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linux/net/sched/cls_fw.c
Patrick McHardy 5c804bfdcc [NET_SCHED]: cls_fw: fix NULL pointer dereference 
When the first fw classifier is initialized, there is a small window
between the ->init() and ->change() calls, during which the classifier
is active but not entirely set up and tp->root is still NULL (->init()
does nothing).

When a packet is queued during this window a NULL pointer dereference
occurs in fw_classify() when trying to dereference head->mask;

Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
2006-12-06 18:39:07 -08:00

417 lines
8.8 KiB
C
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/*
* net/sched/cls_fw.c Classifier mapping ipchains' fwmark to traffic class.
*
* 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.
*
* Authors: Alexey Kuznetsov, <kuznet@ms2.inr.ac.ru>
*
* Changes:
* Karlis Peisenieks <karlis@mt.lv> : 990415 : fw_walk off by one
* Karlis Peisenieks <karlis@mt.lv> : 990415 : fw_delete killed all the filter (and kernel).
* Alex <alex@pilotsoft.com> : 2004xxyy: Added Action extension
*
* JHS: We should remove the CONFIG_NET_CLS_IND from here
* eventually when the meta match extension is made available
*
*/
#include <linux/module.h>
#include <asm/uaccess.h>
#include <asm/system.h>
#include <linux/bitops.h>
#include <linux/types.h>
#include <linux/kernel.h>
#include <linux/sched.h>
#include <linux/string.h>
#include <linux/mm.h>
#include <linux/socket.h>
#include <linux/sockios.h>
#include <linux/in.h>
#include <linux/errno.h>
#include <linux/interrupt.h>
#include <linux/if_ether.h>
#include <linux/inet.h>
#include <linux/netdevice.h>
#include <linux/etherdevice.h>
#include <linux/notifier.h>
#include <linux/netfilter.h>
#include <net/ip.h>
#include <net/route.h>
#include <linux/skbuff.h>
#include <net/sock.h>
#include <net/act_api.h>
#include <net/pkt_cls.h>
#define HTSIZE (PAGE_SIZE/sizeof(struct fw_filter *))
struct fw_head
{
struct fw_filter *ht[HTSIZE];
u32 mask;
};
struct fw_filter
{
struct fw_filter *next;
u32 id;
struct tcf_result res;
#ifdef CONFIG_NET_CLS_IND
char indev[IFNAMSIZ];
#endif /* CONFIG_NET_CLS_IND */
struct tcf_exts exts;
};
static struct tcf_ext_map fw_ext_map = {
.action = TCA_FW_ACT,
.police = TCA_FW_POLICE
};
static __inline__ int fw_hash(u32 handle)
{
if (HTSIZE == 4096)
return ((handle >> 24) & 0xFFF) ^
((handle >> 12) & 0xFFF) ^
(handle & 0xFFF);
else if (HTSIZE == 2048)
return ((handle >> 22) & 0x7FF) ^
((handle >> 11) & 0x7FF) ^
(handle & 0x7FF);
else if (HTSIZE == 1024)
return ((handle >> 20) & 0x3FF) ^
((handle >> 10) & 0x3FF) ^
(handle & 0x3FF);
else if (HTSIZE == 512)
return (handle >> 27) ^
((handle >> 18) & 0x1FF) ^
((handle >> 9) & 0x1FF) ^
(handle & 0x1FF);
else if (HTSIZE == 256) {
u8 *t = (u8 *) &handle;
return t[0] ^ t[1] ^ t[2] ^ t[3];
} else
return handle & (HTSIZE - 1);
}
static int fw_classify(struct sk_buff *skb, struct tcf_proto *tp,
struct tcf_result *res)
{
