Home Home > GIT Browse
summaryrefslogtreecommitdiff
diff options
context:
space:
mode:
authorJohannes Berg <johannes.berg@intel.com>2019-09-20 21:54:17 +0200
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2019-10-11 18:18:49 +0200
commit01ec813e457954d8eeaf768d57d625752d245bc9 (patch)
tree22d17626be18c462161b10ad7197d9d871300b5d
parentcd813e524abcf7dc89231930858f1ac3af372af9 (diff)
nl80211: validate beacon head
commit f88eb7c0d002a67ef31aeb7850b42ff69abc46dc upstream. We currently don't validate the beacon head, i.e. the header, fixed part and elements that are to go in front of the TIM element. This means that the variable elements there can be malformed, e.g. have a length exceeding the buffer size, but most downstream code from this assumes that this has already been checked. Add the necessary checks to the netlink policy. Cc: stable@vger.kernel.org Fixes: ed1b6cc7f80f ("cfg80211/nl80211: add beacon settings") Link: https://lore.kernel.org/r/1569009255-I7ac7fbe9436e9d8733439eab8acbbd35e55c74ef@changeid Signed-off-by: Johannes Berg <johannes.berg@intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
-rw-r--r--net/wireless/nl80211.c38
1 files changed, 38 insertions, 0 deletions
diff --git a/net/wireless/nl80211.c b/net/wireless/nl80211.c
index d9a39f37a49f..ec504c4a397b 100644
--- a/net/wireless/nl80211.c
+++ b/net/wireless/nl80211.c
@@ -199,6 +199,38 @@ cfg80211_get_dev_from_info(struct net *netns, struct genl_info *info)
return __cfg80211_rdev_from_attrs(netns, info->attrs);
}
+static int validate_beacon_head(const struct nlattr *attr,
+ struct netlink_ext_ack *extack)
+{
+ const u8 *data = nla_data(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);
+
+ if (len < fixedlen)
+ goto err;
+
+ if (ieee80211_hdrlen(mgmt->frame_control) !=
+ offsetof(struct ieee80211_mgmt, u.beacon))
+ goto err;
+
+ data += fixedlen;
+ len -= fixedlen;
+
+ for_each_element(elem, data, len) {
+ /* nothing */
+ }
+
+ if (for_each_element_completed(elem, data, len))
+ return 0;
+
+err:
+ NL_SET_ERR_MSG_ATTR(extack, attr, "malformed beacon head");
+ return -EINVAL;
+}
+
/* policy for the attributes */
static const struct nla_policy nl80211_policy[NUM_NL80211_ATTR] = {
[NL80211_ATTR_WIPHY] = { .type = NLA_U32 },
@@ -3738,6 +3770,12 @@ static int nl80211_parse_beacon(struct nlattr *attrs[],
memset(bcn, 0, sizeof(*bcn));
if (attrs[NL80211_ATTR_BEACON_HEAD]) {
+ int ret = validate_beacon_head(attrs[NL80211_ATTR_BEACON_HEAD],
+ NULL);
+
+ if (ret)
+ return ret;
+
bcn->head = nla_data(attrs[NL80211_ATTR_BEACON_HEAD]);
bcn->head_len = nla_len(attrs[NL80211_ATTR_BEACON_HEAD]);
if (!bcn->head_len)