crypto: api - laying defines and checks for statically allocated buffers (13c935bb) · Commits · 戴 / test

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.com Signed-off-by:

Salvatore Mesoraca <s.mesoraca16@gmail.com> Signed-off-by:

Herbert Xu <herbert@gondor.apana.org.au>

crypto/algapi.c

+10 −0

Original line number	Diff line number	Diff line
		@@ -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;

include/crypto/algapi.h

+8 −0

Original line number	Diff line number	Diff line
		@@ -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;

Admin message