diff options
Diffstat (limited to 'net/netfilter/nft_compat.c')
| -rw-r--r-- | net/netfilter/nft_compat.c | 768 |
1 files changed, 768 insertions, 0 deletions
diff --git a/net/netfilter/nft_compat.c b/net/netfilter/nft_compat.c new file mode 100644 index 000000000000..4811f762e060 --- /dev/null +++ b/net/netfilter/nft_compat.c @@ -0,0 +1,768 @@ +/* + * (C) 2012-2013 by Pablo Neira Ayuso <pablo@netfilter.org> + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 as + * published by the Free Software Foundation. + * + * This software has been sponsored by Sophos Astaro <http://www.sophos.com> + */ + +#include <linux/kernel.h> +#include <linux/init.h> +#include <linux/module.h> +#include <linux/netlink.h> +#include <linux/netfilter.h> +#include <linux/netfilter/nfnetlink.h> +#include <linux/netfilter/nf_tables.h> +#include <linux/netfilter/nf_tables_compat.h> +#include <linux/netfilter/x_tables.h> +#include <linux/netfilter_ipv4/ip_tables.h> +#include <linux/netfilter_ipv6/ip6_tables.h> +#include <asm/uaccess.h> /* for set_fs */ +#include <net/netfilter/nf_tables.h> + +union nft_entry { + struct ipt_entry e4; + struct ip6t_entry e6; +}; + +static inline void +nft_compat_set_par(struct xt_action_param *par, void *xt, const void *xt_info) +{ + par->target = xt; + par->targinfo = xt_info; + par->hotdrop = false; +} + +static void nft_target_eval(const struct nft_expr *expr, + struct nft_data data[NFT_REG_MAX + 1], + const struct nft_pktinfo *pkt) +{ + void *info = nft_expr_priv(expr); + struct xt_target *target = expr->ops->data; + struct sk_buff *skb = pkt->skb; + int ret; + + nft_compat_set_par((struct xt_action_param *)&pkt->xt, target, info); + + ret = target->target(skb, &pkt->xt); + + if (pkt->xt.hotdrop) + ret = NF_DROP; + + switch(ret) { + case XT_CONTINUE: + data[NFT_REG_VERDICT].verdict = NFT_CONTINUE; + break; + default: + data[NFT_REG_VERDICT].verdict = ret; + break; + } + return; +} + +static const struct nla_policy nft_target_policy[NFTA_TARGET_MAX + 1] = { + [NFTA_TARGET_NAME] = { .type = NLA_NUL_STRING }, + [NFTA_TARGET_REV] = { .type = NLA_U32 }, + [NFTA_TARGET_INFO] = { .type = NLA_BINARY }, +}; + +static void +nft_target_set_tgchk_param(struct xt_tgchk_param *par, + const struct nft_ctx *ctx, + struct xt_target *target, void *info, + union nft_entry *entry, u8 proto, bool inv) +{ + par->net = &init_net; + par->table = ctx->table->name; + switch (ctx->afi->family) { + case AF_INET: + entry->e4.ip.proto = proto; + entry->e4.ip.invflags = inv ? IPT_INV_PROTO : 0; + break; + case AF_INET6: + entry->e6.ipv6.proto = proto; + entry->e6.ipv6.invflags = inv ? IP6T_INV_PROTO : 0; + break; + } + par->entryinfo = entry; + par->target = target; + par->targinfo = info; + if (ctx->chain->flags & NFT_BASE_CHAIN) { + const struct nft_base_chain *basechain = + nft_base_chain(ctx->chain); + const struct nf_hook_ops *ops = &basechain->ops; + + par->hook_mask = 1 << ops->hooknum; + } + par->family = ctx->afi->family; +} + +static void target_compat_from_user(struct xt_target *t, void *in, void *out) +{ +#ifdef CONFIG_COMPAT + if (t->compat_from_user) { + int pad; + + t->compat_from_user(out, in); + pad = XT_ALIGN(t->targetsize) - t->targetsize; + if (pad > 0) + memset(out + t->targetsize, 0, pad); + } else +#endif + memcpy(out, in, XT_ALIGN(t->targetsize)); +} + +static inline int nft_compat_target_offset(struct xt_target *target) +{ +#ifdef CONFIG_COMPAT + return xt_compat_target_offset(target); +#else + return 0; +#endif +} + +static const struct nla_policy nft_rule_compat_policy[NFTA_RULE_COMPAT_MAX + 1] = { + [NFTA_RULE_COMPAT_PROTO] = { .type = NLA_U32 }, + [NFTA_RULE_COMPAT_FLAGS] = { .type = NLA_U32 }, +}; + +static u8 nft_parse_compat(const struct nlattr *attr, bool *inv) +{ + struct nlattr *tb[NFTA_RULE_COMPAT_MAX+1]; + u32 flags; + int err; + + err = nla_parse_nested(tb, NFTA_RULE_COMPAT_MAX, attr, + nft_rule_compat_policy); + if (err < 0) + return err; + + if (!tb[NFTA_RULE_COMPAT_PROTO] || !tb[NFTA_RULE_COMPAT_FLAGS]) + return -EINVAL; + + flags = ntohl(nla_get_be32(tb[NFTA_RULE_COMPAT_FLAGS])); + if (flags & ~NFT_RULE_COMPAT_F_MASK) + return -EINVAL; + if (flags & NFT_RULE_COMPAT_F_INV) + *inv = true; + + return ntohl(nla_get_be32(tb[NFTA_RULE_COMPAT_PROTO])); +} + +static int +nft_target_init(const struct nft_ctx *ctx, const struct nft_expr *expr, + const struct nlattr * const tb[]) +{ + void *info = nft_expr_priv(expr); + struct xt_target *target = expr->ops->data; + struct xt_tgchk_param par; + size_t size = XT_ALIGN(nla_len(tb[NFTA_TARGET_INFO])); + u8 proto = 0; + bool inv = false; + union nft_entry e = {}; + int ret; + + target_compat_from_user(target, nla_data(tb[NFTA_TARGET_INFO]), info); + + if (ctx->nla[NFTA_RULE_COMPAT]) + proto = nft_parse_compat(ctx->nla[NFTA_RULE_COMPAT], &inv); + + nft_target_set_tgchk_param(&par, ctx, target, info, &e, proto, inv); + + ret = xt_check_target(&par, size, proto, inv); + if (ret < 0) + goto err; + + /* The standard target cannot be used */ + if (target->target == NULL) { + ret = -EINVAL; + goto err; + } + + return 0; +err: + module_put(target->me); + return ret; +} + +static void +nft_target_destroy(const struct nft_expr *expr) +{ + struct xt_target *target = expr->ops->data; + + module_put(target->me); +} + +static int +target_dump_info(struct sk_buff *skb, const struct xt_target *t, const void *in) +{ + int ret; + +#ifdef CONFIG_COMPAT + if (t->compat_to_user) { + mm_segment_t old_fs; + void *out; + + out = kmalloc(XT_ALIGN(t->targetsize), GFP_ATOMIC); + if (out == NULL) + return -ENOMEM; + + /* We want to reuse existing compat_to_user */ + old_fs = get_fs(); + set_fs(KERNEL_DS); + t->compat_to_user(out, in); + set_fs(old_fs); + ret = nla_put(skb, NFTA_TARGET_INFO, XT_ALIGN(t->targetsize), out); + kfree(out); + } else +#endif + ret = nla_put(skb, NFTA_TARGET_INFO, XT_ALIGN(t->targetsize), in); + + return ret; +} + +static int nft_target_dump(struct sk_buff *skb, const struct nft_expr *expr) +{ + const struct xt_target *target = expr->ops->data; + void *info = nft_expr_priv(expr); + + if (nla_put_string(skb, NFTA_TARGET_NAME, target->name) || + nla_put_be32(skb, NFTA_TARGET_REV, htonl(target->revision)) || + target_dump_info(skb, target, info)) + goto nla_put_failure; + + return 0; + +nla_put_failure: + return -1; +} + +static int nft_target_validate(const struct nft_ctx *ctx, + const struct nft_expr *expr, + const struct nft_data **data) +{ + struct xt_target *target = expr->ops->data; + unsigned int hook_mask = 0; + + if (ctx->chain->flags & NFT_BASE_CHAIN) { + const struct nft_base_chain *basechain = + nft_base_chain(ctx->chain); + const struct nf_hook_ops *ops = &basechain->ops; + + hook_mask = 1 << ops->hooknum; + if (hook_mask & target->hooks) + return 0; + + /* This target is being called from an invalid chain */ + return -EINVAL; + } + return 0; +} + +static void nft_match_eval(const struct nft_expr *expr, + struct nft_data data[NFT_REG_MAX + 1], + const struct nft_pktinfo *pkt) +{ + void *info = nft_expr_priv(expr); + struct xt_match *match = expr->ops->data; + struct sk_buff *skb = pkt->skb; + bool ret; + + nft_compat_set_par((struct xt_action_param *)&pkt->xt, match, info); + + ret = match->match(skb, (struct xt_action_param *)&pkt->xt); + + if (pkt->xt.hotdrop) { + data[NFT_REG_VERDICT].verdict = NF_DROP; + return; + } + + switch(ret) { + case true: + data[NFT_REG_VERDICT].verdict = NFT_CONTINUE; + break; + case false: + data[NFT_REG_VERDICT].verdict = NFT_BREAK; + break; + } +} + +static const struct nla_policy nft_match_policy[NFTA_MATCH_MAX + 1] = { + [NFTA_MATCH_NAME] = { .type = NLA_NUL_STRING }, + [NFTA_MATCH_REV] = { .type = NLA_U32 }, + [NFTA_MATCH_INFO] = { .type = NLA_BINARY }, +}; + +/* struct xt_mtchk_param and xt_tgchk_param look very similar */ +static void +nft_match_set_mtchk_param(struct xt_mtchk_param *par, const struct nft_ctx *ctx, + struct xt_match *match, void *info, + union nft_entry *entry, u8 proto, bool inv) +{ + par->net = &init_net; + par->table = ctx->table->name; + switch (ctx->afi->family) { + case AF_INET: + entry->e4.ip.proto = proto; + entry->e4.ip.invflags = inv ? IPT_INV_PROTO : 0; + break; + case AF_INET6: + entry->e6.ipv6.proto = proto; + entry->e6.ipv6.invflags = inv ? IP6T_INV_PROTO : 0; + break; + } + par->entryinfo = entry; + par->match = match; + par->matchinfo = info; + if (ctx->chain->flags & NFT_BASE_CHAIN) { + const struct nft_base_chain *basechain = + nft_base_chain(ctx->chain); + const struct nf_hook_ops *ops = &basechain->ops; + + par->hook_mask = 1 << ops->hooknum; + } + par->family = ctx->afi->family; +} + +static void match_compat_from_user(struct xt_match *m, void *in, void *out) +{ +#ifdef CONFIG_COMPAT + if (m->compat_from_user) { + int pad; + + m->compat_from_user(out, in); + pad = XT_ALIGN(m->matchsize) - m->matchsize; + if (pad > 0) + memset(out + m->matchsize, 0, pad); + } else +#endif + memcpy(out, in, XT_ALIGN(m->matchsize)); +} + +static int +nft_match_init(const struct nft_ctx *ctx, const struct nft_expr *expr, + const struct nlattr * const tb[]) +{ + void *info = nft_expr_priv(expr); + struct xt_match *match = expr->ops->data; + struct xt_mtchk_param par; + size_t size = XT_ALIGN(nla_len(tb[NFTA_MATCH_INFO])); + u8 proto = 0; + bool inv = false; + union nft_entry e = {}; + int ret; + + match_compat_from_user(match, nla_data(tb[NFTA_MATCH_INFO]), info); + + if (ctx->nla[NFTA_RULE_COMPAT]) + proto = nft_parse_compat(ctx->nla[NFTA_RULE_COMPAT], &inv); + + nft_match_set_mtchk_param(&par, ctx, match, info, &e, proto, inv); + + ret = xt_check_match(&par, size, proto, inv); + if (ret < 0) + goto err; + + return 0; +err: + module_put(match->me); + return ret; +} + +static void +nft_match_destroy(const struct nft_expr *expr) +{ + struct xt_match *match = expr->ops->data; + + module_put(match->me); +} + +static int +match_dump_info(struct