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linux-next/net/core/fib_rules.c
Johannes Berg 8cb081746c netlink: make validation more configurable for future strictness 
We currently have two levels of strict validation:

 1) liberal (default)
     - undefined (type >= max) & NLA_UNSPEC attributes accepted
     - attribute length >= expected accepted
     - garbage at end of message accepted
 2) strict (opt-in)
     - NLA_UNSPEC attributes accepted
     - attribute length >= expected accepted

Split out parsing strictness into four different options:
 * TRAILING     - check that there's no trailing data after parsing
                  attributes (in message or nested)
 * MAXTYPE      - reject attrs > max known type
 * UNSPEC       - reject attributes with NLA_UNSPEC policy entries
 * STRICT_ATTRS - strictly validate attribute size

The default for future things should be *everything*.
The current *_strict() is a combination of TRAILING and MAXTYPE,
and is renamed to _deprecated_strict().
The current regular parsing has none of this, and is renamed to
*_parse_deprecated().

Additionally it allows us to selectively set one of the new flags
even on old policies. Notably, the UNSPEC flag could be useful in
this case, since it can be arranged (by filling in the policy) to
not be an incompatible userspace ABI change, but would then going
forward prevent forgetting attribute entries. Similar can apply
to the POLICY flag.

We end up with the following renames:
 * nla_parse           -> nla_parse_deprecated
 * nla_parse_strict    -> nla_parse_deprecated_strict
 * nlmsg_parse         -> nlmsg_parse_deprecated
 * nlmsg_parse_strict  -> nlmsg_parse_deprecated_strict
 * nla_parse_nested    -> nla_parse_nested_deprecated
 * nla_validate_nested -> nla_validate_nested_deprecated

Using spatch, of course:
    @@
    expression TB, MAX, HEAD, LEN, POL, EXT;
    @@
    -nla_parse(TB, MAX, HEAD, LEN, POL, EXT)
    +nla_parse_deprecated(TB, MAX, HEAD, LEN, POL, EXT)

    @@
    expression NLH, HDRLEN, TB, MAX, POL, EXT;
    @@
    -nlmsg_parse(NLH, HDRLEN, TB, MAX, POL, EXT)
    +nlmsg_parse_deprecated(NLH, HDRLEN, TB, MAX, POL, EXT)

    @@
    expression NLH, HDRLEN, TB, MAX, POL, EXT;
    @@
    -nlmsg_parse_strict(NLH, HDRLEN, TB, MAX, POL, EXT)
    +nlmsg_parse_deprecated_strict(NLH, HDRLEN, TB, MAX, POL, EXT)

    @@
    expression TB, MAX, NLA, POL, EXT;
    @@
    -nla_parse_nested(TB, MAX, NLA, POL, EXT)
    +nla_parse_nested_deprecated(TB, MAX, NLA, POL, EXT)

    @@
    expression START, MAX, POL, EXT;
    @@
    -nla_validate_nested(START, MAX, POL, EXT)
    +nla_validate_nested_deprecated(START, MAX, POL, EXT)

    @@
    expression NLH, HDRLEN, MAX, POL, EXT;
    @@
    -nlmsg_validate(NLH, HDRLEN, MAX, POL, EXT)
    +nlmsg_validate_deprecated(NLH, HDRLEN, MAX, POL, EXT)

For this patch, don't actually add the strict, non-renamed versions
yet so that it breaks compile if I get it wrong.

Also, while at it, make nla_validate and nla_parse go down to a
common __nla_validate_parse() function to avoid code duplication.

Ultimately, this allows us to have very strict validation for every
new caller of nla_parse()/nlmsg_parse() etc as re-introduced in the
next patch, while existing things will continue to work as is.

In effect then, this adds fully strict validation for any new command.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2019-04-27 17:07:21 -04:00

