linux/net/sched/cls_route.c
Cong Wang 2e24cd7555 net_sched: fix ops->bind_class() implementations
The current implementations of ops->bind_class() are merely
searching for classid and updating class in the struct tcf_result,
without invoking either of cl_ops->bind_tcf() or
cl_ops->unbind_tcf(). This breaks the design of them as qdisc's
like cbq use them to count filters too. This is why syzbot triggered
the warning in cbq_destroy_class().

In order to fix this, we have to call cl_ops->bind_tcf() and
cl_ops->unbind_tcf() like the filter binding path. This patch does
so by refactoring out two helper functions __tcf_bind_filter()
and __tcf_unbind_filter(), which are lockless and accept a Qdisc
pointer, then teaching each implementation to call them correctly.

Note, we merely pass the Qdisc pointer as an opaque pointer to
each filter, they only need to pass it down to the helper
functions without understanding it at all.

Fixes: 07d79fc7d9 ("net_sched: add reverse binding for tc class")
Reported-and-tested-by: syzbot+0a0596220218fcb603a8@syzkaller.appspotmail.com
Reported-and-tested-by: syzbot+63bdb6006961d8c917c6@syzkaller.appspotmail.com
Cc: Jamal Hadi Salim <jhs@mojatatu.com>
Cc: Jiri Pirko <jiri@resnulli.us>
Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2020-01-27 10:51:43 +01:00

684 lines
14 KiB
C

// SPDX-License-Identifier: GPL-2.0-or-later
/*
* net/sched/cls_route.c ROUTE4 classifier.
*
* Authors: Alexey Kuznetsov, <kuznet@ms2.inr.ac.ru>
*/
#include <linux/module.h>
#include <linux/slab.h>
#include <linux/types.h>
#include <linux/kernel.h>
#include <linux/string.h>
#include <linux/errno.h>
#include <linux/skbuff.h>
#include <net/dst.h>
#include <net/route.h>
#include <net/netlink.h>
#include <net/act_api.h>
#include <net/pkt_cls.h>
/*
* 1. For now we assume that route tags < 256.
* It allows to use direct table lookups, instead of hash tables.
* 2. For now we assume that "from TAG" and "fromdev DEV" statements
* are mutually exclusive.
* 3. "to TAG from ANY" has higher priority, than "to ANY from XXX"
*/
struct route4_fastmap {
struct route4_filter *filter;
u32 id;
int iif;
};
struct route4_head {
struct route4_fastmap fastmap[16];
struct route4_bucket __rcu *table[256 + 1];
struct rcu_head rcu;
};
struct route4_bucket {
/* 16 FROM buckets + 16 IIF buckets + 1 wildcard bucket */
struct route4_filter __rcu *ht[16 + 16 + 1];
struct rcu_head rcu;
};
struct route4_filter {
struct route4_filter __rcu *next;
u32 id;
int iif;
struct tcf_result res;
struct tcf_exts exts;
u32 handle;
struct route4_bucket *bkt;
struct tcf_proto *tp;
struct rcu_work rwork;
};
#define ROUTE4_FAILURE ((struct route4_filter *)(-1L))
static inline int route4_fastmap_hash(u32 id, int iif)
{
return id & 0xF;
}
static DEFINE_SPINLOCK(fastmap_lock);
static void
route4_reset_fastmap(struct route4_head *head)
{
spin_lock_bh(&fastmap_lock);
memset(head->fastmap, 0, sizeof(head->fastmap));
spin_unlock_bh(&fastmap_lock);
}
static void
