[PATCH 7/7] crypto: qce: aead: Schedule fallback algorithm

[Thara Gopinath]

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@xxxxxxxxxx>
---
 drivers/crypto/qce/aead.c | 58 ++++++++++++++++++++++++++++++++-------
 drivers/crypto/qce/aead.h |  3 ++
 2 files changed, 51 insertions(+), 10 deletions(-)

diff --git a/drivers/crypto/qce/aead.c b/drivers/crypto/qce/aead.c
index b594c4bb2640..4c2d024e5296 100644
--- a/drivers/crypto/qce/aead.c
+++ b/drivers/crypto/qce/aead.c
@@ -492,7 +492,20 @@ 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) {
+		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);
 	}
 
 	/*
@@ -533,7 +546,7 @@ 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;
@@ -542,7 +555,12 @@ 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)
@@ -573,20 +591,21 @@ 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;
@@ -597,7 +616,7 @@ 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)
@@ -612,15 +631,32 @@ 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)
 {
+	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));
 	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;
@@ -718,11 +754,13 @@ 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