linux/net/ipv4/fib_rules.c
Thomas Graf e1701c68c1 [NET]: Fix fib_rules compatibility breakage
Based upon a patch from Patrick McHardy.

The fib_rules netlink attribute policy introduced in 2.6.19 broke
userspace compatibilty. When specifying a rule with "from all"
or "to all", iproute adds a zero byte long netlink attribute,
but the policy requires all addresses to have a size equal to
sizeof(struct in_addr)/sizeof(struct in6_addr), resulting in a
validation error.

Check attribute length of FRA_SRC/FRA_DST in the generic framework
by letting the family specific rules implementation provide the
length of an address. Report an error if address length is non
zero but no address attribute is provided. Fix actual bug by
checking address length for non-zero instead of relying on
availability of attribute.

Signed-off-by: Thomas Graf <tgraf@suug.ch>
Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
2007-03-25 18:48:00 -07:00

330 lines
7.1 KiB
C

/*
* INET An implementation of the TCP/IP protocol suite for the LINUX
* operating system. INET is implemented using the BSD Socket
* interface as the means of communication with the user level.
*
* IPv4 Forwarding Information Base: policy rules.
*
* Authors: Alexey Kuznetsov, <kuznet@ms2.inr.ac.ru>
* Thomas Graf <tgraf@suug.ch>
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version
* 2 of the License, or (at your option) any later version.
*
* Fixes:
* Rani Assaf : local_rule cannot be deleted
* Marc Boucher : routing by fwmark
*/
#include <linux/types.h>
#include <linux/kernel.h>
#include <linux/netdevice.h>
#include <linux/netlink.h>
#include <linux/inetdevice.h>
#include <linux/init.h>
#include <linux/list.h>
#include <linux/rcupdate.h>
#include <net/ip.h>
#include <net/route.h>
#include <net/tcp.h>
#include <net/ip_fib.h>
#include <net/fib_rules.h>
static struct fib_rules_ops fib4_rules_ops;
struct fib4_rule
{
struct fib_rule common;
u8 dst_len;
u8 src_len;
u8 tos;
__be32 src;
__be32 srcmask;
__be32 dst;
__be32 dstmask;
#ifdef CONFIG_NET_CLS_ROUTE
u32 tclassid;
#endif
};
static struct fib4_rule default_rule = {
.common = {
.refcnt = ATOMIC_INIT(2),
.pref = 0x7FFF,
.table = RT_TABLE_DEFAULT,
.action = FR_ACT_TO_TBL,
},
};
static struct fib4_rule main_rule = {
.common = {
.refcnt = ATOMIC_INIT(2),
.pref = 0x7FFE,
.table = RT_TABLE_MAIN,
.action = FR_ACT_TO_TBL,
},
};
static struct fib4_rule local_rule = {
.common = {
.refcnt = ATOMIC_INIT(2),
.table = RT_TABLE_LOCAL,
.action = FR_ACT_TO_TBL,
.flags = FIB_RULE_PERMANENT,
},
};
static LIST_HEAD(fib4_rules);
#ifdef CONFIG_NET_CLS_ROUTE
u32 fib_rules_tclass(struct fib_result *res)
{
return res->r ? ((struct fib4_rule *) res->r)->tclassid : 0;
}
#endif
int fib_lookup(struct flowi *flp, struct fib_result *res)
{
struct fib_lookup_arg arg = {
.result = res,
};
int err;
err = fib_rules_lookup(&fib4_rules_ops, flp, 0, &arg);
res->r = arg.rule;
return err;
}
static int fib4_rule_action(struct fib_rule *rule, struct flowi *flp,
int flags, struct fib_lookup_arg *arg)
{
int err = -EAGAIN;
struct fib_table *tbl;
switch (rule->action) {
case FR_ACT_TO_TBL:
break;
case FR_ACT_UNREACHABLE:
err = -ENETUNREACH;
goto errout;
case FR_ACT_PROHIBIT:
err = -EACCES;
goto errout;
case FR_ACT_BLACKHOLE:
default:
err = -EINVAL;
goto errout;
}
if ((tbl = fib_get_table(rule->table)) == NULL)
goto errout;
err = tbl->tb_lookup(tbl, flp, (struct fib_result *) arg->result);
if (err > 0)
err = -EAGAIN;
errout:
return err;
}
void fib_select_default(const struct flowi *flp, struct fib_result *res)
{
if (res->r && res->r->action == FR_ACT_TO_TBL &&
FIB_RES_GW(*res) && FIB_RES_NH(*res).nh_scope == RT_SCOPE_LINK) {
struct fib_table *tb;
if ((tb = fib_get_table(res->r->table)) != NULL)
tb->tb_select_default(tb, flp, res);
}
}
static int fib4_rule_match(struct fib_rule *rule, struct flowi *fl, int flags)
{