route4_set_fastmap(struct route4_head *head, u32 id, int iif,
struct route4_filter *f)
{
int h = route4_fastmap_hash(id, iif);
/* fastmap updates must look atomic to aling id, iff, filter */
spin_lock_bh(&fastmap_lock);
head->fastmap[h].id = id;
head->fastmap[h].iif = iif;
head->fastmap[h].filter = f;
spin_unlock_bh(&fastmap_lock);
}
static inline int route4_hash_to(u32 id)
{
return id & 0xFF;
}
static inline int route4_hash_from(u32 id)
{
return (id >> 16) & 0xF;
}
static inline int route4_hash_iif(int iif)
{
return 16 + ((iif >> 16) & 0xF);
}
static inline int route4_hash_wild(void)
{
return 32;
}
#define ROUTE4_APPLY_RESULT() \
{ \
*res = f->res; \
if (tcf_exts_has_actions(&f->exts)) { \
int r = tcf_exts_exec(skb, &f->exts, res); \
if (r < 0) { \
dont_cache = 1; \
continue; \
} \
return r; \
} else if (!dont_cache) \
route4_set_fastmap(head, id, iif, f); \
return 0; \
}
static int route4_classify(struct sk_buff *skb, const struct tcf_proto *tp,
struct tcf_result *res)
{
struct route4_head *head = rcu_dereference_bh(tp->root);
struct dst_entry *dst;
struct route4_bucket *b;
struct route4_filter *f;
u32 id, h;
int iif, dont_cache = 0;
dst = skb_dst(skb);
if (!dst)
goto failure;
id = dst->tclassid;
iif = inet_iif(skb);
h = route4_fastmap_hash(id, iif);
spin_lock(&fastmap_lock);
if (id == head->fastmap[h].id &&
iif == head->fastmap[h].iif &&
(f = head->fastmap[h].filter) != NULL) {
if (f == ROUTE4_FAILURE) {
spin_unlock(&fastmap_lock);
goto failure;
}
*res = f->res;
spin_unlock(&fastmap_lock);
return 0;
}
spin_unlock(&fastmap_lock);
h = route4_hash_to(id);
restart:
b = rcu_dereference_bh(head->table[h]);
if (b) {
for (f = rcu_dereference_bh(b->ht[route4_hash_from(id)]);
f;
f = rcu_dereference_bh(f->next))
if (f->id == id)
ROUTE4_APPLY_RESULT();
for (f = rcu_dereference_bh(b->ht[route4_hash_iif(iif)]);
f;
f = rcu_dereference_bh(f->next))
if (f->iif == iif)
ROUTE4_APPLY_RESULT();
for (f = rcu_dereference_bh(b->ht[route4_hash_wild()]);
f;
f = rcu_dereference_bh(f->next))
ROUTE4_APPLY_RESULT();
}
if (h < 256) {
h = 256;
id &= ~0xFFFF;
goto restart;
}
if (!dont_cache)
route4_set_fastmap(head, id, iif, ROUTE4_FAILURE);
failure:
return -1;
}
static inline u32 to_hash(u32 id)
{
u32 h = id & 0xFF;
if (id & 0x8000)
h += 256;
return h;
}
static inline u32 from_hash(u32 id)
{
id &= 0xFFFF;
if (id == 0xFFFF)
return 32;
if (!(id & 0x8000)) {
if (id > 255)
return 256;
return id & 0xF;
}
return 16 + (id & 0xF);
}
static void *route4_get(struct tcf_proto *tp, u32 handle)
{
struct route4_head *head = rtnl_dereference(tp->root);
struct route4_bucket *b;
struct route4_filter *f;
unsigned int h1, h2;
h1 = to_hash(handle);
if (h1 > 256)
return NULL;
h2 = from_hash(handle >> 16);
if (h2 > 32)
return NULL;
b = rtnl_dereference(head->table[h1]);
if (b) {
for (f = rtnl_dereference(b->ht[h2]);
f;
f = rtnl_dereference(f->next))
if (f->handle == handle)
return f;
}
return NULL;
}
static int route4_init(struct tcf_proto *tp)
{
struct route4_head *head;
