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Subject[Patch v4 7/7] crypto: qce: aead: Schedule fallback algorithm
Date
Qualcomm crypto engine does not handle the following scenarios and
will issue an abort. In such cases, pass on the transformation to
a fallback algorithm.

- DES3 algorithms with all three keys same.
- AES192 algorithms.
- 0 length messages.

Signed-off-by: Thara Gopinath <thara.gopinath@linaro.org>
---
drivers/crypto/qce/aead.c | 64 ++++++++++++++++++++++++++++++++-------
drivers/crypto/qce/aead.h | 3 ++
2 files changed, 56 insertions(+), 11 deletions(-)

diff --git a/drivers/crypto/qce/aead.c b/drivers/crypto/qce/aead.c
index ef66ae21eae3..6d06a19b48e4 100644
--- a/drivers/crypto/qce/aead.c
+++ b/drivers/crypto/qce/aead.c
@@ -512,7 +512,23 @@ static int qce_aead_crypt(struct aead_request *req, int encrypt)
/* CE does not handle 0 length messages */
if (!rctx->cryptlen) {
if (!(IS_CCM(rctx->flags) && IS_DECRYPT(rctx->flags)))
- return -EINVAL;
+ ctx->need_fallback = true;
+ }
+
+ /* If fallback is needed, schedule and exit */
+ if (ctx->need_fallback) {
+ /* Reset need_fallback in case the same ctx is used for another transaction */
+ ctx->need_fallback = false;
+
+ aead_request_set_tfm(&rctx->fallback_req, ctx->fallback);
+ aead_request_set_callback(&rctx->fallback_req, req->base.flags,
+ req->base.complete, req->base.data);
+ aead_request_set_crypt(&rctx->fallback_req, req->src,
+ req->dst, req->cryptlen, req->iv);
+ aead_request_set_ad(&rctx->fallback_req, req->assoclen);
+
+ return encrypt ? crypto_aead_encrypt(&rctx->fallback_req) :
+ crypto_aead_decrypt(&rctx->fallback_req);
}

/*
@@ -553,7 +569,7 @@ static int qce_aead_ccm_setkey(struct crypto_aead *tfm, const u8 *key,
memcpy(ctx->ccm4309_salt, key + keylen, QCE_CCM4309_SALT_SIZE);
}

- if (keylen != AES_KEYSIZE_128 && keylen != AES_KEYSIZE_256)
+ if (keylen != AES_KEYSIZE_128 && keylen != AES_KEYSIZE_256 && keylen != AES_KEYSIZE_192)
return -EINVAL;

ctx->enc_keylen = keylen;
@@ -562,7 +578,12 @@ static int qce_aead_ccm_setkey(struct crypto_aead *tfm, const u8 *key,
memcpy(ctx->enc_key, key, keylen);
memcpy(ctx->auth_key, key, keylen);

- return 0;
+ if (keylen == AES_KEYSIZE_192)
+ ctx->need_fallback = true;
+
+ return IS_CCM_RFC4309(flags) ?
+ crypto_aead_setkey(ctx->fallback, key, keylen + QCE_CCM4309_SALT_SIZE) :
+ crypto_aead_setkey(ctx->fallback, key, keylen);
}

static int qce_aead_setkey(struct crypto_aead *tfm, const u8 *key, unsigned int keylen)
@@ -593,20 +614,21 @@ static int qce_aead_setkey(struct crypto_aead *tfm, const u8 *key, unsigned int
* The crypto engine does not support any two keys
* being the same for triple des algorithms. The
* verify_skcipher_des3_key does not check for all the
- * below conditions. Return -EINVAL in case any two keys
- * are the same. Revisit to see if a fallback cipher
- * is needed to handle this condition.
+ * below conditions. Schedule fallback in this case.
*/
memcpy(_key, authenc_keys.enckey, DES3_EDE_KEY_SIZE);
if (!((_key[0] ^ _key[2]) | (_key[1] ^ _key[3])) ||
!((_key[2] ^ _key[4]) | (_key[3] ^ _key[5])) ||
!((_key[0] ^ _key[4]) | (_key[1] ^ _key[5])))
- return -EINVAL;
+ ctx->need_fallback = true;
} else if (IS_AES(flags)) {
/* No random key sizes */
if (authenc_keys.enckeylen != AES_KEYSIZE_128 &&
+ authenc_keys.enckeylen != AES_KEYSIZE_192 &&
authenc_keys.enckeylen != AES_KEYSIZE_256)
return -EINVAL;
+ if (authenc_keys.enckeylen == AES_KEYSIZE_192)
+ ctx->need_fallback = true;
}

