[v2,3/3] nl80211: accept only HE capability elements with valid size

Commit Message

Johannes Berg Feb. 14, 2022, 4:29 p.m. UTC

From: Johannes Berg <[e-mail]>

The kernel (driver code) should be able to assume that a station's
HE capabilities are not badly sized, so reject them if they are.

Signed-off-by: Johannes Berg <[e-mail]>
---
 net/wireless/nl80211.c | 17 ++++++++++++++---
 1 file changed, 14 insertions(+), 3 deletions(-)

Patch

diff --git a/net/wireless/nl80211.c b/net/wireless/nl80211.c
index 578bff9c378b..0bdd11abe815 100644
--- a/net/wireless/nl80211.c
+++ b/net/wireless/nl80211.c
@@ -285,6 +285,18 @@  static int validate_ie_attr(const struct nlattr *attr,
 	return -EINVAL;
 }
 
+static int validate_he_capa(const struct nlattr *attr,
+			    struct netlink_ext_ack *extack)
+{
+	if (nla_len(attr) < NL80211_HE_MIN_CAPABILITY_LEN)
+		return -EINVAL;
+
+	if (!ieee80211_he_capa_size_ok(nla_data(attr), nla_len(attr)))
+		return -EINVAL;
+
+	return 0;
+}
+
 /* policy for the attributes */
 static const struct nla_policy nl80211_policy[NUM_NL80211_ATTR];
 
@@ -730,9 +742,8 @@  static const struct nla_policy nl80211_policy[NUM_NL80211_ATTR] = {
 	[NL80211_ATTR_TXQ_MEMORY_LIMIT] = { .type = NLA_U32 },
 	[NL80211_ATTR_TXQ_QUANTUM] = { .type = NLA_U32 },
 	[NL80211_ATTR_HE_CAPABILITY] =
-		NLA_POLICY_RANGE(NLA_BINARY,
-				 NL80211_HE_MIN_CAPABILITY_LEN,
-				 NL80211_HE_MAX_CAPABILITY_LEN),
+		NLA_POLICY_VALIDATE_FN(NLA_BINARY, validate_he_capa,
+				       NL80211_HE_MAX_CAPABILITY_LEN),
 	[NL80211_ATTR_FTM_RESPONDER] =
 		NLA_POLICY_NESTED(nl80211_ftm_responder_policy),
 	[NL80211_ATTR_TIMEOUT] = NLA_POLICY_MIN(NLA_U32, 1),