head = kzalloc(sizeof(struct route4_head), GFP_KERNEL);
if (head == NULL)
return -ENOBUFS;
rcu_assign_pointer(tp->root, head);
return 0;
}
static void __route4_delete_filter(struct route4_filter *f)
{
tcf_exts_destroy(&f->exts);
tcf_exts_put_net(&f->exts);
kfree(f);
}
static void route4_delete_filter_work(struct work_struct *work)
{
struct route4_filter *f = container_of(to_rcu_work(work),
struct route4_filter,
rwork);
rtnl_lock();
__route4_delete_filter(f);
rtnl_unlock();
}
static void route4_queue_work(struct route4_filter *f)
{
tcf_queue_work(&f->rwork, route4_delete_filter_work);
}
static void route4_destroy(struct tcf_proto *tp, bool rtnl_held,
struct netlink_ext_ack *extack)
{
struct route4_head *head = rtnl_dereference(tp->root);
int h1, h2;
if (head == NULL)
return;
for (h1 = 0; h1 <= 256; h1++) {
struct route4_bucket *b;
b = rtnl_dereference(head->table[h1]);
if (b) {
for (h2 = 0; h2 <= 32; h2++) {
struct route4_filter *f;
while ((f = rtnl_dereference(b->ht[h2])) != NULL) {
struct route4_filter *next;
next = rtnl_dereference(f->next);
RCU_INIT_POINTER(b->ht[h2], next);
tcf_unbind_filter(tp, &f->res);
if (tcf_exts_get_net(&f->exts))
route4_queue_work(f);
else
__route4_delete_filter(f);
}
}
RCU_INIT_POINTER(head->table[h1], NULL);
kfree_rcu(b, rcu);
}
}
kfree_rcu(head, rcu);
}
static int route4_delete(struct tcf_proto *tp, void *arg, bool *last,
bool rtnl_held, struct netlink_ext_ack *extack)
{
struct route4_head *head = rtnl_dereference(tp->root);
struct route4_filter *f = arg;
struct route4_filter __rcu **fp;
struct route4_filter *nf;
struct route4_bucket *b;
unsigned int h = 0;
int i, h1;
if (!head || !f)
return -EINVAL;
h = f->handle;
b = f->bkt;
fp = &b->ht[from_hash(h >> 16)];
for (nf = rtnl_dereference(*fp); nf;
fp = &nf->next, nf = rtnl_dereference(*fp)) {
if (nf == f) {
/* unlink it */
RCU_INIT_POINTER(*fp, rtnl_dereference(f->next));
/* Remove any fastmap lookups that might ref filter
* notice we unlink'd the filter so we can't get it
* back in the fastmap.
*/
route4_reset_fastmap(head);
/* Delete it */
tcf_unbind_filter(tp, &f->res);
tcf_exts_get_net(&f->exts);
tcf_queue_work(&f->rwork, route4_delete_filter_work);
/* Strip RTNL protected tree */
for (i = 0; i <= 32; i++) {
struct route4_filter *rt;
rt = rtnl_dereference(b->ht[i]);
if (rt)
goto out;
}
/* OK, session has no flows */
RCU_INIT_POINTER(head->table[to_hash(h)], NULL);
kfree_rcu(b, rcu);
break;
}
}
out:
*last = true;
for (h1 = 0; h1 <= 256; h1++) {
if (rcu_access_pointer(head->table[h1])) {
*last = false;
break;
}
}
return 0;
}
static const struct nla_policy route4_policy[TCA_ROUTE4_MAX + 1] = {
[TCA_ROUTE4_CLASSID] = { .type = NLA_U32 },
[TCA_ROUTE4_TO] = { .type = NLA_U32 },
[TCA_ROUTE4_FROM] = { .type = NLA_U32 },
[TCA_ROUTE4_IIF] = { .type = NLA_U32 },
};
static int route4_set_parms(struct net *net, struct tcf_proto *tp,
unsigned long base, struct route4_filter *f,
u32 handle, struct route4_head *head,
struct nlattr **tb, struct nlattr *est, int new,