struct fw_head *head = (struct fw_head*)tp->root;
struct fw_filter *f;
int r;
u32 id = skb->mark;
if (head != NULL) {
id &= head->mask;
for (f=head->ht[fw_hash(id)]; f; f=f->next) {
if (f->id == id) {
*res = f->res;
#ifdef CONFIG_NET_CLS_IND
if (!tcf_match_indev(skb, f->indev))
continue;
#endif /* CONFIG_NET_CLS_IND */
r = tcf_exts_exec(skb, &f->exts, res);
if (r < 0)
continue;
return r;
}
}
} else {
/* old method */
if (id && (TC_H_MAJ(id) == 0 || !(TC_H_MAJ(id^tp->q->handle)))) {
res->classid = id;
res->class = 0;
return 0;
}
}
return -1;
}
static unsigned long fw_get(struct tcf_proto *tp, u32 handle)
{
struct fw_head *head = (struct fw_head*)tp->root;
struct fw_filter *f;
if (head == NULL)
return 0;
for (f=head->ht[fw_hash(handle)]; f; f=f->next) {
if (f->id == handle)
return (unsigned long)f;
}
return 0;
}
static void fw_put(struct tcf_proto *tp, unsigned long f)
{
}
static int fw_init(struct tcf_proto *tp)
{
return 0;
}
static inline void
fw_delete_filter(struct tcf_proto *tp, struct fw_filter *f)
{
tcf_unbind_filter(tp, &f->res);
tcf_exts_destroy(tp, &f->exts);
kfree(f);
}
static void fw_destroy(struct tcf_proto *tp)
{
struct fw_head *head = (struct fw_head*)xchg(&tp->root, NULL);
struct fw_filter *f;
int h;
if (head == NULL)
return;
for (h=0; h<HTSIZE; h++) {
while ((f=head->ht[h]) != NULL) {
head->ht[h] = f->next;
fw_delete_filter(tp, f);
}
}
kfree(head);
}
static int fw_delete(struct tcf_proto *tp, unsigned long arg)
{
struct fw_head *head = (struct fw_head*)tp->root;
struct fw_filter *f = (struct fw_filter*)arg;
struct fw_filter **fp;
if (head == NULL || f == NULL)
goto out;
for (fp=&head->ht[fw_hash(f->id)]; *fp; fp = &(*fp)->next) {
if (*fp == f) {
tcf_tree_lock(tp);
*fp = f->next;
tcf_tree_unlock(tp);
fw_delete_filter(tp, f);
return 0;
}
}
out:
return -EINVAL;
}
static int
fw_change_attrs(struct tcf_proto *tp, struct fw_filter *f,
struct rtattr **tb, struct rtattr **tca, unsigned long base)
{
struct fw_head *head = (struct fw_head *)tp->root;
struct tcf_exts e;
u32 mask;
int err;
err = tcf_exts_validate(tp, tb, tca[TCA_RATE-1], &e, &fw_ext_map);
if (err < 0)
return err;
err = -EINVAL;
if (tb[TCA_FW_CLASSID-1]) {
if (RTA_PAYLOAD(tb[TCA_FW_CLASSID-1]) != sizeof(u32))
goto errout;
f->res.classid = *(u32*)RTA_DATA(tb[TCA_FW_CLASSID-1]);
tcf_bind_filter(tp, &f->res, base);
}
#ifdef CONFIG_NET_CLS_IND
if (tb[TCA_FW_INDEV-1]) {
err = tcf_change_indev(tp, f->indev, tb[TCA_FW_INDEV-1]);
if (err < 0)
goto errout;
}
#endif /* CONFIG_NET_CLS_IND */
if (tb[TCA_FW_MASK-1]) {
if (RTA_PAYLOAD(tb[TCA_FW_MASK-1]) != sizeof(u32))
goto errout;
mask = *(u32*)RTA_DATA(tb[TCA_FW_MASK-1]);
if (mask != head->mask)
goto errout;
} else if (head->mask != 0xFFFFFFFF)
goto errout;
tcf_exts_change(tp, &f->exts, &e);
return 0;
errout:
tcf_exts_destroy(tp, &e);
return err;
}
static int fw_change(struct tcf_proto *tp, unsigned long base,
u32 handle,
struct rtattr **tca,
unsigned long *arg)
{
struct fw_head *head = (struct fw_head*)tp->root;
