linux/net/sched/act_pedit.c
Cong Wang 981471bd3a net_sched: fix a NULL pointer deref in ipt action
The net pointer in struct xt_tgdtor_param is not explicitly
initialized therefore is still NULL when dereferencing it.
So we have to find a way to pass the correct net pointer to
ipt_destroy_target().

The best way I find is just saving the net pointer inside the per
netns struct tcf_idrinfo, which could make this patch smaller.

Fixes: 0c66dc1ea3 ("netfilter: conntrack: register hooks in netns when needed by ruleset")
Reported-and-tested-by: itugrok@yahoo.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>
2019-08-27 15:05:58 -07:00

532 lines
12 KiB
C

// SPDX-License-Identifier: GPL-2.0-or-later
/*
* net/sched/act_pedit.c Generic packet editor
*
* Authors: Jamal Hadi Salim (2002-4)
*/
#include <linux/types.h>
#include <linux/kernel.h>
#include <linux/string.h>
#include <linux/errno.h>
#include <linux/skbuff.h>
#include <linux/rtnetlink.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/slab.h>
#include <net/netlink.h>
#include <net/pkt_sched.h>
#include <linux/tc_act/tc_pedit.h>
#include <net/tc_act/tc_pedit.h>
#include <uapi/linux/tc_act/tc_pedit.h>
#include <net/pkt_cls.h>
static unsigned int pedit_net_id;
static struct tc_action_ops act_pedit_ops;
static const struct nla_policy pedit_policy[TCA_PEDIT_MAX + 1] = {
[TCA_PEDIT_PARMS] = { .len = sizeof(struct tc_pedit) },
[TCA_PEDIT_KEYS_EX] = { .type = NLA_NESTED },
};
static const struct nla_policy pedit_key_ex_policy[TCA_PEDIT_KEY_EX_MAX + 1] = {
[TCA_PEDIT_KEY_EX_HTYPE] = { .type = NLA_U16 },
[TCA_PEDIT_KEY_EX_CMD] = { .type = NLA_U16 },
};
static struct tcf_pedit_key_ex *tcf_pedit_keys_ex_parse(struct nlattr *nla,
u8 n)
{
struct tcf_pedit_key_ex *keys_ex;
struct tcf_pedit_key_ex *k;
const struct nlattr *ka;
int err = -EINVAL;
int rem;
if (!nla || !n)
return NULL;
keys_ex = kcalloc(n, sizeof(*k), GFP_KERNEL);
if (!keys_ex)
return ERR_PTR(-ENOMEM);
k = keys_ex;
nla_for_each_nested(ka, nla, rem) {
struct nlattr *tb[TCA_PEDIT_KEY_EX_MAX + 1];
if (!n) {
err = -EINVAL;
goto err_out;
}
n--;
if (nla_type(ka) != TCA_PEDIT_KEY_EX) {
err = -EINVAL;
goto err_out;
}
err = nla_parse_nested_deprecated(tb, TCA_PEDIT_KEY_EX_MAX,
ka, pedit_key_ex_policy,
NULL);
if (err)
goto err_out;
if (!tb[TCA_PEDIT_KEY_EX_HTYPE] ||
!tb[TCA_PEDIT_KEY_EX_CMD]) {
err = -EINVAL;
goto err_out;
}
k->htype = nla_get_u16(tb[TCA_PEDIT_KEY_EX_HTYPE]);
k->cmd = nla_get_u16(tb[TCA_PEDIT_KEY_EX_CMD]);
if (k->htype > TCA_PEDIT_HDR_TYPE_MAX ||
k->cmd > TCA_PEDIT_CMD_MAX) {
err = -EINVAL;
goto err_out;
}
k++;
}
if (n) {
err = -EINVAL;
goto err_out;
}
return keys_ex;
err_out:
kfree(keys_ex);
return ERR_PTR(err);
}
static int tcf_pedit_key_ex_dump(struct sk_buff *skb,
struct tcf_pedit_key_ex *keys_ex, int n)
{
struct nlattr *keys_start = nla_nest_start_noflag(skb,
TCA_PEDIT_KEYS_EX);
if (!keys_start)
goto nla_failure;
for (; n > 0; n--) {
struct nlattr *key_start;
