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winaflpt.c
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winaflpt.c
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/*
WinAFL - Intel PT instrumentation and presistence via debugger code
------------------------------------------------
Written and maintained by Ivan Fratric <[email protected]>
Copyright 2016 Google Inc. All Rights Reserved.
Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at
http://www.apache.org/licenses/LICENSE-2.0
Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
*/
#define _CRT_SECURE_NO_WARNINGS
#include <stdio.h>
#include <stdbool.h>
#include "windows.h"
#include "psapi.h"
#include "dbghelp.h"
#include "libipt.h"
#include "ipttool.h"
#include "intel-pt.h"
#include "types.h"
#include "config.h"
#include "debug.h"
#include "alloc-inl.h"
#include "winaflpt.h"
#include "ptdecode.h"
// tests the custom decoders gainst the corresponding
// reference implementatopns from Intel
// used only for debugging
// #define DECODER_CORRECTNESS_TEST
u64 get_cur_time(void);
char *argv_to_cmd(char** argv);
#define CALLCONV_MICROSOFT_X64 0
#define CALLCONV_THISCALL 1
#define CALLCONV_FASTCALL 2
#define CALLCONV_CDECL 3
#define CALLCONV_DEFAULT 4
#define BREAKPOINT_UNKNOWN 0
#define BREAKPOINT_ENTRYPOINT 1
#define BREAKPOINT_MODULELOADED 2
#define BREAKPOINT_FUZZMETHOD 3
#define WINAFL_LOOP_EXCEPTION 0x0AF1
#define DEBUGGER_PROCESS_EXIT 0
#define DEBUGGER_FUZZMETHOD_REACHED 1
#define DEBUGGER_FUZZMETHOD_END 2
#define DEBUGGER_CRASHED 3
#define DEBUGGER_HANGED 4
#define DECODER_TIP_FAST 0
#define DECODER_TIP_REFERENCE 1
#define DECODER_FULL_FAST 2
#define DECODER_FULL_REFERENCE 3
static HANDLE child_handle, child_thread_handle;
static HANDLE devnul_handle = INVALID_HANDLE_VALUE;
static int fuzz_iterations_current;
static DWORD fuzz_thread_id;
static DEBUG_EVENT dbg_debug_event;
static DWORD dbg_continue_status;
static bool dbg_continue_needed;
static uint64_t dbg_timeout_time;
static bool child_entrypoint_reached;
static unsigned char *trace_buffer;
static size_t trace_size;
extern u8 *trace_bits;
extern HANDLE child_handle, child_thread_handle;
extern int fuzz_iterations_current;
extern HANDLE devnul_handle;
extern u8 sinkhole_stds;
extern u64 mem_limit;
extern u64 cpu_aff;
extern char *fuzzer_id;
static FILE *debug_log = NULL;
static struct pt_image_section_cache *section_cache;
static char section_cache_dir[MAX_PATH];
static int wow64_target = 0;
static size_t child_ptr_size = sizeof(void *);
address_range* coverage_ip_ranges = NULL;
size_t num_ip_ranges = 0;
static bool need_build_ranges = true;
static size_t last_ring_buffer_offset = 0;
#define USAGE_CHECK(condition, message) if(!(condition)) FATAL("%s\n", message);
enum {
/* 00 */ FAULT_NONE,
/* 01 */ FAULT_TMOUT,
/* 02 */ FAULT_CRASH,
/* 03 */ FAULT_ERROR,
/* 04 */ FAULT_NOINST,
/* 05 */ FAULT_NOBITS
};
typedef struct _module_info_t {
char module_name[MAX_PATH];
int isid;
void *base;
size_t size;
struct _module_info_t *next;
} module_info_t;
static module_info_t *all_modules = NULL;
typedef struct _winafl_option_t {
bool debug_mode;
int coverage_kind;
module_info_t *coverage_modules;
char fuzz_module[MAX_PATH];
char fuzz_method[MAX_PATH];
unsigned long fuzz_offset;
int fuzz_iterations;
int num_fuz_args;
int callconv;
int decoder;
bool thread_coverage;
unsigned long trace_buffer_size;
unsigned long trace_cache_size;
bool persistent_trace;
void **func_args;
void *sp;
void *fuzz_address;
} winafl_option_t;
static winafl_option_t options;
struct winafl_breakpoint {
void *address;
int type;
unsigned char original_opcode;
char module_name[MAX_PATH];
void *module_base;
struct winafl_breakpoint *next;
};
struct winafl_breakpoint *breakpoints;
static void
winaflpt_options_init(int argc, const char *argv[])
{
int i;
const char *token;
module_info_t *coverage_modules;
/* default values */
options.debug_mode = false;