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/*
* net/core/fib_rules.c Generic Routing Rules
*
* 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, version 2.
*
* Authors: Thomas Graf <tgraf@suug.ch>
*/
#include <linux/types.h>
#include <linux/kernel.h>
#include <linux/slab.h>
#include <linux/list.h>
#include <linux/module.h>
#include <net/net_namespace.h>
#include <net/sock.h>
#include <net/fib_rules.h>
#include <net/ip_tunnels.h>
static const struct fib_kuid_range fib_kuid_range_unset = {
KUIDT_INIT(0),
KUIDT_INIT(~0),
};
bool fib_rule_matchall(const struct fib_rule *rule)
{
if (rule->iifindex || rule->oifindex || rule->mark || rule->tun_id ||
rule->flags)
return false;
if (rule->suppress_ifgroup != -1 || rule->suppress_prefixlen != -1)
return false;
if (!uid_eq(rule->uid_range.start, fib_kuid_range_unset.start) ||
!uid_eq(rule->uid_range.end, fib_kuid_range_unset.end))
return false;
if (fib_rule_port_range_set(&rule->sport_range))
return false;
if (fib_rule_port_range_set(&rule->dport_range))
return false;
return true;
}
EXPORT_SYMBOL_GPL(fib_rule_matchall);
int fib_default_rule_add(struct fib_rules_ops *ops,
u32 pref, u32 table, u32 flags)
{
struct fib_rule *r;
r = kzalloc(ops->rule_size, GFP_KERNEL);
if (r == NULL)
return -ENOMEM;
refcount_set(&r->refcnt, 1);
r->action = FR_ACT_TO_TBL;
r->pref = pref;
r->table = table;
r->flags = flags;
r->proto = RTPROT_KERNEL;
r->fr_net = ops->fro_net;
r->uid_range = fib_kuid_range_unset;
r->suppress_prefixlen = -1;
r->suppress_ifgroup = -1;
/* The lock is not required here, the list in unreacheable
* at the moment this function is called */
list_add_tail(&r->list, &ops->rules_list);
return 0;
}
EXPORT_SYMBOL(fib_default_rule_add);
static u32 fib_default_rule_pref(struct fib_rules_ops *ops)
{
struct list_head *pos;
struct fib_rule *rule;
if (!list_empty(&ops->rules_list)) {
pos = ops->rules_list.next;
if (pos->next != &ops->rules_list) {
rule = list_entry(pos->next, struct fib_rule, list);
if (rule->pref)
return rule->pref - 1;
}
}
return 0;
}
static void notify_rule_change(int event, struct fib_rule *rule,
struct fib_rules_ops *ops, struct nlmsghdr *nlh,
u32 pid);
static struct fib_rules_ops *lookup_rules_ops(struct net *net, int family)
{
struct fib_rules_ops *ops;
rcu_read_lock();
list_for_each_entry_rcu(ops, &net->rules_ops, list) {
if (ops->family == family) {
if (!try_module_get(ops->owner))
ops = NULL;
rcu_read_unlock();
return ops;
}
}
rcu_read_unlock();
return NULL;
}
static void rules_ops_put(struct fib_rules_ops *ops)
{
if (ops)
module_put(ops->owner);
}
static void flush_route_cache(struct fib_rules_ops *ops)
{
if (ops->flush_cache)
ops->flush_cache(ops);
}
static int __fib_rules_register(struct fib_rules_ops *ops)
{
int err = -EEXIST;
struct fib_rules_ops *o;
struct net *net;
net = ops->fro_net;
if (ops->rule_size < sizeof(struct fib_rule))
return -EINVAL;
if (ops->match == NULL || ops->configure == NULL ||
ops->compare == NULL || ops->fill == NULL ||
ops->action == NULL)
return -EINVAL;
spin_lock(&net->rules_mod_lock);
list_for_each_entry(o, &net->rules_ops, list)
if (ops->family == o->family)
goto errout;
list_add_tail_rcu(&ops->list, &net->rules_ops);
err = 0;
errout:
spin_unlock(&net->rules_mod_lock);
return err;
}
struct fib_rules_ops *
fib_rules_register(const struct fib_rules_ops *tmpl, struct net *net)
{
struct fib_rules_ops *ops;
int err;
ops = kmemdup(tmpl, sizeof(*ops), GFP_KERNEL);
if (ops == NULL)
return ERR_PTR(-ENOMEM);
INIT_LIST_HEAD(&ops->rules_list);
ops->fro_net = net;
err = __fib_rules_register(ops);
if (err) {
kfree(ops);
ops = ERR_PTR(err);
}
return ops;
}
EXPORT_SYMBOL_GPL(fib_rules_register);
static void fib_rules_cleanup_ops(struct fib_rules_ops *ops)
{
struct fib_rule *rule, *tmp;
list_for_each_entry_safe(rule, tmp, &ops->rules_list, list) {
list_del_rcu(&rule->list);
if (ops->delete)
ops->delete(rule);
fib_rule_put(rule);
}
}
void fib_rules_unregister(struct fib_rules_ops *ops)
{
struct net *net = ops->fro_net;
