Adapt HMAC to the EVP_MD_CTX changes

This change required some special treatment, as HMAC is intertwined
with EVP_MD.  For now, all local HMAC_CTX variables MUST be
initialised with HMAC_CTX_EMPTY, or whatever happens to be on the
stack will be mistaken for actual pointers to EVP_MD_CTX.  This will
change as soon as HMAC_CTX becomes opaque.

Also, since HMAC_CTX_init() can fail now, its return type changes from
void to int, and it will return 0 on failure, 1 on success.

Reviewed-by: Rich Salz <rsalz@openssl.org>

1 files changed, 50 insertions, 29 deletions

diff --git a/crypto/hmac/hmac.c b/crypto/hmac/hmac.c
index 7699b0b..e0bfbb1 100644
--- a/crypto/hmac/hmac.c
+++ b/crypto/hmac/hmac.c
@@ -83,14 +83,14 @@ int HMAC_Init_ex(HMAC_CTX *ctx, const void *key, int len,
 
     if (key != NULL) {
         reset = 1;
-        j = M_EVP_MD_block_size(md);
+        j = EVP_MD_block_size(md);
         OPENSSL_assert(j <= (int)sizeof(ctx->key));
         if (j < len) {
-            if (!EVP_DigestInit_ex(&ctx->md_ctx, md, impl))
+            if (!EVP_DigestInit_ex(ctx->md_ctx, md, impl))
                 goto err;
-            if (!EVP_DigestUpdate(&ctx->md_ctx, key, len))
+            if (!EVP_DigestUpdate(ctx->md_ctx, key, len))
                 goto err;
-            if (!EVP_DigestFinal_ex(&(ctx->md_ctx), ctx->key,
+            if (!EVP_DigestFinal_ex(ctx->md_ctx, ctx->key,
                                     &ctx->key_length))
                 goto err;
         } else {
@@ -107,19 +107,19 @@ int HMAC_Init_ex(HMAC_CTX *ctx, const void *key, int len,
     if (reset) {
         for (i = 0; i < HMAC_MAX_MD_CBLOCK; i++)
             pad[i] = 0x36 ^ ctx->key[i];
-        if (!EVP_DigestInit_ex(&ctx->i_ctx, md, impl))
+        if (!EVP_DigestInit_ex(ctx->i_ctx, md, impl))
             goto err;
-        if (!EVP_DigestUpdate(&ctx->i_ctx, pad, M_EVP_MD_block_size(md)))
+        if (!EVP_DigestUpdate(ctx->i_ctx, pad, EVP_MD_block_size(md)))
             goto err;
 
         for (i = 0; i < HMAC_MAX_MD_CBLOCK; i++)
             pad[i] = 0x5c ^ ctx->key[i];
-        if (!EVP_DigestInit_ex(&ctx->o_ctx, md, impl))
+        if (!EVP_DigestInit_ex(ctx->o_ctx, md, impl))
             goto err;
-        if (!EVP_DigestUpdate(&ctx->o_ctx, pad, M_EVP_MD_block_size(md)))
+        if (!EVP_DigestUpdate(ctx->o_ctx, pad, EVP_MD_block_size(md)))
             goto err;
     }
-    if (!EVP_MD_CTX_copy_ex(&ctx->md_ctx, &ctx->i_ctx))
+    if (!EVP_MD_CTX_copy_ex(ctx->md_ctx, ctx->i_ctx))
         goto err;
     return 1;
  err:
@@ -139,7 +139,7 @@ int HMAC_Update(HMAC_CTX *ctx, const unsigned char *data, size_t len)
 {
     if (!ctx->md)
         return 0;
-    return EVP_DigestUpdate(&ctx->md_ctx, data, len);
+    return EVP_DigestUpdate(ctx->md_ctx, data, len);
 }
 
 int HMAC_Final(HMAC_CTX *ctx, unsigned char *md, unsigned int *len)
@@ -150,49 +150,70 @@ int HMAC_Final(HMAC_CTX *ctx, unsigned char *md, unsigned int *len)
     if (!ctx->md)
         goto err;
 