options.coverage_kind = COVERAGE_BB;
options.coverage_modules = NULL;
options.fuzz_module[0] = 0;
options.fuzz_method[0] = 0;
options.fuzz_offset = 0;
options.fuzz_iterations = 1000;
options.func_args = NULL;
options.num_fuz_args = 0;
options.thread_coverage = true;
options.callconv = CALLCONV_DEFAULT;
options.decoder = DECODER_FULL_FAST;
options.trace_buffer_size = TRACE_BUFFER_SIZE_DEFAULT;
options.trace_cache_size = 0;
options.persistent_trace = true;
for (i = 0; i < argc; i++) {
token = argv[i];
if (strcmp(token, "-thread_coverage") == 0)
options.thread_coverage = true;
else if (strcmp(token, "-debug") == 0)
options.debug_mode = true;
else if (strcmp(token, "-nopersistent_trace") == 0)
options.persistent_trace = false;
else if (strcmp(token, "-covtype") == 0) {
USAGE_CHECK((i + 1) < argc, "missing coverage type");
token = argv[++i];
if (strcmp(token, "bb") == 0) options.coverage_kind = COVERAGE_BB;
else if (strcmp(token, "edge") == 0) options.coverage_kind = COVERAGE_EDGE;
else USAGE_CHECK(false, "invalid coverage type");
}
else if (strcmp(token, "-coverage_module") == 0) {
USAGE_CHECK((i + 1) < argc, "missing module");
coverage_modules = options.coverage_modules;
options.coverage_modules = (module_info_t *)malloc(sizeof(module_info_t));
options.coverage_modules->next = coverage_modules;
options.coverage_modules->isid = 0;
options.coverage_modules->base = NULL;
options.coverage_modules->size = 0;
strncpy(options.coverage_modules->module_name, argv[++i], MAX_PATH);
}
else if (strcmp(token, "-target_module") == 0) {
USAGE_CHECK((i + 1) < argc, "missing module");
strncpy(options.fuzz_module, argv[++i], MAX_PATH);
}
else if (strcmp(token, "-target_method") == 0) {
USAGE_CHECK((i + 1) < argc, "missing method");
strncpy(options.fuzz_method, argv[++i], MAX_PATH);
}
else if (strcmp(token, "-fuzz_iterations") == 0) {
USAGE_CHECK((i + 1) < argc, "missing number of iterations");
options.fuzz_iterations = atoi(argv[++i]);
}
else if (strcmp(token, "-nargs") == 0) {
USAGE_CHECK((i + 1) < argc, "missing number of arguments");
options.num_fuz_args = atoi(argv[++i]);
}
else if (strcmp(token, "-target_offset") == 0) {
USAGE_CHECK((i + 1) < argc, "missing offset");
options.fuzz_offset = strtoul(argv[++i], NULL, 0);
}
else if (strcmp(token, "-trace_size") == 0) {
USAGE_CHECK((i + 1) < argc, "missing trace size");
options.trace_buffer_size = strtoul(argv[++i], NULL, 0);
}
else if (strcmp(token, "-trace_cache_size") == 0) {
USAGE_CHECK((i + 1) < argc, "missing trace cache size");
options.trace_cache_size = strtoul(argv[++i], NULL, 0);
}
else if (strcmp(token, "-call_convention") == 0) {
USAGE_CHECK((i + 1) < argc, "missing calling convention");
++i;
if (strcmp(argv[i], "stdcall") == 0)
options.callconv = CALLCONV_CDECL;
else if (strcmp(argv[i], "fastcall") == 0)
options.callconv = CALLCONV_FASTCALL;
else if (strcmp(argv[i], "thiscall") == 0)
options.callconv = CALLCONV_THISCALL;
else if (strcmp(argv[i], "ms64") == 0)
options.callconv = CALLCONV_MICROSOFT_X64;
else
FATAL("Unknown calling convention");
} else if (strcmp(token, "-decoder") == 0) {
USAGE_CHECK((i + 1) < argc, "missing decoder");
++i;
if (strcmp(argv[i], "tip") == 0)
options.decoder = DECODER_TIP_FAST;
else if (strcmp(argv[i], "tip_ref") == 0)
options.decoder = DECODER_TIP_REFERENCE;
else if (strcmp(argv[i], "full") == 0)
options.decoder = DECODER_FULL_FAST;
else if (strcmp(argv[i], "full_ref") == 0)
options.decoder = DECODER_FULL_REFERENCE;
else
FATAL("Unknown decoder value");
} else {
FATAL("UNRECOGNIZED OPTION: \"%s\"\n", token);
}
}
if (options.fuzz_module[0] && (options.fuzz_offset == 0) && (options.fuzz_method[0] == 0)) {
FATAL("If fuzz_module is specified, then either fuzz_method or fuzz_offset must be as well");
}
if (options.num_fuz_args) {
options.func_args = (void **)malloc(options.num_fuz_args * sizeof(void *));
}
}
int address_range_compare(const void * a, const void * b) {