spin_lock(&net->rules_mod_lock);
list_del_rcu(&ops->list);
spin_unlock(&net->rules_mod_lock);
fib_rules_cleanup_ops(ops);
kfree_rcu(ops, rcu);
}
EXPORT_SYMBOL_GPL(fib_rules_unregister);
static int uid_range_set(struct fib_kuid_range *range)
{
return uid_valid(range->start) && uid_valid(range->end);
}
static struct fib_kuid_range nla_get_kuid_range(struct nlattr **tb)
{
struct fib_rule_uid_range *in;
struct fib_kuid_range out;
in = (struct fib_rule_uid_range *)nla_data(tb[FRA_UID_RANGE]);
out.start = make_kuid(current_user_ns(), in->start);
out.end = make_kuid(current_user_ns(), in->end);
return out;
}
static int nla_put_uid_range(struct sk_buff *skb, struct fib_kuid_range *range)
{
struct fib_rule_uid_range out = {
from_kuid_munged(current_user_ns(), range->start),
from_kuid_munged(current_user_ns(), range->end)
};
return nla_put(skb, FRA_UID_RANGE, sizeof(out), &out);
}
static int nla_get_port_range(struct nlattr *pattr,
struct fib_rule_port_range *port_range)
{
const struct fib_rule_port_range *pr = nla_data(pattr);
if (!fib_rule_port_range_valid(pr))
return -EINVAL;
port_range->start = pr->start;
port_range->end = pr->end;
return 0;
}
static int nla_put_port_range(struct sk_buff *skb, int attrtype,
struct fib_rule_port_range *range)
{
return nla_put(skb, attrtype, sizeof(*range), range);
}
static int fib_rule_match(struct fib_rule *rule, struct fib_rules_ops *ops,
struct flowi *fl, int flags,
struct fib_lookup_arg *arg)
{
int ret = 0;
if (rule->iifindex && (rule->iifindex != fl->flowi_iif))
goto out;
if (rule->oifindex && (rule->oifindex != fl->flowi_oif))
goto out;
if ((rule->mark ^ fl->flowi_mark) & rule->mark_mask)
goto out;
if (rule->tun_id && (rule->tun_id != fl->flowi_tun_key.tun_id))
goto out;
if (rule->l3mdev && !l3mdev_fib_rule_match(rule->fr_net, fl, arg))
goto out;
if (uid_lt(fl->flowi_uid, rule->uid_range.start) ||
uid_gt(fl->flowi_uid, rule->uid_range.end))
goto out;
ret = ops->match(rule, fl, flags);
out:
return (rule->flags & FIB_RULE_INVERT) ? !ret : ret;
}
int fib_rules_lookup(struct fib_rules_ops *ops, struct flowi *fl,
int flags, struct fib_lookup_arg *arg)
{
struct fib_rule *rule;
int err;
rcu_read_lock();
list_for_each_entry_rcu(rule, &ops->rules_list, list) {
jumped:
if (!fib_rule_match(rule, ops, fl, flags, arg))
continue;
if (rule->action == FR_ACT_GOTO) {
struct fib_rule *target;
target = rcu_dereference(rule->ctarget);
if (target == NULL) {
continue;
} else {
rule = target;
goto jumped;
}
} else if (rule->action == FR_ACT_NOP)
continue;
else
err = ops->action(rule, fl, flags, arg);
if (!err && ops->suppress && ops->suppress(rule, arg))
continue;
if (err != -EAGAIN) {
if ((arg->flags & FIB_LOOKUP_NOREF) ||
likely(refcount_inc_not_zero(&rule->refcnt))) {
arg->rule = rule;
goto out;
}
break;
}
}
err = -ESRCH;
out:
rcu_read_unlock();
return err;
}
EXPORT_SYMBOL_GPL(fib_rules_lookup);
static int call_fib_rule_notifier(struct notifier_block *nb, struct net *net,
enum fib_event_type event_type,
struct fib_rule *rule, int family)
{
struct fib_rule_notifier_info info = {
.info.family = family,
.rule = rule,
};
return call_fib_notifier(nb, net, event_type, &info.info);
}
static int call_fib_rule_notifiers(struct net *net,
enum fib_event_type event_type,
struct fib_rule *rule,
struct fib_rules_ops *ops,
struct netlink_ext_ack *extack)
{
struct fib_rule_notifier_info info = {
.info.family = ops->family,
.info.extack = extack,
.rule = rule,
};
ops->fib_rules_seq++;
return call_fib_notifiers(net, event_type, &info.info);
}
/* Called with rcu_read_lock() */
int fib_rules_dump(struct net *net, struct notifier_block *nb, int family)
{
struct fib_rules_ops *ops;
struct fib_rule *rule;
ops = lookup_rules_ops(net, family);
if (!ops)
return -EAFNOSUPPORT;
list_for_each_entry_rcu(rule, &ops->rules_list, list)
call_fib_rule_notifier(nb, net, FIB_EVENT_RULE_ADD, rule,
family);
rules_ops_put(ops);
return 0;
}
EXPORT_SYMBOL_GPL(fib_rules_dump);
unsigned int fib_rules_seq_read(struct net *net, int family)
{
