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linux/arch/s390/crypto/aes_s390.c
Herbert Xu a760a6656e crypto: api - Fix module load deadlock with fallback algorithms 
With the mandatory algorithm testing at registration, we have
now created a deadlock with algorithms requiring fallbacks.
This can happen if the module containing the algorithm requiring
fallback is loaded first, without the fallback module being loaded
first.  The system will then try to test the new algorithm, find
that it needs to load a fallback, and then try to load that.

As both algorithms share the same module alias, it can attempt
to load the original algorithm again and block indefinitely.

As algorithms requiring fallbacks are a special case, we can fix
this by giving them a different module alias than the rest.  Then
it's just a matter of using the right aliases according to what
algorithms we're trying to find.

Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2009-02-26 14:06:31 +08:00

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/*
* Cryptographic API.
*
* s390 implementation of the AES Cipher Algorithm.
*
* s390 Version:
* Copyright IBM Corp. 2005,2007
* Author(s): Jan Glauber (jang@de.ibm.com)
* Sebastian Siewior (sebastian@breakpoint.cc> SW-Fallback
*
* Derived from "crypto/aes_generic.c"
*
* 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.
*
*/
#define KMSG_COMPONENT "aes_s390"
#define pr_fmt(fmt) KMSG_COMPONENT ": " fmt
#include <crypto/aes.h>
#include <crypto/algapi.h>
#include <linux/err.h>
#include <linux/module.h>
#include <linux/init.h>
#include "crypt_s390.h"
#define AES_KEYLEN_128 1
#define AES_KEYLEN_192 2
#define AES_KEYLEN_256 4
static char keylen_flag = 0;
struct s390_aes_ctx {
u8 iv[AES_BLOCK_SIZE];
u8 key[AES_MAX_KEY_SIZE];
long enc;
long dec;
int key_len;
union {
struct crypto_blkcipher *blk;
struct crypto_cipher *cip;
} fallback;
};
/*
* Check if the key_len is supported by the HW.
* Returns 0 if it is, a positive number if it is not and software fallback is
* required or a negative number in case the key size is not valid
*/
static int need_fallback(unsigned int key_len)
{
switch (key_len) {
case 16:
if (!(keylen_flag & AES_KEYLEN_128))
return 1;
break;
case 24:
if (!(keylen_flag & AES_KEYLEN_192))
return 1;
break;
case 32:
if (!(keylen_flag & AES_KEYLEN_256))
return 1;
break;
default:
return -1;
break;
}
return 0;
}
static int setkey_fallback_cip(struct crypto_tfm *tfm, const u8 *in_key,
unsigned int key_len)
{
struct s390_aes_ctx *sctx = crypto_tfm_ctx(tfm);
int ret;
sctx->fallback.blk->base.crt_flags &= ~CRYPTO_TFM_REQ_MASK;
sctx->fallback.blk->base.crt_flags |= (tfm->crt_flags &
CRYPTO_TFM_REQ_MASK);
ret = crypto_cipher_setkey(sctx->fallback.cip, in_key, key_len);
if (ret) {
