Simplify EVP code for AES CBC.

Change aes_cbc_cipher() to call AES_cbc_encrypt() directly, rather than
via the stream.cbc function pointer. Remove stream.cbc since it is no
longer used. Also provide a separate aes_cbc_init_key() function which
makes this standalone and does not require checking mode flags.

ok joshua@ tb@

1 files changed, 33 insertions, 26 deletions

diff --git a/src/lib/libcrypto/evp/e_aes.c b/src/lib/libcrypto/evp/e_aes.c
index f672c998eb..59ed9e93e2 100644
--- a/src/lib/libcrypto/evp/e_aes.c
+++ b/src/lib/libcrypto/evp/e_aes.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: e_aes.c,v 1.62 2025/05/10 05:54:38 tb Exp $ */
+/* $OpenBSD: e_aes.c,v 1.63 2025/05/18 09:47:38 jsing Exp $ */
 /* ====================================================================
  * Copyright (c) 2001-2011 The OpenSSL Project.  All rights reserved.
  *
@@ -69,7 +69,6 @@ typedef struct {
         AES_KEY ks;
         block128_f block;
         union {
-                cbc128_f cbc;
                 ctr128_f ctr;
         } stream;
 } EVP_AES_KEY;
@@ -175,24 +174,21 @@ aesni_init_key(EVP_CIPHER_CTX *ctx, const unsigned char *key,
         int ret, mode;
         EVP_AES_KEY *dat = (EVP_AES_KEY *)ctx->cipher_data;
 
+        dat->stream.ctr = NULL;
+
         mode = ctx->cipher->flags & EVP_CIPH_MODE;
+
         if ((mode == EVP_CIPH_ECB_MODE || mode == EVP_CIPH_CBC_MODE) &&
             !enc) {
                 ret = aesni_set_decrypt_key(key, ctx->key_len * 8,
                     ctx->cipher_data);
                 dat->block = (block128_f)aesni_decrypt;
-                dat->stream.cbc = mode == EVP_CIPH_CBC_MODE ?
-                    (cbc128_f)aesni_cbc_encrypt : NULL;
         } else {
                 ret = aesni_set_encrypt_key(key, ctx->key_len * 8,
                     ctx->cipher_data);
                 dat->block = (block128_f)aesni_encrypt;
-                if (mode == EVP_CIPH_CBC_MODE)
-                        dat->stream.cbc = (cbc128_f)aesni_cbc_encrypt;
-                else if (mode == EVP_CIPH_CTR_MODE)
+                if (mode == EVP_CIPH_CTR_MODE)
                         dat->stream.ctr = (ctr128_f)aesni_ctr32_encrypt_blocks;
-                else
-                        dat->stream.cbc = NULL;
         }
 
         if (ret < 0) {
@@ -332,18 +328,16 @@ aes_init_key(EVP_CIPHER_CTX *ctx, const unsigned char *key,
         int ret, mode;
         EVP_AES_KEY *dat = (EVP_AES_KEY *)ctx->cipher_data;
 
+        dat->stream.ctr = NULL;
+
         mode = ctx->cipher->flags & EVP_CIPH_MODE;
 
         if ((mode == EVP_CIPH_ECB_MODE || mode == EVP_CIPH_CBC_MODE) && !enc) {
                 ret = AES_set_decrypt_key(key, ctx->key_len * 8, &dat->ks);
                 dat->block = (block128_f)AES_decrypt;
-                dat->stream.cbc = mode == EVP_CIPH_CBC_MODE ?
-                    (cbc128_f)AES_cbc_encrypt : NULL;
         } else {
                 ret = AES_set_encrypt_key(key, ctx->key_len * 8, &dat->ks);
                 dat->block = (block128_f)AES_encrypt;
-                dat->stream.cbc = mode == EVP_CIPH_CBC_MODE ?
-                    (cbc128_f)AES_cbc_encrypt : NULL;
 #ifdef AES_CTR_ASM
                 if (mode == EVP_CIPH_CTR_MODE)
                         dat->stream.ctr = (ctr128_f)AES_ctr32_encrypt;
@@ -359,20 +353,33 @@ aes_init_key(EVP_CIPHER_CTX *ctx, const unsigned char *key,
 }
 
 static int
+aes_cbc_init_key(EVP_CIPHER_CTX *ctx, const unsigned char *key,
+    const unsigned char *iv, int encrypt)
+{
+        EVP_AES_KEY *eak = ctx->cipher_data;
+
+        if (encrypt) {
+                if (AES_set_encrypt_key(key, ctx->key_len * 8, &eak->ks) < 0) {
+                        EVPerror(EVP_R_AES_KEY_SETUP_FAILED);
+                        return 0;
+                }
+        } else {
+                if (AES_set_decrypt_key(key, ctx->key_len * 8, &eak->ks) < 0) {
+                        EVPerror(EVP_R_AES_KEY_SETUP_FAILED);
+                        return 0;
+                }
+        }
+
+        return 1;
+}
+
+static int
 aes_cbc_cipher(EVP_CIPHER_CTX *ctx, unsigned char *out,
     const unsigned char *in, size_t len)
 {
-        EVP_AES_KEY *dat = (EVP_AES_KEY *)ctx->cipher_data;
+        EVP_AES_KEY *eak = ctx->cipher_data;
 
-        if (dat->stream.cbc)
-                (*dat->stream.cbc)(in, out, len, &dat->ks, ctx->iv,
-                    ctx->encrypt);
-        else if (ctx->encrypt)
-                CRYPTO_cbc128_encrypt(in, out, len, &dat->ks, ctx->iv,
-                    dat->block);
-        else
-                CRYPTO_cbc128_decrypt(in, out, len, &dat->ks, ctx->iv,
-                    dat->block);
+        AES_cbc_encrypt(in, out, len, &eak->ks, ctx->iv, ctx->encrypt);
 
         return 1;
 }
@@ -490,7 +497,7 @@ static const EVP_CIPHER aes_128_cbc = {
         .key_len = 16,
         .iv_len = 16,
         .flags = EVP_CIPH_FLAG_DEFAULT_ASN1 | EVP_CIPH_CBC_MODE,
-        .init = aes_init_key,
+        .init = aes_cbc_init_key,
         .do_cipher = aes_cbc_cipher,
         .ctx_size = sizeof(EVP_AES_KEY),
 };
@@ -736,7 +743,7 @@ static const EVP_CIPHER aes_192_cbc = {
         .key_len = 24,
         .iv_len = 16,
         .flags = EVP_CIPH_FLAG_DEFAULT_ASN1 | EVP_CIPH_CBC_MODE,
-        .init = aes_init_key,
+        .init = aes_cbc_init_key,
         .do_cipher = aes_cbc_cipher,
         .ctx_size = sizeof(EVP_AES_KEY),
 };
@@ -982,7 +989,7 @@ static const EVP_CIPHER aes_256_cbc = {
         .key_len = 32,
         .iv_len = 16,
         .flags = EVP_CIPH_FLAG_DEFAULT_ASN1 | EVP_CIPH_CBC_MODE,
-        .init = aes_init_key,
+        .init = aes_cbc_init_key,
         .do_cipher = aes_cbc_cipher,
         .ctx_size = sizeof(EVP_AES_KEY),
 };