unsigned int fib_rules_seq;
struct fib_rules_ops *ops;
ASSERT_RTNL();
ops = lookup_rules_ops(net, family);
if (!ops)
return 0;
fib_rules_seq = ops->fib_rules_seq;
rules_ops_put(ops);
return fib_rules_seq;
}
EXPORT_SYMBOL_GPL(fib_rules_seq_read);
static struct fib_rule *rule_find(struct fib_rules_ops *ops,
struct fib_rule_hdr *frh,
struct nlattr **tb,
struct fib_rule *rule,
bool user_priority)
{
struct fib_rule *r;
list_for_each_entry(r, &ops->rules_list, list) {
if (rule->action && r->action != rule->action)
continue;
if (rule->table && r->table != rule->table)
continue;
if (user_priority && r->pref != rule->pref)
continue;
if (rule->iifname[0] &&
memcmp(r->iifname, rule->iifname, IFNAMSIZ))
continue;
if (rule->oifname[0] &&
memcmp(r->oifname, rule->oifname, IFNAMSIZ))
continue;
if (rule->mark && r->mark != rule->mark)
continue;
if (rule->suppress_ifgroup != -1 &&
r->suppress_ifgroup != rule->suppress_ifgroup)
continue;
if (rule->suppress_prefixlen != -1 &&
r->suppress_prefixlen != rule->suppress_prefixlen)
continue;
if (rule->mark_mask && r->mark_mask != rule->mark_mask)
continue;
if (rule->tun_id && r->tun_id != rule->tun_id)
continue;
if (r->fr_net != rule->fr_net)
continue;
if (rule->l3mdev && r->l3mdev != rule->l3mdev)
continue;
if (uid_range_set(&rule->uid_range) &&
(!uid_eq(r->uid_range.start, rule->uid_range.start) ||
!uid_eq(r->uid_range.end, rule->uid_range.end)))
continue;
if (rule->ip_proto && r->ip_proto != rule->ip_proto)
continue;
if (rule->proto && r->proto != rule->proto)
continue;
if (fib_rule_port_range_set(&rule->sport_range) &&
!fib_rule_port_range_compare(&r->sport_range,
&rule->sport_range))
continue;
if (fib_rule_port_range_set(&rule->dport_range) &&
!fib_rule_port_range_compare(&r->dport_range,
&rule->dport_range))
continue;
if (!ops->compare(r, frh, tb))
continue;
return r;
}
return NULL;
}
#ifdef CONFIG_NET_L3_MASTER_DEV
static int fib_nl2rule_l3mdev(struct nlattr *nla, struct fib_rule *nlrule,
struct netlink_ext_ack *extack)
{
nlrule->l3mdev = nla_get_u8(nla);
if (nlrule->l3mdev != 1) {
NL_SET_ERR_MSG(extack, "Invalid l3mdev attribute");
return -1;
}
return 0;
}
#else
static int fib_nl2rule_l3mdev(struct nlattr *nla, struct fib_rule *nlrule,
struct netlink_ext_ack *extack)
{
NL_SET_ERR_MSG(extack, "l3mdev support is not enabled in kernel");
return -1;
}
#endif
static int fib_nl2rule(struct sk_buff *skb, struct nlmsghdr *nlh,
struct netlink_ext_ack *extack,
struct fib_rules_ops *ops,
struct nlattr *tb[],
struct fib_rule **rule,
bool *user_priority)
{
struct net *net = sock_net(skb->sk);
struct fib_rule_hdr *frh = nlmsg_data(nlh);
struct fib_rule *nlrule = NULL;
int err = -EINVAL;
if (frh->src_len)
if (!tb[FRA_SRC] ||
frh->src_len > (ops->addr_size * 8) ||
nla_len(tb[FRA_SRC]) != ops->addr_size) {
NL_SET_ERR_MSG(extack, "Invalid source address");
goto errout;
}
if (frh->dst_len)
if (!tb[FRA_DST] ||
frh->dst_len > (ops->addr_size * 8) ||
nla_len(tb[FRA_DST]) != ops->addr_size) {
NL_SET_ERR_MSG(extack, "Invalid dst address");
goto errout;
}
nlrule = kzalloc(ops->rule_size, GFP_KERNEL);
if (!nlrule) {
err = -ENOMEM;
goto errout;
}
refcount_set(&nlrule->refcnt, 1);
nlrule->fr_net = net;
if (tb[FRA_PRIORITY]) {
nlrule->pref = nla_get_u32(tb[FRA_PRIORITY]);
*user_priority = true;
} else {
nlrule->pref = fib_default_rule_pref(ops);
}
nlrule->proto = tb[FRA_PROTOCOL] ?
nla_get_u8(tb[FRA_PROTOCOL]) : RTPROT_UNSPEC;
if (tb[FRA_IIFNAME]) {
struct net_device *dev;
nlrule->iifindex = -1;
nla_strlcpy(nlrule->iifname, tb[FRA_IIFNAME], IFNAMSIZ);
dev = __dev_get_by_name(net, nlrule->iifname);
if (dev)
nlrule->iifindex = dev->ifindex;
}
if (tb[FRA_OIFNAME]) {
struct net_device *dev;
nlrule->oifindex = -1;
nla_strlcpy(nlrule->oifname, tb[FRA_OIFNAME], IFNAMSIZ);
dev = __dev_get_by_name(net, nlrule->oifname);
if (dev)
nlrule->oifindex = dev->ifindex;
}
if (tb[FRA_FWMARK]) {
nlrule->mark = nla_get_u32(tb[FRA_FWMARK]);
if (nlrule->mark)
/* compatibility: if the mark value is non-zero all bits