if (((address_range *)a)->start >= ((address_range *)b)->start) return 1;
else return -1;
}
void build_address_ranges() {
int num_loaded_modules;
module_info_t *current_module;
if (coverage_ip_ranges) free(coverage_ip_ranges);
if (!options.coverage_modules) {
num_ip_ranges = 1;
coverage_ip_ranges = (address_range*)malloc(num_ip_ranges * sizeof(address_range));
coverage_ip_ranges[0].start = 0;
coverage_ip_ranges[0].end = 0xFFFFFFFFFFFFFFFFULL;
coverage_ip_ranges[0].collect = 1;
return;
}
// count loaded modules
num_loaded_modules = 0;
current_module = options.coverage_modules;
while (current_module) {
if (current_module->size > 0) {
num_loaded_modules++;
}
current_module = current_module->next;
}
address_range* tmp_buf = (address_range*)malloc(num_loaded_modules * sizeof(address_range));
num_loaded_modules = 0;
current_module = options.coverage_modules;
while (current_module) {
if (current_module->size > 0) {
tmp_buf[num_loaded_modules].start = (uint64_t)current_module->base;
tmp_buf[num_loaded_modules].end = (uint64_t)current_module->base + current_module->size - 1;
tmp_buf[num_loaded_modules].collect = 1;
num_loaded_modules++;
}
current_module = current_module->next;
}
qsort(tmp_buf, num_loaded_modules, sizeof(address_range), address_range_compare);
num_ip_ranges = (size_t)num_loaded_modules * 2 + 1;
coverage_ip_ranges = (address_range*)malloc(num_ip_ranges * sizeof(address_range));
uint64_t current_address = 0;
for (int i = 0; i < num_loaded_modules; i++) {
coverage_ip_ranges[2 * i].start = current_address;
coverage_ip_ranges[2 * i].end = tmp_buf[i].start - 1;
coverage_ip_ranges[2 * i].collect = 0;
coverage_ip_ranges[2 * i + 1] = tmp_buf[i];
current_address = tmp_buf[i].end + 1;
}
coverage_ip_ranges[2 * num_loaded_modules].start = current_address;
coverage_ip_ranges[2 * num_loaded_modules].end = 0xFFFFFFFFFFFFFFFFULL;
coverage_ip_ranges[2 * num_loaded_modules].collect = 0;
free(tmp_buf);
}
// appends new data to the trace_buffer
void append_trace_data(unsigned char *trace_data, size_t append_size) {
size_t space_left = options.trace_buffer_size - trace_size;
if (!space_left) {
// stop collecting trace if the trace buffer is full;
printf("Warning: Trace buffer is full\n");
return;
}
if (append_size > space_left) {
append_size = space_left;
}
if (append_size == 0) return;
memcpy(trace_buffer + trace_size, trace_data, append_size);
trace_size += append_size;
}
// returns true if the ring buffer was overflowed
bool collect_thread_trace(PIPT_TRACE_HEADER traceHeader) {
// printf("ring offset: %u\n", traceHeader->RingBufferOffset);
bool trace_buffer_overflow = false;
unsigned char psb_and_psbend[] = {
0x02, 0x82, 0x02, 0x82, 0x02, 0x82, 0x02, 0x82,
0x02, 0x82, 0x02, 0x82, 0x02, 0x82, 0x02, 0x82,
0x02, 0x23
};
trace_size = 0;
if (options.persistent_trace) {
// an ugly hack: trace might not start with a psb (synchronization) packet
// so we are just adding one. This assumes the state has been properly
// flushed when a breakpoint between two iterations has been hit
// which does appear to be the case. However, if this doesn't occur
// persistent tracing will not work properly
append_trace_data(psb_and_psbend, sizeof(psb_and_psbend));
// first, optimistically assume the buffer didn't overflow
if (traceHeader->RingBufferOffset > last_ring_buffer_offset) {
append_trace_data(traceHeader->Trace + last_ring_buffer_offset, traceHeader->RingBufferOffset - last_ring_buffer_offset);
}
else if (traceHeader->RingBufferOffset < last_ring_buffer_offset) {
append_trace_data(traceHeader->Trace + last_ring_buffer_offset, traceHeader->TraceSize - last_ring_buffer_offset);
append_trace_data(traceHeader->Trace, traceHeader->RingBufferOffset);
}
if (!check_trace_start(trace_buffer, trace_size, (uint64_t)options.fuzz_address)) {
// most likely the ring buffer overflowd, extract what we can (trace tail)
trace_size = 0;
trace_buffer_overflow = true;
printf("Warning: Trace buffer overflowed, trace will be truncated\n");
