[PATCH 4.12 31/84] cfg80211: Check if NAN service ID is of expected size

[Greg Kroah-Hartman]

4.12-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Srinivas Dasari <dasaris@xxxxxxxxxxxxxxxx>

commit 0a27844ce86d039d74221dd56cd8c0349b146b63 upstream.

nla policy checks for only maximum length of the attribute data when the
attribute type is NLA_BINARY. If userspace sends less data than
specified, cfg80211 may access illegal memory. When type is NLA_UNSPEC,
nla policy check ensures that userspace sends minimum specified length
number of bytes.

Remove type assignment to NLA_BINARY from nla_policy of
NL80211_NAN_FUNC_SERVICE_ID to make these NLA_UNSPEC and to make sure
minimum NL80211_NAN_FUNC_SERVICE_ID_LEN bytes are received from
userspace with NL80211_NAN_FUNC_SERVICE_ID.

Fixes: a442b761b24 ("cfg80211: add add_nan_func / del_nan_func")
Signed-off-by: Srinivas Dasari <dasaris@xxxxxxxxxxxxxxxx>
Signed-off-by: Jouni Malinen <jouni@xxxxxxxxxxxxxxxx>
Signed-off-by: Johannes Berg <johannes.berg@xxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
 net/wireless/nl80211.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/net/wireless/nl80211.c
+++ b/net/wireless/nl80211.c
@@ -520,7 +520,7 @@ nl80211_bss_select_policy[NL80211_BSS_SE
 static const struct nla_policy
 nl80211_nan_func_policy[NL80211_NAN_FUNC_ATTR_MAX + 1] = {
 	[NL80211_NAN_FUNC_TYPE] = { .type = NLA_U8 },
-	[NL80211_NAN_FUNC_SERVICE_ID] = { .type = NLA_BINARY,
+	[NL80211_NAN_FUNC_SERVICE_ID] = {
 				    .len = NL80211_NAN_FUNC_SERVICE_ID_LEN },
 	[NL80211_NAN_FUNC_PUBLISH_TYPE] = { .type = NLA_U8 },
 	[NL80211_NAN_FUNC_PUBLISH_BCAST] = { .type = NLA_FLAG },