Add generic wrappers for performing message digest operations.

src/platform/vboot_reference/crypto/sha_utility.c

+/* Copyright (c) 2010 The Chromium OS Authors. All rights reserved.
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ *
+ * Utility functions for message digest functions.
+ */
+
+#include "sha_utility.h"
+
+#include <fcntl.h>
+#include <unistd.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+
+#include "sha.h"
+#include "utility.h"
+
+int digest_type_map[] = {
+  SHA1_DIGEST_ALGORITHM,  /* RSA 1024 */
+  SHA256_DIGEST_ALGORITHM,
+  SHA512_DIGEST_ALGORITHM,
+  SHA1_DIGEST_ALGORITHM,  /* RSA 2048 */
+  SHA256_DIGEST_ALGORITHM,
+  SHA512_DIGEST_ALGORITHM,
+  SHA1_DIGEST_ALGORITHM,  /* RSA 4096 */
+  SHA256_DIGEST_ALGORITHM,
+  SHA512_DIGEST_ALGORITHM,
+  SHA1_DIGEST_ALGORITHM,  /* RSA 8192 */
+  SHA256_DIGEST_ALGORITHM,
+  SHA512_DIGEST_ALGORITHM,
+};
+
+void DigestInit(DigestContext* ctx, int sig_algorithm) {
+  ctx->algorithm = digest_type_map[sig_algorithm];
+  switch(ctx->algorithm) {
+    case SHA1_DIGEST_ALGORITHM:
+      ctx->sha1_ctx = (SHA1_CTX*) Malloc(sizeof(SHA1_CTX));
+      SHA1_init(ctx->sha1_ctx);
+      break;
+    case SHA256_DIGEST_ALGORITHM:
+      ctx->sha256_ctx = (SHA256_CTX*) Malloc(sizeof(SHA256_CTX));
+      SHA256_init(ctx->sha256_ctx);
+      break;
+    case SHA512_DIGEST_ALGORITHM:
+      ctx->sha512_ctx = (SHA512_CTX*) Malloc(sizeof(SHA512_CTX));
+      SHA512_init(ctx->sha512_ctx);
+      break;
+  };
+}
+
+void DigestUpdate(DigestContext* ctx, const uint8_t* data, int len) {
+  switch(ctx->algorithm) {
+    case SHA1_DIGEST_ALGORITHM:
+      SHA1_update(ctx->sha1_ctx, data, len);
+      break;
+    case SHA256_DIGEST_ALGORITHM:
+      SHA256_update(ctx->sha256_ctx, data, len);
+      break;
+    case SHA512_DIGEST_ALGORITHM:
+      SHA512_update(ctx->sha512_ctx, data, len);
+      break;
+  };
+}
+
+uint8_t* DigestFinal(DigestContext* ctx) {
+  uint8_t* digest = NULL;
+  switch(ctx->algorithm) {
+    case SHA1_DIGEST_ALGORITHM:
+      digest = (uint8_t*) Malloc(SHA1_DIGEST_SIZE);
+      Memcpy(digest, SHA1_final(ctx->sha1_ctx), SHA1_DIGEST_SIZE);
+      Free(ctx->sha1_ctx);
+      break;
+    case SHA256_DIGEST_ALGORITHM:
+      digest = (uint8_t*) Malloc(SHA256_DIGEST_SIZE);
+      Memcpy(digest, SHA256_final(ctx->sha256_ctx), SHA256_DIGEST_SIZE);
+      Free(ctx->sha256_ctx);
+      break;
+    case SHA512_DIGEST_ALGORITHM:
+      digest = (uint8_t*) Malloc(SHA512_DIGEST_SIZE);
+      Memcpy(digest, SHA512_final(ctx->sha512_ctx), SHA512_DIGEST_SIZE);
+      Free(ctx->sha512_ctx);
+      break;
+  };
+  return digest;
+}
+
+uint8_t* DigestFile(char* input_file, int sig_algorithm) {
+  int input_fd, len;
+  uint8_t data[SHA1_BLOCK_SIZE];
+  uint8_t* digest = NULL;
+  DigestContext ctx;
+
+  if( (input_fd = open(input_file, O_RDONLY)) == -1 ) {
+    fprintf(stderr, "Couldn't open input file.\n");
+    return NULL;
+  }
+  DigestInit(&ctx, sig_algorithm);
+  while ( (len = read(input_fd, data, SHA1_BLOCK_SIZE)) ==
+          SHA1_BLOCK_SIZE)
+    DigestUpdate(&ctx, data, len);
+  if (len != -1)
+    DigestUpdate(&ctx, data, len);
+  digest = DigestFinal(&ctx);
+  close(input_fd);
+  return digest;
+}
+
+uint8_t* DigestBuf(uint8_t* buf, int len, int sig_algorithm) {

[Chris Masone, 2010/02/05 22:22:39]

some comments explaining what's going on in this fcn might help those whose C-fu
is a bit weak.  Function pointers can be mindbending.

+  uint8_t* digest = (uint8_t*) Malloc(SHA512_DIGEST_SIZE); /* Use the max. */
+  typedef uint8_t* (*Hash_ptr) (const uint8_t*, int, uint8_t*);
+  Hash_ptr hash[] = {
+    SHA1,  /* RSA 1024 */
+    SHA256,
+    SHA512,
+    SHA1,  /* RSA 2048 */
+    SHA256,
+    SHA512,
+    SHA1,  /* RSA 4096 */
+    SHA256,
+    SHA512,
+    SHA1,  /* RSA 8192 */
+    SHA256,
+    SHA512,
+  };
+  return hash[sig_algorithm](buf, len, digest);
+}