Revert "Fix bug in EVP_CIPHER_CTX_get_iv_length()"

This reverts commit f428e2112c6c795db76d804e0fcb36aac40f1477.

Reviewed-by: Hugo Landau <hlandau@openssl.org>
Reviewed-by: Dmitry Belyavskiy <beldmit@gmail.com>
(Merged from https://github.com/openssl/openssl/pull/18946)

1 files changed, 15 insertions, 30 deletions

diff --git a/crypto/evp/evp_lib.c b/crypto/evp/evp_lib.c
index 708583fea3..d5ae5ca4ad 100644
--- a/crypto/evp/evp_lib.c
+++ b/crypto/evp/evp_lib.c
@@ -504,36 +504,21 @@ int EVP_CIPHER_get_iv_length(const EVP_CIPHER *cipher)
 
 int EVP_CIPHER_CTX_get_iv_length(const EVP_CIPHER_CTX *ctx)
 {
-    if (ctx->iv_len < 0) {
-        int rv, len = EVP_CIPHER_get_iv_length(ctx->cipher);
-        size_t v = len;
-        OSSL_PARAM params[2] = { OSSL_PARAM_END, OSSL_PARAM_END };
-
-        if (ctx->cipher->get_ctx_params != NULL) {
-            params[0] = OSSL_PARAM_construct_size_t(OSSL_CIPHER_PARAM_IVLEN,
-                                                    &v);
-            rv = evp_do_ciph_ctx_getparams(ctx->cipher, ctx->algctx, params);
-            if (rv > 0) {
-                if (OSSL_PARAM_modified(params)
-                        && !OSSL_PARAM_get_int(params, &len))
-                    return -1;
-            } else if (rv != EVP_CTRL_RET_UNSUPPORTED) {
-                return -1;
-            }
-        }
-        /* Code below to be removed when legacy support is dropped. */
-        else if ((EVP_CIPHER_get_flags(ctx->cipher)
-                  & EVP_CIPH_CUSTOM_IV_LENGTH) != 0) {
-            rv = EVP_CIPHER_CTX_ctrl((EVP_CIPHER_CTX *)ctx, EVP_CTRL_GET_IVLEN,
-                                     0, &len);
-            if (rv <= 0)
-                return -1;
-        }
-        /*-
-         * Casting away the const is annoying but required here.  We need to
-         * cache the result for performance reasons.
-         */
-        ((EVP_CIPHER_CTX *)ctx)->iv_len = len;
+    int rv, len = EVP_CIPHER_get_iv_length(ctx->cipher);
+    size_t v = len;
+    OSSL_PARAM params[2] = { OSSL_PARAM_END, OSSL_PARAM_END };
+
+    params[0] = OSSL_PARAM_construct_size_t(OSSL_CIPHER_PARAM_IVLEN, &v);
+    rv = evp_do_ciph_ctx_getparams(ctx->cipher, ctx->algctx, params);
+    if (rv == EVP_CTRL_RET_UNSUPPORTED)
+        goto legacy;
+    return rv != 0 ? (int)v : -1;
+    /* Code below to be removed when legacy support is dropped. */
+legacy:
+    if ((EVP_CIPHER_get_flags(ctx->cipher) & EVP_CIPH_CUSTOM_IV_LENGTH) != 0) {
+        rv = EVP_CIPHER_CTX_ctrl((EVP_CIPHER_CTX *)ctx, EVP_CTRL_GET_IVLEN,
+                                 0, &len);
+        return (rv == 1) ? len : -1;
     }
     return len;
 }