The function building probe-request IEs does not validate the band is
supported before dereferencing it. This can result in a panic when
all bands are traversed, as done during sched-scan start.
Warn when this happens and return an empty probe request. Also fix
sched-scan to not waste memory on unsupported bands.
Signed-off-by: Arik Nemtsov <arik@xxxxxxxxxx>
---
This is not cc stable since the panic only started happening once
the 60Ghz band was added. Apparently all sched-scan drivers supported
all possible bands until then.
net/mac80211/scan.c | 3 +++
net/mac80211/util.c | 2 ++
2 files changed, 5 insertions(+)
diff --git a/net/mac80211/scan.c b/net/mac80211/scan.c
index 379f178..1ff04f6 100644
--- a/net/mac80211/scan.c
+++ b/net/mac80211/scan.c
@@ -928,6 +928,9 @@ int ieee80211_request_sched_scan_start(struct ieee80211_sub_if_data *sdata,
}
for (i = 0; i < IEEE80211_NUM_BANDS; i++) {
+ if (!local->hw.wiphy->bands[i])
+ continue;
+
local->sched_scan_ies.ie[i] = kzalloc(2 +
IEEE80211_MAX_SSID_LEN +
local->scan_ies_len +
diff --git a/net/mac80211/util.c b/net/mac80211/util.c
index 64493a7..503412a 100644
--- a/net/mac80211/util.c
+++ b/net/mac80211/util.c
@@ -999,6 +999,8 @@ int ieee80211_build_preq_ies(struct ieee80211_local *local, u8 *buffer,
int ext_rates_len;
sband = local->hw.wiphy->bands[band];
+ if (!WARN_ON_ONCE(sband))
+ return 0;
pos = buffer;
--
1.7.9.5
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