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[CRYPTO] aes: Export generic setkey

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The key expansion routine could be get little more generic, become
a kernel doc entry and then get exported.

Signed-off-by: Sebastian Siewior <sebastian@breakpoint.cc>
Tested-by: Stefan Hellermann <stefan@the2masters.de>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
This commit is contained in:
Sebastian Siewior 2008-04-01 20:58:51 +08:00 committed by Herbert Xu
parent c3715cb90f
commit 5427663f49
2 changed files with 53 additions and 11 deletions
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56
crypto/aes_generic.c
View File

@ -229,18 +229,29 @@ static void __init gen_tabs(void)
ctx->key_enc[8 * i + 15] = t; \
} while (0)
int crypto_aes_set_key(struct crypto_tfm *tfm, const u8 *in_key,
/**
* crypto_aes_expand_key - Expands the AES key as described in FIPS-197
* @ctx: The location where the computed key will be stored.
* @in_key: The supplied key.
* @key_len: The length of the supplied key.
*
* Returns 0 on success. The function fails only if an invalid key size (or
* pointer) is supplied.
* The expanded key size is 240 bytes (max of 14 rounds with a unique 16 bytes
* key schedule plus a 16 bytes key which is used before the first round).
* The decryption key is prepared for the "Equivalent Inverse Cipher" as
* described in FIPS-197. The first slot (16 bytes) of each key (enc or dec) is
* for the initial combination, the second slot for the first round and so on.
*/
int crypto_aes_expand_key(struct crypto_aes_ctx *ctx, const u8 *in_key,
unsigned int key_len)
{
struct crypto_aes_ctx *ctx = crypto_tfm_ctx(tfm);
const __le32 *key = (const __le32 *)in_key;
u32 *flags = &tfm->crt_flags;
u32 i, t, u, v, w, j;
if (key_len % 8) {
*flags |= CRYPTO_TFM_RES_BAD_KEY_LEN;
if (key_len != AES_KEYSIZE_128 && key_len != AES_KEYSIZE_192 &&
key_len != AES_KEYSIZE_256)
return -EINVAL;
}
ctx->key_length = key_len;
@ -250,20 +261,20 @@ int crypto_aes_set_key(struct crypto_tfm *tfm, const u8 *in_key,
ctx->key_dec[key_len + 27] = ctx->key_enc[3] = le32_to_cpu(key[3]);
switch (key_len) {
case 16:
case AES_KEYSIZE_128:
t = ctx->key_enc[3];
for (i = 0; i < 10; ++i)
loop4(i);
break;
case 24:
case AES_KEYSIZE_192:
ctx->key_enc[4] = le32_to_cpu(key[4]);
t = ctx->key_enc[5] = le32_to_cpu(key[5]);
for (i = 0; i < 8; ++i)
loop6(i);
break;
case 32:
case AES_KEYSIZE_256:
ctx->key_enc[4] = le32_to_cpu(key[4]);
ctx->key_enc[5] = le32_to_cpu(key[5]);
ctx->key_enc[6] = le32_to_cpu(key[6]);
@ -284,6 +295,33 @@ int crypto_aes_set_key(struct crypto_tfm *tfm, const u8 *in_key,
}
return 0;
}
EXPORT_SYMBOL_GPL(crypto_aes_expand_key);
/**
* crypto_aes_set_key - Set the AES key.
* @tfm: The %crypto_tfm that is used in the context.
* @in_key: The input key.
* @key_len: The size of the key.
*
* Returns 0 on success, on failure the %CRYPTO_TFM_RES_BAD_KEY_LEN flag in tfm
* is set. The function uses crypto_aes_expand_key() to expand the key.
* &crypto_aes_ctx _must_ be the private data embedded in @tfm which is
* retrieved with crypto_tfm_ctx().
*/
int crypto_aes_set_key(struct crypto_tfm *tfm, const u8 *in_key,
unsigned int key_len)
{
struct crypto_aes_ctx *ctx = crypto_tfm_ctx(tfm);
u32 *flags = &tfm->crt_flags;
int ret;
ret = crypto_aes_expand_key(ctx, in_key, key_len);
if (!ret)
return 0;
*flags |= CRYPTO_TFM_RES_BAD_KEY_LEN;
return -EINVAL;
}
EXPORT_SYMBOL_GPL(crypto_aes_set_key);
/* encrypt a block of text */

8
include/crypto/aes.h
View File

@ -14,11 +14,13 @@
#define AES_KEYSIZE_192 24
#define AES_KEYSIZE_256 32
#define AES_BLOCK_SIZE 16
#define AES_MAX_KEYLENGTH (15 * 16)
#define AES_MAX_KEYLENGTH_U32 (AES_MAX_KEYLENGTH / sizeof(u32))
struct crypto_aes_ctx {
u32 key_length;
u32 key_enc[60];
u32 key_dec[60];
u32 key_enc[AES_MAX_KEYLENGTH_U32];
u32 key_dec[AES_MAX_KEYLENGTH_U32];
};
extern u32 crypto_ft_tab[4][256];
@ -28,4 +30,6 @@ extern u32 crypto_il_tab[4][256];
int crypto_aes_set_key(struct crypto_tfm *tfm, const u8 *in_key,
unsigned int key_len);
int crypto_aes_expand_key(struct crypto_aes_ctx *ctx, const u8 *in_key,
unsigned int key_len);
#endif