sk_buff *skb, const struct xt_match *m, const void *in) +{ + int ret; + +#ifdef CONFIG_COMPAT + if (m->compat_to_user) { + mm_segment_t old_fs; + void *out; + + out = kmalloc(XT_ALIGN(m->matchsize), GFP_ATOMIC); + if (out == NULL) + return -ENOMEM; + + /* We want to reuse existing compat_to_user */ + old_fs = get_fs(); + set_fs(KERNEL_DS); + m->compat_to_user(out, in); + set_fs(old_fs); + ret = nla_put(skb, NFTA_MATCH_INFO, XT_ALIGN(m->matchsize), out); + kfree(out); + } else +#endif + ret = nla_put(skb, NFTA_MATCH_INFO, XT_ALIGN(m->matchsize), in); + + return ret; +} + +static inline int nft_compat_match_offset(struct xt_match *match) +{ +#ifdef CONFIG_COMPAT + return xt_compat_match_offset(match); +#else + return 0; +#endif +} + +static int nft_match_dump(struct sk_buff *skb, const struct nft_expr *expr) +{ + void *info = nft_expr_priv(expr); + struct xt_match *match = expr->ops->data; + + if (nla_put_string(skb, NFTA_MATCH_NAME, match->name) || + nla_put_be32(skb, NFTA_MATCH_REV, htonl(match->revision)) || + match_dump_info(skb, match, info)) + goto nla_put_failure; + + return 0; + +nla_put_failure: + return -1; +} + +static int nft_match_validate(const struct nft_ctx *ctx, + const struct nft_expr *expr, + const struct nft_data **data) +{ + struct xt_match *match = expr->ops->data; + unsigned int hook_mask = 0; + + if (ctx->chain->flags & NFT_BASE_CHAIN) { + const struct nft_base_chain *basechain = + nft_base_chain(ctx->chain); + const struct nf_hook_ops *ops = &basechain->ops; + + hook_mask = 1 << ops->hooknum; + if (hook_mask & match->hooks) + return 0; + + /* This match is being called from an invalid chain */ + return -EINVAL; + } + return 0; +} + +static int +nfnl_compat_fill_info(struct sk_buff *skb, u32 portid, u32 seq, u32 type, + int event, u16 family, const char *name, + int rev, int target) +{ + struct nlmsghdr *nlh; + struct nfgenmsg *nfmsg; + unsigned int flags = portid ? NLM_F_MULTI : 0; + + event |= NFNL_SUBSYS_NFT_COMPAT << 8; + nlh = nlmsg_put(skb, portid, seq, event, sizeof(*nfmsg), flags); + if (nlh == NULL) + goto nlmsg_failure; + + nfmsg = nlmsg_data(nlh); + nfmsg->nfgen_family = family; + nfmsg->version = NFNETLINK_V0; + nfmsg->res_id = 0; + + if (nla_put_string(skb, NFTA_COMPAT_NAME, name) || + nla_put_be32(skb, NFTA_COMPAT_REV, htonl(rev)) || + nla_put_be32(skb, NFTA_COMPAT_TYPE, htonl(target))) + goto nla_put_failure; + + nlmsg_end(skb, nlh); + return skb->len; + +nlmsg_failure: +nla_put_failure: + nlmsg_cancel(skb, nlh); + return -1; +} + +static int +nfnl_compat_get(struct sock *nfnl, struct sk_buff *skb, + const struct nlmsghdr *nlh, const struct nlattr * const tb[]) +{ + int ret = 0, target; + struct nfgenmsg *nfmsg; + const char *fmt; + const char *name; + u32 rev; + struct sk_buff *skb2; + + if (tb[NFTA_COMPAT_NAME] == NULL || + tb[NFTA_COMPAT_REV] == NULL || + tb[NFTA_COMPAT_TYPE] == NULL) + return -EINVAL; + + name = nla_data(tb[NFTA_COMPAT_NAME]); + rev = ntohl(nla_get_be32(tb[NFTA_COMPAT_REV])); + target = ntohl(nla_get_be32(tb[NFTA_COMPAT_TYPE])); + + nfmsg = nlmsg_data(nlh); + + switch(nfmsg->nfgen_family) { + case AF_INET: + fmt = "ipt_%s"; + break; + case AF_INET6: + fmt = "ip6t_%s"; + break; + default: + pr_err("nft_compat: unsupported protocol %d\n", + nfmsg->nfgen_family); + return -EINVAL; + } + + try_then_request_module(xt_find_revision(nfmsg->nfgen_family, name, + rev, target, &ret), + fmt, name); + + if (ret < 0) + return ret; + + skb2 = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL); + if (skb2 == NULL) + return -ENOMEM; + + /* include the best revision for this extension in the message */ + if (nfnl_compat_fill_info(skb2, NETLINK_CB(skb).portid, + nlh->nlmsg_seq, + NFNL_MSG_TYPE(nlh->nlmsg_type), + NFNL_MSG_COMPAT_GET, + nfmsg->nfgen_family, + name, ret, target) <= 0) { + kfree_skb(skb2); + return -ENOSPC; + } + + ret = netlink_unicast(nfnl, skb2, NETLINK_CB(skb).portid, + MSG_DONTWAIT); + if (ret > 0) + ret = 0; + + return ret == -EAGAIN ? -ENOBUFS : ret; +} + +static const struct nla_policy nfnl_compat_policy_get[NFTA_COMPAT_MAX+1] = { + [NFTA_COMPAT_NAME] = { .type = NLA_NUL_STRING, + .len = NFT_COMPAT_NAME_MAX-1 }, + [NFTA_COMPAT_REV] = { .type = NLA_U32 }, + [NFTA_COMPAT_TYPE] = { .type = NLA_U32 }, +}; + +static const struct nfnl_callback nfnl_nft_compat_cb[NFNL_MSG_COMPAT_MAX] = { + [NFNL_MSG_COMPAT_GET] = { .call = nfnl_compat_get, + .attr_count = NFTA_COMPAT_MAX, + .policy = nfnl_compat_policy_get }, +}; + +static const struct nfnetlink_subsystem nfnl_compat_subsys = { + .name = "nft-compat", + .subsys_id = NFNL_SUBSYS_NFT_COMPAT, + .cb_count = NFNL_MSG_COMPAT_MAX, + .cb = nfnl_nft_compat_cb, +}; + +static LIST_HEAD(nft_match_list); + +struct nft_xt { + struct list_head head; + struct nft_expr_ops ops; +}; + +static struct nft_expr_type nft_match_type; + +static const struct nft_expr_ops * +nft_match_select_ops(const struct nft_ctx *ctx, + const struct nlattr * const tb[]) +{ + struct nft_xt *nft_match; + struct xt_match *match; + char *mt_name; + __u32 rev, family; + + if (tb[NFTA_MATCH_NAME] == NULL || + tb[NFTA_MATCH_REV] == NULL || + tb[NFTA_MATCH_INFO] == NULL) + return ERR_PTR(-EINVAL); + + mt_name = nla_data(tb[NFTA_MATCH_NAME]); + rev = ntohl(nla_get_be32(tb[NFTA_MATCH_REV])); + family = ctx->afi->family; + + /* Re-use the existing match if it's already loaded. */ + list_for_each_entry(nft_match, &nft_match_list, head) { + struct xt_match *match = nft_match->ops.data; + + if (strcmp(match->name, mt_name) == 0 && + match->revision == rev && match->family == family) + return &nft_match->ops; + } + + match = xt_request_find_match(family, mt_name, rev); + if (IS_ERR(match)) + return ERR_PTR(-ENOENT); + + /* This is the first time we use this match, allocate operations */ + nft_match = kzalloc(sizeof(struct nft_xt), GFP_KERNEL); + if (nft_match == NULL) + return ERR_PTR(-ENOMEM); + + nft_match->ops.type = &nft_match_type; + nft_match->ops.size = NFT_EXPR_SIZE(XT_ALIGN(match->matchsize) + + nft_compat_match_offset(match)); + nft_match->ops.eval = nft_match_eval; + nft_match->ops.init = nft_match_init; + nft_match->ops.destroy = nft_match_destroy; + nft_match->ops.dump = nft_match_dump; + nft_match->ops.validate = nft_match_validate; + nft_match->ops.data = match; + + list_add(&nft_match->head, &nft_match_list); + + return &nft_match->ops; +} + +static void nft_match_release(void) +{ + struct nft_xt *nft_match; + + list_for_each_entry(nft_match, &nft_match_list, head) + kfree(nft_match); +} + +static struct nft_expr_type nft_match_type __read_mostly = { + .name = "match", + .select_ops = nft_match_select_ops, + .policy = nft_match_policy, + .maxattr = NFTA_MATCH_MAX, + .owner = THIS_MODULE, +}; + +static LIST_HEAD(nft_target_list); + +static struct nft_expr_type nft_target_type; + +static const struct nft_expr_ops * +nft_target_select_ops(const struct nft_ctx *ctx, + const struct nlattr * const tb[]) +{ + struct nft_xt *nft_target; + struct xt_target *target; + char *tg_name; + __u32 rev, family; + + if (tb[NFTA_TARGET_NAME] == NULL || + tb[NFTA_TARGET_REV] == NULL || + tb[NFTA_TARGET_INFO] == NULL) + return ERR_PTR(-EINVAL); + + tg_name = nla_data(tb[NFTA_TARGET_NAME]); + rev = ntohl(nla_get_be32(tb[NFTA_TARGET_REV])); + family = ctx->afi->family; + + /* Re-use the existing target if it's already loaded. */ + list_for_each_entry(nft_target, &nft_match_list, head) { + struct xt_target *target = nft_target->ops.data; + + if (strcmp(target->name, tg_name) == 0 && + target->revision == rev && target->family == family) + return &nft_target->ops; + } + + target = xt_request_find_target(family, tg_name, rev); + if (IS_ERR(target)) + return ERR_PTR(-ENOENT); + + /* This is the first time we use this target, allocate operations */ + nft_target = kzalloc(sizeof(struct nft_xt), GFP_KERNEL); + if (nft_target == NULL) + return ERR_PTR(-ENOMEM); + + nft_target->ops.type = &nft_target_type; + nft_target->ops.size = NFT_EXPR_SIZE(XT_ALIGN(target->targetsize) + + nft_compat_target_offset(target)); + nft_target->ops.eval = nft_target_eval; + nft_target->ops.init = nft_target_init; + nft_target->ops.destroy = nft_target_destroy; + nft_target->ops.dump = nft_target_dump; + nft_target->ops.validate = nft_target_validate; + nft_target->ops.data = target; + + list_add(&nft_target->head, &nft_target_list); + + return &nft_target->ops; +} + +static void nft_target_release(void) +{ + struct nft_xt *nft_target; + + list_for_each_entry(nft_target, &nft_target_list, head) + kfree(nft_target); +} + +static struct nft_expr_type nft_target_type __read_mostly = { + .name = "target", + .select_ops = nft_target_select_ops, + .policy = nft_target_policy, + .maxattr = NFTA_TARGET_MAX, + .owner = THIS_MODULE, +}; + +static int __init nft_compat_module_init(void) +{ + int ret; + + ret = nft_register_expr(&nft_match_type); + if (ret < 0) + return ret; + + ret = nft_register_expr(&nft_target_type); + if (ret < 0) + goto err_match; + + ret = nfnetlink_subsys_register(&nfnl_compat_subsys); + if (ret < 0) { + pr_err("nft_compat: cannot register with nfnetlink.\n"); + goto err_target; + } + + pr_info("nf_tables_compat: (c) 2012 Pablo Neira Ayuso <pablo@netfilter.org>\n"); + + return ret; + +err_target: + nft_unregister_expr(&nft_target_type); +err_match: + nft_unregister_expr(&nft_match_type); + return ret; +} + +static void __exit nft_compat_module_exit(void) +{ + nfnetlink_subsys_unregister(&nfnl_compat_subsys); + nft_unregister_expr(&nft_target_type); + nft_unregister_expr(&nft_match_type); + nft_match_release(); + nft_target_release(); +} + +MODULE_ALIAS_NFNL_SUBSYS(NFNL_SUBSYS_NFT_COMPAT); + +module_init(nft_compat_module_init); +module_exit(nft_compat_module_exit); + +MODULE_LICENSE("GPL"); +MODULE_AUTHOR("Pablo Neira Ayuso <pablo@netfilter.org>"); +MODULE_ALIAS_NFT_EXPR("match"); +MODULE_ALIAS_NFT_EXPR("target"); |