From 13c935bb09948aef0202574ee12bb089459eb43b Mon Sep 17 00:00:00 2001 From: Salvatore Mesoraca Date: Mon, 9 Apr 2018 15:54:46 +0200 Subject: [PATCH] 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.com Signed-off-by: Salvatore Mesoraca Signed-off-by: Herbert Xu --- crypto/algapi.c | 10 ++++++++++ include/crypto/algapi.h | 8 ++++++++ 2 files changed, 18 insertions(+) diff --git a/crypto/algapi.c b/crypto/algapi.c index 2a0271b5f62a..c0755cf4f53f 100644 --- a/crypto/algapi.c +++ b/crypto/algapi.c @@ -10,6 +10,7 @@ * */ +#include #include #include #include @@ -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; diff --git a/include/crypto/algapi.h b/include/crypto/algapi.h index 1aba888241dd..bd5e8ccf1687 100644 --- a/include/crypto/algapi.h +++ b/include/crypto/algapi.h @@ -17,6 +17,14 @@ #include #include +/* + * 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;