Leaked source code of windows server 2003
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138 lines
4.1 KiB

#include "stdafx.h"
#include "password.h"
#include <strsafe.h>
// password categories
enum {STRONG_PWD_UPPER=0,STRONG_PWD_LOWER,STRONG_PWD_NUM,STRONG_PWD_PUNC};
#define STRONG_PWD_CATS (STRONG_PWD_PUNC + 1)
#define NUM_LETTERS 26
#define NUM_NUMBERS 10
#define MIN_PWD_LEN 8
// password must contain at least one each of:
// uppercase, lowercase, punctuation and numbers
DWORD CreateGoodPassword(BYTE *szPwd, DWORD dwLen)
{
if (dwLen-1 < MIN_PWD_LEN)
{
return ERROR_PASSWORD_RESTRICTION;
}
HCRYPTPROV hProv;
DWORD dwErr = 0;
if (CryptAcquireContext(&hProv,NULL,NULL,PROV_RSA_FULL,CRYPT_VERIFYCONTEXT) == FALSE)
{
return GetLastError();
}
// zero it out and decrement the size to allow for trailing '\0'
SecureZeroMemory(szPwd,dwLen);
dwLen--;
// generate a pwd pattern, each byte is in the range
// (0..255) mod STRONG_PWD_CATS
// this indicates which character pool to take a char from
BYTE *pPwdPattern = new BYTE[dwLen];
BOOL fFound[STRONG_PWD_CATS];
do
{
// bug!bug! does CGR() ever fail?
CryptGenRandom(hProv,dwLen,pPwdPattern);
fFound[STRONG_PWD_UPPER] =
fFound[STRONG_PWD_LOWER] =
fFound[STRONG_PWD_PUNC] =
fFound[STRONG_PWD_NUM] = FALSE;
for (DWORD i=0; i < dwLen; i++)
{
fFound[pPwdPattern[i] % STRONG_PWD_CATS] = TRUE;
}
// check that each character category is in the pattern
} while (!fFound[STRONG_PWD_UPPER] || !fFound[STRONG_PWD_LOWER] || !fFound[STRONG_PWD_PUNC] || !fFound[STRONG_PWD_NUM]);
// populate password with random data
// this, in conjunction with pPwdPattern, is
// used to determine the actual data
CryptGenRandom(hProv,dwLen,szPwd);
for (DWORD i=0; i < dwLen; i++)
{
BYTE bChar = 0;
// there is a bias in each character pool because of the % function
switch (pPwdPattern[i] % STRONG_PWD_CATS)
{
case STRONG_PWD_UPPER : bChar = 'A' + szPwd[i] % NUM_LETTERS;
break;
case STRONG_PWD_LOWER : bChar = 'a' + szPwd[i] % NUM_LETTERS;
break;
case STRONG_PWD_NUM : bChar = '0' + szPwd[i] % NUM_NUMBERS;
break;
case STRONG_PWD_PUNC :
default:
char *szPunc="!@#$%^&*()_-+=[{]};:\'\"<>,./?\\|~`";
DWORD dwLenPunc = lstrlenA(szPunc);
bChar = szPunc[szPwd[i] % dwLenPunc];
break;
}
szPwd[i] = bChar;
}
if (pPwdPattern)
{
delete [] pPwdPattern;
}
if (hProv != NULL)
{
CryptReleaseContext(hProv,0);
}
return dwErr;
}
// Creates a secure password
// caller must LocalFree Return pointer
// iSize = size of password to create
LPTSTR CreatePassword(int iSize)
{
LPTSTR pszPassword = NULL;
BYTE *szPwd = new BYTE[iSize];
DWORD dwPwdLen = iSize;
int i = 0;
// use the new secure password generator
// unfortunately this baby doesn't use unicode.
// so we'll call it and then convert it to unicode afterwards.
if (0 == CreateGoodPassword(szPwd,dwPwdLen))
{
#if defined(UNICODE) || defined(_UNICODE)
// convert it to unicode and copy it back into our unicode buffer.
// compute the length
i = MultiByteToWideChar(CP_ACP, 0, (LPSTR) szPwd, -1, NULL, 0);
if (i <= 0)
{goto CreatePassword_Exit;}
pszPassword = (LPTSTR) LocalAlloc(LPTR, i * sizeof(TCHAR));
if (!pszPassword)
{goto CreatePassword_Exit;}
i = MultiByteToWideChar(CP_ACP, 0, (LPSTR) szPwd, -1, pszPassword, i);
if (i <= 0)
{
LocalFree(pszPassword);
pszPassword = NULL;
goto CreatePassword_Exit;
}
// make sure ends with null
pszPassword[i - 1] = 0;
#else
pszPassword = (LPSTR) LocalAlloc(GPTR, _tcslen((LPTSTR) szPwd) * sizeof(TCHAR));
#endif
}
CreatePassword_Exit:
if (szPwd){delete [] szPwd;szPwd=NULL;}
return pszPassword;
}