)
[...]
ret_from_fork_asm (net/arch/x86/entry/entry_64.S:255)
</TASK>
This patch adds a NULL check for ie->mesh_config at the top of
mesh_matches_local() to return false early when the Mesh Configuration
IE is absent.
Fixes: 2e3c8736820b ("mac80211: support functions for mesh")
Reported-by: Weiming Shi <bestswngs@gmail.com>
Signed-off-by: Xiang Mei <xmei5@asu.edu>
Link: https://patch.msgid.link/20260318034244.2595020-1-xmei5@asu.edu
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
| -rw-r--r-- | net/mac80211/mesh.c | 3 |
1 files changed, 3 insertions, 0 deletions
diff --git a/net/mac80211/mesh.c b/net/mac80211/mesh.c index 28624e57aa49..8fdbdf9ba2a9 100644 --- a/net/mac80211/mesh.c +++ b/net/mac80211/mesh.c @@ -79,6 +79,9 @@ bool mesh_matches_local(struct ieee80211_sub_if_data *sdata, * - MDA enabled * - Power management control on fc */ + if (!ie->mesh_config) + return false; + if (!(ifmsh->mesh_id_len == ie->mesh_id_len && memcmp(ifmsh->mesh_id, ie->mesh_id, ie->mesh_id_len) == 0 && (ifmsh->mesh_pp_id == ie->mesh_config->meshconf_psel) && |