Step to UEFI (58) —– 计算MD5

MD5 是目前常用的Hash算法,可以用来校验文件的完整性,或者比对密码等等。本文介绍如何在UEFI下实现计算一个文件MD5的方法。具体算法来自【参考1】,在编译过程中修正了几个关于类型转换的 Warning 。

程序结构很简单,和前一篇关于CRC32的没有多大差别。

#include  <Uefi.h>
#include  <Library/UefiLib.h>
#include  <Library/ShellCEntryLib.h>

#include  <stdio.h>
#include  <stdlib.h>
#include  <wchar.h>

#include <Protocol/EfiShell.h>
#include <Library/ShellLib.h>
#include <Library/MemoryAllocationLib.h>

#include "md5.h"

extern EFI_BOOT_SERVICES         *gBS;
extern EFI_SYSTEM_TABLE			 *gST;
extern EFI_RUNTIME_SERVICES 	 *gRT;

extern EFI_SHELL_PROTOCOL        *gEfiShellProtocol;

int
EFIAPI
main (
  IN int Argc,
  IN CHAR16 **Argv
  )
{
  EFI_FILE_HANDLE   FileHandle;
  RETURN_STATUS     Status;
  EFI_FILE_INFO     *FileInfo = NULL;
  EFI_HANDLE        *HandleBuffer=NULL;
  UINTN  			ReadSize;
  MD5_CTX			ctx;
  char				R[16];
  
  //Check if there is a parameter
  if (Argc == 1) {
	Print(L"Usage: crctest [filename]\n");
	return 0;
  }
  
  //Open the file given by the parameter
  Status = ShellOpenFileByName(Argv[1], (SHELL_FILE_HANDLE *)&FileHandle,
                               EFI_FILE_MODE_READ , 0);

  if(Status != RETURN_SUCCESS) {
        Print(L"OpenFile failed!\n");
		return EFI_SUCCESS;
      }			

  //Get file size	  
  FileInfo = ShellGetFileInfo( (SHELL_FILE_HANDLE)FileHandle);	

  //Allocate a memory buffer
  HandleBuffer = AllocateZeroPool((UINTN) FileInfo-> FileSize);
  if (HandleBuffer == NULL) {
      return (SHELL_OUT_OF_RESOURCES);   }

  ReadSize=(UINTN) FileInfo-> FileSize;
  
  //Load the whole file to the buffer
  Status = ShellReadFile(FileHandle,&ReadSize,HandleBuffer);
  
  MD5_Init(&ctx);
  MD5_Update(&ctx, HandleBuffer, ReadSize);
  MD5_Final((unsigned char *)&R, &ctx);
  
  //Output
  Print(L"File Name: %s\n",Argv[1]);
  Print(L"File Size: %d\n",ReadSize);
  Print(L"File Size: %d\n",ReadSize);
  Print(L"MD5      : %02X%02X%02X%02X%02X%02X%02X%02X%02X%02X%02X%02X%02X%02X%02X%02X\n",
					R[0]&0xFF  ,R[1]&0xFF  ,R[2]&0xFF  ,R[3]&0xFF  ,
					R[4]&0xFF  ,R[5]&0xFF  ,R[6]&0xFF  ,R[7]&0xFF  ,
					R[8]&0xFF  ,R[9]&0xFF  ,R[0xA]&0xFF,R[0xB]&0xFF,
					R[0xC]&0xFF,R[0xD]&0xFF,R[0xE]&0xFF,R[0xF]&0xFF);
  
  FreePool(HandleBuffer);	
  return EFI_SUCCESS;
}

 

运行结果

md51

可以看到,上面的例子能够在Shell下工作正常,但是需要特别注意,我没有验证过 X64 是否正常,如果你有这个需求,请自行验证。

完整的代码下载:

MD5Test

参考:

1.http://openwall.info/wiki/people/solar/software/public-domain-source-code/md5 A portable, fast, and free implementation of the MD5 Message-Digest Algorithm (RFC 1321)

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