if (options.debug_mode) fprintf(debug_log, "Trace buffer overflowed, trace will be truncated\n");
char *trailing_data = traceHeader->Trace + traceHeader->RingBufferOffset;
size_t trailing_size = traceHeader->TraceSize - traceHeader->RingBufferOffset;
append_trace_data(trailing_data, trailing_size);
append_trace_data(traceHeader->Trace, traceHeader->RingBufferOffset);
}
last_ring_buffer_offset = traceHeader->RingBufferOffset;
} else {
// check if the trace buffer overflowed
char *trailing_data = traceHeader->Trace + traceHeader->RingBufferOffset;
size_t trailing_size = traceHeader->TraceSize - traceHeader->RingBufferOffset;
if (findpsb(&trailing_data, &trailing_size)) {
trace_buffer_overflow = true;
printf("Warning: Trace buffer overflowed, trace will be truncated\n");
if (options.debug_mode) fprintf(debug_log, "Trace buffer overflowed, trace will be truncated\n");
append_trace_data(trailing_data, trailing_size);
}
append_trace_data(traceHeader->Trace, traceHeader->RingBufferOffset);
}
return trace_buffer_overflow;
}
// parse PIPT_TRACE_DATA, extract trace bits and add them to the trace_buffer
// returns true if the trace ring buffer overflowed
bool collect_trace(PIPT_TRACE_DATA pTraceData)
{
bool trace_buffer_overflow = false;
PIPT_TRACE_HEADER traceHeader;
DWORD dwTraceSize;
dwTraceSize = pTraceData->TraceSize;
traceHeader = (PIPT_TRACE_HEADER)pTraceData->TraceData;
while (dwTraceSize > (unsigned)(FIELD_OFFSET(IPT_TRACE_HEADER, Trace))) {
if (traceHeader->ThreadId == fuzz_thread_id) {
trace_buffer_overflow = collect_thread_trace(traceHeader);
}
dwTraceSize -= (FIELD_OFFSET(IPT_TRACE_HEADER, Trace) + traceHeader->TraceSize);
traceHeader = (PIPT_TRACE_HEADER)(traceHeader->Trace +
traceHeader->TraceSize);
}
return trace_buffer_overflow;
}
// returns an array of handles for all modules loaded in the target process
DWORD get_all_modules(HMODULE **modules) {
DWORD module_handle_storage_size = 1024 * sizeof(HMODULE);
HMODULE *module_handles = (HMODULE *)malloc(module_handle_storage_size);
DWORD hmodules_size;
while (true) {
if (!EnumProcessModulesEx(child_handle, module_handles, module_handle_storage_size, &hmodules_size, LIST_MODULES_ALL)) {
FATAL("EnumProcessModules failed, %x\n", GetLastError());
}
if (hmodules_size <= module_handle_storage_size) break;
module_handle_storage_size *= 2;
module_handles = (HMODULE *)realloc(module_handles, module_handle_storage_size);
}
*modules = module_handles;
return hmodules_size / sizeof(HMODULE);
}
// parses PE headers and gets the module entypoint
void *get_entrypoint(void *base_address) {
unsigned char headers[4096];
size_t num_read = 0;
if (!ReadProcessMemory(child_handle, base_address, headers, 4096, &num_read) || (num_read != 4096)) {
FATAL("Error reading target memory\n");
}
DWORD pe_offset;
pe_offset = *((DWORD *)(headers + 0x3C));
char *pe = headers + pe_offset;
DWORD signature = *((DWORD *)pe);
if (signature != 0x00004550) {
FATAL("PE signature error\n");
}
pe = pe + 0x18;
WORD magic = *((WORD *)pe);
if ((magic != 0x10b) && (magic != 0x20b)) {
FATAL("Unknown PE magic value\n");
}
DWORD entrypoint_offset = *((DWORD *)(pe + 16));
if (entrypoint_offset == 0) return NULL;
return (char *)base_address + entrypoint_offset;
}
// adds a breakpoint at a specified address
// type, module_name and module_base are all additional information
// that can be accessed later when the breakpoint gets hit
void add_breakpoint(void *address, int type, char *module_name, void *module_base) {
struct winafl_breakpoint *new_breakpoint = (struct winafl_breakpoint *)malloc(sizeof(struct winafl_breakpoint));
size_t rwsize = 0;
if(!ReadProcessMemory(child_handle, address, &(new_breakpoint->original_opcode), 1, &rwsize) || (rwsize != 1)) {
FATAL("Error reading target memory\n");
}
rwsize = 0;
unsigned char cc = 0xCC;
if (!WriteProcessMemory(child_handle, address, &cc, 1, &rwsize) || (rwsize != 1)) {
FATAL("Error writing target memory\n");
}
FlushInstructionCache(child_handle, address, 1);
new_breakpoint->address = address;
new_breakpoint->type = type;
if (module_name) {
strcpy(new_breakpoint->module_name, module_name);
} else {
new_breakpoint->module_name[0] = 0;
}
new_breakpoint->module_base = module_base;
new_breakpoint->next = breakpoints;
breakpoints = new_breakpoint;
}
// damn it Windows, why don't you have a GetProcAddress
// that works on another process
DWORD get_proc_offset(char *data, char *name) {
DWORD pe_offset;
pe_offset = *((DWORD *)(data + 0x3C));
char *pe = data + pe_offset;
DWORD signature = *((DWORD *)pe);
if (signature != 0x00004550) {
return 0;
}
pe = pe + 0x18;
WORD magic = *((WORD *)pe);
DWORD exporttableoffset;
if (magic == 0x10b) {
exporttableoffset = *(DWORD *)(pe + 96);
} else if (magic == 0x20b) {
exporttableoffset = *(DWORD *)(pe + 112);
} else {
return 0;
}
if (!exporttableoffset) return 0;
char *exporttable = data + exporttableoffset;
DWORD numentries = *(DWORD *)(exporttable + 24);
DWORD addresstableoffset = *(DWORD *)(exporttable + 28);
DWORD nameptrtableoffset = *(DWORD *)(exporttable + 32);
DWORD ordinaltableoffset = *(DWORD *)(exporttable + 36);
DWORD *nameptrtable = (DWORD *)(data + nameptrtableoffset);
WORD *ordinaltable = (WORD *)(data + ordinaltableoffset);
DWORD *addresstable = (DWORD *)(data + addresstableoffset);
DWORD i;
for (i = 0; i < numentries; i++) {
char *nameptr = data + nameptrtable[i];
if (strcmp(name, nameptr) == 0) break;
}
if (i == numentries) return 0;
WORD oridnal = ordinaltable[i];
DWORD offset = addresstable[oridnal];
return offset;
}
// attempt to obtain the fuzz_offset in various ways
char *get_fuzz_method_offset(HMODULE module) {
MODULEINFO module_info;
GetModuleInformation(child_handle, module, &module_info, sizeof(module_info));
// if fuzz_offset is defined, use that
if (options.fuzz_offset) {
return (char *)module_info.lpBaseOfDll + options.fuzz_offset;
}
// try the exported symbols next
BYTE *modulebuf = (BYTE *)malloc(module_info.SizeOfImage);
size_t num_read;
if (!ReadProcessMemory(child_handle, module_info.lpBaseOfDll, modulebuf, module_info.SizeOfImage, &num_read) || (num_read != module_info.SizeOfImage)) {
FATAL("Error reading target memory\n");
}
DWORD fuzz_offset = get_proc_offset(modulebuf, options.fuzz_method);
free(modulebuf);
if (fuzz_offset) {
return (char *)module + fuzz_offset;
}
// finally, try the debug symbols
char *fuzz_method = NULL;
char base_name[MAX_PATH];
GetModuleBaseNameA(child_handle, module, (LPSTR)(&base_name), sizeof(base_name));
char module_path[MAX_PATH];
if(!GetModuleFileNameExA(child_handle, module, module_path, sizeof(module_path))) return NULL;
ULONG64 buffer[(sizeof(SYMBOL_INFO) +
MAX_SYM_NAME * sizeof(TCHAR) +
sizeof(ULONG64) - 1) /
sizeof(ULONG64)];
PSYMBOL_INFO pSymbol = (PSYMBOL_INFO)buffer;
pSymbol->SizeOfStruct = sizeof(SYMBOL_INFO);
pSymbol->MaxNameLen = MAX_SYM_NAME;
SymInitialize(child_handle, NULL, false);
DWORD64 sym_base_address = SymLoadModuleEx(child_handle, NULL, module_path, NULL, 0, 0, NULL, 0);
if (SymFromName(child_handle, options.fuzz_method, pSymbol)) {
options.fuzz_offset = (unsigned long)(pSymbol->Address - sym_base_address);
fuzz_method = (char *)module_info.lpBaseOfDll + options.fuzz_offset;
}
SymCleanup(child_handle);
return fuzz_method;
}
// should we collect coverage for this module
module_info_t *is_coverage_module(char *module_name) {
module_info_t *current_module = options.coverage_modules;
while (current_module) {
if (_stricmp(module_name, current_module->module_name) == 0) {
return current_module;
}
current_module = current_module->next;
}
return NULL;
}
// check if the same module was already loaded
module_info_t *get_loaded_module(char *module_name, void *base) {
module_info_t *current_module = all_modules;
while (current_module) {
if (_stricmp(module_name, current_module->module_name) == 0) {
if (base == NULL || base == current_module->base) {
return current_module;
}
}
current_module = current_module->next;
}
return NULL;
}
// find if there is a *different* module that previously occupied
// the same space
module_info_t *get_intersecting_module(char *module_name, void *base, DWORD size) {
module_info_t *current_module = all_modules;
while (current_module) {
if (((uint64_t)current_module->base + current_module->size <= (uint64_t)base) ||
((uint64_t)base + size <= (uint64_t)current_module->base)) {
current_module = current_module->next;
continue;
}
return current_module;
}
return NULL;
}
void on_coverage_module_loaded(HMODULE module, module_info_t *target_module) {
MODULEINFO module_info;
GetModuleInformation(child_handle, module, &module_info, sizeof(module_info));
target_module->base = module_info.lpBaseOfDll;
target_module->size = module_info.SizeOfImage;
need_build_ranges = true;
}
size_t ReadProcessMemory_tolerant(HANDLE hProcess, LPCVOID lpBaseAddress, LPVOID lpBuffer, SIZE_T nSize) {
LPCVOID end_address = (char *)lpBaseAddress + nSize;
LPCVOID cur_address = lpBaseAddress;
MEMORY_BASIC_INFORMATION meminfobuf;
size_t size_read;
size_t total_size_read = 0;
while (cur_address < end_address) {
size_t ret = VirtualQueryEx(hProcess, (LPCVOID)cur_address, &meminfobuf, sizeof(MEMORY_BASIC_INFORMATION));
if (!ret) break;
size_t offset = (size_t)meminfobuf.BaseAddress - (size_t)lpBaseAddress;
size_t to_read = meminfobuf.RegionSize;
if ((offset + to_read) > nSize) {
to_read = nSize - offset;
}
if (ReadProcessMemory(child_handle, meminfobuf.BaseAddress, (char *)lpBuffer + offset, to_read, &size_read)) {
total_size_read += size_read;
}
cur_address = (char *)meminfobuf.BaseAddress + meminfobuf.RegionSize;
}
return total_size_read;
}
void add_module_to_section_cache(HMODULE module, char *module_name) {
module_info_t *loaded_module;
MODULEINFO module_info;
GetModuleInformation(child_handle, module, &module_info, sizeof(module_info));
// handle the case where module was loaded previously
loaded_module = get_loaded_module(module_name, module_info.lpBaseOfDll);
if (loaded_module) {
// same module loaded on the same address, skip
return;
}
// this will *probably* never happen but check for it anyway
loaded_module = get_intersecting_module(module_name, module_info.lpBaseOfDll, module_info.SizeOfImage);
if (loaded_module) {
FATAL("Module %s loaded in the address range that module %s previously occupied. This is currently unsupported.",
module_name, loaded_module->module_name);
}
loaded_module = (module_info_t *)malloc(sizeof(module_info_t));
strcpy(loaded_module->module_name, module_name);
loaded_module->base = module_info.lpBaseOfDll;
loaded_module->size = module_info.SizeOfImage;
// todo put these files in a separate directory and clean it periodically
char tmpfilename[MAX_PATH];
sprintf(tmpfilename, "%s\\sectioncache_%p.dat", section_cache_dir, module_info.lpBaseOfDll);
BYTE *modulebuf = (BYTE *)malloc(module_info.SizeOfImage);
size_t num_read;
if (!ReadProcessMemory(child_handle, module_info.lpBaseOfDll, modulebuf, module_info.SizeOfImage, &num_read) || (num_read != module_info.SizeOfImage)) {
if (!ReadProcessMemory_tolerant(child_handle, module_info.lpBaseOfDll, modulebuf, module_info.SizeOfImage)) {
FATAL("Error reading memory for module %s", module_name);
}
}
// this is pretty horrible, writing a file only to be read again
// but libipt only supports reading sections from file, not memory
FILE *fp = fopen(tmpfilename, "wb");
if (!fp) {
FATAL("Error opening image cache file.");
}
fwrite(modulebuf, 1, module_info.SizeOfImage, fp);
fclose(fp);
loaded_module->isid = pt_iscache_add_file(section_cache, tmpfilename, 0, module_info.SizeOfImage, (uint64_t)module_info.lpBaseOfDll);
free(modulebuf);
if (loaded_module->isid <= 0) {
FATAL("Error adding file to pt cache.");
}
loaded_module->next = all_modules;
all_modules = loaded_module;
}