* are compared unless a mask is explicitly specified.
*/
nlrule->mark_mask = 0xFFFFFFFF;
}
if (tb[FRA_FWMASK])
nlrule->mark_mask = nla_get_u32(tb[FRA_FWMASK]);
if (tb[FRA_TUN_ID])
nlrule->tun_id = nla_get_be64(tb[FRA_TUN_ID]);
err = -EINVAL;
if (tb[FRA_L3MDEV] &&
fib_nl2rule_l3mdev(tb[FRA_L3MDEV], nlrule, extack) < 0)
goto errout_free;
nlrule->action = frh->action;
nlrule->flags = frh->flags;
nlrule->table = frh_get_table(frh, tb);
if (tb[FRA_SUPPRESS_PREFIXLEN])
nlrule->suppress_prefixlen = nla_get_u32(tb[FRA_SUPPRESS_PREFIXLEN]);
else
nlrule->suppress_prefixlen = -1;
if (tb[FRA_SUPPRESS_IFGROUP])
nlrule->suppress_ifgroup = nla_get_u32(tb[FRA_SUPPRESS_IFGROUP]);
else
nlrule->suppress_ifgroup = -1;
if (tb[FRA_GOTO]) {
if (nlrule->action != FR_ACT_GOTO) {
NL_SET_ERR_MSG(extack, "Unexpected goto");
goto errout_free;
}
nlrule->target = nla_get_u32(tb[FRA_GOTO]);
/* Backward jumps are prohibited to avoid endless loops */
if (nlrule->target <= nlrule->pref) {
NL_SET_ERR_MSG(extack, "Backward goto not supported");
goto errout_free;
}
} else if (nlrule->action == FR_ACT_GOTO) {
NL_SET_ERR_MSG(extack, "Missing goto target for action goto");
goto errout_free;
}
if (nlrule->l3mdev && nlrule->table) {
NL_SET_ERR_MSG(extack, "l3mdev and table are mutually exclusive");
goto errout_free;
}
if (tb[FRA_UID_RANGE]) {
if (current_user_ns() != net->user_ns) {
err = -EPERM;
NL_SET_ERR_MSG(extack, "No permission to set uid");
goto errout_free;
}
nlrule->uid_range = nla_get_kuid_range(tb);
if (!uid_range_set(&nlrule->uid_range) ||
!uid_lte(nlrule->uid_range.start, nlrule->uid_range.end)) {
NL_SET_ERR_MSG(extack, "Invalid uid range");
goto errout_free;
}
} else {
nlrule->uid_range = fib_kuid_range_unset;
}
if (tb[FRA_IP_PROTO])
nlrule->ip_proto = nla_get_u8(tb[FRA_IP_PROTO]);
if (tb[FRA_SPORT_RANGE]) {
err = nla_get_port_range(tb[FRA_SPORT_RANGE],
&nlrule->sport_range);
if (err) {
NL_SET_ERR_MSG(extack, "Invalid sport range");
goto errout_free;
}
}
if (tb[FRA_DPORT_RANGE]) {
err = nla_get_port_range(tb[FRA_DPORT_RANGE],
&nlrule->dport_range);
if (err) {
NL_SET_ERR_MSG(extack, "Invalid dport range");
goto errout_free;
}
}
*rule = nlrule;
return 0;
errout_free:
kfree(nlrule);
errout:
return err;
}
static int rule_exists(struct fib_rules_ops *ops, struct fib_rule_hdr *frh,
struct nlattr **tb, struct fib_rule *rule)
{
struct fib_rule *r;
list_for_each_entry(r, &ops->rules_list, list) {
if (r->action != rule->action)
continue;
if (r->table != rule->table)
continue;
if (r->pref != rule->pref)
continue;
if (memcmp(r->iifname, rule->iifname, IFNAMSIZ))
continue;
if (memcmp(r->oifname, rule->oifname, IFNAMSIZ))
continue;
if (r->mark != rule->mark)
continue;
if (r->suppress_ifgroup != rule->suppress_ifgroup)
continue;
if (r->suppress_prefixlen != rule->suppress_prefixlen)
continue;
if (r->mark_mask != rule->mark_mask)
continue;
if (r->tun_id != rule->tun_id)
continue;
if (r->fr_net != rule->fr_net)
continue;
if (r->l3mdev != rule->l3mdev)
continue;
if (!uid_eq(r->uid_range.start, rule->uid_range.start) ||
!uid_eq(r->uid_range.end, rule->uid_range.end))
continue;
if (r->ip_proto != rule->ip_proto)
continue;
if (r->proto != rule->proto)
continue;
if (!fib_rule_port_range_compare(&r->sport_range,
&rule->sport_range))
continue;
if (!fib_rule_port_range_compare(&r->dport_range,
&rule->dport_range))
continue;
if (!ops->compare(r, frh, tb))
continue;
return 1;
}
return 0;
}
int fib_nl_newrule(struct sk_buff *skb, struct nlmsghdr *nlh,
struct netlink_ext_ack *extack)
{
struct net *net = sock_net(skb->sk);
struct fib_rule_hdr *frh = nlmsg_data(nlh);
struct fib_rules_ops *ops = NULL;
struct fib_rule *rule = NULL, *r, *last = NULL;
struct nlattr *tb[FRA_MAX + 1];
int err = -EINVAL, unresolved = 0;
bool user_priority = false;
if (nlh->nlmsg_len < nlmsg_msg_size(sizeof(*frh))) {
NL_SET_ERR_MSG(extack, "Invalid msg length");
goto errout;
}
ops = lookup_rules_ops(net, frh->family);
if (!ops) {
err = -EAFNOSUPPORT;
NL_SET_ERR_MSG(extack, "Rule family not supported");