key_start = nla_nest_start_noflag(skb, TCA_PEDIT_KEY_EX);
if (!key_start)
goto nla_failure;
if (nla_put_u16(skb, TCA_PEDIT_KEY_EX_HTYPE, keys_ex->htype) ||
nla_put_u16(skb, TCA_PEDIT_KEY_EX_CMD, keys_ex->cmd))
goto nla_failure;
nla_nest_end(skb, key_start);
keys_ex++;
}
nla_nest_end(skb, keys_start);
return 0;
nla_failure:
nla_nest_cancel(skb, keys_start);
return -EINVAL;
}
static int tcf_pedit_init(struct net *net, struct nlattr *nla,
struct nlattr *est, struct tc_action **a,
int ovr, int bind, bool rtnl_held,
struct tcf_proto *tp, struct netlink_ext_ack *extack)
{
struct tc_action_net *tn = net_generic(net, pedit_net_id);
struct nlattr *tb[TCA_PEDIT_MAX + 1];
struct tcf_chain *goto_ch = NULL;
struct tc_pedit_key *keys = NULL;
struct tcf_pedit_key_ex *keys_ex;
struct tc_pedit *parm;
struct nlattr *pattr;
struct tcf_pedit *p;
int ret = 0, err;
int ksize;
u32 index;
if (!nla) {
NL_SET_ERR_MSG_MOD(extack, "Pedit requires attributes to be passed");
return -EINVAL;
}
err = nla_parse_nested_deprecated(tb, TCA_PEDIT_MAX, nla,
pedit_policy, NULL);
if (err < 0)
return err;
pattr = tb[TCA_PEDIT_PARMS];
if (!pattr)
pattr = tb[TCA_PEDIT_PARMS_EX];
if (!pattr) {
NL_SET_ERR_MSG_MOD(extack, "Missing required TCA_PEDIT_PARMS or TCA_PEDIT_PARMS_EX pedit attribute");
return -EINVAL;
}
parm = nla_data(pattr);
ksize = parm->nkeys * sizeof(struct tc_pedit_key);
if (nla_len(pattr) < sizeof(*parm) + ksize) {
NL_SET_ERR_MSG_ATTR(extack, pattr, "Length of TCA_PEDIT_PARMS or TCA_PEDIT_PARMS_EX pedit attribute is invalid");
return -EINVAL;
}
keys_ex = tcf_pedit_keys_ex_parse(tb[TCA_PEDIT_KEYS_EX], parm->nkeys);
if (IS_ERR(keys_ex))
return PTR_ERR(keys_ex);
index = parm->index;
err = tcf_idr_check_alloc(tn, &index, a, bind);
if (!err) {
if (!parm->nkeys) {
tcf_idr_cleanup(tn, index);
NL_SET_ERR_MSG_MOD(extack, "Pedit requires keys to be passed");
ret = -EINVAL;
goto out_free;
}
ret = tcf_idr_create(tn, index, est, a,
&act_pedit_ops, bind, false);
if (ret) {
tcf_idr_cleanup(tn, index);
goto out_free;
}
ret = ACT_P_CREATED;
} else if (err > 0) {
if (bind)
goto out_free;
if (!ovr) {
ret = -EEXIST;
goto out_release;
}
} else {
ret = err;
goto out_free;
}
err = tcf_action_check_ctrlact(parm->action, tp, &goto_ch, extack);
if (err < 0) {
ret = err;
goto out_release;
}
p = to_pedit(*a);
spin_lock_bh(&p->tcf_lock);
if (ret == ACT_P_CREATED ||
(p->tcfp_nkeys && p->tcfp_nkeys != parm->nkeys)) {
keys = kmalloc(ksize, GFP_ATOMIC);
if (!keys) {
spin_unlock_bh(&p->tcf_lock);
ret = -ENOMEM;
goto put_chain;
}
kfree(p->tcfp_keys);
p->tcfp_keys = keys;
p->tcfp_nkeys = parm->nkeys;
}
memcpy(p->tcfp_keys, parm->keys, ksize);
p->tcfp_flags = parm->flags;
goto_ch = tcf_action_set_ctrlact(*a, parm->action, goto_ch);
kfree(p->tcfp_keys_ex);
p->tcfp_keys_ex = keys_ex;
spin_unlock_bh(&p->tcf_lock);
if (goto_ch)
tcf_chain_put_by_act(goto_ch);
if (ret == ACT_P_CREATED)
tcf_idr_insert(tn, *a);
return ret;
put_chain:
if (goto_ch)
tcf_chain_put_by_act(goto_ch);
