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Windows: enhancements to the mechanism preserving file timestamps, especially for keyfiles.

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This commit is contained in:
Mounir IDRASSI
2019-12-08 22:51:49 +01:00
parent 7f1e21e6a1
commit 5e96a5c44c
8 changed files with 139 additions and 79 deletions
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61
src/Common/Keyfiles.c
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@@ -149,50 +149,41 @@ void KeyFileCloneAll (KeyFile *firstKeyFile, KeyFile **outputKeyFile)
static BOOL KeyFileProcess (unsigned __int8 *keyPool, unsigned __int32 keyPoolSize, KeyFile *keyFile)
{
FILE *f;
unsigned __int8 buffer[64 * 1024];
unsigned __int32 crc = 0xffffffff;
unsigned __int32 writePos = 0;
size_t bytesRead, totalRead = 0;
DWORD bytesRead, totalRead = 0;
int status = TRUE;
HANDLE src;
FILETIME ftCreationTime;
FILETIME ftLastWriteTime;
FILETIME ftLastAccessTime;
BOOL bReadStatus = FALSE;
BOOL bTimeStampValid = FALSE;
/* Remember the last access time of the keyfile. It will be preserved in order to prevent
an adversary from determining which file may have been used as keyfile. */
src = CreateFile (keyFile->FileName,
GENERIC_READ | GENERIC_WRITE,
GENERIC_READ | FILE_WRITE_ATTRIBUTES,
FILE_SHARE_READ | FILE_SHARE_WRITE, NULL, OPEN_EXISTING, 0, NULL);
if (src != INVALID_HANDLE_VALUE)
{
if (GetFileTime ((HANDLE) src, &ftCreationTime, &ftLastAccessTime, &ftLastWriteTime))
bTimeStampValid = TRUE;
/* We tell Windows not to update the Last Access timestamp in order to prevent
an adversary from determining which file may have been used as keyfile. */
FILETIME ftLastAccessTime;
ftLastAccessTime.dwHighDateTime = 0xFFFFFFFF;
ftLastAccessTime.dwLowDateTime = 0xFFFFFFFF;
SetFileTime (src, NULL, &ftLastAccessTime, NULL);
}
else
{
/* try to open without FILE_WRITE_ATTRIBUTES in case we are in a ReadOnly filesystem (e.g. CD) */
src = CreateFile (keyFile->FileName,
GENERIC_READ,
FILE_SHARE_READ | FILE_SHARE_WRITE, NULL, OPEN_EXISTING, 0, NULL);
if (src == INVALID_HANDLE_VALUE)
return FALSE;
}
finally_do_arg (HANDLE, src,
while ((bReadStatus = ReadFile (src, buffer, sizeof (buffer), &bytesRead, NULL)) && (bytesRead > 0))
{
if (finally_arg != INVALID_HANDLE_VALUE)
CloseHandle (finally_arg);
});
f = _wfopen (keyFile->FileName, L"rb");
if (f == NULL) return FALSE;
while ((bytesRead = fread (buffer, 1, sizeof (buffer), f)) > 0)
{
size_t i;
if (ferror (f))
{
status = FALSE;
goto close;
}
DWORD i;
for (i = 0; i < bytesRead; i++)
{
@@ -211,7 +202,7 @@ static BOOL KeyFileProcess (unsigned __int8 *keyPool, unsigned __int32 keyPoolSi
}
}
if (ferror (f))
if (!bReadStatus)
{
status = FALSE;
}
@@ -223,13 +214,9 @@ static BOOL KeyFileProcess (unsigned __int8 *keyPool, unsigned __int32 keyPoolSi
close:
DWORD err = GetLastError();
fclose (f);
if (bTimeStampValid && !IsFileOnReadOnlyFilesystem (keyFile->FileName))
{
// Restore the keyfile timestamp
SetFileTime (src, &ftCreationTime, &ftLastAccessTime, &ftLastWriteTime);
}
CloseHandle (src);
burn (buffer, sizeof (buffer));
SetLastError (err);
return status;