goto errout;
}
err = nlmsg_parse_deprecated(nlh, sizeof(*frh), tb, FRA_MAX,
ops->policy, extack);
if (err < 0) {
NL_SET_ERR_MSG(extack, "Error parsing msg");
goto errout;
}
err = fib_nl2rule(skb, nlh, extack, ops, tb, &rule, &user_priority);
if (err)
goto errout;
if ((nlh->nlmsg_flags & NLM_F_EXCL) &&
rule_exists(ops, frh, tb, rule)) {
err = -EEXIST;
goto errout_free;
}
err = ops->configure(rule, skb, frh, tb, extack);
if (err < 0)
goto errout_free;
err = call_fib_rule_notifiers(net, FIB_EVENT_RULE_ADD, rule, ops,
extack);
if (err < 0)
goto errout_free;
list_for_each_entry(r, &ops->rules_list, list) {
if (r->pref == rule->target) {
RCU_INIT_POINTER(rule->ctarget, r);
break;
}
}
if (rcu_dereference_protected(rule->ctarget, 1) == NULL)
unresolved = 1;
list_for_each_entry(r, &ops->rules_list, list) {
if (r->pref > rule->pref)
break;
last = r;
}
if (last)
list_add_rcu(&rule->list, &last->list);
else
list_add_rcu(&rule->list, &ops->rules_list);
if (ops->unresolved_rules) {
/*
* There are unresolved goto rules in the list, check if
* any of them are pointing to this new rule.
*/
list_for_each_entry(r, &ops->rules_list, list) {
if (r->action == FR_ACT_GOTO &&
r->target == rule->pref &&
rtnl_dereference(r->ctarget) == NULL) {
rcu_assign_pointer(r->ctarget, rule);
if (--ops->unresolved_rules == 0)
break;
}
}
}
if (rule->action == FR_ACT_GOTO)
ops->nr_goto_rules++;
if (unresolved)
ops->unresolved_rules++;
if (rule->tun_id)
ip_tunnel_need_metadata();
notify_rule_change(RTM_NEWRULE, rule, ops, nlh, NETLINK_CB(skb).portid);
flush_route_cache(ops);
rules_ops_put(ops);
return 0;
errout_free:
kfree(rule);
errout:
rules_ops_put(ops);
return err;
}
EXPORT_SYMBOL_GPL(fib_nl_newrule);
int fib_nl_delrule(struct sk_buff *skb, struct nlmsghdr *nlh,
struct netlink_ext_ack *extack)
{
struct net *net = sock_net(skb->sk);
struct fib_rule_hdr *frh = nlmsg_data(nlh);
struct fib_rules_ops *ops = NULL;
struct fib_rule *rule = NULL, *r, *nlrule = NULL;
struct nlattr *tb[FRA_MAX+1];
int err = -EINVAL;
bool user_priority = false;
if (nlh->nlmsg_len < nlmsg_msg_size(sizeof(*frh))) {
NL_SET_ERR_MSG(extack, "Invalid msg length");
goto errout;
}
ops = lookup_rules_ops(net, frh->family);
if (ops == NULL) {
err = -EAFNOSUPPORT;
NL_SET_ERR_MSG(extack, "Rule family not supported");
goto errout;
}
err = nlmsg_parse_deprecated(nlh, sizeof(*frh), tb, FRA_MAX,
ops->policy, extack);
if (err < 0) {
NL_SET_ERR_MSG(extack, "Error parsing msg");
goto errout;
}
err = fib_nl2rule(skb, nlh, extack, ops, tb, &nlrule, &user_priority);
if (err)
goto errout;
rule = rule_find(ops, frh, tb, nlrule, user_priority);
if (!rule) {
err = -ENOENT;
goto errout;
}
if (rule->flags & FIB_RULE_PERMANENT) {
err = -EPERM;
goto errout;
}
if (ops->delete) {
err = ops->delete(rule);
if (err)
goto errout;
}
if (rule->tun_id)
ip_tunnel_unneed_metadata();
list_del_rcu(&rule->list);
if (rule->action == FR_ACT_GOTO) {
ops->nr_goto_rules--;
if (rtnl_dereference(rule->ctarget) == NULL)
ops->unresolved_rules--;
}
/*
* Check if this rule is a target to any of them. If so,
* adjust to the next one with the same preference or
* disable them. As this operation is eventually very
* expensive, it is only performed if goto rules, except
* current if it is goto rule, have actually been added.
*/
if (ops->nr_goto_rules > 0) {
struct fib_rule *n;
n = list_next_entry(rule, list);
if (&n->list == &ops->rules_list || n->pref != rule->pref)
n = NULL;
list_for_each_entry(r, &ops->rules_list, list) {
if (rtnl_dereference(r->ctarget) != rule)
continue;
rcu_assign_pointer(r->ctarget, n);
if (!n)
ops->unresolved_rules++;
}
}
call_fib_rule_notifiers(net, FIB_EVENT_RULE_DEL, rule, ops,
NULL);
notify_rule_change(RTM_DELRULE, rule, ops, nlh,
NETLINK_CB(skb).portid);
fib_rule_put(rule);
flush_route_cache(ops);
rules_ops_put(ops);
kfree(nlrule);
return 0;
errout:
kfree(nlrule);
rules_ops_put(ops);
return err;
}
EXPORT_SYMBOL_GPL(fib_nl_delrule);
static inline size_t fib_rule_nlmsg_size(struct fib_rules_ops *ops,