out_release:
tcf_idr_release(*a, bind);
out_free:
kfree(keys_ex);
return ret;
}
static void tcf_pedit_cleanup(struct tc_action *a)
{
struct tcf_pedit *p = to_pedit(a);
struct tc_pedit_key *keys = p->tcfp_keys;
kfree(keys);
kfree(p->tcfp_keys_ex);
}
static bool offset_valid(struct sk_buff *skb, int offset)
{
if (offset > 0 && offset > skb->len)
return false;
if (offset < 0 && -offset > skb_headroom(skb))
return false;
return true;
}
static int pedit_skb_hdr_offset(struct sk_buff *skb,
enum pedit_header_type htype, int *hoffset)
{
int ret = -EINVAL;
switch (htype) {
case TCA_PEDIT_KEY_EX_HDR_TYPE_ETH:
if (skb_mac_header_was_set(skb)) {
*hoffset = skb_mac_offset(skb);
ret = 0;
}
break;
case TCA_PEDIT_KEY_EX_HDR_TYPE_NETWORK:
case TCA_PEDIT_KEY_EX_HDR_TYPE_IP4:
case TCA_PEDIT_KEY_EX_HDR_TYPE_IP6:
*hoffset = skb_network_offset(skb);
ret = 0;
break;
case TCA_PEDIT_KEY_EX_HDR_TYPE_TCP:
case TCA_PEDIT_KEY_EX_HDR_TYPE_UDP:
if (skb_transport_header_was_set(skb)) {
*hoffset = skb_transport_offset(skb);
ret = 0;
}
break;
default:
ret = -EINVAL;
break;
}
return ret;
}
static int tcf_pedit_act(struct sk_buff *skb, const struct tc_action *a,
struct tcf_result *res)
{
struct tcf_pedit *p = to_pedit(a);
int i;
if (skb_unclone(skb, GFP_ATOMIC))
return p->tcf_action;
spin_lock(&p->tcf_lock);
tcf_lastuse_update(&p->tcf_tm);
if (p->tcfp_nkeys > 0) {
struct tc_pedit_key *tkey = p->tcfp_keys;
struct tcf_pedit_key_ex *tkey_ex = p->tcfp_keys_ex;
enum pedit_header_type htype =
TCA_PEDIT_KEY_EX_HDR_TYPE_NETWORK;
enum pedit_cmd cmd = TCA_PEDIT_KEY_EX_CMD_SET;
for (i = p->tcfp_nkeys; i > 0; i--, tkey++) {
u32 *ptr, hdata;
int offset = tkey->off;
int hoffset;
u32 val;
int rc;
if (tkey_ex) {
htype = tkey_ex->htype;
cmd = tkey_ex->cmd;
tkey_ex++;
}
rc = pedit_skb_hdr_offset(skb, htype, &hoffset);
if (rc) {
pr_info("tc action pedit bad header type specified (0x%x)\n",
htype);
goto bad;
}
if (tkey->offmask) {
u8 *d, _d;
if (!offset_valid(skb, hoffset + tkey->at)) {
pr_info("tc action pedit 'at' offset %d out of bounds\n",
hoffset + tkey->at);
goto bad;
}
d = skb_header_pointer(skb, hoffset + tkey->at,
sizeof(_d), &_d);
if (!d)
goto bad;
offset += (*d & tkey->offmask) >> tkey->shift;
}
if (offset % 4) {
pr_info("tc action pedit offset must be on 32 bit boundaries\n");
goto bad;
}
if (!offset_valid(skb, hoffset + offset)) {
pr_info("tc action pedit offset %d out of bounds\n",
hoffset + offset);
goto bad;
}
ptr = skb_header_pointer(skb, hoffset + offset,
sizeof(hdata), &hdata);
if (!ptr)
goto bad;
/* just do it, baby */
switch (cmd) {
case TCA_PEDIT_KEY_EX_CMD_SET:
val = tkey->val;
break;
case TCA_PEDIT_KEY_EX_CMD_ADD:
val = (*ptr + tkey->val) & ~tkey->mask;
break;
default:
pr_info("tc action pedit bad command (%d)\n",
cmd);
goto bad;
}
*ptr = ((*ptr & tkey->mask) ^ val);
if (ptr == &hdata)
skb_store_bits(skb, hoffset + offset, ptr, 4);
}
goto done;
} else {
WARN(1, "pedit BUG: index %d\n", p->tcf_index);
}
bad:
p->tcf_qstats.overlimits++;
done:
bstats_update(&p->tcf_bstats, skb);
spin_unlock(&p->tcf_lock);
return p->tcf_action;
}
static int tcf_pedit_dump(struct sk_buff *skb, struct tc_action *a,
int bind, int ref)
{
unsigned char *b = skb_tail_pointer(skb);
struct tcf_pedit *p = to_pedit(a);
struct tc_pedit *opt;
struct tcf_t t;
int s;
s = struct_size(opt, keys, p->tcfp_nkeys);
/* netlink spinlocks held above us - must use ATOMIC */
opt = kzalloc(s, GFP_ATOMIC);
if (unlikely(!opt))
return -ENOBUFS;
spin_lock_bh(&p->tcf_lock);
memcpy(opt->keys, p->tcfp_keys,
p->tcfp_nkeys * sizeof(struct tc_pedit_key));
opt->index = p->tcf_index;
opt->nkeys = p->tcfp_nkeys;
opt->flags = p->tcfp_flags;
opt->action = p->tcf_action;
opt->refcnt = refcount_read(&p->tcf_refcnt) - ref;
opt->bindcnt = atomic_read(&p->tcf_bindcnt) - bind;
if (p->tcfp_keys_ex) {
if (tcf_pedit_key_ex_dump(skb,
p->tcfp_keys_ex,
p->tcfp_nkeys))
goto nla_put_failure;
if (nla_put(skb, TCA_PEDIT_PARMS_EX, s, opt))
goto nla_put_failure;
} else {
if (nla_put(skb, TCA_PEDIT_PARMS, s, opt))
goto nla_put_failure;
}
tcf_tm_dump(&t, &p->tcf_tm);
if (nla_put_64bit(skb, TCA_PEDIT_TM, sizeof(t), &t, TCA_PEDIT_PAD))
goto nla_put_failure;
spin_unlock_bh(&p->tcf_lock);
kfree(opt);
return skb->len;
nla_put_failure:
spin_unlock_bh(&p->tcf_lock);
nlmsg_trim(skb, b);
kfree(opt);
return -1;
}
static int tcf_pedit_walker(struct net *net, struct sk_buff *skb,
struct netlink_callback *cb, int type,
const struct tc_action_ops *ops,
struct netlink_ext_ack *extack)
{
struct tc_action_net *tn = net_generic(net, pedit_net_id);
return tcf_generic_walker(tn, skb, cb, type, ops, extack);
}
static int tcf_pedit_search(struct net *net, struct tc_action **a, u32 index)
{
struct tc_action_net *tn = net_generic(net, pedit_net_id);
return tcf_idr_search(tn, a, index);
}
static struct tc_action_ops act_pedit_ops = {
.kind = "pedit",
.id = TCA_ID_PEDIT,
.owner = THIS_MODULE,
.act = tcf_pedit_act,
.dump = tcf_pedit_dump,
.cleanup = tcf_pedit_cleanup,
.init = tcf_pedit_init,
.walk = tcf_pedit_walker,
.lookup = tcf_pedit_search,
.size = sizeof(struct tcf_pedit),
};
static __net_init int pedit_init_net(struct net *net)
{
struct tc_action_net *tn = net_generic(net, pedit_net_id);
return tc_action_net_init(net, tn, &act_pedit_ops);
}
static void __net_exit pedit_exit_net(struct list_head *net_list)
{
tc_action_net_exit(net_list, pedit_net_id);
}
static struct pernet_operations pedit_net_ops = {
.init = pedit_init_net,
.exit_batch = pedit_exit_net,
.id = &pedit_net_id,
.size = sizeof(struct tc_action_net),
};
MODULE_AUTHOR("Jamal Hadi Salim(2002-4)");
MODULE_DESCRIPTION("Generic Packet Editor actions");
MODULE_LICENSE("GPL");
static int __init pedit_init_module(void)
{
return tcf_register_action(&act_pedit_ops, &pedit_net_ops);
}
static void __exit pedit_cleanup_module(void)
{
tcf_unregister_action(&act_pedit_ops, &pedit_net_ops);
}
module_init(pedit_init_module);
module_exit(pedit_cleanup_module);