From 7f7216cfaf3f07a41fe6e88b779bdc9690c2d515 Mon Sep 17 00:00:00 2001 From: Gary R Hook Date: Tue, 25 Jul 2017 14:21:34 -0500 Subject: [PATCH] crypto: ccp - Rework the unit-size check for XTS-AES The CCP supports a limited set of unit-size values. Change the check for this parameter such that acceptable values match the enumeration. Then clarify the conditions under which we must use the fallback implementation. Signed-off-by: Gary R Hook Signed-off-by: Herbert Xu --- drivers/crypto/ccp/ccp-crypto-aes-xts.c | 57 ++++++++++++--------------------- 1 file changed, 20 insertions(+), 37 deletions(-) diff --git a/drivers/crypto/ccp/ccp-crypto-aes-xts.c b/drivers/crypto/ccp/ccp-crypto-aes-xts.c index 2b5d3a6..5c2df88 100644 --- a/drivers/crypto/ccp/ccp-crypto-aes-xts.c +++ b/drivers/crypto/ccp/ccp-crypto-aes-xts.c @@ -39,46 +39,26 @@ struct ccp_unit_size_map { u32 value; }; -static struct ccp_unit_size_map unit_size_map[] = { +static struct ccp_unit_size_map xts_unit_sizes[] = { { - .size = 4096, - .value = CCP_XTS_AES_UNIT_SIZE_4096, - }, - { - .size = 2048, - .value = CCP_XTS_AES_UNIT_SIZE_2048, - }, - { - .size = 1024, - .value = CCP_XTS_AES_UNIT_SIZE_1024, + .size = 16, + .value = CCP_XTS_AES_UNIT_SIZE_16, }, { - .size = 512, + .size = 512, .value = CCP_XTS_AES_UNIT_SIZE_512, }, { - .size = 256, - .value = CCP_XTS_AES_UNIT_SIZE__LAST, - }, - { - .size = 128, - .value = CCP_XTS_AES_UNIT_SIZE__LAST, - }, - { - .size = 64, - .value = CCP_XTS_AES_UNIT_SIZE__LAST, - }, - { - .size = 32, - .value = CCP_XTS_AES_UNIT_SIZE__LAST, + .size = 1024, + .value = CCP_XTS_AES_UNIT_SIZE_1024, }, { - .size = 16, - .value = CCP_XTS_AES_UNIT_SIZE_16, + .size = 2048, + .value = CCP_XTS_AES_UNIT_SIZE_2048, }, { - .size = 1, - .value = CCP_XTS_AES_UNIT_SIZE__LAST, + .size = 4096, + .value = CCP_XTS_AES_UNIT_SIZE_4096, }, }; @@ -138,16 +118,19 @@ static int ccp_aes_xts_crypt(struct ablkcipher_request *req, if (!req->info) return -EINVAL; + /* Check conditions under which the CCP can fulfill a request. The + * device can handle input plaintext of a length that is a multiple + * of the unit_size, bug the crypto implementation only supports + * the unit_size being equal to the input length. This limits the + * number of scenarios we can handle. + */ unit_size = CCP_XTS_AES_UNIT_SIZE__LAST; - if (req->nbytes <= unit_size_map[0].size) { - for (unit = 0; unit < ARRAY_SIZE(unit_size_map); unit++) { - if (!(req->nbytes & (unit_size_map[unit].size - 1))) { - unit_size = unit_size_map[unit].value; - break; - } + for (unit = 0; unit < ARRAY_SIZE(xts_unit_sizes); unit++) { + if (req->nbytes == xts_unit_sizes[unit].size) { + unit_size = unit; + break; } } - if ((unit_size == CCP_XTS_AES_UNIT_SIZE__LAST) || (ctx->u.aes.key_len != AES_KEYSIZE_128)) { SKCIPHER_REQUEST_ON_STACK(subreq, ctx->u.aes.tfm_skcipher); -- 2.7.4