ctx->enc_keylen = authenc_keys.enckeylen;
@@ -617,7 +639,7 @@ static int qce_aead_setkey(struct crypto_aead *tfm, const u8 *key, unsigned int
memset(ctx->auth_key, 0, sizeof(ctx->auth_key));
memcpy(ctx->auth_key, authenc_keys.authkey, authenc_keys.authkeylen);

- return 0;
+ return crypto_aead_setkey(ctx->fallback, key, keylen);
}

static int qce_aead_setauthsize(struct crypto_aead *tfm, unsigned int authsize)
@@ -632,15 +654,33 @@ static int qce_aead_setauthsize(struct crypto_aead *tfm, unsigned int authsize)
return -EINVAL;
}
ctx->authsize = authsize;
- return 0;
+
+ return crypto_aead_setauthsize(ctx->fallback, authsize);
}

static int qce_aead_init(struct crypto_aead *tfm)
{
- crypto_aead_set_reqsize(tfm, sizeof(struct qce_aead_reqctx));
+ struct qce_aead_ctx *ctx = crypto_aead_ctx(tfm);
+
+ ctx->need_fallback = false;
+ ctx->fallback = crypto_alloc_aead(crypto_tfm_alg_name(&tfm->base),
+ 0, CRYPTO_ALG_NEED_FALLBACK);
+
+ if (IS_ERR(ctx->fallback))
+ return PTR_ERR(ctx->fallback);
+
+ crypto_aead_set_reqsize(tfm, sizeof(struct qce_aead_reqctx) +
+ crypto_aead_reqsize(ctx->fallback));
return 0;
}

+static void qce_aead_exit(struct crypto_aead *tfm)
+{
+ struct qce_aead_ctx *ctx = crypto_aead_ctx(tfm);
+
+ crypto_free_aead(ctx->fallback);
+}
+
struct qce_aead_def {
unsigned long flags;
const char *name;
@@ -738,11 +778,13 @@ static int qce_aead_register_one(const struct qce_aead_def *def, struct qce_devi
alg->encrypt = qce_aead_encrypt;
alg->decrypt = qce_aead_decrypt;
alg->init = qce_aead_init;
+ alg->exit = qce_aead_exit;

alg->base.cra_priority = 300;
alg->base.cra_flags = CRYPTO_ALG_ASYNC |
CRYPTO_ALG_ALLOCATES_MEMORY |
- CRYPTO_ALG_KERN_DRIVER_ONLY;
+ CRYPTO_ALG_KERN_DRIVER_ONLY |
+ CRYPTO_ALG_NEED_FALLBACK;
alg->base.cra_ctxsize = sizeof(struct qce_aead_ctx);
alg->base.cra_alignmask = 0;
alg->base.cra_module = THIS_MODULE;
diff --git a/drivers/crypto/qce/aead.h b/drivers/crypto/qce/aead.h
index 3d1f2039930b..efb8477cc088 100644
--- a/drivers/crypto/qce/aead.h
+++ b/drivers/crypto/qce/aead.h
@@ -19,6 +19,8 @@ struct qce_aead_ctx {
unsigned int enc_keylen;
unsigned int auth_keylen;
unsigned int authsize;
+ bool need_fallback;
+ struct crypto_aead *fallback;
};

struct qce_aead_reqctx {
@@ -39,6 +41,7 @@ struct qce_aead_reqctx {
u8 ccm_nonce[QCE_MAX_NONCE];
u8 ccmresult_buf[QCE_BAM_BURST_SIZE];
u8 ccm_rfc4309_iv[QCE_MAX_IV_SIZE];
+ struct aead_request fallback_req;
};

static inline struct qce_alg_template *to_aead_tmpl(struct crypto_aead *tfm)
--
2.25.1
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