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=qpxydaacu1rq...@mail.gmail.com Signed-off-by: Salvatore Mesoraca <s.mesorac...@gmail.com> --- 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 2a0271b..c0755cf 100644 --- a/crypto/algapi.c +++ b/crypto/algapi.c @@ -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; diff --git a/include/crypto/algapi.h b/include/crypto/algapi.h index 1aba888..bd5e8cc 100644 --- a/include/crypto/algapi.h +++ b/include/crypto/algapi.h @@ -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; -- 1.9.1
