@@ -200,8 +200,10 @@ enum {
* NLA_NUL_STRING Maximum length of string (excluding NUL)
* NLA_FLAG Unused
* NLA_BINARY Maximum length of attribute payload
- * NLA_NESTED Don't use `len' field -- length verification is
- * done by checking len of nested header (or empty)
+ * NLA_NESTED Length verification is done by checking len of
+ * nested header (or empty); len field is used if
+ * validation_data is also used, for the max attr
+ * number in the nested policy.
* NLA_U8, NLA_U16,
* NLA_U32, NLA_U64,
* NLA_S8, NLA_S16,
@@ -224,6 +226,10 @@ enum {
* NLA_REJECT This attribute is always rejected and validation data
* may point to a string to report as the error instead
* of the generic one in extended ACK.
+ * NLA_NESTED Points to a nested policy to validate, must also set
+ * `len' to the max attribute number.
+ * Note that nla_parse() will validate, but of course not
+ * parse, the nested sub-policies.
* All other Unused
*
* Example:
@@ -247,6 +253,9 @@ struct nla_policy {
#define NLA_POLICY_ETH_ADDR NLA_POLICY_EXACT_LEN(ETH_ALEN)
#define NLA_POLICY_ETH_ADDR_COMPAT NLA_POLICY_EXACT_LEN_WARN(ETH_ALEN)
+#define NLA_POLICY_NESTED(maxattr, policy) \
+ { .type = NLA_NESTED, .validation_data = policy, .len = maxattr }
+
/**
* struct nl_info - netlink source information
* @nlh: Netlink message header of original request
@@ -67,6 +67,11 @@ static int validate_nla_bitfield32(const struct nlattr *nla,
return 0;
}
+static int nla_validate_parse(const struct nlattr *head, int len, int maxtype,
+ const struct nla_policy *policy,
+ struct netlink_ext_ack *extack, bool *extack_set,
+ struct nlattr **tb);
+
static int validate_nla(const struct nlattr *nla, int maxtype,
const struct nla_policy *policy,
struct netlink_ext_ack *extack, bool *extack_set)
@@ -148,6 +153,18 @@ static int validate_nla(const struct nlattr *nla, int maxtype,
*/
if (attrlen == 0)
break;
+ if (attrlen < NLA_HDRLEN)
+ return -ERANGE;
+ if (pt->validation_data) {
+ int err;
+
+ err = nla_validate_parse(nla_data(nla), nla_len(nla),
+ pt->len, pt->validation_data,
+ extack, extack_set, NULL);
+ if (err < 0)
+ return err;
+ }
+ break;
default:
if (pt->len)
minlen = pt->len;