diff options
author | Tudor Ambarus | 2021-07-20 11:55:34 +0300 |
---|---|---|
committer | Herbert Xu | 2021-07-30 10:58:34 +0800 |
commit | bf2db8e74249e691cbd1df7fca01810d8f48532b (patch) | |
tree | 99e10d71d9a962d3b98d1b87ba8f981e83c4a23b | |
parent | 76d579f251a2d8501f4504b07355c8738b72c2bd (diff) |
crypto: atmel-aes - Add fallback to XTS software implementation
XTS is supported just for input lengths with data units of 128-bit blocks.
Add a fallback to software implementation when the last block is shorter
than 128 bits.
Signed-off-by: Tudor Ambarus <tudor.ambarus@microchip.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
-rw-r--r-- | drivers/crypto/atmel-aes.c | 55 |
1 files changed, 51 insertions, 4 deletions
diff --git a/drivers/crypto/atmel-aes.c b/drivers/crypto/atmel-aes.c index 9ec007b4f8fc..e74fcaac551e 100644 --- a/drivers/crypto/atmel-aes.c +++ b/drivers/crypto/atmel-aes.c @@ -143,6 +143,7 @@ struct atmel_aes_xts_ctx { struct atmel_aes_base_ctx base; u32 key2[AES_KEYSIZE_256 / sizeof(u32)]; + struct crypto_skcipher *fallback_tfm; }; #if IS_ENABLED(CONFIG_CRYPTO_DEV_ATMEL_AUTHENC) @@ -155,6 +156,7 @@ struct atmel_aes_authenc_ctx { struct atmel_aes_reqctx { unsigned long mode; u8 lastc[AES_BLOCK_SIZE]; + struct skcipher_request fallback_req; }; #if IS_ENABLED(CONFIG_CRYPTO_DEV_ATMEL_AUTHENC) @@ -1083,6 +1085,22 @@ static int atmel_aes_ctr_start(struct atmel_aes_dev *dd) return atmel_aes_ctr_transfer(dd); } +static int atmel_aes_xts_fallback(struct skcipher_request *req, bool enc) +{ + struct atmel_aes_reqctx *rctx = skcipher_request_ctx(req); + struct atmel_aes_xts_ctx *ctx = crypto_skcipher_ctx( + crypto_skcipher_reqtfm(req)); + + skcipher_request_set_tfm(&rctx->fallback_req, ctx->fallback_tfm); + skcipher_request_set_callback(&rctx->fallback_req, req->base.flags, + req->base.complete, req->base.data); + skcipher_request_set_crypt(&rctx->fallback_req, req->src, req->dst, + req->cryptlen, req->iv); + + return enc ? crypto_skcipher_encrypt(&rctx->fallback_req) : + crypto_skcipher_decrypt(&rctx->fallback_req); +} + static int atmel_aes_crypt(struct skcipher_request *req, unsigned long mode) { struct crypto_skcipher *skcipher = crypto_skcipher_reqtfm(req); @@ -1091,8 +1109,14 @@ static int atmel_aes_crypt(struct skcipher_request *req, unsigned long mode) struct atmel_aes_dev *dd; u32 opmode = mode & AES_FLAGS_OPMODE_MASK; - if (opmode == AES_FLAGS_XTS && req->cryptlen < XTS_BLOCK_SIZE) - return -EINVAL; + if (opmode == AES_FLAGS_XTS) { + if (req->cryptlen < XTS_BLOCK_SIZE) + return -EINVAL; + + if (!IS_ALIGNED(req->cryptlen, XTS_BLOCK_SIZE)) + return atmel_aes_xts_fallback(req, + mode & AES_FLAGS_ENCRYPT); + } /* * ECB, CBC, CFB, OFB or CTR mode require the plaintext and ciphertext @@ -1864,6 +1888,13 @@ static int atmel_aes_xts_setkey(struct crypto_skcipher *tfm, const u8 *key, if (err) return err; + crypto_skcipher_clear_flags(ctx->fallback_tfm, CRYPTO_TFM_REQ_MASK); + crypto_skcipher_set_flags(ctx->fallback_tfm, tfm->base.crt_flags & + CRYPTO_TFM_REQ_MASK); + err = crypto_skcipher_setkey(ctx->fallback_tfm, key, keylen); + if (err) + return err; + memcpy(ctx->base.key, key, keylen/2); memcpy(ctx->key2, key + keylen/2, keylen/2); ctx->base.keylen = keylen/2; @@ -1884,18 +1915,33 @@ static int atmel_aes_xts_decrypt(struct skcipher_request *req) static int atmel_aes_xts_init_tfm(struct crypto_skcipher *tfm) { struct atmel_aes_xts_ctx *ctx = crypto_skcipher_ctx(tfm); + const char *tfm_name = crypto_tfm_alg_name(&tfm->base); - crypto_skcipher_set_reqsize(tfm, sizeof(struct atmel_aes_reqctx)); + ctx->fallback_tfm = crypto_alloc_skcipher(tfm_name, 0, + CRYPTO_ALG_NEED_FALLBACK); + if (IS_ERR(ctx->fallback_tfm)) + return PTR_ERR(ctx->fallback_tfm); + + crypto_skcipher_set_reqsize(tfm, sizeof(struct atmel_aes_reqctx) + + crypto_skcipher_reqsize(ctx->fallback_tfm)); ctx->base.start = atmel_aes_xts_start; return 0; } +static void atmel_aes_xts_exit_tfm(struct crypto_skcipher *tfm) +{ + struct atmel_aes_xts_ctx *ctx = crypto_skcipher_ctx(tfm); + + crypto_free_skcipher(ctx->fallback_tfm); +} + static struct skcipher_alg aes_xts_alg = { .base.cra_name = "xts(aes)", .base.cra_driver_name = "atmel-xts-aes", .base.cra_blocksize = AES_BLOCK_SIZE, .base.cra_ctxsize = sizeof(struct atmel_aes_xts_ctx), + .base.cra_flags = CRYPTO_ALG_NEED_FALLBACK, .min_keysize = 2 * AES_MIN_KEY_SIZE, .max_keysize = 2 * AES_MAX_KEY_SIZE, @@ -1904,6 +1950,7 @@ static struct skcipher_alg aes_xts_alg = { .encrypt = atmel_aes_xts_encrypt, .decrypt = atmel_aes_xts_decrypt, .init = atmel_aes_xts_init_tfm, + .exit = atmel_aes_xts_exit_tfm, }; #if IS_ENABLED(CONFIG_CRYPTO_DEV_ATMEL_AUTHENC) @@ -2373,7 +2420,7 @@ static void atmel_aes_unregister_algs(struct atmel_aes_dev *dd) static void atmel_aes_crypto_alg_init(struct crypto_alg *alg) { - alg->cra_flags = CRYPTO_ALG_ASYNC; + alg->cra_flags |= CRYPTO_ALG_ASYNC; alg->cra_alignmask = 0xf; alg->cra_priority = ATMEL_AES_PRIORITY; alg->cra_module = THIS_MODULE; |