c0ef44cbed
commit 77251e41f89a813b4090f5199442f217bbf11297 upstream.
When a crypto template needs to be instantiated, CRYPTO_MSG_ALG_REQUEST
is sent to crypto_chain. cryptomgr_schedule_probe() handles this by
starting a thread to instantiate the template, then waiting for this
thread to complete via crypto_larval::completion.
This can deadlock because instantiating the template may require loading
modules, and this (apparently depending on userspace) may need to wait
for the crc-t10dif module (lib/crc-t10dif.c) to be loaded. But
crc-t10dif's module_init function uses crypto_register_notifier() and
therefore takes crypto_chain.rwsem for write. That can't proceed until
the notifier callback has finished, as it holds this semaphore for read.
Fix this by removing the wait on crypto_larval::completion from within
cryptomgr_schedule_probe(). It's actually unnecessary because
crypto_alg_mod_lookup() calls crypto_larval_wait() itself after sending
CRYPTO_MSG_ALG_REQUEST.
This only actually became a problem in v4.20 due to commit b76377543b73
("crc-t10dif: Pick better transform if one becomes available"), but the
unnecessary wait was much older.
BugLink: https://bugzilla.kernel.org/show_bug.cgi?id=207159
Reported-by: Mike Gerow <gerow@google.com>
Fixes: 398710379f
("crypto: algapi - Move larval completion into algboss")
Cc: <stable@vger.kernel.org> # v3.6+
Cc: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Eric Biggers <ebiggers@google.com>
Reported-by: Kai Lüke <kai@kinvolk.io>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
299 lines
6 KiB
C
299 lines
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 <crypto/internal/aead.h>
|
|
#include <linux/completion.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/signal.h>
|
|
#include <linux/slab.h>
|
|
#include <linux/string.h>
|
|
|
|
#include "internal.h"
|
|
|
|
struct cryptomgr_param {
|
|
struct rtattr *tb[CRYPTO_MAX_ATTRS + 2];
|
|
|
|
struct {
|
|
struct rtattr attr;
|
|
struct crypto_attr_type data;
|
|
} type;
|
|
|
|
union {
|
|
struct rtattr attr;
|
|
struct {
|
|
struct rtattr attr;
|
|
struct crypto_attr_alg data;
|
|
} alg;
|
|
struct {
|
|
struct rtattr attr;
|
|
struct crypto_attr_u32 data;
|
|
} nu32;
|
|
} attrs[CRYPTO_MAX_ATTRS];
|
|
|
|
char template[CRYPTO_MAX_ALG_NAME];
|
|
|
|
struct crypto_larval *larval;
|
|
|
|
u32 otype;
|
|
u32 omask;
|
|
};
|
|
|
|
struct crypto_test_param {
|
|
char driver[CRYPTO_MAX_ALG_NAME];
|
|
char alg[CRYPTO_MAX_ALG_NAME];
|
|
u32 type;
|
|
};
|
|
|
|
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 out;
|
|
|
|
do {
|
|
if (tmpl->create) {
|
|
err = tmpl->create(tmpl, param->tb);
|
|
continue;
|
|
}
|
|
|
|
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);
|
|
|
|
out:
|
|
complete_all(¶m->larval->completion);
|
|
crypto_alg_put(¶m->larval->alg);
|
|
kfree(param);
|
|
module_put_and_exit(0);
|
|
}
|
|
|
|
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;
|
|
int i;
|
|
|
|
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);
|
|
|
|
i = 0;
|
|
for (;;) {
|
|
int notnum = 0;
|
|
|
|
name = ++p;
|
|
|
|
for (; isalnum(*p) || *p == '-' || *p == '_'; p++)
|
|
notnum |= !isdigit(*p);
|
|
|
|
if (*p == '(') {
|
|
int recursion = 0;
