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3b96766f0e
linux/net/mac80211/debugfs_key.c
Johannes Berg 3b96766f0e mac80211: fix key vs. sta locking problems 
Up to now, key manipulation is supposed to run under RTNL to
avoid concurrent manipulations and also allow the set_key()
hardware callback to sleep. This is not feasible because STA
structs are rcu-protected and thus a lot of operations there
cannot take the RTNL. Also, key references are rcu-protected
so we cannot do things atomically.

This patch changes key locking completely:
 * key operations are now atomic
 * hardware crypto offload is enabled and disabled from
   a workqueue, due to that key freeing is also delayed
 * debugfs code is also run from a workqueue
 * keys reference STAs (and vice versa!) so during STA
   unlink the STAs key reference is removed but not the
   keys STA reference, to avoid races key todo work is
   run before STA destruction.
 * fewer STA operations now need the RTNL which was
   required due to key operations

This fixes the locking problems lockdep pointed out and also
makes things more light-weight because the rtnl isn't required
as much.

Note that the key todo lock/key mutex are global locks, this
is not required, of course, they could be per-hardware instead.

Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
2008-04-08 16:44:45 -04:00

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/*
* Copyright 2003-2005 Devicescape Software, Inc.
* Copyright (c) 2006 Jiri Benc <jbenc@suse.cz>
* Copyright 2007 Johannes Berg <johannes@sipsolutions.net>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*/
#include <linux/kobject.h>
#include "ieee80211_i.h"
#include "ieee80211_key.h"
#include "debugfs.h"
#include "debugfs_key.h"
#define KEY_READ(name, prop, buflen, format_string) \
static ssize_t key_##name##_read(struct file *file, \
char __user *userbuf, \
size_t count, loff_t *ppos) \
{ \
char buf[buflen]; \
struct ieee80211_key *key = file->private_data; \
int res = scnprintf(buf, buflen, format_string, key->prop); \
return simple_read_from_buffer(userbuf, count, ppos, buf, res); \
}
#define KEY_READ_D(name) KEY_READ(name, name, 20, "%d\n")
#define KEY_READ_X(name) KEY_READ(name, name, 20, "0x%x\n")
#define KEY_OPS(name) \
static const struct file_operations key_ ##name## _ops = { \
.read = key_##name##_read, \
.open = mac80211_open_file_generic, \
}
#define KEY_FILE(name, format) \
KEY_READ_##format(name) \
KEY_OPS(name)
#define KEY_CONF_READ(name, buflen, format_string) \
KEY_READ(conf_##name, conf.name, buflen, format_string)
#define KEY_CONF_READ_D(name) KEY_CONF_READ(name, 20, "%d\n")
#define KEY_CONF_OPS(name) \
static const struct file_operations key_ ##name## _ops = { \
.read = key_conf_##name##_read, \
.open = mac80211_open_file_generic, \
}
#define KEY_CONF_FILE(name, format) \
KEY_CONF_READ_##format(name) \
KEY_CONF_OPS(name)
KEY_CONF_FILE(keylen, D);
KEY_CONF_FILE(keyidx, D);
KEY_CONF_FILE(hw_key_idx, D);
KEY_FILE(flags, X);
KEY_FILE(tx_rx_count, D);
KEY_READ(ifindex, sdata->dev->ifindex, 20, "%d\n");
KEY_OPS(ifindex);
static ssize_t key_algorithm_read(struct file *file,
char __user *userbuf,
size_t count, loff_t *ppos)
{
char *alg;
struct ieee80211_key *key = file->private_data;
switch (key->conf.alg) {
case ALG_WEP:
alg = "WEP\n";
break;
case ALG_TKIP:
alg = "TKIP\n";
break;
case ALG_CCMP:
alg = "CCMP\n";
break;
default:
return 0;
}
return simple_read_from_buffer(userbuf, count, ppos, alg, strlen(alg));
}
KEY_OPS(algorithm);
static ssize_t key_tx_spec_read(struct file *file, char __user *userbuf,
size_t count, loff_t *ppos)
{
const u8 *tpn;
char buf[20];
int len;
struct ieee80211_key *key = file->private_data;
switch (key->conf.alg) {
case ALG_WEP:
len = scnprintf(buf, sizeof(buf), "\n");
break;
case ALG_TKIP:
len = scnprintf(buf, sizeof(buf), "%08x %04x\n",
key->u.tkip.iv32,
key->u.tkip.iv16);
break;
case ALG_CCMP:
tpn = key->u.ccmp.tx_pn;
len = scnprintf(buf, sizeof(buf), "%02x%02x%02x%02x%02x%02x\n",
