Clean up EVP_CIPHER_CTX_init() usage in cmac.c

This replaces usage of EVP_CIPHER_CTX_init() with EVEP_CIPHER_CTX_new(),
and EVP_CIPHER_CTX_cleanup() with EVP_CIPHER_CTX_reset().

This also replaces usage of malloc with calloc, and free with freezero.

ok tb@

diff --git a/lib/libcrypto/cmac/cmac.c b/lib/libcrypto/cmac/cmac.c
index 9fe9076..29f5048 100644 (file)
--- a/lib/libcrypto/cmac/cmac.c
+++ b/lib/libcrypto/cmac/cmac.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: cmac.c,v 1.18 2023/12/18 21:15:00 tb Exp $ */
+/* $OpenBSD: cmac.c,v 1.19 2024/01/28 14:55:40 joshua Exp $ */
 /* Written by Dr Stephen N Henson (steve@openssl.org) for the OpenSSL
  * project.
  */
@@ -68,7 +68,7 @@
  * The temporary block tbl is a scratch buffer that holds intermediate secrets.
  */
 struct CMAC_CTX_st {
-       EVP_CIPHER_CTX cctx;
+       EVP_CIPHER_CTX *cipher_ctx;
        unsigned char k1[EVP_MAX_BLOCK_LENGTH];
        unsigned char k2[EVP_MAX_BLOCK_LENGTH];
        unsigned char tbl[EVP_MAX_BLOCK_LENGTH];
@@ -112,19 +112,26 @@ CMAC_CTX_new(void)
 {
        CMAC_CTX *ctx;
 
-       ctx = malloc(sizeof(CMAC_CTX));
-       if (!ctx)
-               return NULL;
-       EVP_CIPHER_CTX_init(&ctx->cctx);
+       if ((ctx = calloc(1, sizeof(CMAC_CTX))) == NULL)
+               goto err;
+       if ((ctx->cipher_ctx = EVP_CIPHER_CTX_new()) == NULL)
+               goto err;
+
        ctx->nlast_block = -1;
+
        return ctx;
+
+ err:
+       CMAC_CTX_free(ctx);
+
+       return NULL;
 }
 LCRYPTO_ALIAS(CMAC_CTX_new);
 
 void
 CMAC_CTX_cleanup(CMAC_CTX *ctx)
 {
-       EVP_CIPHER_CTX_cleanup(&ctx->cctx);
+       EVP_CIPHER_CTX_reset(ctx->cipher_ctx);
        explicit_bzero(ctx->tbl, EVP_MAX_BLOCK_LENGTH);
        explicit_bzero(ctx->k1, EVP_MAX_BLOCK_LENGTH);
        explicit_bzero(ctx->k2, EVP_MAX_BLOCK_LENGTH);
@@ -136,7 +143,7 @@ LCRYPTO_ALIAS(CMAC_CTX_cleanup);
 EVP_CIPHER_CTX *
 CMAC_CTX_get0_cipher_ctx(CMAC_CTX *ctx)
 {
-       return &ctx->cctx;
+       return ctx->cipher_ctx;
 }
 LCRYPTO_ALIAS(CMAC_CTX_get0_cipher_ctx);
 
@@ -147,7 +154,8 @@ CMAC_CTX_free(CMAC_CTX *ctx)
                return;
 
        CMAC_CTX_cleanup(ctx);
-       free(ctx);
+       EVP_CIPHER_CTX_free(ctx->cipher_ctx);
+       freezero(ctx, sizeof(CMAC_CTX));
 }
 LCRYPTO_ALIAS(CMAC_CTX_free);
 
@@ -158,9 +166,9 @@ CMAC_CTX_copy(CMAC_CTX *out, const CMAC_CTX *in)
 
        if (in->nlast_block == -1)
                return 0;
-       if (!EVP_CIPHER_CTX_copy(&out->cctx, &in->cctx))
+       if (!EVP_CIPHER_CTX_copy(out->cipher_ctx, in->cipher_ctx))
                return 0;
-       block_size = EVP_CIPHER_CTX_block_size(&in->cctx);
+       block_size = EVP_CIPHER_CTX_block_size(in->cipher_ctx);
        memcpy(out->k1, in->k1, block_size);
        memcpy(out->k2, in->k2, block_size);
        memcpy(out->tbl, in->tbl, block_size);
@@ -182,7 +190,7 @@ CMAC_Init(CMAC_CTX *ctx, const void *key, size_t keylen,
                /* Not initialised */
                if (ctx->nlast_block == -1)
                        return 0;
-               if (!EVP_EncryptInit_ex(&ctx->cctx, NULL, NULL, NULL, zero_iv))
+               if (!EVP_EncryptInit_ex(ctx->cipher_ctx, NULL, NULL, NULL, zero_iv))
                        return 0;
                explicit_bzero(ctx->tbl, sizeof(ctx->tbl));
                ctx->nlast_block = 0;
@@ -198,17 +206,17 @@ CMAC_Init(CMAC_CTX *ctx, const void *key, size_t keylen,
                 */
                if ((cipher->flags & EVP_CIPH_FLAG_CUSTOM_CIPHER) != 0)
                        return 0;
-               if (!EVP_EncryptInit_ex(&ctx->cctx, cipher, NULL, NULL, NULL))
+               if (!EVP_EncryptInit_ex(ctx->cipher_ctx, cipher, NULL, NULL, NULL))
                        return 0;
        }
 