-    if (!EVP_DigestFinal_ex(&ctx->md_ctx, buf, &i))
+    if (!EVP_DigestFinal_ex(ctx->md_ctx, buf, &i))
         goto err;
-    if (!EVP_MD_CTX_copy_ex(&ctx->md_ctx, &ctx->o_ctx))
+    if (!EVP_MD_CTX_copy_ex(ctx->md_ctx, ctx->o_ctx))
         goto err;
-    if (!EVP_DigestUpdate(&ctx->md_ctx, buf, i))
+    if (!EVP_DigestUpdate(ctx->md_ctx, buf, i))
         goto err;
-    if (!EVP_DigestFinal_ex(&ctx->md_ctx, md, len))
+    if (!EVP_DigestFinal_ex(ctx->md_ctx, md, len))
         goto err;
     return 1;
  err:
     return 0;
 }
 
-void HMAC_CTX_init(HMAC_CTX *ctx)
+int 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);
+    if (ctx->i_ctx == NULL)
+        ctx->i_ctx = EVP_MD_CTX_create();
+    else
+        EVP_MD_CTX_init(ctx->i_ctx);
+    if (ctx->i_ctx == NULL)
+        goto err;
+    if (ctx->o_ctx == NULL)
+        ctx->o_ctx = EVP_MD_CTX_create();
+    else
+        EVP_MD_CTX_init(ctx->o_ctx);
+    if (ctx->o_ctx == NULL)
+        goto err;
+    if (ctx->md_ctx == NULL)
+        ctx->md_ctx = EVP_MD_CTX_create();
+    else
+        EVP_MD_CTX_init(ctx->md_ctx);
+    if (ctx->md_ctx == NULL)
+        goto err;
     ctx->md = NULL;
+    return 1;
+ err:
+    HMAC_CTX_cleanup(ctx);
+    return 0;
 }
 
 int HMAC_CTX_copy(HMAC_CTX *dctx, HMAC_CTX *sctx)
 {
-    HMAC_CTX_init(dctx);
-    if (!EVP_MD_CTX_copy_ex(&dctx->i_ctx, &sctx->i_ctx))
+    if (!HMAC_CTX_init(dctx))
+        goto err;
+    if (!EVP_MD_CTX_copy_ex(dctx->i_ctx, sctx->i_ctx))
         goto err;
-    if (!EVP_MD_CTX_copy_ex(&dctx->o_ctx, &sctx->o_ctx))
+    if (!EVP_MD_CTX_copy_ex(dctx->o_ctx, sctx->o_ctx))
         goto err;
-    if (!EVP_MD_CTX_copy_ex(&dctx->md_ctx, &sctx->md_ctx))
+    if (!EVP_MD_CTX_copy_ex(dctx->md_ctx, sctx->md_ctx))
         goto err;
     memcpy(dctx->key, sctx->key, HMAC_MAX_MD_CBLOCK);
     dctx->key_length = sctx->key_length;
     dctx->md = sctx->md;
     return 1;
  err:
+    HMAC_CTX_cleanup(dctx);
     return 0;
 }
 
 void 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);
+    EVP_MD_CTX_destroy(ctx->i_ctx);
+    EVP_MD_CTX_destroy(ctx->o_ctx);
+    EVP_MD_CTX_destroy(ctx->md_ctx);
     memset(ctx, 0, sizeof(*ctx));
 }
 
@@ -200,7 +221,7 @@ unsigned char *HMAC(const EVP_MD *evp_md, const void *key, int key_len,
                     const unsigned char *d, size_t n, unsigned char *md,
                     unsigned int *md_len)
 {
-    HMAC_CTX c;
+    HMAC_CTX c = HMAC_CTX_EMPTY;
     static unsigned char m[EVP_MAX_MD_SIZE];
 
     if (md == NULL)
@@ -221,7 +242,7 @@ unsigned char *HMAC(const EVP_MD *evp_md, const void *key, int key_len,
 
 void HMAC_CTX_set_flags(HMAC_CTX *ctx, unsigned long flags)
 {
-    M_EVP_MD_CTX_set_flags(&ctx->i_ctx, flags);
-    M_EVP_MD_CTX_set_flags(&ctx->o_ctx, flags);
-    M_EVP_MD_CTX_set_flags(&ctx->md_ctx, flags);
+    EVP_MD_CTX_set_flags(ctx->i_ctx, flags);
+    EVP_MD_CTX_set_flags(ctx->o_ctx, flags);
+    EVP_MD_CTX_set_flags(ctx->md_ctx, flags);
 }