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Diffstat (limited to 'examples/afl_frida/afl-frida.c')
| -rw-r--r-- | examples/afl_frida/afl-frida.c | 541 |
1 files changed, 541 insertions, 0 deletions
diff --git a/examples/afl_frida/afl-frida.c b/examples/afl_frida/afl-frida.c new file mode 100644 index 00000000..2ad5a72a --- /dev/null +++ b/examples/afl_frida/afl-frida.c @@ -0,0 +1,541 @@ +/* + american fuzzy lop++ - afl-frida skeleton example + ------------------------------------------------- + + Copyright 2020 AFLplusplus Project. All rights reserved. + + Written mostly by meme -> https://github.com/meme/hotwax + + Modificationy by Marc Heuse <mh@mh-sec.de> + + 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 + + HOW-TO + ====== + + You only need to change the following: + + 1. set the defines and function call parameters. + 2. dl load the library you want to fuzz, lookup the functions you need + and setup the calls to these. + 3. in the while loop you call the functions in the necessary order - + incl the cleanup. the cleanup is important! + + Just look these steps up in the code, look for "// STEP x:" + +*/ + +#include <stdio.h> +#include <stdint.h> +#include <unistd.h> +#include <stdint.h> +#include <stddef.h> +#include <sys/shm.h> +#include <dlfcn.h> + +#ifndef __APPLE__ + #include <sys/wait.h> + #include <sys/personality.h> +#endif + +int debug = 0; + +// STEP 1: + +// The presets are for the example libtestinstr.so: + +/* What is the name of the library to fuzz */ +#define TARGET_LIBRARY "libtestinstr.so" + +/* What is the name of the function to fuzz */ +#define TARGET_FUNCTION "testinstr" + +/* here you need to specify the parameter for the target function */ +static void *(*o_function)(uint8_t *, int); + +// END STEP 1 + +#include "frida-gum.h" + +G_BEGIN_DECLS + +#define GUM_TYPE_FAKE_EVENT_SINK (gum_fake_event_sink_get_type()) +G_DECLARE_FINAL_TYPE(GumFakeEventSink, gum_fake_event_sink, GUM, + FAKE_EVENT_SINK, GObject) + +struct _GumFakeEventSink { + + GObject parent; + GumEventType mask; + +}; + +GumEventSink *gum_fake_event_sink_new(void); +void gum_fake_event_sink_reset(GumFakeEventSink *self); + +G_END_DECLS + +static void gum_fake_event_sink_iface_init(gpointer g_iface, + gpointer iface_data); +static void gum_fake_event_sink_finalize(GObject *obj); +static GumEventType gum_fake_event_sink_query_mask(GumEventSink *sink); +static void gum_fake_event_sink_process(GumEventSink *sink, const GumEvent *ev); +void instr_basic_block(GumStalkerIterator *iterator, GumStalkerOutput *output, + gpointer user_data); +void afl_setup(void); +void afl_start_forkserver(void); +int __afl_persistent_loop(unsigned int max_cnt); + +static void gum_fake_event_sink_class_init(GumFakeEventSinkClass *klass) { + + GObjectClass *object_class = G_OBJECT_CLASS(klass); + object_class->finalize = gum_fake_event_sink_finalize; + +} + +static void gum_fake_event_sink_iface_init(gpointer g_iface, + gpointer iface_data) { + + GumEventSinkInterface *iface = (GumEventSinkInterface *)g_iface; + iface->query_mask = gum_fake_event_sink_query_mask; + iface->process = gum_fake_event_sink_process; + +} + +G_DEFINE_TYPE_EXTENDED(GumFakeEventSink, gum_fake_event_sink, G_TYPE_OBJECT, 0, + G_IMPLEMENT_INTERFACE(GUM_TYPE_EVENT_SINK, + gum_fake_event_sink_iface_init)) + +#include "../../config.h" + +// Shared memory fuzzing. +int __afl_sharedmem_fuzzing = 1; +extern unsigned int * __afl_fuzz_len; +extern unsigned char *__afl_fuzz_ptr; + +// Notify AFL about persistent mode. +static volatile char AFL_PERSISTENT[] = "##SIG_AFL_PERSISTENT##"; +int __afl_persistent_loop(unsigned int); + +// Notify AFL about deferred forkserver. +static volatile char AFL_DEFER_FORKSVR[] = "##SIG_AFL_DEFER_FORKSRV##"; +void __afl_manual_init(); + +// Because we do our own logging. +extern uint8_t * __afl_area_ptr; +static __thread guint64 previous_pc; + +// Frida stuff below. +typedef struct { + + GumAddress base_address; + guint64 code_start, code_end; + +} range_t; + +inline static void afl_maybe_log(guint64 current_pc) { + + // fprintf(stderr, "PC: %p ^ %p\n", current_pc, previous_pc); + + current_pc = (current_pc >> 4) ^ (current_pc << 8); + current_pc &= MAP_SIZE - 1; + + __afl_area_ptr[current_pc ^ previous_pc]++; + previous_pc = current_pc >> 1; + +} + +static void on_basic_block(GumCpuContext *context, gpointer user_data) { + + afl_maybe_log((guint64)user_data); + +} + +void instr_basic_block(GumStalkerIterator *iterator, GumStalkerOutput *output, + gpointer user_data) { + + range_t *range = (range_t *)user_data; + + const cs_insn *instr; + gboolean begin = TRUE; + while (gum_stalker_iterator_next(iterator, &instr)) { + + if (begin) { + + if (instr->address >= range->code_start && + instr->address <= range->code_end) { + + gum_stalker_iterator_put_callout(iterator, on_basic_block, + (gpointer)instr->address, NULL); + begin = FALSE; + + } + + } + + gum_stalker_iterator_keep(iterator); + + } + +} + +static void gum_fake_event_sink_init(GumFakeEventSink *self) { + +} + +static void gum_fake_event_sink_finalize(GObject *obj) { + + G_OBJECT_CLASS(gum_fake_event_sink_parent_class)->finalize(obj); + +} + +GumEventSink *gum_fake_event_sink_new(void) { + + GumFakeEventSink *sink; + sink = (GumFakeEventSink *)g_object_new(GUM_TYPE_FAKE_EVENT_SINK, NULL); + return GUM_EVENT_SINK(sink); + +} + +void gum_fake_event_sink_reset(GumFakeEventSink *self) { + +} + +static GumEventType gum_fake_event_sink_query_mask(GumEventSink *sink) { + + return 0; + +} + +typedef struct library_list { + + uint8_t *name; + uint64_t addr_start, addr_end; + +} library_list_t; + +#define MAX_LIB_COUNT 256 +static library_list_t liblist[MAX_LIB_COUNT]; +static u32 liblist_cnt; + +void read_library_information() { + +#if defined(__linux__) + FILE *f; + u8 buf[1024], *b, *m, *e, *n; + + if ((f = fopen("/proc/self/maps", "r")) == NULL) { + + fprintf(stderr, "Error: cannot open /proc/self/maps\n"); + exit(-1); + + } + + if (debug) fprintf(stderr, "Library list:\n"); + while (fgets(buf, sizeof(buf), f)) { + + if (strstr(buf, " r-x")) { + + if (liblist_cnt >= MAX_LIB_COUNT) { + + fprintf( + stderr, + "Warning: too many libraries to old, maximum count of %d reached\n", + liblist_cnt); + return; + + } + + b = buf; + m = index(buf, '-'); + e = index(buf, ' '); + if ((n = rindex(buf, '/')) == NULL) n = rindex(buf, ' '); + if (n && + ((*n >= '0' && *n <= '9') || *n == '[' || *n == '{' || *n == '(')) + n = NULL; + else + n++; + if (b && m && e && n && *n) { + + *m++ = 0; + *e = 0; + if (n[strlen(n) - 1] == '\n') n[strlen(n) - 1] = 0; + + if (rindex(n, '/') != NULL) { + + n = rindex(n, '/'); + n++; + + } + + liblist[liblist_cnt].name = strdup(n); + liblist[liblist_cnt].addr_start = strtoull(b, NULL, 16); + liblist[liblist_cnt].addr_end = strtoull(m, NULL, 16); + if (debug) + fprintf( + stderr, "%s:%llx (%llx-%llx)\n", liblist[liblist_cnt].name, + liblist[liblist_cnt].addr_end - liblist[liblist_cnt].addr_start, + liblist[liblist_cnt].addr_start, + liblist[liblist_cnt].addr_end - 1); + liblist_cnt++; + + } + + } + + } + + if (debug) fprintf(stderr, "\n"); + +#elif defined(__FreeBSD__) + int mib[] = {CTL_KERN, KERN_PROC, KERN_PROC_VMMAP, getpid()}; + char * buf, *start, *end; + size_t miblen = sizeof(mib) / sizeof(mib[0]); + size_t len; + + if (debug) fprintf(stderr, "Library list:\n"); + if (sysctl(mib, miblen, NULL, &len, NULL, 0) == -1) { return; } + + len = len * 4 / 3; + + buf = mmap(NULL, len, PROT_READ | PROT_WRITE, MAP_SHARED | MAP_ANON, -1, 0); + if (buf == MAP_FAILED) { return; } + if (sysctl(mib, miblen, buf, &len, NULL, 0) == -1) { + + munmap(buf, len); + return; + + } + + start = buf; + end = buf + len; + + while (start < end) { + + struct kinfo_vmentry *region = (struct kinfo_vmentry *)start; + size_t size = region->kve_structsize; + + if (size == 0) { break; } + + if ((region->kve_protection & KVME_PROT_READ) && + !(region->kve_protection & KVME_PROT_EXEC)) { + + liblist[liblist_cnt].name = + region->kve_path[0] != '\0' ? strdup(region->kve_path) : 0; + liblist[liblist_cnt].addr_start = region->kve_start; + liblist[liblist_cnt].addr_end = region->kve_end; + + if (debug) { + + fprintf(stderr, "%s:%x (%lx-%lx)\n", liblist[liblist_cnt].name, + liblist[liblist_cnt].addr_end - liblist[liblist_cnt].addr_start, + liblist[liblist_cnt].addr_start, + liblist[liblist_cnt].addr_end - 1); + + } + + liblist_cnt++; + + } + + start += size; + + } + +#endif + +} + +library_list_t *find_library(char *name) { + + char *filename = rindex(name, '/'); + + if (filename) + filename++; + else + filename = name; + +#if defined(__linux__) + u32 i; + for (i = 0; i < liblist_cnt; i++) + if (strcmp(liblist[i].name, filename) == 0) return &liblist[i]; +#elif defined(__APPLE__) && defined(__LP64__) + kern_return_t err; + static library_list_t lib; + + // get the list of all loaded modules from dyld + // the task_info mach API will get the address of the dyld all_image_info + // struct for the given task from which we can get the names and load + // addresses of all modules + task_dyld_info_data_t task_dyld_info; + mach_msg_type_number_t count = TASK_DYLD_INFO_COUNT; + err = task_info(mach_task_self(), TASK_DYLD_INFO, + (task_info_t)&task_dyld_info, &count); + + const struct dyld_all_image_infos *all_image_infos = + (const struct dyld_all_image_infos *)task_dyld_info.all_image_info_addr; + const struct dyld_image_info *image_infos = all_image_infos->infoArray; + + for (size_t i = 0; i < all_image_infos->infoArrayCount; i++) { + + const char * image_name = image_infos[i].imageFilePath; + mach_vm_address_t image_load_address = + (mach_vm_address_t)image_infos[i].imageLoadAddress; + if (strstr(image_name, name)) { + + lib.name = name; + lib.addr_start = (u64)image_load_address; + lib.addr_end = 0; + return &lib; + + } + + } + +#endif + + return NULL; + +} + +static void gum_fake_event_sink_process(GumEventSink * sink, + const GumEvent *ev) { + +} + +/* Because this CAN be called more than