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linux-stable/net/netfilter/nft_dynset.c
Liping Zhang b2fbd04498 netfilter: nf_tables: validate the name size when possible 
Currently, if the user add a stateful object with the name size exceed
NFT_OBJ_MAXNAMELEN - 1 (i.e. 31), we truncate it down to 31 silently.
This is not friendly, furthermore, this will cause duplicated stateful
objects when the first 31 characters of the name is same. So limit the
stateful object's name size to NFT_OBJ_MAXNAMELEN - 1.

After apply this patch, error message will be printed out like this:
  # name_32=$(printf "%0.sQ" {1..32})
  # nft add counter filter $name_32
  <cmdline>:1:1-52: Error: Could not process rule: Numerical result out
  of range
  add counter filter QQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQ
  ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

Also this patch cleans up the codes which missing the name size limit
validation in nftables.

Fixes: e50092404c ("netfilter: nf_tables: add stateful objects")
Signed-off-by: Liping Zhang <zlpnobody@gmail.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
2017-01-23 23:36:50 +01:00

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/*
* Copyright (c) 2015 Patrick McHardy <kaber@trash.net>
*
* 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.
*
*/
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/netlink.h>
#include <linux/netfilter.h>
#include <linux/netfilter/nf_tables.h>
#include <net/netfilter/nf_tables.h>
#include <net/netfilter/nf_tables_core.h>
struct nft_dynset {
struct nft_set *set;
struct nft_set_ext_tmpl tmpl;
enum nft_dynset_ops op:8;
enum nft_registers sreg_key:8;
enum nft_registers sreg_data:8;
bool invert;
u64 timeout;
struct nft_expr *expr;
struct nft_set_binding binding;
};
static void *nft_dynset_new(struct nft_set *set, const struct nft_expr *expr,
struct nft_regs *regs)
{
const struct nft_dynset *priv = nft_expr_priv(expr);
struct nft_set_ext *ext;
u64 timeout;
void *elem;
if (set->size && !atomic_add_unless(&set->nelems, 1, set->size))
return NULL;
timeout = priv->timeout ? : set->timeout;
elem = nft_set_elem_init(set, &priv->tmpl,
&regs->data[priv->sreg_key],
&regs->data[priv->sreg_data],
timeout, GFP_ATOMIC);
if (elem == NULL)
goto err1;
ext = nft_set_elem_ext(set, elem);
if (priv->expr != NULL &&
nft_expr_clone(nft_set_ext_expr(ext), priv->expr) < 0)
goto err2;
return elem;
err2:
nft_set_elem_destroy(set, elem, false);
err1:
if (set->size)
atomic_dec(&set->nelems);
return NULL;
}
static void nft_dynset_eval(const struct nft_expr *expr,
struct nft_regs *regs,
const struct nft_pktinfo *pkt)
{
const struct nft_dynset *priv = nft_expr_priv(expr);
struct nft_set *set = priv->set;
const struct nft_set_ext *ext;
const struct nft_expr *sexpr;
u64 timeout;
if (set->ops->update(set, &regs->data[priv->sreg_key], nft_dynset_new,
expr, regs, &ext)) {
sexpr = NULL;
if (nft_set_ext_exists(ext, NFT_SET_EXT_EXPR))
sexpr = nft_set_ext_expr(ext);
if (priv->op == NFT_DYNSET_OP_UPDATE &&
nft_set_ext_exists(ext, NFT_SET_EXT_EXPIRATION)) {
timeout = priv->timeout ? : set->timeout;
*nft_set_ext_expiration(ext) = jiffies + timeout;
} else if (sexpr == NULL)
goto out;
if (sexpr != NULL)
sexpr->ops->eval(sexpr, regs, pkt);
if (priv->invert)
regs->verdict.code = NFT_BREAK;
return;
}
out:
if (!priv->invert)
regs->verdict.code = NFT_BREAK;
}
static const struct nla_policy nft_dynset_policy[NFTA_DYNSET_MAX + 1] = {
[NFTA_DYNSET_SET_NAME] = { .type = NLA_STRING,
.len = NFT_SET_MAXNAMELEN - 1 },
[NFTA_DYNSET_SET_ID] = { .type = NLA_U32 },
[NFTA_DYNSET_OP] = { .type = NLA_U32 },
[NFTA_DYNSET_SREG_KEY] = { .type = NLA_U32 },
[NFTA_DYNSET_SREG_DATA] = { .type = NLA_U32 },
[NFTA_DYNSET_TIMEOUT] = { .type = NLA_U64 },
[NFTA_DYNSET_EXPR] = { .type = NLA_NESTED },
[NFTA_DYNSET_FLAGS] = { .type = NLA_U32 },
};
static int nft_dynset_init(const struct nft_ctx *ctx,
const struct nft_expr *expr,
const struct nlattr * const tb[])
{
struct nft_dynset *priv = nft_expr_priv(expr);
u8 genmask = nft_genmask_next(ctx->net);
struct nft_set *set;
u64 timeout;
int err;
if (tb[NFTA_DYNSET_SET_NAME] == NULL ||
