cfg80211: Validate frequencies nested in NL80211_ATTR_SCAN_FREQUENCIES

validate_scan_freqs() retrieves frequencies from attributes
nested in the attribute NL80211_ATTR_SCAN_FREQUENCIES with
nla_get_u32(), which reads 4 bytes from each attribute
without validating the size of data received. Attributes
nested in NL80211_ATTR_SCAN_FREQUENCIES don't have an nla policy.

Validate size of each attribute before parsing to avoid potential buffer
overread.

Fixes: 2a519311926 ("cfg80211/nl80211: scanning (and mac80211 update to use it)")
Cc: stable@vger.kernel.org
Signed-off-by: Srinivas Dasari <dasaris@qti.qualcomm.com>
Signed-off-by: Jouni Malinen <jouni@qca.qualcomm.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

diff --git a/net/wireless/nl80211.c b/net/wireless/nl80211.c
index 59f1ea5a83ef019ee3215f8ce4b94232d2def930..571aed1e6f362594e6a7cfe5e917b577914376bd 100644 (file)
--- a/net/wireless/nl80211.c
+++ b/net/wireless/nl80211.c
@@ -6469,6 +6469,10 @@ static int validate_scan_freqs(struct nlattr *freqs)
        struct nlattr *attr1, *attr2;
        int n_channels = 0, tmp1, tmp2;
 
+       nla_for_each_nested(attr1, freqs, tmp1)
+               if (nla_len(attr1) != sizeof(u32))
+                       return 0;
+
        nla_for_each_nested(attr1, freqs, tmp1) {
                n_channels++;
                /*