[PATCH v2 04/22] nl80211: correctly validate S1G beacon head

Thomas Pedersen
2020-08-31T20:56:15Z

The S1G beacon has a different header size than regular
beacons, so adjust the beacon head validator.

Signed-off-by: Thomas Pedersen <thomas@adapt-ip.com>
---
net/wireless/nl80211.c | 16 +++++++++++++---
net/wireless/util.c | 5 +++++
2 files changed, 18 insertions(+), 3 deletions(-)

diff --git a/net/wireless/nl80211.c b/net/wireless/nl80211.c
index 7da4d84bcc1a..3bf595c828db 100644
--- a/net/wireless/nl80211.c
+++ b/net/wireless/nl80211.c
@@ -209,14 +209,24 @@ static int validate_beacon_head(const struct nlattr *attr,
unsigned int len = nla_len(attr);
const struct element *elem;
const struct ieee80211_mgmt *mgmt = (void *)data;
- unsigned int fixedlen = offsetof(struct ieee80211_mgmt,
- u.beacon.variable);
+ bool s1g_bcn = ieee80211_is_s1g_beacon(mgmt->frame_control);
+ unsigned int fixedlen, hdrlen;
+
+ if (s1g_bcn) {
+ fixedlen = offsetof(struct ieee80211_ext,
+ u.s1g_beacon.variable);
+ hdrlen = offsetof(struct ieee80211_ext, u.s1g_beacon);
+ } else {
+ fixedlen = offsetof(struct ieee80211_mgmt,
+ u.beacon.variable);
+ hdrlen = offsetof(struct ieee80211_mgmt, u.beacon);
+ }

if (len < fixedlen)
goto err;

if (ieee80211_hdrlen(mgmt->frame_control) !=
- offsetof(struct ieee80211_mgmt, u.beacon))
+ hdrlen)
goto err;

data += fixedlen;
diff --git a/net/wireless/util.c b/net/wireless/util.c
index 4a9ff9ef513f..49e7c0cbbf62 100644
--- a/net/wireless/util.c
+++ b/net/wireless/util.c
@@ -399,6 +399,11 @@ unsigned int __attribute_const__ ieee80211_hdrlen(__le16 fc)
{
unsigned int hdrlen = 24;

+ if (ieee80211_is_ext(fc)) {
+ hdrlen = 4;
+ goto out;
+ }
+
if (ieee80211_is_data(fc)) {
if (ieee80211_has_a4(fc))
hdrlen = 30;
--
2.20.1