bool ovr, struct netlink_ext_ack *extack)
{
u32 id = 0, to = 0, nhandle = 0x8000;
struct route4_filter *fp;
unsigned int h1;
struct route4_bucket *b;
int err;
err = tcf_exts_validate(net, tp, tb, est, &f->exts, ovr, true, extack);
if (err < 0)
return err;
if (tb[TCA_ROUTE4_TO]) {
if (new && handle & 0x8000)
return -EINVAL;
to = nla_get_u32(tb[TCA_ROUTE4_TO]);
if (to > 0xFF)
return -EINVAL;
nhandle = to;
}
if (tb[TCA_ROUTE4_FROM]) {
if (tb[TCA_ROUTE4_IIF])
return -EINVAL;
id = nla_get_u32(tb[TCA_ROUTE4_FROM]);
if (id > 0xFF)
return -EINVAL;
nhandle |= id << 16;
} else if (tb[TCA_ROUTE4_IIF]) {
id = nla_get_u32(tb[TCA_ROUTE4_IIF]);
if (id > 0x7FFF)
return -EINVAL;
nhandle |= (id | 0x8000) << 16;
} else
nhandle |= 0xFFFF << 16;
if (handle && new) {
nhandle |= handle & 0x7F00;
if (nhandle != handle)
return -EINVAL;
}
h1 = to_hash(nhandle);
b = rtnl_dereference(head->table[h1]);
if (!b) {
b = kzalloc(sizeof(struct route4_bucket), GFP_KERNEL);
if (b == NULL)
return -ENOBUFS;
rcu_assign_pointer(head->table[h1], b);
} else {
unsigned int h2 = from_hash(nhandle >> 16);
for (fp = rtnl_dereference(b->ht[h2]);
fp;
fp = rtnl_dereference(fp->next))
if (fp->handle == f->handle)
return -EEXIST;
}
if (tb[TCA_ROUTE4_TO])
f->id = to;
if (tb[TCA_ROUTE4_FROM])
f->id = to | id<<16;
else if (tb[TCA_ROUTE4_IIF])
f->iif = id;
f->handle = nhandle;
f->bkt = b;
f->tp = tp;
if (tb[TCA_ROUTE4_CLASSID]) {
f->res.classid = nla_get_u32(tb[TCA_ROUTE4_CLASSID]);
tcf_bind_filter(tp, &f->res, base);
}
return 0;
}
static int route4_change(struct net *net, struct sk_buff *in_skb,
struct tcf_proto *tp, unsigned long base, u32 handle,
struct nlattr **tca, void **arg, bool ovr,
bool rtnl_held, struct netlink_ext_ack *extack)
{
struct route4_head *head = rtnl_dereference(tp->root);
struct route4_filter __rcu **fp;
struct route4_filter *fold, *f1, *pfp, *f = NULL;
struct route4_bucket *b;
struct nlattr *opt = tca[TCA_OPTIONS];
struct nlattr *tb[TCA_ROUTE4_MAX + 1];
unsigned int h, th;
int err;
bool new = true;
if (opt == NULL)
return handle ? -EINVAL : 0;
err = nla_parse_nested_deprecated(tb, TCA_ROUTE4_MAX, opt,
route4_policy, NULL);
if (err < 0)
return err;
fold = *arg;
if (fold && handle && fold->handle != handle)
return -EINVAL;
err = -ENOBUFS;
f = kzalloc(sizeof(struct route4_filter), GFP_KERNEL);
if (!f)
goto errout;
err = tcf_exts_init(&f->exts, net, TCA_ROUTE4_ACT, TCA_ROUTE4_POLICE);
if (err < 0)
goto errout;
if (fold) {
f->id = fold->id;
f->iif = fold->iif;
f->res = fold->res;
f->handle = fold->handle;
f->tp = fold->tp;
f->bkt = fold->bkt;
new = false;
}
err = route4_set_parms(net, tp, base, f, handle, head, tb,
tca[TCA_RATE], new, ovr, extack);
if (err < 0)
goto errout;
h = from_hash(f->handle >> 16);
fp = &f->bkt->ht[h];
for (pfp = rtnl_dereference(*fp);
(f1 = rtnl_dereference(*fp)) != NULL;
fp = &f1->next)
if (f->handle < f1->handle)
break;
tcf_block_netif_keep_dst(tp->chain->block);
rcu_assign_pointer(f->next, f1);
