nl80211: use netlink policy validation function for elements

Instead of open-coding a lot of calls to is_valid_ie_attr(),
add this validation directly to the policy, now that we can.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>

diff --git a/net/wireless/nl80211.c b/net/wireless/nl80211.c
index 3e368c3f1df233b4ce1e30287bde15767d46da99..758bb069d000d207b8904506479ae717fdeae9d8 100644 (file)
--- a/net/wireless/nl80211.c
+++ b/net/wireless/nl80211.c
@@ -200,6 +200,36 @@ cfg80211_get_dev_from_info(struct net *netns, struct genl_info *info)
        return __cfg80211_rdev_from_attrs(netns, info->attrs);
 }
 
+static int validate_ie_attr(const struct nlattr *attr,
+                           struct netlink_ext_ack *extack)
+{
+       const u8 *pos;
+       int len;
+
+       pos = nla_data(attr);
+       len = nla_len(attr);
+
+       while (len) {
+               u8 elemlen;
+
+               if (len < 2)
+                       goto error;
+               len -= 2;
+
+               elemlen = pos[1];
+               if (elemlen > len)
+                       goto error;
+
+               len -= elemlen;
+               pos += 2 + elemlen;
+       }
+
+       return 0;
+error:
+       NL_SET_ERR_MSG_ATTR(extack, attr, "malformed information elements");
+       return -EINVAL;
+}
+
 /* policy for the attributes */
 static const struct nla_policy
 nl80211_ftm_responder_policy[NL80211_FTM_RESP_ATTR_MAX + 1] = {
@@ -250,8 +280,9 @@ static const struct nla_policy nl80211_policy[NUM_NL80211_ATTR] = {
        [NL80211_ATTR_DTIM_PERIOD] = { .type = NLA_U32 },
        [NL80211_ATTR_BEACON_HEAD] = { .type = NLA_BINARY,
                                       .len = IEEE80211_MAX_DATA_LEN },
-       [NL80211_ATTR_BEACON_TAIL] = { .type = NLA_BINARY,
-                                      .len = IEEE80211_MAX_DATA_LEN },
+       [NL80211_ATTR_BEACON_TAIL] =
+               NLA_POLICY_VALIDATE_FN(NLA_BINARY, validate_ie_attr,
+                                      IEEE80211_MAX_DATA_LEN),
        [NL80211_ATTR_STA_AID] =
                NLA_POLICY_RANGE(NLA_U16, 1, IEEE80211_MAX_AID),
        [NL80211_ATTR_STA_FLAGS] = { .type = NLA_NESTED },
@@ -282,8 +313,9 @@ static const struct nla_policy nl80211_policy[NUM_NL80211_ATTR] = {
        [NL80211_ATTR_HT_CAPABILITY] = { .len = NL80211_HT_CAPABILITY_LEN },
 
        [NL80211_ATTR_MGMT_SUBTYPE] = { .type = NLA_U8 },
-       [NL80211_ATTR_IE] = { .type = NLA_BINARY,
-                             .len = IEEE80211_MAX_DATA_LEN },
+       [NL80211_ATTR_IE] = NLA_POLICY_VALIDATE_FN(NLA_BINARY,
+                                                  validate_ie_attr,
+                                                  IEEE80211_MAX_DATA_LEN),
        [NL80211_ATTR_SCAN_FREQUENCIES] = { .type = NLA_NESTED },
        [NL80211_ATTR_SCAN_SSIDS] = { .type = NLA_NESTED },
 
@@ -341,10 +373,12 @@ static const struct nla_policy nl80211_policy[NUM_NL80211_ATTR] = {
                NLA_POLICY_RANGE(NLA_U32,
                                 NL80211_HIDDEN_SSID_NOT_IN_USE,
                                 NL80211_HIDDEN_SSID_ZERO_CONTENTS),
-       [NL80211_ATTR_IE_PROBE_RESP] = { .type = NLA_BINARY,
-                                        .len = IEEE80211_MAX_DATA_LEN },
-       [NL80211_ATTR_IE_ASSOC_RESP] = { .type = NLA_BINARY,
-                                        .len = IEEE80211_MAX_DATA_LEN },
+       [NL80211_ATTR_IE_PROBE_RESP] =
+               NLA_POLICY_VALIDATE_FN(NLA_BINARY, validate_ie_attr,
+                                      IEEE80211_MAX_DATA_LEN),
+       [NL80211_ATTR_IE_ASSOC_RESP] =
+               NLA_POLICY_VALIDATE_FN(NLA_BINARY, validate_ie_attr,
+                                      IEEE80211_MAX_DATA_LEN),
        [NL80211_ATTR_ROAM_SUPPORT] = { .type = NLA_FLAG },
        [NL80211_ATTR_SCHED_SCAN_MATCH] = { .type = NLA_NESTED },
        [NL80211_ATTR_TX_NO_CCK_RATE] = { .type = NLA_FLAG },
@@ -649,36 +683,6 @@ static int nl80211_prepare_wdev_dump(struct netlink_callback *cb,
        return 0;
 }
 
