Don't store an HMAC key for longer than we need

[openssl.git] / crypto / hmac / hmac.c

diff --git a/crypto/hmac/hmac.c b/crypto/hmac/hmac.c
index e4031b44a576c636a993064371456b323ccad567..a94550a37a96ced3c5266572ac1f94e5c67e70d5 100644 (file)
--- a/crypto/hmac/hmac.c
+++ b/crypto/hmac/hmac.c
@@ -1,7 +1,7 @@
 /*
  * Copyright 1995-2018 The OpenSSL Project Authors. All Rights Reserved.
  *
 /*
  * Copyright 1995-2018 The OpenSSL Project Authors. All Rights Reserved.
  *

- * Licensed under the OpenSSL license (the "License").  You may not use
+ * Licensed under the Apache License 2.0 (the "License").  You may not use

  * this file except in compliance with the License.  You can obtain a copy
  * in the file LICENSE in the source distribution or at
  * https://www.openssl.org/source/license.html
  * this file except in compliance with the License.  You can obtain a copy
  * in the file LICENSE in the source distribution or at
  * https://www.openssl.org/source/license.html


@@ -13,21 +13,22 @@
 #include "internal/cryptlib.h"
 #include <openssl/hmac.h>
 #include <openssl/opensslconf.h>
 #include "internal/cryptlib.h"
 #include <openssl/hmac.h>
 #include <openssl/opensslconf.h>

-#include "hmac_lcl.h"
+#include "hmac_local.h"

 
 int HMAC_Init_ex(HMAC_CTX *ctx, const void *key, int len,
                  const EVP_MD *md, ENGINE *impl)
 {
 
 int HMAC_Init_ex(HMAC_CTX *ctx, const void *key, int len,
                  const EVP_MD *md, ENGINE *impl)
 {

-    int rv = 0;
-    int i, j, reset = 0;
+    int rv = 0, reset = 0;
+    int i, j;

     unsigned char pad[HMAC_MAX_MD_CBLOCK_SIZE];
     unsigned char pad[HMAC_MAX_MD_CBLOCK_SIZE];

+    unsigned int keytmp_length;
+    unsigned char keytmp[HMAC_MAX_MD_CBLOCK_SIZE];

 
     /* 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) {
 
     /* 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 if (ctx->md) {
         md = ctx->md;
         ctx->md = md;
     } else if (ctx->md) {
         md = ctx->md;


@@ -35,37 +36,43 @@ int HMAC_Init_ex(HMAC_CTX *ctx, const void *key, int len,
         return 0;
     }
 
         return 0;
     }
 

+    /*
+     * The HMAC construction is not allowed to be used with the
+     * extendable-output functions (XOF) shake128 and shake256.
+     */
+    if ((EVP_MD_flags(md) & EVP_MD_FLAG_XOF) != 0)
+        return 0;
+

     if (key != NULL) {
         reset = 1;
     if (key != NULL) {
         reset = 1;

+

         j = EVP_MD_block_size(md);
         j = EVP_MD_block_size(md);

-        if (!ossl_assert(j <= (int)sizeof(ctx->key)))
+        if (!ossl_assert(j <= (int)sizeof(keytmp)))

             return 0;
         if (j < len) {
             if (!EVP_DigestInit_ex(ctx->md_ctx, md, impl)
                     || !EVP_DigestUpdate(ctx->md_ctx, key, len)
             return 0;
         if (j < len) {
             if (!EVP_DigestInit_ex(ctx->md_ctx, md, impl)
                     || !EVP_DigestUpdate(ctx->md_ctx, key, len)

-                    || !EVP_DigestFinal_ex(ctx->md_ctx, ctx->key,
-                                           &ctx->key_length))
+                    || !EVP_DigestFinal_ex(ctx->md_ctx, keytmp,
+                                           &keytmp_length))

                 return 0;
         } else {
                 return 0;
         } else {

-            if (len < 0 || len > (int)sizeof(ctx->key))
+            if (len < 0 || len > (int)sizeof(keytmp))

                 return 0;
                 return 0;

-            memcpy(ctx->key, key, len);
-            ctx->key_length = len;
+            memcpy(keytmp, key, len);
+            keytmp_length = len;

