linux/net/decnet/dn_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

274 lines
5.7 KiB
C

/*
* DECnet An implementation of the DECnet protocol suite for the LINUX
* operating system. DECnet is implemented using the BSD Socket
* interface as the means of communication with the user level.
*
* DECnet Routing Forwarding Information Base (Rules)
*
* Author: Steve Whitehouse <SteveW@ACM.org>
* Mostly copied from Alexey Kuznetsov's ipv4/fib_rules.c
*
*
* Changes:
* Steve Whitehouse <steve@chygwyn.com>
* Updated for Thomas Graf's generic rules
*
*/
#include <linux/net.h>
#include <linux/init.h>
#include <linux/netlink.h>
#include <linux/rtnetlink.h>
#include <linux/netdevice.h>
#include <linux/spinlock.h>
#include <linux/list.h>
#include <linux/rcupdate.h>
#include <net/neighbour.h>
#include <net/dst.h>
#include <net/flow.h>
#include <net/fib_rules.h>
#include <net/dn.h>
#include <net/dn_fib.h>
#include <net/dn_neigh.h>
#include <net/dn_dev.h>
static struct fib_rules_ops dn_fib_rules_ops;
struct dn_fib_rule
{
struct fib_rule common;
unsigned char dst_len;
unsigned char src_len;
__le16 src;
__le16 srcmask;
__le16 dst;
__le16 dstmask;
__le16 srcmap;
u8 flags;
};
static struct dn_fib_rule default_rule = {
.common = {
.refcnt = ATOMIC_INIT(2),
.pref = 0x7fff,
.table = RT_TABLE_MAIN,
.action = FR_ACT_TO_TBL,
},
};
static LIST_HEAD(dn_fib_rules);
int dn_fib_lookup(struct flowi *flp, struct dn_fib_res *res)
{
struct fib_lookup_arg arg = {
.result = res,
};
int err;
err = fib_rules_lookup(&dn_fib_rules_ops, flp, 0, &arg);
res->r = arg.rule;
return err;
}
static int dn_fib_rule_action(struct fib_rule *rule, struct flowi *flp,
int flags, struct fib_lookup_arg *arg)
{
int err = -EAGAIN;
struct dn_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;
}
tbl = dn_fib_get_table(rule->table, 0);
if (tbl == NULL)
goto errout;
err = tbl->lookup(tbl, flp, (struct dn_fib_res *)arg->result);
if (err > 0)
err = -EAGAIN;
errout:
return err;
}
static struct nla_policy dn_fib_rule_policy[FRA_MAX+1] __read_mostly = {
FRA_GENERIC_POLICY,
};
static int dn_fib_rule_match(struct fib_rule *rule, struct flowi *fl, int flags)
{
struct dn_fib_rule *r = (struct dn_fib_rule *)rule;
__le16 daddr = fl->fld_dst;
__le16 saddr = fl->fld_src;
if (((saddr ^ r->src) & r->srcmask) ||
((daddr ^ r->dst) & r->dstmask))
return 0;
return 1;
}
static int dn_fib_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 dn_fib_rule *r = (struct dn_fib_rule *)rule;
if (frh->tos)
goto errout;
if (rule->table == RT_TABLE_UNSPEC) {
if (rule->action == FR_ACT_TO_TBL) {
struct dn_fib_table *table;
table = dn_fib_empty_table();
if (table == NULL) {
err = -ENOBUFS;
goto errout;
}
rule->table = table->n;
}
}
if (frh->src_len)
r->src = nla_get_le16(tb[FRA_SRC]);
if (frh->dst_len)
r->dst = nla_get_le16(tb[FRA_DST]);
r->src_len = frh->src_len;
r->srcmask = dnet_make_mask(r->src_len);
r->dst_len = frh->dst_len;
r->dstmask = dnet_make_mask(r->dst_len);
err = 0;
errout:
return err;
}
static int dn_fib_rule_compare(struct fib_rule *rule, struct fib_rule_hdr *frh,
struct nlattr **tb)
{
struct dn_fib_rule *r = (struct dn_fib_rule *)rule;
if (frh->src_len && (r->src_len != frh->src_len))
return 0;
if (frh->dst_len && (r->dst_len != frh->dst_len))
return 0;
if (frh->src_len && (r->src != nla_get_le16(tb[FRA_SRC])))
return 0;
if (frh->dst_len && (r->dst != nla_get_le16(tb[FRA_DST])))
return 0;
return 1;
}
unsigned dnet_addr_type(__le16 addr)
{
struct flowi fl = { .nl_u = { .dn_u = { .daddr = addr } } };
struct dn_fib_res res;
unsigned ret = RTN_UNICAST;
struct dn_fib_table *tb = dn_fib_get_table(RT_TABLE_LOCAL, 0);
res.r = NULL;
if (tb) {
if (!tb->lookup(tb, &fl, &res)) {
ret = res.type;
dn_fib_res_put(&res);
}
}
return ret;
}
static int dn_fib_rule_fill(struct fib_rule *rule, struct sk_buff *skb,
struct nlmsghdr *nlh, struct fib_rule_hdr *frh)
{
struct dn_fib_rule *r = (struct dn_fib_rule *)rule;
frh->family = AF_DECnet;
frh->dst_len = r->dst_len;
frh->src_len = r->src_len;
frh->tos = 0;
if (r->dst_len)
NLA_PUT_LE16(skb, FRA_DST, r->dst);
if (r->src_len)
NLA_PUT_LE16(skb, FRA_SRC, r->src);
return 0;
nla_put_failure:
return -ENOBUFS;
}
static u32 dn_fib_rule_default_pref(void)
{
struct list_head *pos;
struct fib_rule *rule;
if (!list_empty(&dn_fib_rules)) {
pos = dn_fib_rules.next;
if (pos->next != &dn_fib_rules) {
rule = list_entry(pos->next, struct fib_rule, list);
if (rule->pref)
return rule->pref - 1;
}
}
return 0;
}
int dn_fib_dump_rules(struct sk_buff *skb, struct netlink_callback *cb)
{
return fib_rules_dump(skb, cb, AF_DECnet);
}
static struct fib_rules_ops dn_fib_rules_ops = {
.family = AF_DECnet,
.rule_size = sizeof(struct dn_fib_rule),
.addr_size = sizeof(u16),
.action = dn_fib_rule_action,
.match = dn_fib_rule_match,
.configure = dn_fib_rule_configure,
.compare = dn_fib_rule_compare,
.fill = dn_fib_rule_fill,
.default_pref = dn_fib_rule_default_pref,
.nlgroup = RTNLGRP_DECnet_RULE,
.policy = dn_fib_rule_policy,
.rules_list = &dn_fib_rules,
.owner = THIS_MODULE,
};
void __init dn_fib_rules_init(void)
{
list_add_tail(&default_rule.common.list, &dn_fib_rules);
fib_rules_register(&dn_fib_rules_ops);
}
void __exit dn_fib_rules_cleanup(void)
{
fib_rules_unregister(&dn_fib_rules_ops);
}