From ca5d7d5f7aeb2f8d3edb5d3ee9ed3344ca3b1c12 Mon Sep 17 00:00:00 2001
From: Herbert Xu <herbert@gondor.apana.org.au>
Date: Fri, 18 Apr 2025 11:00:59 +0800
Subject: [PATCH] crypto: cbcmac - Use API partial block handling

Use the Crypto API partial block handling.

Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
---
 crypto/ccm.c | 61 +++++++++++++++++++++-------------------------------
 1 file changed, 25 insertions(+), 36 deletions(-)

diff --git a/crypto/ccm.c b/crypto/ccm.c
index a0610ff6ce02..f3f455e4908b 100644
--- a/crypto/ccm.c
+++ b/crypto/ccm.c
@@ -10,11 +10,12 @@
 #include <crypto/internal/hash.h>
 #include <crypto/internal/skcipher.h>
 #include <crypto/scatterwalk.h>
+#include <crypto/utils.h>
 #include <linux/err.h>
-#include <linux/init.h>
 #include <linux/kernel.h>
 #include <linux/module.h>
 #include <linux/slab.h>
+#include <linux/string.h>
 
 struct ccm_instance_ctx {
 	struct crypto_skcipher_spawn ctr;
@@ -54,11 +55,6 @@ struct cbcmac_tfm_ctx {
 	struct crypto_cipher *child;
 };
 
-struct cbcmac_desc_ctx {
-	unsigned int len;
-	u8 dg[];
-};
-
 static inline struct crypto_ccm_req_priv_ctx *crypto_ccm_reqctx(
 	struct aead_request *req)
 {
@@ -783,12 +779,10 @@ static int crypto_cbcmac_digest_setkey(struct crypto_shash *parent,
 
 static int crypto_cbcmac_digest_init(struct shash_desc *pdesc)
 {
-	struct cbcmac_desc_ctx *ctx = shash_desc_ctx(pdesc);
 	int bs = crypto_shash_digestsize(pdesc->tfm);
+	u8 *dg = shash_desc_ctx(pdesc);
 
-	ctx->len = 0;
-	memset(ctx->dg, 0, bs);
-
+	memset(dg, 0, bs);
 	return 0;
 }
 
@@ -797,39 +791,34 @@ static int crypto_cbcmac_digest_update(struct shash_desc *pdesc, const u8 *p,
 {
 	struct crypto_shash *parent = pdesc->tfm;
 	struct cbcmac_tfm_ctx *tctx = crypto_shash_ctx(parent);
-	struct cbcmac_desc_ctx *ctx = shash_desc_ctx(pdesc);
 	struct crypto_cipher *tfm = tctx->child;
 	int bs = crypto_shash_digestsize(parent);
-
-	while (len > 0) {
-		unsigned int l = min(len, bs - ctx->len);
-
-		crypto_xor(&ctx->dg[ctx->len], p, l);
-		ctx->len +=l;
-		len -= l;
-		p += l;
-
-		if (ctx->len == bs) {
-			crypto_cipher_encrypt_one(tfm, ctx->dg, ctx->dg);
-			ctx->len = 0;
-		}
-	}
-
-	return 0;
+	u8 *dg = shash_desc_ctx(pdesc);
+
+	do {
+		crypto_xor(dg, p, bs);
+		crypto_cipher_encrypt_one(tfm, dg, dg);
+		p += bs;
+		len -= bs;
+	} while (len >= bs);
+	return len;
 }
 
-static int crypto_cbcmac_digest_final(struct shash_desc *pdesc, u8 *out)
+static int crypto_cbcmac_digest_finup(struct shash_desc *pdesc, const u8 *src,
+				      unsigned int len, u8 *out)
 {
 	struct crypto_shash *parent = pdesc->tfm;
 	struct cbcmac_tfm_ctx *tctx = crypto_shash_ctx(parent);
-	struct cbcmac_desc_ctx *ctx = shash_desc_ctx(pdesc);
 	struct crypto_cipher *tfm = tctx->child;
 	int bs = crypto_shash_digestsize(parent);
+	u8 *dg = shash_desc_ctx(pdesc);
 
-	if (ctx->len)
-		crypto_cipher_encrypt_one(tfm, ctx->dg, ctx->dg);
-
-	memcpy(out, ctx->dg, bs);
+	if (len) {
+		crypto_xor(dg, src, len);
+		crypto_cipher_encrypt_one(tfm, out, dg);
+		return 0;
+	}
+	memcpy(out, dg, bs);
 	return 0;
 }
 
@@ -886,16 +875,16 @@ static int cbcmac_create(struct crypto_template *tmpl, struct rtattr **tb)
 	inst->alg.base.cra_blocksize = alg->cra_blocksize;
 
 	inst->alg.digestsize = alg->cra_blocksize;
-	inst->alg.descsize = sizeof(struct cbcmac_desc_ctx) +
-			     alg->cra_blocksize;
+	inst->alg.descsize = alg->cra_blocksize;
 
+	inst->alg.base.cra_flags = CRYPTO_AHASH_ALG_BLOCK_ONLY;
 	inst->alg.base.cra_ctxsize = sizeof(struct cbcmac_tfm_ctx);
 	inst->alg.base.cra_init = cbcmac_init_tfm;
 	inst->alg.base.cra_exit = cbcmac_exit_tfm;
 
 	inst->alg.init = crypto_cbcmac_digest_init;
 	inst->alg.update = crypto_cbcmac_digest_update;
-	inst->alg.final = crypto_cbcmac_digest_final;
+	inst->alg.finup = crypto_cbcmac_digest_finup;
 	inst->alg.setkey = crypto_cbcmac_digest_setkey;
 
 	inst->free = shash_free_singlespawn_instance;
-- 
2.50.1