f6ac858589
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>
307 lines
7.8 KiB
C
307 lines
7.8 KiB
C
/*
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* Copyright (c) 2015 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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*/
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#include <linux/kernel.h>
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#include <linux/module.h>
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#include <linux/init.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_dynset {
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struct nft_set *set;
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struct nft_set_ext_tmpl tmpl;
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enum nft_dynset_ops op:8;
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enum nft_registers sreg_key:8;
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enum nft_registers sreg_data:8;
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bool invert;
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u64 timeout;
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struct nft_expr *expr;
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struct nft_set_binding binding;
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};
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static void *nft_dynset_new(struct nft_set *set, const struct nft_expr *expr,
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struct nft_regs *regs)
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{
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const struct nft_dynset *priv = nft_expr_priv(expr);
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struct nft_set_ext *ext;
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u64 timeout;
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void *elem;
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if (!atomic_add_unless(&set->nelems, 1, set->size))
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return NULL;
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timeout = priv->timeout ? : set->timeout;
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elem = nft_set_elem_init(set, &priv->tmpl,
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®s->data[priv->sreg_key],
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®s->data[priv->sreg_data],
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timeout, GFP_ATOMIC);
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if (elem == NULL)
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goto err1;
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ext = nft_set_elem_ext(set, elem);
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if (priv->expr != NULL &&
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nft_expr_clone(nft_set_ext_expr(ext), priv->expr) < 0)
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goto err2;
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return elem;
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err2:
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nft_set_elem_destroy(set, elem, false);
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err1:
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if (set->size)
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atomic_dec(&set->nelems);
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return NULL;
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}
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static void nft_dynset_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_dynset *priv = nft_expr_priv(expr);
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struct nft_set *set = priv->set;
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const struct nft_set_ext *ext;
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const struct nft_expr *sexpr;
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u64 timeout;
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if (set->ops->update(set, ®s->data[priv->sreg_key], nft_dynset_new,
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expr, regs, &ext)) {
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sexpr = NULL;
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if (nft_set_ext_exists(ext, NFT_SET_EXT_EXPR))
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sexpr = nft_set_ext_expr(ext);
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if (priv->op == NFT_DYNSET_OP_UPDATE &&
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nft_set_ext_exists(ext, NFT_SET_EXT_EXPIRATION)) {
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timeout = priv->timeout ? : set->timeout;
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*nft_set_ext_expiration(ext) = get_jiffies_64() + timeout;
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}
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if (sexpr != NULL)
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sexpr->ops->eval(sexpr, regs, pkt);
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if (priv->invert)
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regs->verdict.code = NFT_BREAK;
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return;
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}
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if (!priv->invert)
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regs->verdict.code = NFT_BREAK;
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}
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static const struct nla_policy nft_dynset_policy[NFTA_DYNSET_MAX + 1] = {
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[NFTA_DYNSET_SET_NAME] = { .type = NLA_STRING,
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.len = NFT_SET_MAXNAMELEN - 1 },
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[NFTA_DYNSET_SET_ID] = { .type = NLA_U32 },
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[NFTA_DYNSET_OP] = { .type = NLA_U32 },
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[NFTA_DYNSET_SREG_KEY] = { .type = NLA_U32 },
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[NFTA_DYNSET_SREG_DATA] = { .type = NLA_U32 },
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[NFTA_DYNSET_TIMEOUT] = { .type = NLA_U64 },
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[NFTA_DYNSET_EXPR] = { .type = NLA_NESTED },
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[NFTA_DYNSET_FLAGS] = { .type = NLA_U32 },
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};
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static int nft_dynset_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_dynset *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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u64 timeout;
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int err;
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lockdep_assert_held(&ctx->net->nft.commit_mutex);
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if (tb[NFTA_DYNSET_SET_NAME] == NULL ||
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tb[NFTA_DYNSET_OP] == NULL ||
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tb[NFTA_DYNSET_SREG_KEY] == NULL)
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return -EINVAL;
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if (tb[NFTA_DYNSET_FLAGS]) {
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u32 flags = ntohl(nla_get_be32(tb[NFTA_DYNSET_FLAGS]));
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if (flags & ~NFT_DYNSET_F_INV)
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return -EINVAL;
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if (flags & NFT_DYNSET_F_INV)
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priv->invert = true;
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}
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set = nft_set_lookup_global(ctx->net, ctx->table,
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tb[NFTA_DYNSET_SET_NAME],
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tb[NFTA_DYNSET_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->ops->update == NULL)
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return -EOPNOTSUPP;
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if (set->flags & NFT_SET_CONSTANT)
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return -EBUSY;
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priv->op = ntohl(nla_get_be32(tb[NFTA_DYNSET_OP]));
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switch (priv->op) {
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case NFT_DYNSET_OP_ADD:
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break;
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case NFT_DYNSET_OP_UPDATE:
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if (!(set->flags & NFT_SET_TIMEOUT))
