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![Pablo Neira Ayuso](/assets/img/avatar_default.png)
Anonymous sets that are bound to rules from the same transaction trigger
a kernel splat from the abort path due to double set list removal and
double free.
This patch updates the logic to search for the transaction that is
responsible for creating the set and disable the set list removal and
release, given the rule is now responsible for this. Lookup is reverse
since the transaction that adds the set is likely to be at the tail of
the list.
Moreover, this patch adds the unbind step to deliver the event from the
commit path. This should not be done from the worker thread, since we
have no guarantees of in-order delivery to the listener.
This patch removes the assumption that both activate and deactivate
callbacks need to be provided.
Fixes: cd5125d8f5
("netfilter: nf_tables: split set destruction in deactivate and destroy phase")
Reported-by: Mikhail Morfikov <mmorfikov@gmail.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
237 lines
5.9 KiB
C
237 lines
5.9 KiB
C
/*
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* Copyright (c) 2009 Patrick McHardy <kaber@trash.net>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*
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* Development of this code funded by Astaro AG (http://www.astaro.com/)
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*/
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#include <linux/kernel.h>
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#include <linux/init.h>
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#include <linux/list.h>
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#include <linux/rbtree.h>
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#include <linux/netlink.h>
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#include <linux/netfilter.h>
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#include <linux/netfilter/nf_tables.h>
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#include <net/netfilter/nf_tables.h>
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#include <net/netfilter/nf_tables_core.h>
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struct nft_lookup {
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struct nft_set *set;
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enum nft_registers sreg:8;
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enum nft_registers dreg:8;
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bool invert;
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struct nft_set_binding binding;
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};
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void nft_lookup_eval(const struct nft_expr *expr,
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struct nft_regs *regs,
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const struct nft_pktinfo *pkt)
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{
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const struct nft_lookup *priv = nft_expr_priv(expr);
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const struct nft_set *set = priv->set;
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const struct nft_set_ext *ext;
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bool found;
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found = set->ops->lookup(nft_net(pkt), set, ®s->data[priv->sreg],
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&ext) ^ priv->invert;
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if (!found) {
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regs->verdict.code = NFT_BREAK;
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return;
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}
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if (set->flags & NFT_SET_MAP)
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nft_data_copy(®s->data[priv->dreg],
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nft_set_ext_data(ext), set->dlen);
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}
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static const struct nla_policy nft_lookup_policy[NFTA_LOOKUP_MAX + 1] = {
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[NFTA_LOOKUP_SET] = { .type = NLA_STRING,
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.len = NFT_SET_MAXNAMELEN - 1 },
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[NFTA_LOOKUP_SET_ID] = { .type = NLA_U32 },
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[NFTA_LOOKUP_SREG] = { .type = NLA_U32 },
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[NFTA_LOOKUP_DREG] = { .type = NLA_U32 },
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[NFTA_LOOKUP_FLAGS] = { .type = NLA_U32 },
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};
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static int nft_lookup_init(const struct nft_ctx *ctx,
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const struct nft_expr *expr,
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const struct nlattr * const tb[])
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{
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struct nft_lookup *priv = nft_expr_priv(expr);
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u8 genmask = nft_genmask_next(ctx->net);
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struct nft_set *set;
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u32 flags;
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int err;
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if (tb[NFTA_LOOKUP_SET] == NULL ||
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tb[NFTA_LOOKUP_SREG] == NULL)
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return -EINVAL;
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set = nft_set_lookup_global(ctx->net, ctx->table, tb[NFTA_LOOKUP_SET],
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tb[NFTA_LOOKUP_SET_ID], genmask);
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if (IS_ERR(set))
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return PTR_ERR(set);
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if (set->flags & NFT_SET_EVAL)
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return -EOPNOTSUPP;
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priv->sreg = nft_parse_register(tb[NFTA_LOOKUP_SREG]);
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err = nft_validate_register_load(priv->sreg, set->klen);
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if (err < 0)
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return err;
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if (tb[NFTA_LOOKUP_FLAGS]) {
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flags = ntohl(nla_get_be32(tb[NFTA_LOOKUP_FLAGS]));
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if (flags & ~NFT_LOOKUP_F_INV)
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return -EINVAL;
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if (flags & NFT_LOOKUP_F_INV) {
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if (set->flags & NFT_SET_MAP)
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return -EINVAL;
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priv->invert = true;
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}
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}
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if (tb[NFTA_LOOKUP_DREG] != NULL) {
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if (priv->invert)
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return -EINVAL;
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if (!(set->flags & NFT_SET_MAP))
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return -EINVAL;
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priv->dreg = nft_parse_register(tb[NFTA_LOOKUP_DREG]);
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err = nft_validate_register_store(ctx, priv->dreg, NULL,
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set->dtype, set->dlen);
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if (err < 0)
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return err;
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} else if (set->flags & NFT_SET_MAP)
