From f441ba2ad34102692b9836923776f017b40afc88 Mon Sep 17 00:00:00 2001 From: Ard Biesheuvel Date: Tue, 7 Jul 2020 09:32:03 +0300 Subject: [PATCH] crypto: mediatek - use AES library for GCM key derivation The Mediatek accelerator driver calls into a dynamically allocated skcipher of the ctr(aes) variety to perform GCM key derivation, which involves AES encryption of a single block consisting of NUL bytes. There is no point in using the skcipher API for this, so use the AES library interface instead. Signed-off-by: Ard Biesheuvel Signed-off-by: Herbert Xu --- drivers/crypto/Kconfig | 3 +- drivers/crypto/mediatek/mtk-aes.c | 63 ++++--------------------------- 2 files changed, 9 insertions(+), 57 deletions(-) diff --git a/drivers/crypto/Kconfig b/drivers/crypto/Kconfig index 7bc58bf99703..585ad584e421 100644 --- a/drivers/crypto/Kconfig +++ b/drivers/crypto/Kconfig @@ -758,10 +758,9 @@ config CRYPTO_DEV_ZYNQMP_AES config CRYPTO_DEV_MEDIATEK tristate "MediaTek's EIP97 Cryptographic Engine driver" depends on (ARM && ARCH_MEDIATEK) || COMPILE_TEST - select CRYPTO_AES + select CRYPTO_LIB_AES select CRYPTO_AEAD select CRYPTO_SKCIPHER - select CRYPTO_CTR select CRYPTO_SHA1 select CRYPTO_SHA256 select CRYPTO_SHA512 diff --git a/drivers/crypto/mediatek/mtk-aes.c b/drivers/crypto/mediatek/mtk-aes.c index 78d660d963e2..4ad3571ab6af 100644 --- a/drivers/crypto/mediatek/mtk-aes.c +++ b/drivers/crypto/mediatek/mtk-aes.c @@ -137,8 +137,6 @@ struct mtk_aes_gcm_ctx { u32 authsize; size_t textlen; - - struct crypto_skcipher *ctr; }; struct mtk_aes_drv { @@ -996,17 +994,8 @@ static int mtk_aes_gcm_setkey(struct crypto_aead *aead, const u8 *key, u32 keylen) { struct mtk_aes_base_ctx *ctx = crypto_aead_ctx(aead); - struct mtk_aes_gcm_ctx *gctx = mtk_aes_gcm_ctx_cast(ctx); - struct crypto_skcipher *ctr = gctx->ctr; - struct { - u32 hash[4]; - u8 iv[8]; - - struct crypto_wait wait; - - struct scatterlist sg[1]; - struct skcipher_request req; - } *data; + u8 hash[AES_BLOCK_SIZE] __aligned(4) = {}; + struct crypto_aes_ctx aes_ctx; int err; switch (keylen) { @@ -1026,39 +1015,18 @@ static int mtk_aes_gcm_setkey(struct crypto_aead *aead, const u8 *key, ctx->keylen = SIZE_IN_WORDS(keylen); - /* Same as crypto_gcm_setkey() from crypto/gcm.c */ - crypto_skcipher_clear_flags(ctr, CRYPTO_TFM_REQ_MASK); - crypto_skcipher_set_flags(ctr, crypto_aead_get_flags(aead) & - CRYPTO_TFM_REQ_MASK); - err = crypto_skcipher_setkey(ctr, key, keylen); + err = aes_expandkey(&aes_ctx, key, keylen); if (err) return err; - data = kzalloc(sizeof(*data) + crypto_skcipher_reqsize(ctr), - GFP_KERNEL); - if (!data) - return -ENOMEM; - - crypto_init_wait(&data->wait); - sg_init_one(data->sg, &data->hash, AES_BLOCK_SIZE); - skcipher_request_set_tfm(&data->req, ctr); - skcipher_request_set_callback(&data->req, CRYPTO_TFM_REQ_MAY_SLEEP | - CRYPTO_TFM_REQ_MAY_BACKLOG, - crypto_req_done, &data->wait); - skcipher_request_set_crypt(&data->req, data->sg, data->sg, - AES_BLOCK_SIZE, data->iv); - - err = crypto_wait_req(crypto_skcipher_encrypt(&data->req), - &data->wait); - if (err) - goto out; + aes_encrypt(&aes_ctx, hash, hash); + memzero_explicit(&aes_ctx, sizeof(aes_ctx)); mtk_aes_write_state_le(ctx->key, (const u32 *)key, keylen); - mtk_aes_write_state_be(ctx->key + ctx->keylen, data->hash, + mtk_aes_write_state_be(ctx->key + ctx->keylen, (const u32 *)hash, AES_BLOCK_SIZE); -out: - kzfree(data); - return err; + + return 0; } static int mtk_aes_gcm_setauthsize(struct crypto_aead *aead, @@ -1095,32 +1063,17 @@ static int mtk_aes_gcm_init(struct crypto_aead *aead) { struct mtk_aes_gcm_ctx *ctx = crypto_aead_ctx(aead); - ctx->ctr = crypto_alloc_skcipher("ctr(aes)", 0, - CRYPTO_ALG_ASYNC); - if (IS_ERR(ctx->ctr)) { - pr_err("Error allocating ctr(aes)\n"); - return PTR_ERR(ctx->ctr); - } - crypto_aead_set_reqsize(aead, sizeof(struct mtk_aes_reqctx)); ctx->base.start = mtk_aes_gcm_start; return 0; } -static void mtk_aes_gcm_exit(struct crypto_aead *aead) -{ - struct mtk_aes_gcm_ctx *ctx = crypto_aead_ctx(aead); - - crypto_free_skcipher(ctx->ctr); -} - static struct aead_alg aes_gcm_alg = { .setkey = mtk_aes_gcm_setkey, .setauthsize = mtk_aes_gcm_setauthsize, .encrypt = mtk_aes_gcm_encrypt, .decrypt = mtk_aes_gcm_decrypt, .init = mtk_aes_gcm_init, - .exit = mtk_aes_gcm_exit, .ivsize = GCM_AES_IV_SIZE, .maxauthsize = AES_BLOCK_SIZE,