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return -EOPNOTSUPP;
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break;
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default:
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return -EOPNOTSUPP;
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}
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timeout = 0;
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if (tb[NFTA_DYNSET_TIMEOUT] != NULL) {
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if (!(set->flags & NFT_SET_TIMEOUT))
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return -EINVAL;
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timeout = msecs_to_jiffies(be64_to_cpu(nla_get_be64(
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tb[NFTA_DYNSET_TIMEOUT])));
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}
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priv->sreg_key = nft_parse_register(tb[NFTA_DYNSET_SREG_KEY]);
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err = nft_validate_register_load(priv->sreg_key, set->klen);
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if (err < 0)
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return err;
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if (tb[NFTA_DYNSET_SREG_DATA] != NULL) {
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if (!(set->flags & NFT_SET_MAP))
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return -EINVAL;
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if (set->dtype == NFT_DATA_VERDICT)
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return -EOPNOTSUPP;
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priv->sreg_data = nft_parse_register(tb[NFTA_DYNSET_SREG_DATA]);
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err = nft_validate_register_load(priv->sreg_data, 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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if (tb[NFTA_DYNSET_EXPR] != NULL) {
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if (!(set->flags & NFT_SET_EVAL))
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return -EINVAL;
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priv->expr = nft_expr_init(ctx, tb[NFTA_DYNSET_EXPR]);
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if (IS_ERR(priv->expr))
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return PTR_ERR(priv->expr);
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err = -EOPNOTSUPP;
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if (!(priv->expr->ops->type->flags & NFT_EXPR_STATEFUL))
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goto err1;
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if (priv->expr->ops->type->flags & NFT_EXPR_GC) {
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if (set->flags & NFT_SET_TIMEOUT)
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goto err1;
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if (!set->ops->gc_init)
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goto err1;
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set->ops->gc_init(set);
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}
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}
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nft_set_ext_prepare(&priv->tmpl);
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nft_set_ext_add_length(&priv->tmpl, NFT_SET_EXT_KEY, set->klen);
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if (set->flags & NFT_SET_MAP)
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nft_set_ext_add_length(&priv->tmpl, NFT_SET_EXT_DATA, set->dlen);
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if (priv->expr != NULL)
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nft_set_ext_add_length(&priv->tmpl, NFT_SET_EXT_EXPR,
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priv->expr->ops->size);
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if (set->flags & NFT_SET_TIMEOUT) {
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if (timeout || set->timeout)
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nft_set_ext_add(&priv->tmpl, NFT_SET_EXT_EXPIRATION);
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}
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priv->timeout = timeout;
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err = nf_tables_bind_set(ctx, set, &priv->binding);
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if (err < 0)
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goto err1;
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if (set->size == 0)
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set->size = 0xffff;
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priv->set = set;
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return 0;
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err1:
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if (priv->expr != NULL)
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nft_expr_destroy(ctx, priv->expr);
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return err;
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}
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static void nft_dynset_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_dynset *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_dynset_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_dynset *priv = nft_expr_priv(expr);
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if (priv->expr != NULL)
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nft_expr_destroy(ctx, priv->expr);
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nf_tables_destroy_set(ctx, priv->set);
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}
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static int nft_dynset_dump(struct sk_buff *skb, const struct nft_expr *expr)
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{
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const struct nft_dynset *priv = nft_expr_priv(expr);
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u32 flags = priv->invert ? NFT_DYNSET_F_INV : 0;
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if (nft_dump_register(skb, NFTA_DYNSET_SREG_KEY, priv->sreg_key))
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goto nla_put_failure;
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if (priv->set->flags & NFT_SET_MAP &&
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nft_dump_register(skb, NFTA_DYNSET_SREG_DATA, priv->sreg_data))
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goto nla_put_failure;
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if (nla_put_be32(skb, NFTA_DYNSET_OP, htonl(priv->op)))
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goto nla_put_failure;
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if (nla_put_string(skb, NFTA_DYNSET_SET_NAME, priv->set->name))
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goto nla_put_failure;
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if (nla_put_be64(skb, NFTA_DYNSET_TIMEOUT,
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cpu_to_be64(jiffies_to_msecs(priv->timeout)),
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NFTA_DYNSET_PAD))
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goto nla_put_failure;
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if (priv->expr && nft_expr_dump(skb, NFTA_DYNSET_EXPR, priv->expr))
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goto nla_put_failure;
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if (nla_put_be32(skb, NFTA_DYNSET_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 const struct nft_expr_ops nft_dynset_ops = {
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.type = &nft_dynset_type,
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.size = NFT_EXPR_SIZE(sizeof(struct nft_dynset)),
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.eval = nft_dynset_eval,
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.init = nft_dynset_init,
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.destroy = nft_dynset_destroy,
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.deactivate = nft_dynset_deactivate,
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.dump = nft_dynset_dump,
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};
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struct nft_expr_type nft_dynset_type __read_mostly = {
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.name = "dynset",
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.ops = &nft_dynset_ops,
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.policy = nft_dynset_policy,
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.maxattr = NFTA_DYNSET_MAX,
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.owner = THIS_MODULE,
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};
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