tpn[0], tpn[1], tpn[2], tpn[3], tpn[4], tpn[5]);
break;
default:
return 0;
}
return simple_read_from_buffer(userbuf, count, ppos, buf, len);
}
KEY_OPS(tx_spec);
static ssize_t key_rx_spec_read(struct file *file, char __user *userbuf,
size_t count, loff_t *ppos)
{
struct ieee80211_key *key = file->private_data;
char buf[14*NUM_RX_DATA_QUEUES+1], *p = buf;
int i, len;
const u8 *rpn;
switch (key->conf.alg) {
case ALG_WEP:
len = scnprintf(buf, sizeof(buf), "\n");
break;
case ALG_TKIP:
for (i = 0; i < NUM_RX_DATA_QUEUES; i++)
p += scnprintf(p, sizeof(buf)+buf-p,
"%08x %04x\n",
key->u.tkip.iv32_rx[i],
key->u.tkip.iv16_rx[i]);
len = p - buf;
break;
case ALG_CCMP:
for (i = 0; i < NUM_RX_DATA_QUEUES; i++) {
rpn = key->u.ccmp.rx_pn[i];
p += scnprintf(p, sizeof(buf)+buf-p,
"%02x%02x%02x%02x%02x%02x\n",
rpn[0], rpn[1], rpn[2],
rpn[3], rpn[4], rpn[5]);
}
len = p - buf;
break;
default:
return 0;
}
return simple_read_from_buffer(userbuf, count, ppos, buf, len);
}
KEY_OPS(rx_spec);
static ssize_t key_replays_read(struct file *file, char __user *userbuf,
size_t count, loff_t *ppos)
{
struct ieee80211_key *key = file->private_data;
char buf[20];
int len;
if (key->conf.alg != ALG_CCMP)
return 0;
len = scnprintf(buf, sizeof(buf), "%u\n", key->u.ccmp.replays);
return simple_read_from_buffer(userbuf, count, ppos, buf, len);
}
KEY_OPS(replays);
static ssize_t key_key_read(struct file *file, char __user *userbuf,
size_t count, loff_t *ppos)
{
struct ieee80211_key *key = file->private_data;
int i, res, bufsize = 2 * key->conf.keylen + 2;
char *buf = kmalloc(bufsize, GFP_KERNEL);
char *p = buf;
for (i = 0; i < key->conf.keylen; i++)
p += scnprintf(p, bufsize + buf - p, "%02x", key->conf.key[i]);
p += scnprintf(p, bufsize+buf-p, "\n");
res = simple_read_from_buffer(userbuf, count, ppos, buf, p - buf);
kfree(buf);
return res;
}
KEY_OPS(key);
#define DEBUGFS_ADD(name) \
key->debugfs.name = debugfs_create_file(#name, 0400,\
key->debugfs.dir, key, &key_##name##_ops);
void ieee80211_debugfs_key_add(struct ieee80211_key *key)
{
static int keycount;
char buf[50];
DECLARE_MAC_BUF(mac);
struct sta_info *sta;
if (!key->local->debugfs.keys)
return;
sprintf(buf, "%d", keycount);
keycount++;
key->debugfs.dir = debugfs_create_dir(buf,
key->local->debugfs.keys);
if (!key->debugfs.dir)
return;
rcu_read_lock();
sta = rcu_dereference(key->sta);
if (sta)
sprintf(buf, "../../stations/%s", print_mac(mac, sta->addr));
rcu_read_unlock();
/* using sta as a boolean is fine outside RCU lock */
if (sta)
key->debugfs.stalink =
debugfs_create_symlink("station", key->debugfs.dir, buf);
DEBUGFS_ADD(keylen);
DEBUGFS_ADD(flags);
DEBUGFS_ADD(keyidx);
DEBUGFS_ADD(hw_key_idx);
DEBUGFS_ADD(tx_rx_count);
DEBUGFS_ADD(algorithm);
DEBUGFS_ADD(tx_spec);
DEBUGFS_ADD(rx_spec);
DEBUGFS_ADD(replays);
DEBUGFS_ADD(key);
DEBUGFS_ADD(ifindex);
};
#define DEBUGFS_DEL(name) \
debugfs_remove(key->debugfs.name); key->debugfs.name = NULL;
void ieee80211_debugfs_key_remove(struct ieee80211_key *key)
{
if (!key)
return;
DEBUGFS_DEL(keylen);
DEBUGFS_DEL(flags);
DEBUGFS_DEL(keyidx);
DEBUGFS_DEL(hw_key_idx);
DEBUGFS_DEL(tx_rx_count);
DEBUGFS_DEL(algorithm);
DEBUGFS_DEL(tx_spec);
DEBUGFS_DEL(rx_spec);
DEBUGFS_DEL(replays);
DEBUGFS_DEL(key);
DEBUGFS_DEL(ifindex);
debugfs_remove(key->debugfs.stalink);
key->debugfs.stalink = NULL;
debugfs_remove(key->debugfs.dir);
key->debugfs.dir = NULL;
}
void ieee80211_debugfs_key_add_default(struct ieee80211_sub_if_data *sdata)
{
char buf[50];
if (!sdata->debugfsdir)
return;
sprintf(buf, "../keys/%d", sdata->default_key->conf.keyidx);
sdata->debugfs.default_key =
debugfs_create_symlink("default_key", sdata->debugfsdir, buf);
}
void ieee80211_debugfs_key_remove_default(struct ieee80211_sub_if_data *sdata)
{
if (!sdata)
return;
debugfs_remove(sdata->debugfs.default_key);
sdata->debugfs.default_key = NULL;
}
void ieee80211_debugfs_key_sta_del(struct ieee80211_key *key,
struct sta_info *sta)
{
debugfs_remove(key->debugfs.stalink);
key->debugfs.stalink = NULL;
}
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