tb[NFTA_DYNSET_OP] == NULL ||
tb[NFTA_DYNSET_SREG_KEY] == NULL)
return -EINVAL;
if (tb[NFTA_DYNSET_FLAGS]) {
u32 flags = ntohl(nla_get_be32(tb[NFTA_DYNSET_FLAGS]));
if (flags & ~NFT_DYNSET_F_INV)
return -EINVAL;
if (flags & NFT_DYNSET_F_INV)
priv->invert = true;
}
set = nf_tables_set_lookup(ctx->table, tb[NFTA_DYNSET_SET_NAME],
genmask);
if (IS_ERR(set)) {
if (tb[NFTA_DYNSET_SET_ID])
set = nf_tables_set_lookup_byid(ctx->net,
tb[NFTA_DYNSET_SET_ID],
genmask);
if (IS_ERR(set))
return PTR_ERR(set);
}
if (set->ops->update == NULL)
return -EOPNOTSUPP;
if (set->flags & NFT_SET_CONSTANT)
return -EBUSY;
priv->op = ntohl(nla_get_be32(tb[NFTA_DYNSET_OP]));
switch (priv->op) {
case NFT_DYNSET_OP_ADD:
break;
case NFT_DYNSET_OP_UPDATE:
if (!(set->flags & NFT_SET_TIMEOUT))
return -EOPNOTSUPP;
break;
default:
return -EOPNOTSUPP;
}
timeout = 0;
if (tb[NFTA_DYNSET_TIMEOUT] != NULL) {
if (!(set->flags & NFT_SET_TIMEOUT))
return -EINVAL;
timeout = msecs_to_jiffies(be64_to_cpu(nla_get_be64(
tb[NFTA_DYNSET_TIMEOUT])));
}
priv->sreg_key = nft_parse_register(tb[NFTA_DYNSET_SREG_KEY]);
err = nft_validate_register_load(priv->sreg_key, set->klen);;
if (err < 0)
return err;
if (tb[NFTA_DYNSET_SREG_DATA] != NULL) {
if (!(set->flags & NFT_SET_MAP))
return -EINVAL;
if (set->dtype == NFT_DATA_VERDICT)
return -EOPNOTSUPP;
priv->sreg_data = nft_parse_register(tb[NFTA_DYNSET_SREG_DATA]);
err = nft_validate_register_load(priv->sreg_data, set->dlen);
if (err < 0)
return err;
} else if (set->flags & NFT_SET_MAP)
return -EINVAL;
if (tb[NFTA_DYNSET_EXPR] != NULL) {
if (!(set->flags & NFT_SET_EVAL))
return -EINVAL;
if (!(set->flags & NFT_SET_ANONYMOUS))
return -EOPNOTSUPP;
priv->expr = nft_expr_init(ctx, tb[NFTA_DYNSET_EXPR]);
if (IS_ERR(priv->expr))
return PTR_ERR(priv->expr);
err = -EOPNOTSUPP;
if (!(priv->expr->ops->type->flags & NFT_EXPR_STATEFUL))
goto err1;
} else if (set->flags & NFT_SET_EVAL)
return -EINVAL;
nft_set_ext_prepare(&priv->tmpl);
nft_set_ext_add_length(&priv->tmpl, NFT_SET_EXT_KEY, set->klen);
if (set->flags & NFT_SET_MAP)
nft_set_ext_add_length(&priv->tmpl, NFT_SET_EXT_DATA, set->dlen);
if (priv->expr != NULL)
nft_set_ext_add_length(&priv->tmpl, NFT_SET_EXT_EXPR,
priv->expr->ops->size);
if (set->flags & NFT_SET_TIMEOUT) {
if (timeout || set->timeout)
nft_set_ext_add(&priv->tmpl, NFT_SET_EXT_EXPIRATION);
}
priv->timeout = timeout;
err = nf_tables_bind_set(ctx, set, &priv->binding);
if (err < 0)
goto err1;
priv->set = set;
return 0;
err1:
if (priv->expr != NULL)
nft_expr_destroy(ctx, priv->expr);
return err;
}
static void nft_dynset_destroy(const struct nft_ctx *ctx,
const struct nft_expr *expr)
{
struct nft_dynset *priv = nft_expr_priv(expr);
nf_tables_unbind_set(ctx, priv->set, &priv->binding);
if (priv->expr != NULL)
nft_expr_destroy(ctx, priv->expr);
}
static int nft_dynset_dump(struct sk_buff *skb, const struct nft_expr *expr)
{
const struct nft_dynset *priv = nft_expr_priv(expr);
u32 flags = priv->invert ? NFT_DYNSET_F_INV : 0;
if (nft_dump_register(skb, NFTA_DYNSET_SREG_KEY, priv->sreg_key))
goto nla_put_failure;
if (priv->set->flags & NFT_SET_MAP &&
nft_dump_register(skb, NFTA_DYNSET_SREG_DATA, priv->sreg_data))
goto nla_put_failure;
if (nla_put_be32(skb, NFTA_DYNSET_OP, htonl(priv->op)))
goto nla_put_failure;
if (nla_put_string(skb, NFTA_DYNSET_SET_NAME, priv->set->name))
goto nla_put_failure;
if (nla_put_be64(skb, NFTA_DYNSET_TIMEOUT,
cpu_to_be64(jiffies_to_msecs(priv->timeout)),
NFTA_DYNSET_PAD))
goto nla_put_failure;
if (priv->expr && nft_expr_dump(skb, NFTA_DYNSET_EXPR, priv->expr))
goto nla_put_failure;
if (nla_put_be32(skb, NFTA_DYNSET_FLAGS, htonl(flags)))
goto nla_put_failure;
return 0;
nla_put_failure:
return -1;
}
static const struct nft_expr_ops nft_dynset_ops = {
.type = &nft_dynset_type,
.size = NFT_EXPR_SIZE(sizeof(struct nft_dynset)),
.eval = nft_dynset_eval,
.init = nft_dynset_init,
.destroy = nft_dynset_destroy,
.dump = nft_dynset_dump,
};
struct nft_expr_type nft_dynset_type __read_mostly = {
.name = "dynset",
.ops = &nft_dynset_ops,
.policy = nft_dynset_policy,
.maxattr = NFTA_DYNSET_MAX,
.owner = THIS_MODULE,
};
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