// called when a potentialy interesting module gets loaded
void on_module_loaded(HMODULE module, char *module_name) {
MODULEINFO module_info;
GetModuleInformation(child_handle, module, &module_info, sizeof(module_info));
// printf("In on_module_loaded, name: %s, base: %p\n", module_name, module_info.lpBaseOfDll);
module_info_t *coverage_module = is_coverage_module(module_name);
if (coverage_module) {
on_coverage_module_loaded(module, coverage_module);
}
if (options.decoder == DECODER_FULL_FAST || options.decoder == DECODER_FULL_REFERENCE) {
add_module_to_section_cache(module, module_name);
}
if (_stricmp(module_name, options.fuzz_module) == 0) {
char * fuzz_address = get_fuzz_method_offset(module);
if (!fuzz_address) {
FATAL("Error determining target method address\n");
}
// printf("Fuzz method address: %p\n", fuzz_address);
options.fuzz_address = fuzz_address;
add_breakpoint(fuzz_address, BREAKPOINT_FUZZMETHOD, NULL, 0);
}
}
void read_stack(void *stack_addr, void **buffer, size_t numitems) {
size_t numrw = 0;
#ifdef _WIN64
if (wow64_target) {
uint32_t *buf32 = (uint32_t *)malloc(numitems * child_ptr_size);
ReadProcessMemory(child_handle, stack_addr, buf32, numitems * child_ptr_size, &numrw);
for (size_t i = 0; i < numitems; i++) {
buffer[i] = (void *)((size_t)buf32[i]);
}
free(buf32);
return;
}
#endif
ReadProcessMemory(child_handle, stack_addr, buffer, numitems * child_ptr_size, &numrw);
}
void write_stack(void *stack_addr, void **buffer, size_t numitems) {
size_t numrw = 0;
#ifdef _WIN64
if (wow64_target) {
uint32_t *buf32 = (uint32_t *)malloc(numitems * child_ptr_size);
for (size_t i = 0; i < numitems; i++) {
buf32[i] = (uint32_t)((size_t)buffer[i]);
}
WriteProcessMemory(child_handle, stack_addr, buf32, numitems * child_ptr_size, &numrw);
free(buf32);
return;
}
#endif
WriteProcessMemory(child_handle, stack_addr, buffer, numitems * child_ptr_size, &numrw);
}
// called when the target method is called *for the first time only*
void on_target_method(DWORD thread_id) {
// printf("in OnTargetMethod\n");
fuzz_thread_id = thread_id;
size_t numrw = 0;
CONTEXT lcContext;
lcContext.ContextFlags = CONTEXT_ALL;
HANDLE thread_handle = OpenThread(THREAD_ALL_ACCESS, FALSE, thread_id);
GetThreadContext(thread_handle, &lcContext);
// read out and save the params
#ifdef _WIN64
options.sp = (void *)lcContext.Rsp;
#else
options.sp = (void *)lcContext.Esp;
#endif
switch (options.callconv) {
#ifdef _WIN64
case CALLCONV_DEFAULT:
case CALLCONV_MICROSOFT_X64:
if (options.num_fuz_args > 0) options.func_args[0] = (void *)lcContext.Rcx;
if (options.num_fuz_args > 1) options.func_args[1] = (void *)lcContext.Rdx;
if (options.num_fuz_args > 2) options.func_args[2] = (void *)lcContext.R8;
if (options.num_fuz_args > 3) options.func_args[3] = (void *)lcContext.R9;
if (options.num_fuz_args > 4) {
read_stack((void *)(lcContext.Rsp + 5 * child_ptr_size), options.func_args + 4, options.num_fuz_args - 4);
}
break;
case CALLCONV_CDECL:
if (options.num_fuz_args > 0) {
read_stack((void *)(lcContext.Rsp + child_ptr_size), options.func_args, options.num_fuz_args);
}
break;
case CALLCONV_FASTCALL:
if (options.num_fuz_args > 0) options.func_args[0] = (void *)lcContext.Rcx;
if (options.num_fuz_args > 1) options.func_args[1] = (void *)lcContext.Rdx;
if (options.num_fuz_args > 3) {
read_stack((void *)(lcContext.Rsp + child_ptr_size), options.func_args + 2, options.num_fuz_args - 2);
}
break;
case CALLCONV_THISCALL:
if (options.num_fuz_args > 0) options.func_args[0] = (void *)lcContext.Rcx;
if (options.num_fuz_args > 3) {
read_stack((void *)(lcContext.Rsp + child_ptr_size), options.func_args + 1, options.num_fuz_args - 1);
}
break;
#else
case CALLCONV_MICROSOFT_X64:
FATAL("X64 callong convention not supported for 32-bit targets");
break;
case CALLCONV_DEFAULT:
case CALLCONV_CDECL:
if (options.num_fuz_args > 0) {
read_stack((void *)(lcContext.Esp + child_ptr_size), options.func_args, options.num_fuz_args);
}