struct fib_rule *rule)
{
size_t payload = NLMSG_ALIGN(sizeof(struct fib_rule_hdr))
+ nla_total_size(IFNAMSIZ) /* FRA_IIFNAME */
+ nla_total_size(IFNAMSIZ) /* FRA_OIFNAME */
+ nla_total_size(4) /* FRA_PRIORITY */
+ nla_total_size(4) /* FRA_TABLE */
+ nla_total_size(4) /* FRA_SUPPRESS_PREFIXLEN */
+ nla_total_size(4) /* FRA_SUPPRESS_IFGROUP */
+ nla_total_size(4) /* FRA_FWMARK */
+ nla_total_size(4) /* FRA_FWMASK */
+ nla_total_size_64bit(8) /* FRA_TUN_ID */
+ nla_total_size(sizeof(struct fib_kuid_range))
+ nla_total_size(1) /* FRA_PROTOCOL */
+ nla_total_size(1) /* FRA_IP_PROTO */
+ nla_total_size(sizeof(struct fib_rule_port_range)) /* FRA_SPORT_RANGE */
+ nla_total_size(sizeof(struct fib_rule_port_range)); /* FRA_DPORT_RANGE */
if (ops->nlmsg_payload)
payload += ops->nlmsg_payload(rule);
return payload;
}
static int fib_nl_fill_rule(struct sk_buff *skb, struct fib_rule *rule,
u32 pid, u32 seq, int type, int flags,
struct fib_rules_ops *ops)
{
struct nlmsghdr *nlh;
struct fib_rule_hdr *frh;
nlh = nlmsg_put(skb, pid, seq, type, sizeof(*frh), flags);
if (nlh == NULL)
return -EMSGSIZE;
frh = nlmsg_data(nlh);
frh->family = ops->family;
frh->table = rule->table;
if (nla_put_u32(skb, FRA_TABLE, rule->table))
goto nla_put_failure;
if (nla_put_u32(skb, FRA_SUPPRESS_PREFIXLEN, rule->suppress_prefixlen))
goto nla_put_failure;
frh->res1 = 0;
frh->res2 = 0;
frh->action = rule->action;
frh->flags = rule->flags;
if (nla_put_u8(skb, FRA_PROTOCOL, rule->proto))
goto nla_put_failure;
if (rule->action == FR_ACT_GOTO &&
rcu_access_pointer(rule->ctarget) == NULL)
frh->flags |= FIB_RULE_UNRESOLVED;
if (rule->iifname[0]) {
if (nla_put_string(skb, FRA_IIFNAME, rule->iifname))
goto nla_put_failure;
if (rule->iifindex == -1)
frh->flags |= FIB_RULE_IIF_DETACHED;
}
if (rule->oifname[0]) {
if (nla_put_string(skb, FRA_OIFNAME, rule->oifname))
goto nla_put_failure;
if (rule->oifindex == -1)
frh->flags |= FIB_RULE_OIF_DETACHED;
}
if ((rule->pref &&
nla_put_u32(skb, FRA_PRIORITY, rule->pref)) ||
(rule->mark &&
nla_put_u32(skb, FRA_FWMARK, rule->mark)) ||
((rule->mark_mask || rule->mark) &&
nla_put_u32(skb, FRA_FWMASK, rule->mark_mask)) ||
(rule->target &&
nla_put_u32(skb, FRA_GOTO, rule->target)) ||
(rule->tun_id &&
nla_put_be64(skb, FRA_TUN_ID, rule->tun_id, FRA_PAD)) ||
(rule->l3mdev &&
nla_put_u8(skb, FRA_L3MDEV, rule->l3mdev)) ||
(uid_range_set(&rule->uid_range) &&
nla_put_uid_range(skb, &rule->uid_range)) ||
(fib_rule_port_range_set(&rule->sport_range) &&
nla_put_port_range(skb, FRA_SPORT_RANGE, &rule->sport_range)) ||
(fib_rule_port_range_set(&rule->dport_range) &&
nla_put_port_range(skb, FRA_DPORT_RANGE, &rule->dport_range)) ||
(rule->ip_proto && nla_put_u8(skb, FRA_IP_PROTO, rule->ip_proto)))
goto nla_put_failure;
if (rule->suppress_ifgroup != -1) {
if (nla_put_u32(skb, FRA_SUPPRESS_IFGROUP, rule->suppress_ifgroup))
goto nla_put_failure;
}
if (ops->fill(rule, skb, frh) < 0)
goto nla_put_failure;
nlmsg_end(skb, nlh);
return 0;
nla_put_failure:
nlmsg_cancel(skb, nlh);
return -EMSGSIZE;
}
static int dump_rules(struct sk_buff *skb, struct netlink_callback *cb,
struct fib_rules_ops *ops)
{
int idx = 0;
struct fib_rule *rule;
int err = 0;
rcu_read_lock();
list_for_each_entry_rcu(rule, &ops->rules_list, list) {
if (idx < cb->args[1])
goto skip;
err = fib_nl_fill_rule(skb, rule, NETLINK_CB(cb->skb).portid,
cb->nlh->nlmsg_seq, RTM_NEWRULE,
NLM_F_MULTI, ops);
if (err)
break;
skip:
idx++;
}
rcu_read_unlock();
cb->args[1] = idx;
rules_ops_put(ops);
return err;
}
static int fib_valid_dumprule_req(const struct nlmsghdr *nlh,
struct netlink_ext_ack *extack)
{
struct fib_rule_hdr *frh;
if (nlh->nlmsg_len < nlmsg_msg_size(sizeof(*frh))) {
NL_SET_ERR_MSG(extack, "Invalid header for fib rule dump request");
return -EINVAL;
}
frh = nlmsg_data(nlh);
if (frh->dst_len || frh->src_len || frh->tos || frh->table ||
frh->res1 || frh->res2 || frh->action || frh->flags) {
NL_SET_ERR_MSG(extack,
"Invalid values in header for fib rule dump request");