once, it will return the LAST range */ +static int enumerate_ranges(const GumRangeDetails *details, + gpointer user_data) { + + GumMemoryRange *code_range = (GumMemoryRange *)user_data; + memcpy(code_range, details->range, sizeof(*code_range)); + return 0; + +} + +int main() { + +#ifndef __APPLE__ + (void)personality(ADDR_NO_RANDOMIZE); // disable ASLR +#endif + + // STEP 2: load the library you want to fuzz and lookup the functions, + // inclusive of the cleanup functions. + // If there is just one function, then there is nothing to change + // or add here. + + void *dl = dlopen(TARGET_LIBRARY, RTLD_LAZY); + if (!dl) { + + fprintf(stderr, "Could not load %s\n", TARGET_LIBRARY); + exit(-1); + + } + + if (!(o_function = dlsym(dl, TARGET_FUNCTION))) { + + fprintf(stderr, "Could not find function %s\n", TARGET_FUNCTION); + exit(-1); + + } + + // END STEP 2 + + read_library_information(); + library_list_t *lib = find_library(TARGET_LIBRARY); + + if (lib == NULL) { + + fprintf(stderr, "Could not find target library\n"); + exit(-1); + + } + + gum_init_embedded(); + if (!gum_stalker_is_supported()) { + + gum_deinit_embedded(); + return 1; + + } + + GumStalker *stalker = gum_stalker_new(); + + /* + This does not work here as we load a shared library. pretty sure this + would also be easily solvable with frida gum, but I already have all the + code I need from afl-untracer + + GumAddress base_address = gum_module_find_base_address(TARGET_LIBRARY); + GumMemoryRange code_range; + gum_module_enumerate_ranges(TARGET_LIBRARY, GUM_PAGE_RX, enumerate_ranges, + &code_range); + guint64 code_start = code_range.base_address - base_address; + guint64 code_end = (code_range.base_address + code_range.size) - base_address; + range_t instr_range = {base_address, code_start, code_end}; + */ + range_t instr_range = {0, lib->addr_start, lib->addr_end}; + + GumStalkerTransformer *transformer = + gum_stalker_transformer_make_from_callback(instr_basic_block, + &instr_range, NULL); + + GumEventSink *event_sink = gum_fake_event_sink_new(); + + // to ensure that the signatures are not optimized out + memcpy(__afl_area_ptr, (void *)AFL_PERSISTENT, sizeof(AFL_PERSISTENT) + 1); + memcpy(__afl_area_ptr + 32, (void *)AFL_DEFER_FORKSVR, + sizeof(AFL_DEFER_FORKSVR) + 1); + __afl_manual_init(); + + // + // any expensive target library initialization that has to be done just once + // - put that here + // + + gum_stalker_follow_me(stalker, transformer, event_sink); + + while (__afl_persistent_loop(UINT32_MAX) != 0) { + + previous_pc = 0; // Required! + +#ifdef _DEBUG + fprintf(stderr, "CLIENT crc: %016llx len: %u\n", hash64(__afl_fuzz_ptr, *__a + fprintf(stderr, "RECV:"); + for (int i = 0; i < *__afl_fuzz_len; i++) + fprintf(stderr, "%02x", __afl_fuzz_ptr[i]); + fprintf(stderr,"\n"); +#endif + + // STEP 3: ensure the minimum length is present and setup the target + // function to fuzz. + + if (*__afl_fuzz_len > 0) { + + __afl_fuzz_ptr[*__afl_fuzz_len] = 0; // if you need to null terminate + (*o_function)(__afl_fuzz_ptr, *__afl_fuzz_len); + + } + + // END STEP 3 + + } + + gum_stalker_unfollow_me(stalker); + + while (gum_stalker_garbage_collect(stalker)) + g_usleep(10000); + + g_object_unref(stalker); + g_object_unref(transformer); + g_object_unref(event_sink); + gum_deinit_embedded(); + + return 0; + +} + |