[PATCH 3.16 099/192] cfg80211: Validate frequencies nested in NL80211_ATTR_SCAN_FREQUENCIES

Ben Hutchings
2017-10-09T13:07:06Z

From: Srinivas Dasari <dasaris@qti.qualcomm.com>

commit d7f13f7450369281a5d0ea463cc69890a15923ae upstream.

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)")
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>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
---
net/wireless/nl80211.c | 4 ++++
1 file changed, 4 insertions(+)

--- a/net/wireless/nl80211.c
+++ b/net/wireless/nl80211.c
@@ -5288,6 +5288,10 @@ static int validate_scan_freqs(struct nl
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++;
/*