         }
         }

-        if (ctx->key_length != HMAC_MAX_MD_CBLOCK_SIZE)
-            memset(&ctx->key[ctx->key_length], 0,
-                   HMAC_MAX_MD_CBLOCK_SIZE - ctx->key_length);
-    }
+        if (keytmp_length != HMAC_MAX_MD_CBLOCK_SIZE)
+            memset(&keytmp[keytmp_length], 0,
+                   HMAC_MAX_MD_CBLOCK_SIZE - keytmp_length);

 
 

-    if (reset) {

         for (i = 0; i < HMAC_MAX_MD_CBLOCK_SIZE; i++)
         for (i = 0; i < HMAC_MAX_MD_CBLOCK_SIZE; i++)

-            pad[i] = 0x36 ^ ctx->key[i];
+            pad[i] = 0x36 ^ keytmp[i];

         if (!EVP_DigestInit_ex(ctx->i_ctx, md, impl)
                 || !EVP_DigestUpdate(ctx->i_ctx, pad, EVP_MD_block_size(md)))
             goto err;
 
         for (i = 0; i < HMAC_MAX_MD_CBLOCK_SIZE; i++)
         if (!EVP_DigestInit_ex(ctx->i_ctx, md, impl)
                 || !EVP_DigestUpdate(ctx->i_ctx, pad, EVP_MD_block_size(md)))
             goto err;
 
         for (i = 0; i < HMAC_MAX_MD_CBLOCK_SIZE; i++)

-            pad[i] = 0x5c ^ ctx->key[i];
+            pad[i] = 0x5c ^ keytmp[i];

         if (!EVP_DigestInit_ex(ctx->o_ctx, md, impl)
                 || !EVP_DigestUpdate(ctx->o_ctx, pad, EVP_MD_block_size(md)))
             goto err;
         if (!EVP_DigestInit_ex(ctx->o_ctx, md, impl)
                 || !EVP_DigestUpdate(ctx->o_ctx, pad, EVP_MD_block_size(md)))
             goto err;


@@ -74,12 +81,14 @@ int HMAC_Init_ex(HMAC_CTX *ctx, const void *key, int len,
         goto err;
     rv = 1;
  err:
         goto err;
     rv = 1;
  err:

-    if (reset)
+    if (reset) {
+        OPENSSL_cleanse(keytmp, sizeof(keytmp));

         OPENSSL_cleanse(pad, sizeof(pad));
         OPENSSL_cleanse(pad, sizeof(pad));

+    }

     return rv;
 }
 
     return rv;
 }
 

-#if OPENSSL_API_COMPAT < 0x10100000L
+#ifndef OPENSSL_NO_DEPRECATED_1_1_0

 int HMAC_Init(HMAC_CTX *ctx, const void *key, int len, const EVP_MD *md)
 {
     if (key && md)
 int HMAC_Init(HMAC_CTX *ctx, const void *key, int len, const EVP_MD *md)
 {
     if (key && md)


@@ -142,8 +151,6 @@ static void hmac_ctx_cleanup(HMAC_CTX *ctx)
     EVP_MD_CTX_reset(ctx->o_ctx);
     EVP_MD_CTX_reset(ctx->md_ctx);
     ctx->md = NULL;
     EVP_MD_CTX_reset(ctx->o_ctx);
     EVP_MD_CTX_reset(ctx->md_ctx);
     ctx->md = NULL;

-    ctx->key_length = 0;
-    OPENSSL_cleanse(ctx->key, sizeof(ctx->key));

 }
 
 void HMAC_CTX_free(HMAC_CTX *ctx)
 }
 
 void HMAC_CTX_free(HMAC_CTX *ctx)


@@ -194,8 +201,6 @@ int HMAC_CTX_copy(HMAC_CTX *dctx, HMAC_CTX *sctx)
         goto err;
     if (!EVP_MD_CTX_copy_ex(dctx->md_ctx, sctx->md_ctx))
         goto err;
         goto err;
     if (!EVP_MD_CTX_copy_ex(dctx->md_ctx, sctx->md_ctx))
         goto err;

-    memcpy(dctx->key, sctx->key, HMAC_MAX_MD_CBLOCK_SIZE);
-    dctx->key_length = sctx->key_length;

     dctx->md = sctx->md;
     return 1;
  err:
     dctx->md = sctx->md;
     return 1;
  err: