Don't use internal knowledge about EVP_MD_CTX in and MD BIO

There is no need for us to be diving inside the EVP_MD_CTX in the
implementation of an MD BIO. We can just use public APIs. By doing this
certain calls (such as getting the MD out of the BIO were not working
correctly) where providers are in use.

Reviewed-by: Richard Levitte <levitte@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/10116)

diff --git a/crypto/evp/bio_md.c b/crypto/evp/bio_md.c
index 8d502d0bf74a02e1b7e4688fc42b8080764da975..aca177e9da7b9aeef78ca2c9b1ba3b5bfb942f14 100644 (file)
--- a/crypto/evp/bio_md.c
+++ b/crypto/evp/bio_md.c
@@ -9,11 +9,8 @@
 
 #include <stdio.h>
 #include <errno.h>
-#include "internal/cryptlib.h"
 #include <openssl/buffer.h>
 #include <openssl/evp.h>
-#include "crypto/evp.h"
-#include "evp_local.h"
 #include "internal/bio.h"
 
 /*
@@ -148,7 +145,7 @@ static long md_ctrl(BIO *b, int cmd, long num, void *ptr)
     switch (cmd) {
     case BIO_CTRL_RESET:
         if (BIO_get_init(b))
-            ret = EVP_DigestInit_ex(ctx, ctx->digest, NULL);
+            ret = EVP_DigestInit_ex(ctx, EVP_MD_CTX_md(ctx), NULL);
         else
             ret = 0;
         if (ret > 0)
@@ -157,7 +154,7 @@ static long md_ctrl(BIO *b, int cmd, long num, void *ptr)
     case BIO_C_GET_MD:
         if (BIO_get_init(b)) {
             ppmd = ptr;
-            *ppmd = ctx->digest;
+            *ppmd = EVP_MD_CTX_md(ctx);
         } else
             ret = 0;
         break;
@@ -223,7 +220,7 @@ static int md_gets(BIO *bp, char *buf, int size)
 
     ctx = BIO_get_data(bp);
 
-    if (size < ctx->digest->md_size)
+    if (size < EVP_MD_CTX_size(ctx))
         return 0;
 
     if (EVP_DigestFinal_ex(ctx, (unsigned char *)buf, &ret) <= 0)