tfm->crt_flags &= ~CRYPTO_TFM_RES_MASK;
tfm->crt_flags |= (sctx->fallback.blk->base.crt_flags &
CRYPTO_TFM_RES_MASK);
}
return ret;
}
static int aes_set_key(struct crypto_tfm *tfm, const u8 *in_key,
unsigned int key_len)
{
struct s390_aes_ctx *sctx = crypto_tfm_ctx(tfm);
u32 *flags = &tfm->crt_flags;
int ret;
ret = need_fallback(key_len);
if (ret < 0) {
*flags |= CRYPTO_TFM_RES_BAD_KEY_LEN;
return -EINVAL;
}
sctx->key_len = key_len;
if (!ret) {
memcpy(sctx->key, in_key, key_len);
return 0;
}
return setkey_fallback_cip(tfm, in_key, key_len);
}
static void aes_encrypt(struct crypto_tfm *tfm, u8 *out, const u8 *in)
{
const struct s390_aes_ctx *sctx = crypto_tfm_ctx(tfm);
if (unlikely(need_fallback(sctx->key_len))) {
crypto_cipher_encrypt_one(sctx->fallback.cip, out, in);
return;
}
switch (sctx->key_len) {
case 16:
crypt_s390_km(KM_AES_128_ENCRYPT, &sctx->key, out, in,
AES_BLOCK_SIZE);
break;
case 24:
crypt_s390_km(KM_AES_192_ENCRYPT, &sctx->key, out, in,
AES_BLOCK_SIZE);
break;
case 32:
crypt_s390_km(KM_AES_256_ENCRYPT, &sctx->key, out, in,
AES_BLOCK_SIZE);
break;
}
}
static void aes_decrypt(struct crypto_tfm *tfm, u8 *out, const u8 *in)
{
const struct s390_aes_ctx *sctx = crypto_tfm_ctx(tfm);
if (unlikely(need_fallback(sctx->key_len))) {
crypto_cipher_decrypt_one(sctx->fallback.cip, out, in);
return;
}
switch (sctx->key_len) {
case 16:
crypt_s390_km(KM_AES_128_DECRYPT, &sctx->key, out, in,
AES_BLOCK_SIZE);
break;
case 24:
crypt_s390_km(KM_AES_192_DECRYPT, &sctx->key, out, in,
AES_BLOCK_SIZE);
break;
case 32:
crypt_s390_km(KM_AES_256_DECRYPT, &sctx->key, out, in,
AES_BLOCK_SIZE);
break;
}
}
static int fallback_init_cip(struct crypto_tfm *tfm)
{
const char *name = tfm->__crt_alg->cra_name;
struct s390_aes_ctx *sctx = crypto_tfm_ctx(tfm);
sctx->fallback.cip = crypto_alloc_cipher(name, 0,
CRYPTO_ALG_ASYNC | CRYPTO_ALG_NEED_FALLBACK);
if (IS_ERR(sctx->fallback.cip)) {
pr_err("Allocating AES fallback algorithm %s failed\n",
name);
return PTR_ERR(sctx->fallback.blk);
}
return 0;
}
static void fallback_exit_cip(struct crypto_tfm *tfm)
{
struct s390_aes_ctx *sctx = crypto_tfm_ctx(tfm);
crypto_free_cipher(sctx->fallback.cip);
sctx->fallback.cip = NULL;
}
static struct crypto_alg aes_alg = {
.cra_name = "aes",
.cra_driver_name = "aes-s390",
.cra_priority = CRYPT_S390_PRIORITY,
.cra_flags = CRYPTO_ALG_TYPE_CIPHER |
CRYPTO_ALG_NEED_FALLBACK,
.cra_blocksize = AES_BLOCK_SIZE,
.cra_ctxsize = sizeof(struct s390_aes_ctx),
.cra_module = THIS_MODULE,
.cra_list = LIST_HEAD_INIT(aes_alg.cra_list),
.cra_init = fallback_init_cip,
.cra_exit = fallback_exit_cip,
.cra_u = {
.cipher = {
.cia_min_keysize = AES_MIN_KEY_SIZE,
.cia_max_keysize = AES_MAX_KEY_SIZE,
.cia_setkey = aes_set_key,
.cia_encrypt = aes_encrypt,
.cia_decrypt = aes_decrypt,
}
}
};
