s390x: AES OFB/CFB: Maintain running IV from cipher context

Copy the current IV from the cipher context into the kmo/kmf param before
the operation, and copy the modified IV back to the context afterwards.
Without this, an application that obtains the running IV from the context
would still get the original IV, but not the updated one.

This implementation in e_aes.c now matches the code in cipher_aes_hw_s390x.inc
that is used for the provider implementation.

Signed-off-by: Ingo Franzki <ifranzki@linux.ibm.com>

Reviewed-by: Patrick Steuer <patrick.steuer@de.ibm.com>
Reviewed-by: Tomas Mraz <tomas@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/16291)

crypto/evp/e_aes.c

@@ -1010,9 +1010,12 @@ static int s390x_aes_ofb_cipher(EVP_CIPHER_CTX *ctx, unsigned char *out,
                                 const unsigned char *in, size_t len)
 {
     S390X_AES_OFB_CTX *cctx = EVP_C_DATA(S390X_AES_OFB_CTX, ctx);
+    const int ivlen = EVP_CIPHER_CTX_get_iv_length(ctx);
+    unsigned char *iv = EVP_CIPHER_CTX_iv_noconst(ctx);
     int n = cctx->res;
     int rem;
 
+    memcpy(cctx->kmo.param.cv, iv, ivlen);
     while (n && len) {
         *out = *in ^ cctx->kmo.param.cv[n];
         n = (n + 1) & 0xf;
@@ -1041,6 +1044,7 @@ static int s390x_aes_ofb_cipher(EVP_CIPHER_CTX *ctx, unsigned char *out,
         }
     }
 
+    memcpy(iv, cctx->kmo.param.cv, ivlen);
     cctx->res = n;
     return 1;
 }
@@ -1071,10 +1075,13 @@ static int s390x_aes_cfb_cipher(EVP_CIPHER_CTX *ctx, unsigned char *out,
     S390X_AES_CFB_CTX *cctx = EVP_C_DATA(S390X_AES_CFB_CTX, ctx);
     const int keylen = EVP_CIPHER_CTX_get_key_length(ctx);
     const int enc = EVP_CIPHER_CTX_is_encrypting(ctx);
+    const int ivlen = EVP_CIPHER_CTX_get_iv_length(ctx);
+    unsigned char *iv = EVP_CIPHER_CTX_iv_noconst(ctx);
     int n = cctx->res;
     int rem;
     unsigned char tmp;
 
+    memcpy(cctx->kmf.param.cv, iv, ivlen);
     while (n && len) {
         tmp = *in;
         *out = cctx->kmf.param.cv[n] ^ tmp;
@@ -1107,6 +1114,7 @@ static int s390x_aes_cfb_cipher(EVP_CIPHER_CTX *ctx, unsigned char *out,
         }
     }
 
+    memcpy(iv, cctx->kmf.param.cv, ivlen);
     cctx->res = n;
     return 1;
 }
@@ -1134,8 +1142,12 @@ static int s390x_aes_cfb8_cipher(EVP_CIPHER_CTX *ctx, unsigned char *out,
                                  const unsigned char *in, size_t len)
 {
     S390X_AES_CFB_CTX *cctx = EVP_C_DATA(S390X_AES_CFB_CTX, ctx);
+    const int ivlen = EVP_CIPHER_CTX_get_iv_length(ctx);
+    unsigned char *iv = EVP_CIPHER_CTX_iv_noconst(ctx);
 
+    memcpy(cctx->kmf.param.cv, iv, ivlen);
     s390x_kmf(in, len, out, cctx->fc, &cctx->kmf.param);
+    memcpy(iv, cctx->kmf.param.cv, ivlen);
     return 1;
 }