return -EINVAL;
}
if (nlmsg_attrlen(nlh, sizeof(*frh))) {
NL_SET_ERR_MSG(extack, "Invalid data after header in fib rule dump request");
return -EINVAL;
}
return 0;
}
static int fib_nl_dumprule(struct sk_buff *skb, struct netlink_callback *cb)
{
const struct nlmsghdr *nlh = cb->nlh;
struct net *net = sock_net(skb->sk);
struct fib_rules_ops *ops;
int idx = 0, family;
if (cb->strict_check) {
int err = fib_valid_dumprule_req(nlh, cb->extack);
if (err < 0)
return err;
}
family = rtnl_msg_family(nlh);
if (family != AF_UNSPEC) {
/* Protocol specific dump request */
ops = lookup_rules_ops(net, family);
if (ops == NULL)
return -EAFNOSUPPORT;
dump_rules(skb, cb, ops);
return skb->len;
}
rcu_read_lock();
list_for_each_entry_rcu(ops, &net->rules_ops, list) {
if (idx < cb->args[0] || !try_module_get(ops->owner))
goto skip;
if (dump_rules(skb, cb, ops) < 0)
break;
cb->args[1] = 0;
skip:
idx++;
}
rcu_read_unlock();
cb->args[0] = idx;
return skb->len;
}
static void notify_rule_change(int event, struct fib_rule *rule,
struct fib_rules_ops *ops, struct nlmsghdr *nlh,
u32 pid)
{
struct net *net;
struct sk_buff *skb;
int err = -ENOBUFS;
net = ops->fro_net;
skb = nlmsg_new(fib_rule_nlmsg_size(ops, rule), GFP_KERNEL);
if (skb == NULL)
goto errout;
err = fib_nl_fill_rule(skb, rule, pid, nlh->nlmsg_seq, event, 0, ops);
if (err < 0) {
/* -EMSGSIZE implies BUG in fib_rule_nlmsg_size() */
WARN_ON(err == -EMSGSIZE);
kfree_skb(skb);
goto errout;
}
rtnl_notify(skb, net, pid, ops->nlgroup, nlh, GFP_KERNEL);
return;
errout:
if (err < 0)
rtnl_set_sk_err(net, ops->nlgroup, err);
}
static void attach_rules(struct list_head *rules, struct net_device *dev)
{
struct fib_rule *rule;
list_for_each_entry(rule, rules, list) {
if (rule->iifindex == -1 &&
strcmp(dev->name, rule->iifname) == 0)
rule->iifindex = dev->ifindex;
if (rule->oifindex == -1 &&
strcmp(dev->name, rule->oifname) == 0)
rule->oifindex = dev->ifindex;
}
}
static void detach_rules(struct list_head *rules, struct net_device *dev)
{
struct fib_rule *rule;
list_for_each_entry(rule, rules, list) {
if (rule->iifindex == dev->ifindex)
rule->iifindex = -1;
if (rule->oifindex == dev->ifindex)
rule->oifindex = -1;
}
}
static int fib_rules_event(struct notifier_block *this, unsigned long event,
void *ptr)
{
struct net_device *dev = netdev_notifier_info_to_dev(ptr);
struct net *net = dev_net(dev);
struct fib_rules_ops *ops;
ASSERT_RTNL();
switch (event) {
case NETDEV_REGISTER:
list_for_each_entry(ops, &net->rules_ops, list)
attach_rules(&ops->rules_list, dev);
break;
case NETDEV_CHANGENAME:
list_for_each_entry(ops, &net->rules_ops, list) {
detach_rules(&ops->rules_list, dev);
attach_rules(&ops->rules_list, dev);
}
break;
case NETDEV_UNREGISTER:
list_for_each_entry(ops, &net->rules_ops, list)
detach_rules(&ops->rules_list, dev);
break;
}
return NOTIFY_DONE;
}
static struct notifier_block fib_rules_notifier = {
.notifier_call = fib_rules_event,
};
static int __net_init fib_rules_net_init(struct net *net)
{
INIT_LIST_HEAD(&net->rules_ops);
spin_lock_init(&net->rules_mod_lock);
return 0;
}
static void __net_exit fib_rules_net_exit(struct net *net)
{
WARN_ON_ONCE(!list_empty(&net->rules_ops));
}
static struct pernet_operations fib_rules_net_ops = {
.init = fib_rules_net_init,
.exit = fib_rules_net_exit,
};
static int __init fib_rules_init(void)
{
int err;
rtnl_register(PF_UNSPEC, RTM_NEWRULE, fib_nl_newrule, NULL, 0);
rtnl_register(PF_UNSPEC, RTM_DELRULE, fib_nl_delrule, NULL, 0);
rtnl_register(PF_UNSPEC, RTM_GETRULE, NULL, fib_nl_dumprule, 0);
err = register_pernet_subsys(&fib_rules_net_ops);
if (err < 0)
goto fail;
err = register_netdevice_notifier(&fib_rules_notifier);
if (err < 0)
goto fail_unregister;
return 0;
fail_unregister:
unregister_pernet_subsys(&fib_rules_net_ops);
fail:
rtnl_unregister(PF_UNSPEC, RTM_NEWRULE);
rtnl_unregister(PF_UNSPEC, RTM_DELRULE);
rtnl_unregister(PF_UNSPEC, RTM_GETRULE);
return err;
}
subsys_initcall(fib_rules_init);
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