static int setkey_fallback_blk(struct crypto_tfm *tfm, const u8 *key,
unsigned int len)
{
struct s390_aes_ctx *sctx = crypto_tfm_ctx(tfm);
unsigned int ret;
sctx->fallback.blk->base.crt_flags &= ~CRYPTO_TFM_REQ_MASK;
sctx->fallback.blk->base.crt_flags |= (tfm->crt_flags &
CRYPTO_TFM_REQ_MASK);
ret = crypto_blkcipher_setkey(sctx->fallback.blk, key, len);
if (ret) {
tfm->crt_flags &= ~CRYPTO_TFM_RES_MASK;
tfm->crt_flags |= (sctx->fallback.blk->base.crt_flags &
CRYPTO_TFM_RES_MASK);
}
return ret;
}
static int fallback_blk_dec(struct blkcipher_desc *desc,
struct scatterlist *dst, struct scatterlist *src,
unsigned int nbytes)
{
unsigned int ret;
struct crypto_blkcipher *tfm;
struct s390_aes_ctx *sctx = crypto_blkcipher_ctx(desc->tfm);
tfm = desc->tfm;
desc->tfm = sctx->fallback.blk;
ret = crypto_blkcipher_decrypt_iv(desc, dst, src, nbytes);
desc->tfm = tfm;
return ret;
}
static int fallback_blk_enc(struct blkcipher_desc *desc,
struct scatterlist *dst, struct scatterlist *src,
unsigned int nbytes)
{
unsigned int ret;
struct crypto_blkcipher *tfm;
struct s390_aes_ctx *sctx = crypto_blkcipher_ctx(desc->tfm);
tfm = desc->tfm;
desc->tfm = sctx->fallback.blk;
ret = crypto_blkcipher_encrypt_iv(desc, dst, src, nbytes);
desc->tfm = tfm;
return ret;
}
static int ecb_aes_set_key(struct crypto_tfm *tfm, const u8 *in_key,
unsigned int key_len)
{
struct s390_aes_ctx *sctx = crypto_tfm_ctx(tfm);
int ret;
ret = need_fallback(key_len);
if (ret > 0) {
sctx->key_len = key_len;
return setkey_fallback_blk(tfm, in_key, key_len);
}
switch (key_len) {
case 16:
sctx->enc = KM_AES_128_ENCRYPT;
sctx->dec = KM_AES_128_DECRYPT;
break;
case 24:
sctx->enc = KM_AES_192_ENCRYPT;
sctx->dec = KM_AES_192_DECRYPT;
break;
case 32:
sctx->enc = KM_AES_256_ENCRYPT;
sctx->dec = KM_AES_256_DECRYPT;
break;
}
return aes_set_key(tfm, in_key, key_len);
}
static int ecb_aes_crypt(struct blkcipher_desc *desc, long func, void *param,
struct blkcipher_walk *walk)
{
int ret = blkcipher_walk_virt(desc, walk);
unsigned int nbytes;
while ((nbytes = walk->nbytes)) {
/* only use complete blocks */
unsigned int n = nbytes & ~(AES_BLOCK_SIZE - 1);
u8 *out = walk->dst.virt.addr;
u8 *in = walk->src.virt.addr;
ret = crypt_s390_km(func, param, out, in, n);
BUG_ON((ret < 0) || (ret != n));
nbytes &= AES_BLOCK_SIZE - 1;
ret = blkcipher_walk_done(desc, walk, nbytes);
}
return ret;
}
static int ecb_aes_encrypt(struct blkcipher_desc *desc,
struct scatterlist *dst, struct scatterlist *src,
unsigned int nbytes)
{
struct s390_aes_ctx *sctx = crypto_blkcipher_ctx(desc->tfm);
struct blkcipher_walk walk;
if (unlikely(need_fallback(sctx->key_len)))
return fallback_blk_enc(desc, dst, src, nbytes);
blkcipher_walk_init(&walk, dst, src, nbytes);
return ecb_aes_crypt(desc, sctx->enc, sctx->key, &walk);
}
static int ecb_aes_decrypt(struct blkcipher_desc *desc,
struct scatterlist *dst, struct scatterlist *src,
unsigned int nbytes)
{
struct s390_aes_ctx *sctx = crypto_blkcipher_ctx(desc->tfm);
struct blkcipher_walk walk;
if (unlikely(need_fallback(sctx->key_len)))
return fallback_blk_dec(desc, dst, src, nbytes);
blkcipher_walk_init(&walk, dst, src, nbytes);
return ecb_aes_crypt(desc, sctx->dec, sctx->key, &walk);
}
static int fallback_init_blk(struct crypto_tfm *tfm)
{
const char *name = tfm->__crt_alg->cra_name;
struct s390_aes_ctx *sctx = crypto_tfm_ctx(tfm);
sctx->fallback.blk = crypto_alloc_blkcipher(name, 0,
CRYPTO_ALG_ASYNC | CRYPTO_ALG_NEED_FALLBACK);
if (IS_ERR(sctx->fallback.blk)) {
pr_err("Allocating AES fallback algorithm %s failed\n",
name);
return PTR_ERR(sctx->fallback.blk);
}
return 0;
}
static void fallback_exit_blk(struct crypto_tfm *tfm)
{
struct s390_aes_ctx *sctx = crypto_tfm_ctx(tfm);
crypto_free_blkcipher(sctx->fallback.blk);
sctx->fallback.blk = NULL;
}
static struct crypto_alg ecb_aes_alg = {
.cra_name = "ecb(aes)",
.cra_driver_name = "ecb-aes-s390",
.cra_priority = CRYPT_S390_COMPOSITE_PRIORITY,
.cra_flags = CRYPTO_ALG_TYPE_BLKCIPHER |
CRYPTO_ALG_NEED_FALLBACK,
.cra_blocksize = AES_BLOCK_SIZE,
.cra_ctxsize = sizeof(struct s390_aes_ctx),
.cra_type = &crypto_blkcipher_type,
.cra_module = THIS_MODULE,
.cra_list = LIST_HEAD_INIT(ecb_aes_alg.cra_list),
.cra_init = fallback_init_blk,
.cra_exit = fallback_exit_blk,
.cra_u = {
.blkcipher = {
.min_keysize = AES_MIN_KEY_SIZE,
.max_keysize = AES_MAX_KEY_SIZE,
.setkey = ecb_aes_set_key,
.encrypt = ecb_aes_encrypt,
.decrypt = ecb_aes_decrypt,
}
}
};
static int cbc_aes_set_key(struct crypto_tfm *tfm, const u8 *in_key,
unsigned int key_len)
{
struct s390_aes_ctx *sctx = crypto_tfm_ctx(tfm);
int ret;
ret = need_fallback(key_len);
if (ret > 0) {
sctx->key_len = key_len;
return setkey_fallback_blk(tfm, in_key, key_len);
}
switch (key_len) {
case 16:
sctx->enc = KMC_AES_128_ENCRYPT;
sctx->dec = KMC_AES_128_DECRYPT;
break;
case 24:
sctx->enc = KMC_AES_192_ENCRYPT;
sctx->dec = KMC_AES_192_DECRYPT;
break;
case 32:
sctx->enc = KMC_AES_256_ENCRYPT;
sctx->dec = KMC_AES_256_DECRYPT;
break;
}
return aes_set_key(tfm, in_key, key_len);
}
static int cbc_aes_crypt(struct blkcipher_desc *desc, long func, void *param,
struct blkcipher_walk *walk)
{
int ret = blkcipher_walk_virt(desc, walk);
unsigned int nbytes = walk->nbytes;
if (!nbytes)
goto out;
memcpy(param, walk->iv, AES_BLOCK_SIZE);
do {
/* only use complete blocks */
unsigned int n = nbytes & ~(AES_BLOCK_SIZE - 1);
u8 *out = walk->dst.virt.addr;
u8 *in = walk->src.virt.addr;
ret = crypt_s390_kmc(func, param, out, in, n);
BUG_ON((ret < 0) || (ret != n));
nbytes &= AES_BLOCK_SIZE - 1;
ret = blkcipher_walk_done(desc, walk, nbytes);
} while ((nbytes = walk->nbytes));
memcpy(walk->iv, param, AES_BLOCK_SIZE);
out:
return ret;
}
static int cbc_aes_encrypt(struct blkcipher_desc *desc,
struct scatterlist *dst, struct scatterlist *src,
unsigned int nbytes)
{
struct s390_aes_ctx *sctx = crypto_blkcipher_ctx(desc->tfm);
struct blkcipher_walk walk;
if (unlikely(need_fallback(sctx->key_len)))
return fallback_blk_enc(desc, dst, src, nbytes);
blkcipher_walk_init(&walk, dst, src, nbytes);
return cbc_aes_crypt(desc, sctx->enc, sctx->iv, &walk);
}
static int cbc_aes_decrypt(struct blkcipher_desc *desc,
struct scatterlist *dst, struct scatterlist *src,
unsigned int nbytes)
{
struct s390_aes_ctx *sctx = crypto_blkcipher_ctx(desc->tfm);
struct blkcipher_walk walk;
if (unlikely(need_fallback(sctx->key_len)))
return fallback_blk_dec(desc, dst, src, nbytes);
blkcipher_walk_init(&walk, dst, src, nbytes);
return cbc_aes_crypt(desc, sctx->dec, sctx->iv, &walk);
}
static struct crypto_alg cbc_aes_alg = {
.cra_name = "cbc(aes)",
.cra_driver_name = "cbc-aes-s390",
.cra_priority = CRYPT_S390_COMPOSITE_PRIORITY,
.cra_flags = CRYPTO_ALG_TYPE_BLKCIPHER |
CRYPTO_ALG_NEED_FALLBACK,
.cra_blocksize = AES_BLOCK_SIZE,
.cra_ctxsize = sizeof(struct s390_aes_ctx),
.cra_type = &crypto_blkcipher_type,
.cra_module = THIS_MODULE,
.cra_list = LIST_HEAD_INIT(cbc_aes_alg.cra_list),
.cra_init = fallback_init_blk,
.cra_exit = fallback_exit_blk,
.cra_u = {
.blkcipher = {
.min_keysize = AES_MIN_KEY_SIZE,
.max_keysize = AES_MAX_KEY_SIZE,
.ivsize = AES_BLOCK_SIZE,
.setkey = cbc_aes_set_key,
.encrypt = cbc_aes_encrypt,
.decrypt = cbc_aes_decrypt,
}
}
};
static int __init aes_s390_init(void)
{
int ret;
if (crypt_s390_func_available(KM_AES_128_ENCRYPT))
keylen_flag |= AES_KEYLEN_128;
if (crypt_s390_func_available(KM_AES_192_ENCRYPT))
keylen_flag |= AES_KEYLEN_192;
if (crypt_s390_func_available(KM_AES_256_ENCRYPT))
keylen_flag |= AES_KEYLEN_256;
if (!keylen_flag)
return -EOPNOTSUPP;
/* z9 109 and z9 BC/EC only support 128 bit key length */
if (keylen_flag == AES_KEYLEN_128)
pr_info("AES hardware acceleration is only available for"
" 128-bit keys\n");
ret = crypto_register_alg(&aes_alg);
if (ret)
goto aes_err;
ret = crypto_register_alg(&ecb_aes_alg);
if (ret)
goto ecb_aes_err;
ret = crypto_register_alg(&cbc_aes_alg);
if (ret)
goto cbc_aes_err;
out:
return ret;
cbc_aes_err:
crypto_unregister_alg(&ecb_aes_alg);
ecb_aes_err:
crypto_unregister_alg(&aes_alg);
aes_err:
goto out;
}
static void __exit aes_s390_fini(void)
{
crypto_unregister_alg(&cbc_aes_alg);
crypto_unregister_alg(&ecb_aes_alg);
crypto_unregister_alg(&aes_alg);
}
module_init(aes_s390_init);
module_exit(aes_s390_fini);
MODULE_ALIAS("aes-all");
MODULE_DESCRIPTION("Rijndael (AES) Cipher Algorithm");
MODULE_LICENSE("GPL");
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