diff options
Diffstat (limited to 'net/netlink')
| -rw-r--r-- | net/netlink/af_netlink.c | 5 | ||||
| -rw-r--r-- | net/netlink/policy.c | 61 |
2 files changed, 66 insertions, 0 deletions
diff --git a/net/netlink/af_netlink.c b/net/netlink/af_netlink.c index df675a8e1918..daca50d6bb12 100644 --- a/net/netlink/af_netlink.c +++ b/net/netlink/af_netlink.c @@ -2420,6 +2420,8 @@ void netlink_ack(struct sk_buff *in_skb, struct nlmsghdr *nlh, int err, tlvlen += nla_total_size(sizeof(u32)); if (nlk_has_extack && extack && extack->cookie_len) tlvlen += nla_total_size(extack->cookie_len); + if (err && nlk_has_extack && extack && extack->policy) + tlvlen += netlink_policy_dump_attr_size_estimate(extack->policy); if (tlvlen) flags |= NLM_F_ACK_TLVS; @@ -2452,6 +2454,9 @@ void netlink_ack(struct sk_buff *in_skb, struct nlmsghdr *nlh, int err, if (extack->cookie_len) WARN_ON(nla_put(skb, NLMSGERR_ATTR_COOKIE, extack->cookie_len, extack->cookie)); + if (extack->policy) + netlink_policy_dump_write_attr(skb, extack->policy, + NLMSGERR_ATTR_POLICY); } nlmsg_end(skb, rep); diff --git a/net/netlink/policy.c b/net/netlink/policy.c index 4383436759e2..8d7c900e27f4 100644 --- a/net/netlink/policy.c +++ b/net/netlink/policy.c @@ -196,12 +196,54 @@ bool netlink_policy_dump_loop(struct netlink_policy_dump_state *state) return !netlink_policy_dump_finished(state); } +int netlink_policy_dump_attr_size_estimate(const struct nla_policy *pt) +{ + /* nested + type */ + int common = 2 * nla_attr_size(sizeof(u32)); + + switch (pt->type) { + case NLA_UNSPEC: + case NLA_REJECT: + /* these actually don't need any space */ + return 0; + case NLA_NESTED: + case NLA_NESTED_ARRAY: + /* common, policy idx, policy maxattr */ + return common + 2 * nla_attr_size(sizeof(u32)); + case NLA_U8: + case NLA_U16: + case NLA_U32: + case NLA_U64: + case NLA_MSECS: + case NLA_S8: + case NLA_S16: + case NLA_S32: + case NLA_S64: + /* maximum is common, u64 min/max with padding */ + return common + + 2 * (nla_attr_size(0) + nla_attr_size(sizeof(u64))); + case NLA_BITFIELD32: + return common + nla_attr_size(sizeof(u32)); + case NLA_STRING: + case NLA_NUL_STRING: + case NLA_BINARY: + /* maximum is common, u32 min-length/max-length */ + return common + 2 * nla_attr_size(sizeof(u32)); + case NLA_FLAG: + return common; + } + + /* this should then cause a warning later */ + return 0; +} + static int __netlink_policy_dump_write_attr(struct netlink_policy_dump_state *state, struct sk_buff *skb, const struct nla_policy *pt, int nestattr) { + int estimate = netlink_policy_dump_attr_size_estimate(pt); enum netlink_attribute_type type; struct nlattr *attr; @@ -334,6 +376,8 @@ __netlink_policy_dump_write_attr(struct netlink_policy_dump_state *state, goto nla_put_failure; nla_nest_end(skb, attr); + WARN_ON(attr->nla_len > estimate); + return 0; nla_put_failure: nla_nest_cancel(skb, attr); @@ -341,6 +385,23 @@ nla_put_failure: } /** + * netlink_policy_dump_write_attr - write a given attribute policy + * @skb: the message skb to write to + * @pt: the attribute's policy + * @nestattr: the nested attribute ID to use + * + * Returns: 0 on success, an error code otherwise; -%ENODATA is + * special, indicating that there's no policy data and + * the attribute is generally rejected. + */ +int netlink_policy_dump_write_attr(struct sk_buff *skb, + const struct nla_policy *pt, + int nestattr) +{ + return __netlink_policy_dump_write_attr(NULL, skb, pt, nestattr); +} + +/** * netlink_policy_dump_write - write current policy dump attributes * @skb: the message skb to write to * @state: the policy dump state |