Ensure MD and key initialized before processing HMAC

Ensure both MD and key have been initialized before processing HMAC.
Releasing HMAC_CTX in error path of HMAC().
In regress test, added test 4,5,6 and cleaned up the code.

ok jsing@

1 files changed, 18 insertions, 4 deletions

diff --git a/lib/libcrypto/hmac/hmac.c b/lib/libcrypto/hmac/hmac.c
index 8fd980b0522..84917662ca8 100644
--- a/lib/libcrypto/hmac/hmac.c
+++ b/lib/libcrypto/hmac/hmac.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: hmac.c,v 1.23 2017/01/29 17:49:23 beck Exp $ */
+/* $OpenBSD: hmac.c,v 1.24 2017/03/03 10:39:07 inoguchi Exp $ */
 /* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
  * All rights reserved.
  *
@@ -70,11 +70,17 @@ HMAC_Init_ex(HMAC_CTX *ctx, const void *key, int len, const EVP_MD *md,
 	int i, j, reset = 0;
 	unsigned char pad[HMAC_MAX_MD_CBLOCK];
 
+	/* If we are changing MD then we must have a key */
+	if (md != NULL && md != ctx->md && (key == NULL || len < 0))
+		return 0;
+
 	if (md != NULL) {
 		reset = 1;
 		ctx->md = md;
-	} else
+	} else if (ctx->md != NULL)
 		md = ctx->md;
+	else
+		return 0;
 
 	if (key != NULL) {
 		reset = 1;
@@ -92,7 +98,7 @@ HMAC_Init_ex(HMAC_CTX *ctx, const void *key, int len, const EVP_MD *md,
 			    &ctx->key_length))
 				goto err;
 		} else {
-			if ((size_t)len > sizeof(ctx->key)) {
+			if (len < 0 || (size_t)len > sizeof(ctx->key)) {
 				EVPerror(EVP_R_BAD_KEY_LENGTH);
 				goto err;
 			}
@@ -137,6 +143,9 @@ HMAC_Init(HMAC_CTX *ctx, const void *key, int len, const EVP_MD *md)
 int
 HMAC_Update(HMAC_CTX *ctx, const unsigned char *data, size_t len)
 {
+	if (ctx->md == NULL)
+		return 0;
+
 	return EVP_DigestUpdate(&ctx->md_ctx, data, len);
 }
 
@@ -146,6 +155,9 @@ HMAC_Final(HMAC_CTX *ctx, unsigned char *md, unsigned int *len)
 	unsigned int i;
 	unsigned char buf[EVP_MAX_MD_SIZE];
 
+	if (ctx->md == NULL)
+		goto err;
+
 	if (!EVP_DigestFinal_ex(&ctx->md_ctx, buf, &i))
 		goto err;
 	if (!EVP_MD_CTX_copy_ex(&ctx->md_ctx, &ctx->o_ctx))
@@ -165,6 +177,7 @@ HMAC_CTX_init(HMAC_CTX *ctx)
 	EVP_MD_CTX_init(&ctx->i_ctx);
 	EVP_MD_CTX_init(&ctx->o_ctx);
 	EVP_MD_CTX_init(&ctx->md_ctx);
+	ctx->md = NULL;
 }
 
 int
@@ -190,7 +203,7 @@ HMAC_CTX_cleanup(HMAC_CTX *ctx)
 	EVP_MD_CTX_cleanup(&ctx->i_ctx);
 	EVP_MD_CTX_cleanup(&ctx->o_ctx);
 	EVP_MD_CTX_cleanup(&ctx->md_ctx);
-	memset(ctx, 0, sizeof *ctx);
+	explicit_bzero(ctx, sizeof(*ctx));
 }
 
 unsigned char *
@@ -212,6 +225,7 @@ HMAC(const EVP_MD *evp_md, const void *key, int key_len, const unsigned char *d,
 	HMAC_CTX_cleanup(&c);
 	return md;
 err:
+	HMAC_CTX_cleanup(&c);
 	return NULL;
 }