rcu_assign_pointer(*fp, f);
if (fold && fold->handle && f->handle != fold->handle) {
th = to_hash(fold->handle);
h = from_hash(fold->handle >> 16);
b = rtnl_dereference(head->table[th]);
if (b) {
fp = &b->ht[h];
for (pfp = rtnl_dereference(*fp); pfp;
fp = &pfp->next, pfp = rtnl_dereference(*fp)) {
if (pfp == f) {
*fp = f->next;
break;
}
}
}
}
route4_reset_fastmap(head);
*arg = f;
if (fold) {
tcf_unbind_filter(tp, &fold->res);
tcf_exts_get_net(&fold->exts);
tcf_queue_work(&fold->rwork, route4_delete_filter_work);
}
return 0;
errout:
if (f)
tcf_exts_destroy(&f->exts);
kfree(f);
return err;
}
static void route4_walk(struct tcf_proto *tp, struct tcf_walker *arg,
bool rtnl_held)
{
struct route4_head *head = rtnl_dereference(tp->root);
unsigned int h, h1;
if (head == NULL || arg->stop)
return;
for (h = 0; h <= 256; h++) {
struct route4_bucket *b = rtnl_dereference(head->table[h]);
if (b) {
for (h1 = 0; h1 <= 32; h1++) {
struct route4_filter *f;
for (f = rtnl_dereference(b->ht[h1]);
f;
f = rtnl_dereference(f->next)) {
if (arg->count < arg->skip) {
arg->count++;
continue;
}
if (arg->fn(tp, f, arg) < 0) {
arg->stop = 1;
return;
}
arg->count++;
}
}
}
}
}
static int route4_dump(struct net *net, struct tcf_proto *tp, void *fh,
struct sk_buff *skb, struct tcmsg *t, bool rtnl_held)
{
struct route4_filter *f = fh;
struct nlattr *nest;
u32 id;
if (f == NULL)
return skb->len;
t->tcm_handle = f->handle;
nest = nla_nest_start_noflag(skb, TCA_OPTIONS);
if (nest == NULL)
goto nla_put_failure;
if (!(f->handle & 0x8000)) {
id = f->id & 0xFF;
if (nla_put_u32(skb, TCA_ROUTE4_TO, id))
goto nla_put_failure;
}
if (f->handle & 0x80000000) {
if ((f->handle >> 16) != 0xFFFF &&
nla_put_u32(skb, TCA_ROUTE4_IIF, f->iif))
goto nla_put_failure;
} else {
id = f->id >> 16;
if (nla_put_u32(skb, TCA_ROUTE4_FROM, id))
goto nla_put_failure;
}
if (f->res.classid &&
nla_put_u32(skb, TCA_ROUTE4_CLASSID, f->res.classid))
goto nla_put_failure;
if (tcf_exts_dump(skb, &f->exts) < 0)
goto nla_put_failure;
nla_nest_end(skb, nest);
if (tcf_exts_dump_stats(skb, &f->exts) < 0)
goto nla_put_failure;
return skb->len;
nla_put_failure:
nla_nest_cancel(skb, nest);
return -1;
}
static void route4_bind_class(void *fh, u32 classid, unsigned long cl, void *q,
unsigned long base)
{
struct route4_filter *f = fh;
if (f && f->res.classid == classid) {
if (cl)
__tcf_bind_filter(q, &f->res, base);
else
__tcf_unbind_filter(q, &f->res);
}
}
static struct tcf_proto_ops cls_route4_ops __read_mostly = {
.kind = "route",
.classify = route4_classify,
.init = route4_init,
.destroy = route4_destroy,
.get = route4_get,
.change = route4_change,
.delete = route4_delete,
.walk = route4_walk,
.dump = route4_dump,
.bind_class = route4_bind_class,
.owner = THIS_MODULE,
};
static int __init init_route4(void)
{
return register_tcf_proto_ops(&cls_route4_ops);
}
static void __exit exit_route4(void)
{
unregister_tcf_proto_ops(&cls_route4_ops);
}
module_init(init_route4)
module_exit(exit_route4)
MODULE_LICENSE("GPL");