diff options
| -rw-r--r-- | include/net/netlink.h | 12 | ||||
| -rw-r--r-- | lib/nlattr.c | 51 |
2 files changed, 62 insertions, 1 deletions
diff --git a/include/net/netlink.h b/include/net/netlink.h index 91907852da1c..3698ca8ff92c 100644 --- a/include/net/netlink.h +++ b/include/net/netlink.h @@ -172,6 +172,7 @@ enum { NLA_FLAG, NLA_MSECS, NLA_NESTED, + NLA_NESTED_ARRAY, NLA_NUL_STRING, NLA_BINARY, NLA_S8, @@ -200,7 +201,8 @@ enum { * NLA_NUL_STRING Maximum length of string (excluding NUL) * NLA_FLAG Unused * NLA_BINARY Maximum length of attribute payload - * NLA_NESTED Length verification is done by checking len of + * NLA_NESTED, + * NLA_NESTED_ARRAY 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. @@ -230,6 +232,12 @@ enum { * `len' to the max attribute number. * Note that nla_parse() will validate, but of course not * parse, the nested sub-policies. + * NLA_NESTED_ARRAY Points to a nested policy to validate, must also set + * `len' to the max attribute number. The difference to + * NLA_NESTED is the structure - NLA_NESTED has the + * nested attributes directly inside, while an array has + * the nested attributes at another level down and the + * attributes directly in the nesting don't matter. * All other Unused * * Example: @@ -255,6 +263,8 @@ struct nla_policy { #define NLA_POLICY_NESTED(maxattr, policy) \ { .type = NLA_NESTED, .validation_data = policy, .len = maxattr } +#define NLA_POLICY_NESTED_ARRAY(maxattr, policy) \ + { .type = NLA_NESTED_ARRAY, .validation_data = policy, .len = maxattr } /** * struct nl_info - netlink source information diff --git a/lib/nlattr.c b/lib/nlattr.c index 04750f88477c..2f8feff669a7 100644 --- a/lib/nlattr.c +++ b/lib/nlattr.c @@ -67,6 +67,34 @@ static int validate_nla_bitfield32(const struct nlattr *nla, return 0; } +static int nla_validate_array(const struct nlattr *head, int len, int maxtype, + const struct nla_policy *policy, + struct netlink_ext_ack *extack) +{ + const struct nlattr *entry; + int rem; + + nla_for_each_attr(entry, head, len, rem) { + int ret; + + if (nla_len(entry) == 0) + continue; + + if (nla_len(entry) < NLA_HDRLEN) { + NL_SET_ERR_MSG_ATTR(extack, entry, + "Array element too short"); + return -ERANGE; + } + + ret = nla_validate(nla_data(entry), nla_len(entry), + maxtype, policy, extack); + if (ret < 0) + return ret; + } + + return 0; +} + static int validate_nla(const struct nlattr *nla, int maxtype, const struct nla_policy *policy, struct netlink_ext_ack *extack) @@ -169,6 +197,29 @@ static int validate_nla(const struct nlattr *nla, int maxtype, } } break; + case NLA_NESTED_ARRAY: + /* a nested array attribute is allowed to be empty; if its not, + * it must have a size of at least NLA_HDRLEN. + */ + if (attrlen == 0) + break; + if (attrlen < NLA_HDRLEN) + goto out_err; + if (pt->validation_data) { + int err; + + err = nla_validate_array(nla_data(nla), nla_len(nla), + pt->len, pt->validation_data, + extack); + if (err < 0) { + /* + * return directly to preserve the inner + * error message/attribute pointer + */ + return err; + } + } + break; default: if (pt->len) minlen = pt->len; |