diff options
Diffstat (limited to 'net/netfilter/nfnetlink.c')
| -rw-r--r-- | net/netfilter/nfnetlink.c | 194 |
1 files changed, 184 insertions, 10 deletions
diff --git a/net/netfilter/nfnetlink.c b/net/netfilter/nfnetlink.c index 572d87dc116..c138b8fbe28 100644 --- a/net/netfilter/nfnetlink.c +++ b/net/netfilter/nfnetlink.c @@ -61,6 +61,14 @@ void nfnl_unlock(__u8 subsys_id) } EXPORT_SYMBOL_GPL(nfnl_unlock); +#ifdef CONFIG_PROVE_LOCKING +int lockdep_nfnl_is_held(u8 subsys_id) +{ + return lockdep_is_held(&table[subsys_id].mutex); +} +EXPORT_SYMBOL_GPL(lockdep_nfnl_is_held); +#endif + int nfnetlink_subsys_register(const struct nfnetlink_subsystem *n) { nfnl_lock(n->subsys_id); @@ -147,9 +155,6 @@ static int nfnetlink_rcv_msg(struct sk_buff *skb, struct nlmsghdr *nlh) const struct nfnetlink_subsystem *ss; int type, err; - if (!ns_capable(net->user_ns, CAP_NET_ADMIN)) - return -EPERM; - /* All the messages must at least contain nfgenmsg */ if (nlmsg_len(nlh) < sizeof(struct nfgenmsg)) return 0; @@ -217,25 +222,194 @@ replay: } } +static void nfnetlink_rcv_batch(struct sk_buff *skb, struct nlmsghdr *nlh, + u_int16_t subsys_id) +{ + struct sk_buff *nskb, *oskb = skb; + struct net *net = sock_net(skb->sk); + const struct nfnetlink_subsystem *ss; + const struct nfnl_callback *nc; + bool success = true, done = false; + int err; + + if (subsys_id >= NFNL_SUBSYS_COUNT) + return netlink_ack(skb, nlh, -EINVAL); +replay: + nskb = netlink_skb_clone(oskb, GFP_KERNEL); + if (!nskb) + return netlink_ack(oskb, nlh, -ENOMEM); + + nskb->sk = oskb->sk; + skb = nskb; + + nfnl_lock(subsys_id); + ss = rcu_dereference_protected(table[subsys_id].subsys, + lockdep_is_held(&table[subsys_id].mutex)); + if (!ss) { +#ifdef CONFIG_MODULES + nfnl_unlock(subsys_id); + request_module("nfnetlink-subsys-%d", subsys_id); + nfnl_lock(subsys_id); + ss = rcu_dereference_protected(table[subsys_id].subsys, + lockdep_is_held(&table[subsys_id].mutex)); + if (!ss) +#endif + { + nfnl_unlock(subsys_id); + netlink_ack(skb, nlh, -EOPNOTSUPP); + return kfree_skb(nskb); + } + } + + if (!ss->commit || !ss->abort) { + nfnl_unlock(subsys_id); + netlink_ack(skb, nlh, -EOPNOTSUPP); + return kfree_skb(skb); + } + + while (skb->len >= nlmsg_total_size(0)) { + int msglen, type; + + nlh = nlmsg_hdr(skb); + err = 0; + + if (nlh->nlmsg_len < NLMSG_HDRLEN) { + err = -EINVAL; + goto ack; + } + + /* Only requests are handled by the kernel */ + if (!(nlh->nlmsg_flags & NLM_F_REQUEST)) { + err = -EINVAL; + goto ack; + } + + type = nlh->nlmsg_type; + if (type == NFNL_MSG_BATCH_BEGIN) { + /* Malformed: Batch begin twice */ + success = false; + goto done; + } else if (type == NFNL_MSG_BATCH_END) { + done = true; + goto done; + } else if (type < NLMSG_MIN_TYPE) { + err = -EINVAL; + goto ack; + } + + /* We only accept a batch with messages for the same + * subsystem. + */ + if (NFNL_SUBSYS_ID(type) != subsys_id) { + err = -EINVAL; + goto ack; + } + + nc = nfnetlink_find_client(type, ss); + if (!nc) { + err = -EINVAL; + goto ack; + } + + { + int min_len = nlmsg_total_size(sizeof(struct nfgenmsg)); + u_int8_t cb_id = NFNL_MSG_TYPE(nlh->nlmsg_type); + struct nlattr *cda[ss->cb[cb_id].attr_count + 1]; + struct nlattr *attr = (void *)nlh + min_len; + int attrlen = nlh->nlmsg_len - min_len; + + err = nla_parse(cda, ss->cb[cb_id].attr_count, + attr, attrlen, ss->cb[cb_id].policy); + if (err < 0) + goto ack; + + if (nc->call_batch) { + err = nc->call_batch(net->nfnl, skb, nlh, + (const struct nlattr **)cda); + } + + /* The lock was released to autoload some module, we + * have to abort and start from scratch using the + * original skb. + */ + if (err == -EAGAIN) { + ss->abort(skb); + nfnl_unlock(subsys_id); + kfree_skb(nskb); + goto replay; + } + } +ack: + if (nlh->nlmsg_flags & NLM_F_ACK || err) { + /* We don't stop processing the batch on errors, thus, + * userspace gets all the errors that the batch + * triggers. + */ + netlink_ack(skb, nlh, err); + if (err) + success = false; + } + + msglen = NLMSG_ALIGN(nlh->nlmsg_len); + if (msglen > skb->len) + msglen = skb->len; + skb_pull(skb, msglen); + } +done: + if (success && done) + ss->commit(skb); + else + ss->abort(skb); + + nfnl_unlock(subsys_id); + kfree_skb(nskb); +} + static void nfnetlink_rcv(struct sk_buff *skb) { - netlink_rcv_skb(skb, &nfnetlink_rcv_msg); + struct nlmsghdr *nlh = nlmsg_hdr(skb); + int msglen; + + if (nlh->nlmsg_len < NLMSG_HDRLEN || + skb->len < nlh->nlmsg_len) + return; + + if (!netlink_net_capable(skb, CAP_NET_ADMIN)) { + netlink_ack(skb, nlh, -EPERM); + return; + } + + if (nlh->nlmsg_type == NFNL_MSG_BATCH_BEGIN) { + struct nfgenmsg *nfgenmsg; + + msglen = NLMSG_ALIGN(nlh->nlmsg_len); + if (msglen > skb->len) + msglen = skb->len; + + if (nlh->nlmsg_len < NLMSG_HDRLEN || + skb->len < NLMSG_HDRLEN + sizeof(struct nfgenmsg)) + return; + + nfgenmsg = nlmsg_data(nlh); + skb_pull(skb, msglen); + nfnetlink_rcv_batch(skb, nlh, nfgenmsg->res_id); + } else { + netlink_rcv_skb(skb, &nfnetlink_rcv_msg); + } } #ifdef CONFIG_MODULES -static void nfnetlink_bind(int group) +static int nfnetlink_bind(int group) { const struct nfnetlink_subsystem *ss; int type = nfnl_group2type[group]; rcu_read_lock(); ss = nfnetlink_get_subsys(type); - if (!ss) { - rcu_read_unlock(); - request_module("nfnetlink-subsys-%d", type); - return; - } rcu_read_unlock(); + if (!ss) + request_module("nfnetlink-subsys-%d", type); + return 0; } #endif |