From: Johannes Berg <johannes.berg@xxxxxxxxx>
commit 768c0b19b50665e337c96858aa2b7928d6dcf756 upstream.
Before attempting to parse an extended element, verify that
the extended element ID is present.
Fixes: 41cbb0f5a295 ("mac80211: add support for HE")
Reported-by: syzbot+59bdff68edce82e393b6@xxxxxxxxxxxxxxxxxxxxxxxxx
Link: https://lore.kernel.org/r/20211211201023.f30a1b128c07.I5cacc176da94ba316877c6e10fe3ceec8b4dbd7d@changeid
Cc: stable@xxxxxxxxxxxxxxx
Signed-off-by: Johannes Berg <johannes.berg@xxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
net/mac80211/util.c | 7 ++++++-
1 file changed, 6 insertions(+), 1 deletion(-)
--- a/net/mac80211/util.c
+++ b/net/mac80211/util.c
@@ -950,7 +950,12 @@ static void ieee80211_parse_extension_el
struct ieee802_11_elems *elems)
{
const void *data = elem->data + 1;
- u8 len = elem->datalen - 1;
+ u8 len;
+
+ if (!elem->datalen)
+ return;
+
+ len = elem->datalen - 1;
switch (elem->data[0]) {
case WLAN_EID_EXT_HE_MU_EDCA:
