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ntdll: Only set the security cookie if it has not already been set.

This commit is contained in:
Erich E. Hoover 2015-07-10 14:52:33 -06:00 committed by Alexandre Julliard
parent abf4d5910f
commit e9d7cf99ad
1 changed files with 37 additions and 12 deletions
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49
dlls/ntdll/virtual.c
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@ -61,6 +61,12 @@ WINE_DECLARE_DEBUG_CHANNEL(module);
#define MAP_NORESERVE 0
#endif
#ifdef _WIN64
#define DEFAULT_SECURITY_COOKIE_64 (((ULONGLONG)0x00002b99 << 32) | 0x2ddfa232)
#endif
#define DEFAULT_SECURITY_COOKIE_32 0xbb40e64e
#define DEFAULT_SECURITY_COOKIE_16 (DEFAULT_SECURITY_COOKIE_32 >> 16)
/* File view */
struct file_view
{
@ -1053,6 +1059,36 @@ static NTSTATUS stat_mapping_file( struct file_view *view, struct stat *st )
return status;
}
/***********************************************************************
* set_security_cookie
*
* Create a random security cookie for buffer overflow protection. Make
* sure it does not accidentally match the default cookie value.
*/
static void set_security_cookie(ULONG_PTR *cookie)
{
static ULONG seed;
if (!cookie) return;
if (!seed) seed = NtGetTickCount() ^ GetCurrentProcessId();
while (1)
{
if (*cookie == DEFAULT_SECURITY_COOKIE_16)
*cookie = RtlRandom( &seed ) >> 16; /* leave the high word clear */
else if (*cookie == DEFAULT_SECURITY_COOKIE_32)
*cookie = RtlRandom( &seed );
#ifdef DEFAULT_SECURITY_COOKIE_64
else if (*cookie == DEFAULT_SECURITY_COOKIE_64)
{
*cookie = RtlRandom( &seed );
/* fill up, but keep the highest word clear */
*cookie ^= (ULONG_PTR)RtlRandom( &seed ) << 16;
}
#endif
else
break;
}
}
/***********************************************************************
* map_image
@ -1285,18 +1321,7 @@ static NTSTATUS map_image( HANDLE hmapping, int fd, char *base, SIZE_T total_siz
loadcfg = RtlImageDirectoryEntryToData( (HMODULE)ptr, TRUE,
IMAGE_DIRECTORY_ENTRY_LOAD_CONFIG, &loadcfg_size );
if (loadcfg && loadcfg_size >= sizeof(*loadcfg))
{
static ULONG seed;
ULONG_PTR *cookie = (ULONG_PTR *)loadcfg->SecurityCookie;
if (!seed) seed = NtGetTickCount() ^ GetCurrentProcessId();
if (cookie)
{
*cookie = RtlRandom( &seed );
if (sizeof(ULONG_PTR) > sizeof(ULONG)) /* fill up, but keep the highest word clear */
*cookie ^= (ULONG_PTR)RtlRandom( &seed ) << 16;
}
}
set_security_cookie((ULONG_PTR *)loadcfg->SecurityCookie);
/* set the image protections */