struct fw_filter *f = (struct fw_filter *) *arg;
struct rtattr *opt = tca[TCA_OPTIONS-1];
struct rtattr *tb[TCA_FW_MAX];
int err;
if (!opt)
return handle ? -EINVAL : 0;
if (rtattr_parse_nested(tb, TCA_FW_MAX, opt) < 0)
return -EINVAL;
if (f != NULL) {
if (f->id != handle && handle)
return -EINVAL;
return fw_change_attrs(tp, f, tb, tca, base);
}
if (!handle)
return -EINVAL;
if (head == NULL) {
u32 mask = 0xFFFFFFFF;
if (tb[TCA_FW_MASK-1]) {
if (RTA_PAYLOAD(tb[TCA_FW_MASK-1]) != sizeof(u32))
return -EINVAL;
mask = *(u32*)RTA_DATA(tb[TCA_FW_MASK-1]);
}
head = kzalloc(sizeof(struct fw_head), GFP_KERNEL);
if (head == NULL)
return -ENOBUFS;
head->mask = mask;
tcf_tree_lock(tp);
tp->root = head;
tcf_tree_unlock(tp);
}
f = kzalloc(sizeof(struct fw_filter), GFP_KERNEL);
if (f == NULL)
return -ENOBUFS;
f->id = handle;
err = fw_change_attrs(tp, f, tb, tca, base);
if (err < 0)
goto errout;
f->next = head->ht[fw_hash(handle)];
tcf_tree_lock(tp);
head->ht[fw_hash(handle)] = f;
tcf_tree_unlock(tp);
*arg = (unsigned long)f;
return 0;
errout:
kfree(f);
return err;
}
static void fw_walk(struct tcf_proto *tp, struct tcf_walker *arg)
{
struct fw_head *head = (struct fw_head*)tp->root;
int h;
if (head == NULL)
arg->stop = 1;
if (arg->stop)
return;
for (h = 0; h < HTSIZE; h++) {
struct fw_filter *f;
for (f = head->ht[h]; f; f = f->next) {
if (arg->count < arg->skip) {
arg->count++;
continue;
}
if (arg->fn(tp, (unsigned long)f, arg) < 0) {
arg->stop = 1;
return;
}
arg->count++;
}
}
}
static int fw_dump(struct tcf_proto *tp, unsigned long fh,
struct sk_buff *skb, struct tcmsg *t)
{
struct fw_head *head = (struct fw_head *)tp->root;
struct fw_filter *f = (struct fw_filter*)fh;
unsigned char *b = skb->tail;
struct rtattr *rta;
if (f == NULL)
return skb->len;
t->tcm_handle = f->id;
if (!f->res.classid && !tcf_exts_is_available(&f->exts))
return skb->len;
rta = (struct rtattr*)b;
RTA_PUT(skb, TCA_OPTIONS, 0, NULL);
if (f->res.classid)
RTA_PUT(skb, TCA_FW_CLASSID, 4, &f->res.classid);
#ifdef CONFIG_NET_CLS_IND
if (strlen(f->indev))
RTA_PUT(skb, TCA_FW_INDEV, IFNAMSIZ, f->indev);
#endif /* CONFIG_NET_CLS_IND */
if (head->mask != 0xFFFFFFFF)
RTA_PUT(skb, TCA_FW_MASK, 4, &head->mask);
if (tcf_exts_dump(skb, &f->exts, &fw_ext_map) < 0)
goto rtattr_failure;
rta->rta_len = skb->tail - b;
if (tcf_exts_dump_stats(skb, &f->exts, &fw_ext_map) < 0)
goto rtattr_failure;
return skb->len;
rtattr_failure:
skb_trim(skb, b - skb->data);
return -1;
}
static struct tcf_proto_ops cls_fw_ops = {
.next = NULL,
.kind = "fw",
.classify = fw_classify,
.init = fw_init,
.destroy = fw_destroy,
.get = fw_get,
.put = fw_put,
.change = fw_change,
.delete = fw_delete,
.walk = fw_walk,
.dump = fw_dump,
.owner = THIS_MODULE,
};
static int __init init_fw(void)
{
return register_tcf_proto_ops(&cls_fw_ops);
}
static void __exit exit_fw(void)
{
unregister_tcf_proto_ops(&cls_fw_ops);
}
module_init(init_fw)
module_exit(exit_fw)
MODULE_LICENSE("GPL");
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