-/* IE validation */
-static bool is_valid_ie_attr(const struct nlattr *attr)
-{
-       const u8 *pos;
-       int len;
-
-       if (!attr)
-               return true;
-
-       pos = nla_data(attr);
-       len = nla_len(attr);
-
-       while (len) {
-               u8 elemlen;
-
-               if (len < 2)
-                       return false;
-               len -= 2;
-
-               elemlen = pos[1];
-               if (elemlen > len)
-                       return false;
-
-               len -= elemlen;
-               pos += 2 + elemlen;
-       }
-
-       return true;
-}
-
 /* message building helper */
 static inline void *nl80211hdr_put(struct sk_buff *skb, u32 portid, u32 seq,
                                   int flags, u8 cmd)
@@ -4018,12 +4022,6 @@ static int nl80211_parse_beacon(struct cfg80211_registered_device *rdev,
        bool haveinfo = false;
        int err;
 
-       if (!is_valid_ie_attr(attrs[NL80211_ATTR_BEACON_TAIL]) ||
-           !is_valid_ie_attr(attrs[NL80211_ATTR_IE]) ||
-           !is_valid_ie_attr(attrs[NL80211_ATTR_IE_PROBE_RESP]) ||
-           !is_valid_ie_attr(attrs[NL80211_ATTR_IE_ASSOC_RESP]))
-               return -EINVAL;
-
        memset(bcn, 0, sizeof(*bcn));
 
        if (attrs[NL80211_ATTR_BEACON_HEAD]) {
@@ -6189,8 +6187,9 @@ static const struct nla_policy
        [NL80211_MESH_SETUP_USERSPACE_AUTH] = { .type = NLA_FLAG },
        [NL80211_MESH_SETUP_AUTH_PROTOCOL] = { .type = NLA_U8 },
        [NL80211_MESH_SETUP_USERSPACE_MPM] = { .type = NLA_FLAG },
-       [NL80211_MESH_SETUP_IE] = { .type = NLA_BINARY,
-                                   .len = IEEE80211_MAX_DATA_LEN },
+       [NL80211_MESH_SETUP_IE] =
+               NLA_POLICY_VALIDATE_FN(NLA_BINARY, validate_ie_attr,
+                                      IEEE80211_MAX_DATA_LEN),
        [NL80211_MESH_SETUP_USERSPACE_AMPE] = { .type = NLA_FLAG },
 };
 
@@ -6370,8 +6369,6 @@ static int nl80211_parse_mesh_setup(struct genl_info *info,
        if (tb[NL80211_MESH_SETUP_IE]) {
                struct nlattr *ieattr =
                        tb[NL80211_MESH_SETUP_IE];
-               if (!is_valid_ie_attr(ieattr))
-                       return -EINVAL;
                setup->ie = nla_data(ieattr);
                setup->ie_len = nla_len(ieattr);
        }
@@ -7004,9 +7001,6 @@ static int nl80211_trigger_scan(struct sk_buff *skb, struct genl_info *info)
        int err, tmp, n_ssids = 0, n_channels, i;
        size_t ie_len;
 
-       if (!is_valid_ie_attr(info->attrs[NL80211_ATTR_IE]))
-               return -EINVAL;
-
        wiphy = &rdev->wiphy;
 
        if (wdev->iftype == NL80211_IFTYPE_NAN)
@@ -7360,9 +7354,6 @@ nl80211_parse_sched_scan(struct wiphy *wiphy, struct wireless_dev *wdev,
        struct nlattr *tb[NL80211_SCHED_SCAN_MATCH_ATTR_MAX + 1];
        s32 default_match_rssi = NL80211_SCAN_RSSI_THOLD_OFF;
 
