Better error messages, allow larger-than-needed input when reading.

src/platform/vboot_reference/misclibs/file_keys.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 file and key handling.
  */
 
 #include "file_keys.h"
 
 #include <fcntl.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
 #include <sys/stat.h>
 #include <sys/types.h>
 #include <unistd.h>
 
 #include "cryptolib.h"
 #include "signature_digest.h"
 #include "utility.h"
 
 uint8_t* BufferFromFile(const char* input_file, uint64_t* len) {
   int fd;
   struct stat stat_fd;
   uint8_t* buf = NULL;
 
   if ((fd = open(input_file, O_RDONLY)) == -1) {
-    debug("Couldn't open file.\n");
+    debug("Couldn't open file %s\n", input_file);
     return NULL;
   }
 
   if (-1 == fstat(fd, &stat_fd)) {
-    debug("Couldn't stat file.\n");
+    debug("Couldn't stat file %s\n", input_file);
     return NULL;
   }
   *len = stat_fd.st_size;
 
   buf = (uint8_t*) Malloc(*len);
   if (!buf) {
-    error("Couldn't allocate %ld bytes.\n", *len);
+    error("Couldn't allocate %ld bytes for file %s\n", *len, input_file);
     return NULL;
   }
 
   if (*len != read(fd, buf, *len)) {
-    debug("Couldn't read file into a buffer.\n");
+    debug("Couldn't read file %s into a buffer\n", input_file);
     return NULL;
   }
 
   close(fd);
   return buf;
 }
 
 RSAPublicKey* RSAPublicKeyFromFile(const char* input_file) {
   uint64_t len;
   RSAPublicKey* key = NULL;
   uint8_t* buf = BufferFromFile(input_file, &len);
   if (buf)
     key = RSAPublicKeyFromBuf(buf, len);
   Free(buf);
   return key;
 }
 
 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 ) {
-    debug("Couldn't open input file.\n");
+    debug("Couldn't open %s\n", input_file);
     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);
@@ skipping 31 matching lines @@
   if (fread(signature, signature_size, 1, cmd_out) != 1) {
     debug("Couldn't read signature.\n");
     pclose(cmd_out);
     Free(signature);
     return NULL;
   }
 
   pclose(cmd_out);
   return signature;
 }