linux/net/sched/act_pedit.c
Davide Caratti 6ac86ca352 net/sched: act_pedit: validate the control action inside init()
the following script:

 # tc filter add dev crash0 egress matchall \
 > action pedit ex munge ip ttl set 10 pass index 90
 # tc actions replace action pedit \
 > ex munge ip ttl set 10 goto chain 42 index 90 cookie c1a0c1a0
 # tc actions show action pedit

had the following output:

 Error: Failed to init TC action chain.
 We have an error talking to the kernel
 total acts 1

         action order 0:  pedit action goto chain 42 keys 1
          index 90 ref 2 bind 1
          key #0  at ipv4+8: val 0a000000 mask 00ffffff
         cookie c1a0c1a0

Then, the first packet transmitted by crash0 made the kernel crash:

 BUG: unable to handle kernel NULL pointer dereference at 0000000000000000
 #PF error: [normal kernel read fault]
 PGD 0 P4D 0
 Oops: 0000 [#1] SMP PTI
 CPU: 2 PID: 0 Comm: swapper/2 Not tainted 5.0.0-rc4.gotochain_crash+ #533
 Hardware name: Red Hat KVM, BIOS 0.5.1 01/01/2011
 RIP: 0010:tcf_action_exec+0xb8/0x100
 Code: 00 00 00 20 74 1d 83 f8 03 75 09 49 83 c4 08 4d 39 ec 75 bc 48 83 c4 10 5b 5d 41 5c 41 5d 41 5e 41 5f c3 49 8b 97 a8 00 00 00 <48> 8b 12 48 89 55 00 48 83 c4 10 5b 5d 41 5c 41 5d 41 5e 41 5f c3
 RSP: 0018:ffff94a73db03be0 EFLAGS: 00010246
 RAX: 000000002000002a RBX: ffff94a6ee4c0700 RCX: 000000000000000a
 RDX: 0000000000000000 RSI: ffff94a6ed22c800 RDI: 0000000000000000
 RBP: ffff94a73db03c80 R08: ffff94a7386fa4c8 R09: ffff94a73229ea20
 R10: 0000000000000000 R11: 0000000000000000 R12: ffff94a6ed22cb00
 R13: ffff94a6ed22cb08 R14: 0000000000000001 R15: ffff94a6ed22c800
 FS:  0000000000000000(0000) GS:ffff94a73db00000(0000) knlGS:0000000000000000
 CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
 CR2: 0000000000000000 CR3: 000000007120e002 CR4: 00000000001606e0
 Call Trace:
  <IRQ>
  tcf_classify+0x58/0x120
  __dev_queue_xmit+0x40a/0x890
  ? ip6_finish_output2+0x369/0x590
  ip6_finish_output2+0x369/0x590
  ? ip6_output+0x68/0x110
  ip6_output+0x68/0x110
  ? nf_hook.constprop.35+0x79/0xc0
  mld_sendpack+0x16f/0x220
  mld_ifc_timer_expire+0x195/0x2c0
  ? igmp6_timer_handler+0x70/0x70
  call_timer_fn+0x2b/0x130
  run_timer_softirq+0x3e8/0x440
  ? tick_sched_timer+0x37/0x70
  __do_softirq+0xe3/0x2f5
  irq_exit+0xf0/0x100
  smp_apic_timer_interrupt+0x6c/0x130
  apic_timer_interrupt+0xf/0x20
  </IRQ>
 RIP: 0010:native_safe_halt+0x2/0x10
 Code: 4e ff ff ff 7f f3 c3 65 48 8b 04 25 00 5c 01 00 f0 80 48 02 20 48 8b 00 a8 08 74 8b eb c1 90 90 90 90 90 90 90 90 90 90 fb f4 <c3> 0f 1f 00 66 2e 0f 1f 84 00 00 00 00 00 f4 c3 90 90 90 90 90 90
 RSP: 0018:ffffab1740387eb8 EFLAGS: 00000246 ORIG_RAX: ffffffffffffff13
 RAX: ffffffffb18184f0 RBX: 0000000000000002 RCX: 0000000000000001
 RDX: 0000000000000001 RSI: 0000000000000087 RDI: 0000000000000002
 RBP: 0000000000000002 R08: 000f168fa695f9a9 R09: 0000000000000020
 R10: 0000000000000004 R11: 0000000000000000 R12: 0000000000000000
 R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
  ? __sched_text_end+0x1/0x1
  default_idle+0x1c/0x140
  do_idle+0x1c4/0x280
  cpu_startup_entry+0x19/0x20
  start_secondary+0x1a7/0x200
  secondary_startup_64+0xa4/0xb0
 Modules linked in: act_pedit veth ip6table_filter ip6_tables iptable_filter binfmt_misc ext4 mbcache jbd2 crct10dif_pclmul crc32_pclmul ghash_clmulni_intel snd_hda_codec_generic snd_hda_intel snd_hda_codec snd_hwdep aesni_intel snd_hda_core crypto_simd snd_seq cryptd glue_helper snd_seq_device snd_pcm joydev snd_timer pcspkr virtio_balloon snd soundcore i2c_piix4 nfsd auth_rpcgss nfs_acl lockd grace sunrpc ip_tables xfs qxl ata_generic pata_acpi drm_kms_helper virtio_net net_failover syscopyarea sysfillrect sysimgblt failover virtio_blk fb_sys_fops virtio_console ttm drm crc32c_intel serio_raw ata_piix virtio_pci libata virtio_ring virtio floppy dm_mirror dm_region_hash dm_log dm_mod
 CR2: 0000000000000000

Validating the control action within tcf_pedit_init() proved to fix the
above issue. A TDC selftest is added to verify the correct behavior.

Fixes: db50514f9a ("net: sched: add termination action to allow goto chain")
Fixes: 97763dc0f4 ("net_sched: reject unknown tcfa_action values")
Signed-off-by: Davide Caratti <dcaratti@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2019-03-21 13:26:41 -07:00

531 lines
12 KiB
C

/*
* net/sched/act_pedit.c Generic packet editor
*
* 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: 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(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(skb, TCA_PEDIT_KEYS_EX);
if (!keys_start)
goto nla_failure;
for (; n > 0; n--) {
struct nlattr *key_start;
key_start = nla_nest_start(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;
if (!nla) {
NL_SET_ERR_MSG_MOD(extack, "Pedit requires attributes to be passed");
return -EINVAL;
}
err = nla_parse_nested(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);
err = tcf_idr_check_alloc(tn, &parm->index, a, bind);
if (!err) {
if (!parm->nkeys) {
tcf_idr_cleanup(tn, parm->index);
NL_SET_ERR_MSG_MOD(extack, "Pedit requires keys to be passed");
ret = -EINVAL;
goto out_free;
}
ret = tcf_idr_create(tn, parm->index, est, a,
&act_pedit_ops, bind, false);
if (ret) {
tcf_idr_cleanup(tn, parm->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(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);