break;
case CALLCONV_FASTCALL:
if (options.num_fuz_args > 0) options.func_args[0] = (void *)lcContext.Ecx;
if (options.num_fuz_args > 1) options.func_args[1] = (void *)lcContext.Edx;
if (options.num_fuz_args > 3) {
read_stack((void *)(lcContext.Esp + child_ptr_size), options.func_args + 2, options.num_fuz_args - 2);
}
break;
case CALLCONV_THISCALL:
if (options.num_fuz_args > 0) options.func_args[0] = (void *)lcContext.Ecx;
if (options.num_fuz_args > 3) {
read_stack((void *)(lcContext.Esp + child_ptr_size), options.func_args + 1, options.num_fuz_args - 1);
}
break;
#endif
default:
break;
}
// todo store any target-specific additional context here
// modify the return address on the stack so that an exception is triggered
// when the target function finishes executing
// another option would be to allocate a block of executable memory
// and point return address over there, but this is quicker
size_t return_address = WINAFL_LOOP_EXCEPTION;
WriteProcessMemory(child_handle, options.sp, &return_address, child_ptr_size, &numrw);
CloseHandle(thread_handle);
}
// called every time the target method returns
void on_target_method_ended(DWORD thread_id) {
// printf("in OnTargetMethodEnded\n");
CONTEXT lcContext;
lcContext.ContextFlags = CONTEXT_ALL;
HANDLE thread_handle = OpenThread(THREAD_ALL_ACCESS, FALSE, thread_id);
GetThreadContext(thread_handle, &lcContext);
// restore params
#ifdef _WIN64
lcContext.Rip = (size_t)options.fuzz_address;
lcContext.Rsp = (size_t)options.sp;
#else
lcContext.Eip = (size_t)options.fuzz_address;
lcContext.Esp = (size_t)options.sp;
#endif
switch (options.callconv) {
#ifdef _WIN64
case CALLCONV_DEFAULT:
case CALLCONV_MICROSOFT_X64:
if (options.num_fuz_args > 0) lcContext.Rcx = (size_t)options.func_args[0];
if (options.num_fuz_args > 1) lcContext.Rdx = (size_t)options.func_args[1];
if (options.num_fuz_args > 2) lcContext.R8 = (size_t)options.func_args[2];
if (options.num_fuz_args > 3) lcContext.R9 = (size_t)options.func_args[3];
if (options.num_fuz_args > 4) {
write_stack((void *)(lcContext.Rsp + 5 * child_ptr_size), options.func_args + 4, options.num_fuz_args - 4);
}
break;
case CALLCONV_CDECL:
if (options.num_fuz_args > 0) {
write_stack((void *)(lcContext.Rsp + child_ptr_size), options.func_args, options.num_fuz_args);
}
break;
case CALLCONV_FASTCALL:
if (options.num_fuz_args > 0) lcContext.Rcx = (size_t)options.func_args[0];
if (options.num_fuz_args > 1) lcContext.Rdx = (size_t)options.func_args[1];
if (options.num_fuz_args > 3) {
write_stack((void *)(lcContext.Rsp + child_ptr_size), options.func_args + 2, options.num_fuz_args - 2);
}
break;
case CALLCONV_THISCALL:
if (options.num_fuz_args > 0) lcContext.Rcx = (size_t)options.func_args[0];
if (options.num_fuz_args > 3) {
write_stack((void *)(lcContext.Rsp + child_ptr_size), options.func_args + 1, options.num_fuz_args - 1);
}
break;
#else
case CALLCONV_MICROSOFT_X64:
FATAL("X64 callong convention not supported for 32-bit targets");
break;
case CALLCONV_DEFAULT:
case CALLCONV_CDECL:
if (options.num_fuz_args > 0) {
write_stack((void *)(lcContext.Esp + child_ptr_size), options.func_args, options.num_fuz_args);
}
break;
case CALLCONV_FASTCALL:
if (options.num_fuz_args > 0) lcContext.Ecx = (size_t)options.func_args[0];
if (options.num_fuz_args > 1) lcContext.Edx = (size_t)options.func_args[1];
if (options.num_fuz_args > 3) {
write_stack((void *)(lcContext.Esp + child_ptr_size), options.func_args + 2, options.num_fuz_args - 2);
}
break;
case CALLCONV_THISCALL:
if (options.num_fuz_args > 0) lcContext.Ecx = (size_t)options.func_args[0];
if (options.num_fuz_args > 3) {
write_stack((void *)(lcContext.Esp + child_ptr_size), options.func_args + 1, options.num_fuz_args - 1);
}
break;
#endif
default:
break;
}
// todo restore any target-specific additional context here
SetThreadContext(thread_handle, &lcContext);
CloseHandle(thread_handle);
}
// called when process entrypoint gets reached