Commit 13c935bb authored by Salvatore Mesoraca's avatar Salvatore Mesoraca Committed by Herbert Xu

crypto: api - laying defines and checks for statically allocated buffers

In preparation for the removal of VLAs[1] from crypto code.
We create 2 new compile-time constants: all ciphers implemented
in Linux have a block size less than or equal to 16 bytes and
the most demanding hw require 16 bytes alignment for the block
buffer.
We also enforce these limits in crypto_check_alg when a new
cipher is registered.

[1] http://lkml.kernel.org/r/CA+55aFzCG-zNmZwX4A2FQpadafLfEzK6CC=qPXydAacU1RqZWA@mail.gmail.comSigned-off-by: 's avatarSalvatore Mesoraca <s.mesoraca16@gmail.com>
Signed-off-by: 's avatarHerbert Xu <herbert@gondor.apana.org.au>
parent c4e84858
......@@ -10,6 +10,7 @@
*
*/
#include <crypto/algapi.h>
#include <linux/err.h>
#include <linux/errno.h>
#include <linux/fips.h>
......@@ -59,6 +60,15 @@ static int crypto_check_alg(struct crypto_alg *alg)
if (alg->cra_blocksize > PAGE_SIZE / 8)
return -EINVAL;
if (!alg->cra_type && (alg->cra_flags & CRYPTO_ALG_TYPE_MASK) ==
CRYPTO_ALG_TYPE_CIPHER) {
if (alg->cra_alignmask > MAX_CIPHER_ALIGNMASK)
return -EINVAL;
if (alg->cra_blocksize > MAX_CIPHER_BLOCKSIZE)
return -EINVAL;
}
if (alg->cra_priority < 0)
return -EINVAL;
......
......@@ -17,6 +17,14 @@
#include <linux/kernel.h>
#include <linux/skbuff.h>
/*
* Maximum values for blocksize and alignmask, used to allocate
* static buffers that are big enough for any combination of
* ciphers and architectures.
*/
#define MAX_CIPHER_BLOCKSIZE 16
#define MAX_CIPHER_ALIGNMASK 15
struct crypto_aead;
struct crypto_instance;
struct module;
......
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