struct fib4_rule *r = (struct fib4_rule *) rule;
__be32 daddr = fl->fl4_dst;
__be32 saddr = fl->fl4_src;
if (((saddr ^ r->src) & r->srcmask) ||
((daddr ^ r->dst) & r->dstmask))
return 0;
if (r->tos && (r->tos != fl->fl4_tos))
return 0;
return 1;
}
static struct fib_table *fib_empty_table(void)
{
u32 id;
for (id = 1; id <= RT_TABLE_MAX; id++)
if (fib_get_table(id) == NULL)
return fib_new_table(id);
return NULL;
}
static struct nla_policy fib4_rule_policy[FRA_MAX+1] __read_mostly = {
FRA_GENERIC_POLICY,
[FRA_FLOW] = { .type = NLA_U32 },
};
static int fib4_rule_configure(struct fib_rule *rule, struct sk_buff *skb,
struct nlmsghdr *nlh, struct fib_rule_hdr *frh,
struct nlattr **tb)
{
int err = -EINVAL;
struct fib4_rule *rule4 = (struct fib4_rule *) rule;
if (frh->tos & ~IPTOS_TOS_MASK)
goto errout;
if (rule->table == RT_TABLE_UNSPEC) {
if (rule->action == FR_ACT_TO_TBL) {
struct fib_table *table;
table = fib_empty_table();
if (table == NULL) {
err = -ENOBUFS;
goto errout;
}
rule->table = table->tb_id;
}
}
if (frh->src_len)
rule4->src = nla_get_be32(tb[FRA_SRC]);
if (frh->dst_len)
rule4->dst = nla_get_be32(tb[FRA_DST]);
#ifdef CONFIG_NET_CLS_ROUTE
if (tb[FRA_FLOW])
rule4->tclassid = nla_get_u32(tb[FRA_FLOW]);
#endif
rule4->src_len = frh->src_len;
rule4->srcmask = inet_make_mask(rule4->src_len);
rule4->dst_len = frh->dst_len;
rule4->dstmask = inet_make_mask(rule4->dst_len);
rule4->tos = frh->tos;
err = 0;
errout:
return err;
}
static int fib4_rule_compare(struct fib_rule *rule, struct fib_rule_hdr *frh,
struct nlattr **tb)
{
struct fib4_rule *rule4 = (struct fib4_rule *) rule;
if (frh->src_len && (rule4->src_len != frh->src_len))
return 0;
if (frh->dst_len && (rule4->dst_len != frh->dst_len))
return 0;
if (frh->tos && (rule4->tos != frh->tos))
return 0;
#ifdef CONFIG_NET_CLS_ROUTE
if (tb[FRA_FLOW] && (rule4->tclassid != nla_get_u32(tb[FRA_FLOW])))
return 0;
#endif
if (frh->src_len && (rule4->src != nla_get_be32(tb[FRA_SRC])))
return 0;
if (frh->dst_len && (rule4->dst != nla_get_be32(tb[FRA_DST])))
return 0;
return 1;
}
static int fib4_rule_fill(struct fib_rule *rule, struct sk_buff *skb,
struct nlmsghdr *nlh, struct fib_rule_hdr *frh)
{
struct fib4_rule *rule4 = (struct fib4_rule *) rule;
frh->family = AF_INET;
frh->dst_len = rule4->dst_len;
frh->src_len = rule4->src_len;
frh->tos = rule4->tos;
if (rule4->dst_len)
NLA_PUT_BE32(skb, FRA_DST, rule4->dst);
if (rule4->src_len)
NLA_PUT_BE32(skb, FRA_SRC, rule4->src);
#ifdef CONFIG_NET_CLS_ROUTE
if (rule4->tclassid)
NLA_PUT_U32(skb, FRA_FLOW, rule4->tclassid);
#endif
return 0;
nla_put_failure:
return -ENOBUFS;
}
int fib4_rules_dump(struct sk_buff *skb, struct netlink_callback *cb)
{
return fib_rules_dump(skb, cb, AF_INET);
}
static u32 fib4_rule_default_pref(void)
{
struct list_head *pos;
struct fib_rule *rule;
if (!list_empty(&fib4_rules)) {
pos = fib4_rules.next;
if (pos->next != &fib4_rules) {
rule = list_entry(pos->next, struct fib_rule, list);
if (rule->pref)
return rule->pref - 1;
}
}
return 0;
}
static size_t fib4_rule_nlmsg_payload(struct fib_rule *rule)
{
return nla_total_size(4) /* dst */
+ nla_total_size(4) /* src */
+ nla_total_size(4); /* flow */
}
static struct fib_rules_ops fib4_rules_ops = {
.family = AF_INET,
.rule_size = sizeof(struct fib4_rule),
.addr_size = sizeof(u32),
.action = fib4_rule_action,
.match = fib4_rule_match,
.configure = fib4_rule_configure,
.compare = fib4_rule_compare,
.fill = fib4_rule_fill,
.default_pref = fib4_rule_default_pref,
.nlmsg_payload = fib4_rule_nlmsg_payload,
.nlgroup = RTNLGRP_IPV4_RULE,
.policy = fib4_rule_policy,
.rules_list = &fib4_rules,
.owner = THIS_MODULE,
};
void __init fib4_rules_init(void)
{
list_add_tail(&local_rule.common.list, &fib4_rules);
list_add_tail(&main_rule.common.list, &fib4_rules);
list_add_tail(&default_rule.common.list, &fib4_rules);
fib_rules_register(&fib4_rules_ops);
}