From: tb <tb@openbsd.org>
Date: Tue, 26 Dec 2023 08:39:28 +0000 (+0000)
Subject: EVP_CipherInit_ex() merge two code paths
X-Git-Url: http://artulab.com/gitweb/?a=commitdiff_plain;h=522874ac1bcf47333cf371da2055e3bdbd8dbd14;p=openbsd

EVP_CipherInit_ex() merge two code paths

Clean up the cipher context unconditionally if the cipher is being set.
This allows doing the dance to retain the key wrap flag only once and
makes it more obvious that allocating the cipher data doesn't leak.

suggested by/ok jsing
---

diff --git a/lib/libcrypto/evp/evp_enc.c b/lib/libcrypto/evp/evp_enc.c
index 1bde05f4935..7c25b59dce5 100644
--- a/lib/libcrypto/evp/evp_enc.c
+++ b/lib/libcrypto/evp/evp_enc.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: evp_enc.c,v 1.79 2023/12/23 13:05:06 tb Exp $ */
+/* $OpenBSD: evp_enc.c,v 1.80 2023/12/26 08:39:28 tb Exp $ */
 /* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
  * All rights reserved.
  *
@@ -93,23 +93,18 @@ EVP_CipherInit_ex(EVP_CIPHER_CTX *ctx, const EVP_CIPHER *cipher, ENGINE *engine,
 	}
 
 	/*
-	 * If the ctx is reused and a cipher is passed in, reset the ctx but
-	 * remember enc and whether key wrap was enabled.
+	 * Set up cipher and context. Allocate cipher data and initialize ctx.
+	 * On ctx reuse only retain encryption direction and key wrap flag.
 	 */
-	if (cipher != NULL && ctx->cipher != NULL) {
+	if (cipher != NULL) {
 		unsigned long flags = ctx->flags;
 
 		EVP_CIPHER_CTX_cleanup(ctx);
-
 		ctx->encrypt = enc;
 		ctx->flags = flags & EVP_CIPHER_CTX_FLAG_WRAP_ALLOW;
-	}
 
-	/* Set up cipher. Allocate cipher data and initialize if necessary. */
-	if (cipher != NULL) {
 		ctx->cipher = cipher;
 		ctx->key_len = cipher->key_len;
-		ctx->flags &= EVP_CIPHER_CTX_FLAG_WRAP_ALLOW;
 
 		if (ctx->cipher->ctx_size != 0) {
 			ctx->cipher_data = calloc(1, ctx->cipher->ctx_size);