|
|
|
|
for (;;) {
|
|
if (!*++p)
|
|
goto err_free_param;
|
|
if (*p == '(')
|
|
recursion++;
|
|
else if (*p == ')' && !recursion--)
|
|
break;
|
|
}
|
|
|
|
notnum = 1;
|
|
p++;
|
|
}
|
|
|
|
len = p - name;
|
|
if (!len)
|
|
goto err_free_param;
|
|
|
|
if (notnum) {
|
|
param->attrs[i].alg.attr.rta_len =
|
|
sizeof(param->attrs[i].alg);
|
|
param->attrs[i].alg.attr.rta_type = CRYPTOA_ALG;
|
|
memcpy(param->attrs[i].alg.data.name, name, len);
|
|
} else {
|
|
param->attrs[i].nu32.attr.rta_len =
|
|
sizeof(param->attrs[i].nu32);
|
|
param->attrs[i].nu32.attr.rta_type = CRYPTOA_U32;
|
|
param->attrs[i].nu32.data.num =
|
|
simple_strtol(name, NULL, 0);
|
|
}
|
|
|
|
param->tb[i + 1] = ¶m->attrs[i].attr;
|
|
i++;
|
|
|
|
if (i >= CRYPTO_MAX_ATTRS)
|
|
goto err_free_param;
|
|
|
|
if (*p == ')')
|
|
break;
|
|
|
|
if (*p != ',')
|
|
goto err_free_param;
|
|
}
|
|
|
|
if (!i)
|
|
goto err_free_param;
|
|
|
|
param->tb[i + 1] = NULL;
|
|
|
|
param->type.attr.rta_len = sizeof(param->type);
|
|
param->type.attr.rta_type = CRYPTOA_TYPE;
|
|
param->type.data.type = larval->alg.cra_flags & ~CRYPTO_ALG_TESTED;
|
|
param->type.data.mask = larval->mask & ~CRYPTO_ALG_TESTED;
|
|
param->tb[0] = ¶m->type.attr;
|
|
|
|
param->otype = larval->alg.cra_flags;
|
|
param->omask = larval->mask;
|
|
|
|
crypto_alg_get(&larval->alg);
|
|
param->larval = larval;
|
|
|
|
thread = kthread_run(cryptomgr_probe, param, "cryptomgr_probe");
|
|
if (IS_ERR(thread))
|
|
goto err_put_larval;
|
|
|
|
return NOTIFY_STOP;
|
|
|
|
err_put_larval:
|
|
crypto_alg_put(&larval->alg);
|
|
err_free_param:
|
|
kfree(param);
|
|
err_put_module:
|
|
module_put(THIS_MODULE);
|
|
err:
|
|
return NOTIFY_OK;
|
|
}
|
|
|
|
static int cryptomgr_test(void *data)
|
|
{
|
|
struct crypto_test_param *param = data;
|
|
u32 type = param->type;
|
|
int err = 0;
|
|
|
|
#ifdef CONFIG_CRYPTO_MANAGER_DISABLE_TESTS
|
|
goto skiptest;
|
|
#endif
|
|
|
|
if (type & CRYPTO_ALG_TESTED)
|
|
goto skiptest;
|
|
|
|
err = alg_test(param->driver, param->alg, type, CRYPTO_ALG_TESTED);
|
|
|
|
skiptest:
|
|
crypto_alg_tested(param->driver, err);
|
|
|
|
kfree(param);
|
|
module_put_and_exit(0);
|
|
}
|
|
|
|
static int cryptomgr_schedule_test(struct crypto_alg *alg)
|
|
{
|
|
struct task_struct *thread;
|
|
struct crypto_test_param *param;
|
|
u32 type;
|
|
|
|
if (!try_module_get(THIS_MODULE))
|
|
goto err;
|
|
|
|
param = kzalloc(sizeof(*param), GFP_KERNEL);
|
|
if (!param)
|
|
goto err_put_module;
|
|
|
|
memcpy(param->driver, alg->cra_driver_name, sizeof(param->driver));
|
|
memcpy(param->alg, alg->cra_name, sizeof(param->alg));
|
|
type = alg->cra_flags;
|
|
|
|
/* Do not test internal algorithms. */
|
|
if (type & CRYPTO_ALG_INTERNAL)
|
|
type |= CRYPTO_ALG_TESTED;
|
|
|
|
param->type = type;
|
|
|
|
thread = kthread_run(cryptomgr_test, param, "cryptomgr_test");
|
|
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);
|
|
case CRYPTO_MSG_ALG_REGISTER:
|
|
return cryptomgr_schedule_test(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);
|
|
}
|
|
|
|
subsys_initcall(cryptomgr_init);
|
|
module_exit(cryptomgr_exit);
|
|
|
|
MODULE_LICENSE("GPL");
|
|
MODULE_DESCRIPTION("Crypto Algorithm Manager");
|