-       if (!is_valid_ie_attr(attrs[NL80211_ATTR_IE]))
-               return ERR_PTR(-EINVAL);
-
        if (attrs[NL80211_ATTR_SCAN_FREQUENCIES]) {
                n_channels = validate_scan_freqs(
                                attrs[NL80211_ATTR_SCAN_FREQUENCIES]);
@@ -8330,9 +8321,6 @@ static int nl80211_authenticate(struct sk_buff *skb, struct genl_info *info)
        struct key_parse key;
        bool local_state_change;
 
-       if (!is_valid_ie_attr(info->attrs[NL80211_ATTR_IE]))
-               return -EINVAL;
-
        if (!info->attrs[NL80211_ATTR_MAC])
                return -EINVAL;
 
@@ -8571,9 +8559,6 @@ static int nl80211_associate(struct sk_buff *skb, struct genl_info *info)
            dev->ieee80211_ptr->conn_owner_nlportid != info->snd_portid)
                return -EPERM;
 
-       if (!is_valid_ie_attr(info->attrs[NL80211_ATTR_IE]))
-               return -EINVAL;
-
        if (!info->attrs[NL80211_ATTR_MAC] ||
            !info->attrs[NL80211_ATTR_SSID] ||
            !info->attrs[NL80211_ATTR_WIPHY_FREQ])
@@ -8697,9 +8682,6 @@ static int nl80211_deauthenticate(struct sk_buff *skb, struct genl_info *info)
            dev->ieee80211_ptr->conn_owner_nlportid != info->snd_portid)
                return -EPERM;
 
-       if (!is_valid_ie_attr(info->attrs[NL80211_ATTR_IE]))
-               return -EINVAL;
-
        if (!info->attrs[NL80211_ATTR_MAC])
                return -EINVAL;
 
@@ -8748,9 +8730,6 @@ static int nl80211_disassociate(struct sk_buff *skb, struct genl_info *info)
            dev->ieee80211_ptr->conn_owner_nlportid != info->snd_portid)
                return -EPERM;
 
-       if (!is_valid_ie_attr(info->attrs[NL80211_ATTR_IE]))
-               return -EINVAL;
-
        if (!info->attrs[NL80211_ATTR_MAC])
                return -EINVAL;
 
@@ -8825,9 +8804,6 @@ static int nl80211_join_ibss(struct sk_buff *skb, struct genl_info *info)
 
        memset(&ibss, 0, sizeof(ibss));
 
-       if (!is_valid_ie_attr(info->attrs[NL80211_ATTR_IE]))
-               return -EINVAL;
-
        if (!info->attrs[NL80211_ATTR_SSID] ||
            !nla_len(info->attrs[NL80211_ATTR_SSID]))
                return -EINVAL;
@@ -9265,9 +9241,6 @@ static int nl80211_connect(struct sk_buff *skb, struct genl_info *info)
 
        memset(&connect, 0, sizeof(connect));
 
-       if (!is_valid_ie_attr(info->attrs[NL80211_ATTR_IE]))
-               return -EINVAL;
-
        if (!info->attrs[NL80211_ATTR_SSID] ||
            !nla_len(info->attrs[NL80211_ATTR_SSID]))
                return -EINVAL;
@@ -9498,8 +9471,6 @@ static int nl80211_update_connect_params(struct sk_buff *skb,
                return -EOPNOTSUPP;
 
        if (info->attrs[NL80211_ATTR_IE]) {
-               if (!is_valid_ie_attr(info->attrs[NL80211_ATTR_IE]))
-                       return -EINVAL;
                connect.ie = nla_data(info->attrs[NL80211_ATTR_IE]);
                connect.ie_len = nla_len(info->attrs[NL80211_ATTR_IE]);
                changed |= UPDATE_ASSOC_IES;
@@ -12159,8 +12130,7 @@ static int nl80211_update_ft_ies(struct sk_buff *skb, struct genl_info *info)
                return -EOPNOTSUPP;
 
        if (!info->attrs[NL80211_ATTR_MDID] ||
-           !info->attrs[NL80211_ATTR_IE] ||
-           !is_valid_ie_attr(info->attrs[NL80211_ATTR_IE]))
+           !info->attrs[NL80211_ATTR_IE])
                return -EINVAL;
 
        memset(&ft_params, 0, sizeof(ft_params));