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return -EINVAL;
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priv->binding.flags = set->flags & NFT_SET_MAP;
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err = nf_tables_bind_set(ctx, set, &priv->binding);
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if (err < 0)
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return err;
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priv->set = set;
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return 0;
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}
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static void nft_lookup_deactivate(const struct nft_ctx *ctx,
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const struct nft_expr *expr,
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enum nft_trans_phase phase)
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{
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struct nft_lookup *priv = nft_expr_priv(expr);
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if (phase == NFT_TRANS_PREPARE)
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return;
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nf_tables_unbind_set(ctx, priv->set, &priv->binding,
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phase == NFT_TRANS_COMMIT);
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}
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static void nft_lookup_destroy(const struct nft_ctx *ctx,
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const struct nft_expr *expr)
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{
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struct nft_lookup *priv = nft_expr_priv(expr);
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nf_tables_destroy_set(ctx, priv->set);
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}
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static int nft_lookup_dump(struct sk_buff *skb, const struct nft_expr *expr)
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{
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const struct nft_lookup *priv = nft_expr_priv(expr);
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u32 flags = priv->invert ? NFT_LOOKUP_F_INV : 0;
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if (nla_put_string(skb, NFTA_LOOKUP_SET, priv->set->name))
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goto nla_put_failure;
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if (nft_dump_register(skb, NFTA_LOOKUP_SREG, priv->sreg))
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goto nla_put_failure;
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if (priv->set->flags & NFT_SET_MAP)
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if (nft_dump_register(skb, NFTA_LOOKUP_DREG, priv->dreg))
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goto nla_put_failure;
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if (nla_put_be32(skb, NFTA_LOOKUP_FLAGS, htonl(flags)))
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goto nla_put_failure;
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return 0;
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nla_put_failure:
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return -1;
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}
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static int nft_lookup_validate_setelem(const struct nft_ctx *ctx,
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struct nft_set *set,
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const struct nft_set_iter *iter,
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struct nft_set_elem *elem)
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{
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const struct nft_set_ext *ext = nft_set_elem_ext(set, elem->priv);
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struct nft_ctx *pctx = (struct nft_ctx *)ctx;
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const struct nft_data *data;
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int err;
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if (nft_set_ext_exists(ext, NFT_SET_EXT_FLAGS) &&
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*nft_set_ext_flags(ext) & NFT_SET_ELEM_INTERVAL_END)
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return 0;
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data = nft_set_ext_data(ext);
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switch (data->verdict.code) {
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case NFT_JUMP:
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case NFT_GOTO:
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pctx->level++;
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err = nft_chain_validate(ctx, data->verdict.chain);
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if (err < 0)
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return err;
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pctx->level--;
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break;
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default:
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break;
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}
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return 0;
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}
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static int nft_lookup_validate(const struct nft_ctx *ctx,
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const struct nft_expr *expr,
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const struct nft_data **d)
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{
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const struct nft_lookup *priv = nft_expr_priv(expr);
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struct nft_set_iter iter;
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if (!(priv->set->flags & NFT_SET_MAP) ||
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priv->set->dtype != NFT_DATA_VERDICT)
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return 0;
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iter.genmask = nft_genmask_next(ctx->net);
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iter.skip = 0;
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iter.count = 0;
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iter.err = 0;
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iter.fn = nft_lookup_validate_setelem;
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priv->set->ops->walk(ctx, priv->set, &iter);
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if (iter.err < 0)
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return iter.err;
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return 0;
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}
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static const struct nft_expr_ops nft_lookup_ops = {
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.type = &nft_lookup_type,
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.size = NFT_EXPR_SIZE(sizeof(struct nft_lookup)),
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.eval = nft_lookup_eval,
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.init = nft_lookup_init,
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.deactivate = nft_lookup_deactivate,
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.destroy = nft_lookup_destroy,
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.dump = nft_lookup_dump,
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.validate = nft_lookup_validate,
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};
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struct nft_expr_type nft_lookup_type __read_mostly = {
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.name = "lookup",
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.ops = &nft_lookup_ops,
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.policy = nft_lookup_policy,
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.maxattr = NFTA_LOOKUP_MAX,
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.owner = THIS_MODULE,
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};
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