        /* Non-NULL key means initialisation is complete. */
        if (key != NULL) {
-               if (EVP_CIPHER_CTX_cipher(&ctx->cctx) == NULL)
+               if (EVP_CIPHER_CTX_cipher(ctx->cipher_ctx) == NULL)
                        return 0;
 
                /* make_kn() only supports block sizes of 8 and 16 bytes. */
-               block_size = EVP_CIPHER_CTX_block_size(&ctx->cctx);
+               block_size = EVP_CIPHER_CTX_block_size(ctx->cipher_ctx);
                if (block_size != 8 && block_size != 16)
                        return 0;
 
@@ -216,11 +224,11 @@ CMAC_Init(CMAC_CTX *ctx, const void *key, size_t keylen,
                 * Section 6.1, step 1: store the intermediate secret CIPH_K(0)
                 * in ctx->tbl.
                 */
-               if (!EVP_CIPHER_CTX_set_key_length(&ctx->cctx, keylen))
+               if (!EVP_CIPHER_CTX_set_key_length(ctx->cipher_ctx, keylen))
                        return 0;
-               if (!EVP_EncryptInit_ex(&ctx->cctx, NULL, NULL, key, zero_iv))
+               if (!EVP_EncryptInit_ex(ctx->cipher_ctx, NULL, NULL, key, zero_iv))
                        return 0;
-               if (!EVP_Cipher(&ctx->cctx, ctx->tbl, zero_iv, block_size))
+               if (!EVP_Cipher(ctx->cipher_ctx, ctx->tbl, zero_iv, block_size))
                        return 0;
 
                /* Section 6.1, step 2: compute k1 from intermediate secret. */
@@ -233,7 +241,7 @@ CMAC_Init(CMAC_CTX *ctx, const void *key, size_t keylen,
                ctx->nlast_block = 0;
 
                /* Reset context again to get ready for the first data block. */
-               if (!EVP_EncryptInit_ex(&ctx->cctx, NULL, NULL, NULL, zero_iv))
+               if (!EVP_EncryptInit_ex(ctx->cipher_ctx, NULL, NULL, NULL, zero_iv))
                        return 0;
        }
 
@@ -251,7 +259,7 @@ CMAC_Update(CMAC_CTX *ctx, const void *in, size_t dlen)
                return 0;
        if (dlen == 0)
                return 1;
-       block_size = EVP_CIPHER_CTX_block_size(&ctx->cctx);
+       block_size = EVP_CIPHER_CTX_block_size(ctx->cipher_ctx);
        /* Copy into partial block if we need to */
        if (ctx->nlast_block > 0) {
                size_t nleft;
@@ -267,13 +275,13 @@ CMAC_Update(CMAC_CTX *ctx, const void *in, size_t dlen)
                        return 1;
                data += nleft;
                /* Else not final block so encrypt it */
-               if (!EVP_Cipher(&ctx->cctx, ctx->tbl, ctx->last_block,
+               if (!EVP_Cipher(ctx->cipher_ctx, ctx->tbl, ctx->last_block,
                    block_size))
                        return 0;
        }
        /* Encrypt all but one of the complete blocks left */
        while (dlen > block_size) {
-               if (!EVP_Cipher(&ctx->cctx, ctx->tbl, data, block_size))
+               if (!EVP_Cipher(ctx->cipher_ctx, ctx->tbl, data, block_size))
                        return 0;
                dlen -= block_size;
                data += block_size;
@@ -292,7 +300,7 @@ CMAC_Final(CMAC_CTX *ctx, unsigned char *out, size_t *poutlen)
 
        if (ctx->nlast_block == -1)
                return 0;
-       block_size = EVP_CIPHER_CTX_block_size(&ctx->cctx);
+       block_size = EVP_CIPHER_CTX_block_size(ctx->cipher_ctx);
        *poutlen = (size_t)block_size;
        if (!out)
                return 1;
@@ -308,7 +316,7 @@ CMAC_Final(CMAC_CTX *ctx, unsigned char *out, size_t *poutlen)
                for (i = 0; i < block_size; i++)
                        out[i] = ctx->last_block[i] ^ ctx->k2[i];
        }
-       if (!EVP_Cipher(&ctx->cctx, out, out, block_size)) {
+       if (!EVP_Cipher(ctx->cipher_ctx, out, out, block_size)) {
                explicit_bzero(out, block_size);
                return 0;
        }
@@ -327,6 +335,6 @@ CMAC_resume(CMAC_CTX *ctx)
         * So reinitialising using the last decrypted block will allow
         * CMAC to continue after calling CMAC_Final().
         */
-       return EVP_EncryptInit_ex(&ctx->cctx, NULL, NULL, NULL, ctx->tbl);
+       return EVP_EncryptInit_ex(ctx->cipher_ctx, NULL, NULL, NULL, ctx->tbl);
 }
 LCRYPTO_ALIAS(CMAC_resume);