persistent mode harness
MODIFY
src/afl-fuzz-init.c
src/afl-fuzz-init.c
@@ -1940,17 +1940,17 @@ void check_binary(u8* fname) {
}
- if ((qemu_mode || unicorn_mode) &&
+ if ((qemu_mode) &&
memmem(f_data, f_len, SHM_ENV_VAR, strlen(SHM_ENV_VAR) + 1)) {
SAYF("\n" cLRD "[-] " cRST
"This program appears to be instrumented with afl-gcc, but is being "
"run in\n"
- " QEMU or Unicorn mode (-Q or -U). This is probably not what you "
+ " QEMU mode (-Q). This is probably not what you "
"want -\n"
" this setup will be slow and offer no practical benefits.\n");
- FATAL("Instrumentation found in -Q or -U mode");
+ FATAL("Instrumentation found in -Q mode");
}

MODIFY
unicorn_mode/samples/c/harness.c
unicorn_mode/samples/c/harness.c
// Memory map for the code to be tested
// Arbitrary address where code to test will be loaded
-#define BASE_ADDRESS (0x100000)
-#define CODE_ADDRESS (0x101119)
-#define END_ADDRESS (0x1011d7)
+static const int64_t BASE_ADDRESS = 0x100000;
+static const int64_t CODE_ADDRESS = 0x101119;
+static const int64_t END_ADDRESS = 0x1011d7;
// Address of the stack (Some random address again)
-#define STACK_ADDRESS (((int64_t) 0x01) << 58)
+static const int64_t STACK_ADDRESS = (((int64_t) 0x01) << 58);
// Size of the stack (arbitrarily chosen, just make it big enough)
-#define STACK_SIZE (0x10000)
+static const int64_t STACK_SIZE = 0x10000;
// Location where the input will be placed (make sure the emulated program knows this somehow, too ;) )
-#define INPUT_LOCATION (0x10000)
+static const int64_t INPUT_LOCATION = 0x10000;
// Inside the location, we have an ofset in our special case
-#define INPUT_OFFSET (0x16)
+static const int64_t INPUT_OFFSET = 0x16;
// Maximum allowable size of mutated data from AFL
-#define INPUT_SIZE_MAX (0x10000)
+static const int64_t INPUT_SIZE_MAX = 0x10000;
// Alignment for unicorn mappings (seems to be needed)
-#define ALIGNMENT ((uint64_t) 0x1000)
+static const int64_t ALIGNMENT = 0x1000;
+
+// In our special case, we emulate main(), so argc is needed.
+static const uint64_t EMULATED_ARGC = 2;
static void hook_block(uc_engine *uc, uint64_t address, uint32_t size, void *user_data) {
printf(">>> Tracing basic block at 0x%"PRIx64 ", block size = 0x%x\n", address, size);
@@ -100,10 +103,22 @@ static bool place_input_callback(
void *data
){
// printf("Placing input with len %ld to %x\n", input_len, DATA_ADDRESS);
- if (input_len >= INPUT_SIZE_MAX - INPUT_OFFSET) {
- // Test input too long, ignore this testcase
+ if (input_len < 1 || input_len >= INPUT_SIZE_MAX - INPUT_OFFSET) {
+ // Test input too short or too long, ignore this testcase
return false;
}
+ // We need a valid c string, make sure it never goes out of bounds.
+ input[input_len-1] = '\0';
+
+ // For persistent mode, we have to set up stack and memory each time.
+ uc_reg_write(uc, UC_X86_REG_RIP, &CODE_ADDRESS); // Set the instruction pointer back
+ // Set up the function parameters accordingly RSI, RDI (see calling convention/disassembly)
+ uc_reg_write(uc, UC_X86_REG_RSI, &INPUT_LOCATION); // argv
+ uc_reg_write(uc, UC_X86_REG_RDI, &EMULATED_ARGC); // argc == 2
+
+ // Make sure the input is 0 terminated.
+ //input[input_len-1] = '\0';
+ // Write the testcase to unicorn.
uc_mem_write(uc, INPUT_LOCATION + INPUT_OFFSET, input, input_len);
return true;
}
@@ -188,11 +203,6 @@ int main(int argc, char **argv, char **envp) {
uc_mem_write(uc, 0x10008, "\x16\x00\x01", 3); // little endian of 0x10016, see above
- // Set up the function parameters accordingly RSI, RDI (see calling convention/disassembly)
- uint64_t input_location = INPUT_LOCATION;
- uc_reg_write(uc, UC_X86_REG_RSI, &input_location); // argv
- uint64_t emulated_argc = 2;
- uc_reg_write(uc, UC_X86_REG_RDI, &emulated_argc); // argc == 2
// If we want tracing output, set the callbacks here
if (tracing) {
@@ -212,9 +222,9 @@ int main(int argc, char **argv, char **envp) {
&end_address, // Where to exit (this is an array)
1, // Count of end addresses
NULL, // Optional calback to run after each exec
- false,
- 1, // For persistent mode: How many rounds to run
- NULL
+ false, // true, if the optional callback should be run also for non-crashes
+ 100, // For persistent mode: How many rounds to run
+ NULL // additional data pointer
);
switch(afl_ret) {
case UC_AFL_RET_ERROR:

persistent mode harness