kernel-ark/crypto/cryptomgr.c
Herbert Xu 1605b8471d [CRYPTO] cryptomgr: Fix use after free
By the time kthread_run returns the param may have already been freed
so writing the returned thread_struct pointer to param is wrong.

In fact, we don't need it in param anyway so this patch simply puts it
on the stack.

Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2007-05-09 13:04:39 +10:00

177 lines
3.6 KiB
C

/*
* Create default crypto algorithm instances.
*
* Copyright (c) 2006 Herbert Xu <herbert@gondor.apana.org.au>
*
* 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.
*
*/
#include <linux/crypto.h>
#include <linux/ctype.h>
#include <linux/err.h>
#include <linux/init.h>
#include <linux/kthread.h>
#include <linux/module.h>
#include <linux/notifier.h>
#include <linux/rtnetlink.h>
#include <linux/sched.h>
#include <linux/string.h>
#include "internal.h"
struct cryptomgr_param {
struct rtattr *tb[CRYPTOA_MAX];
struct {
struct rtattr attr;
struct crypto_attr_type data;
} type;
struct {
struct rtattr attr;
struct crypto_attr_alg data;
} alg;
struct {
char name[CRYPTO_MAX_ALG_NAME];
} larval;
char template[CRYPTO_MAX_ALG_NAME];
};
static int cryptomgr_probe(void *data)
{
struct cryptomgr_param *param = data;
struct crypto_template *tmpl;
struct crypto_instance *inst;
int err;
tmpl = crypto_lookup_template(param->template);
if (!tmpl)
goto err;
do {
inst = tmpl->alloc(param->tb);
if (IS_ERR(inst))
err = PTR_ERR(inst);
else if ((err = crypto_register_instance(tmpl, inst)))
tmpl->free(inst);
} while (err == -EAGAIN && !signal_pending(current));
crypto_tmpl_put(tmpl);
if (err)
goto err;
out:
kfree(param);
module_put_and_exit(0);
err:
crypto_larval_error(param->larval.name, param->type.data.type,
param->type.data.mask);
goto out;
}
static int cryptomgr_schedule_probe(struct crypto_larval *larval)
{
struct task_struct *thread;
struct cryptomgr_param *param;
const char *name = larval->alg.cra_name;
const char *p;
unsigned int len;
if (!try_module_get(THIS_MODULE))
goto err;
param = kzalloc(sizeof(*param), GFP_KERNEL);
if (!param)
goto err_put_module;
for (p = name; isalnum(*p) || *p == '-' || *p == '_'; p++)
;
len = p - name;
if (!len || *p != '(')
goto err_free_param;
memcpy(param->template, name, len);
name = p + 1;
len = 0;
for (p = name; *p; p++) {
for (; isalnum(*p) || *p == '-' || *p == '_' || *p == '('; p++)
;
if (*p != ')')
goto err_free_param;
len = p - name;
}
if (!len || name[len + 1])
goto err_free_param;
param->type.attr.rta_len = sizeof(param->type);
param->type.attr.rta_type = CRYPTOA_TYPE;
param->type.data.type = larval->alg.cra_flags;
param->type.data.mask = larval->mask;
param->tb[CRYPTOA_TYPE - 1] = &param->type.attr;
param->alg.attr.rta_len = sizeof(param->alg);
param->alg.attr.rta_type = CRYPTOA_ALG;
memcpy(param->alg.data.name, name, len);
param->tb[CRYPTOA_ALG - 1] = &param->alg.attr;
memcpy(param->larval.name, larval->alg.cra_name, CRYPTO_MAX_ALG_NAME);
thread = kthread_run(cryptomgr_probe, param, "cryptomgr");
if (IS_ERR(thread))
goto err_free_param;
return NOTIFY_STOP;
err_free_param:
kfree(param);
err_put_module:
module_put(THIS_MODULE);
err:
return NOTIFY_OK;
}
static int cryptomgr_notify(struct notifier_block *this, unsigned long msg,
void *data)
{
switch (msg) {
case CRYPTO_MSG_ALG_REQUEST:
return cryptomgr_schedule_probe(data);
}
return NOTIFY_DONE;
}
static struct notifier_block cryptomgr_notifier = {
.notifier_call = cryptomgr_notify,
};
static int __init cryptomgr_init(void)
{
return crypto_register_notifier(&cryptomgr_notifier);
}
static void __exit cryptomgr_exit(void)
{
int err = crypto_unregister_notifier(&cryptomgr_notifier);
BUG_ON(err);
}
module_init(cryptomgr_init);
module_exit(cryptomgr_exit);
MODULE_LICENSE("GPL");
MODULE_DESCRIPTION("Crypto Algorithm Manager");