diff options
Diffstat (limited to 'frida_mode/src/instrument')
| -rw-r--r-- | frida_mode/src/instrument/instrument.c | 53 | ||||
| -rw-r--r-- | frida_mode/src/instrument/instrument_debug.c | 129 |
2 files changed, 176 insertions, 6 deletions
diff --git a/frida_mode/src/instrument/instrument.c b/frida_mode/src/instrument/instrument.c index 67eadc3f..cd1ac0be 100644 --- a/frida_mode/src/instrument/instrument.c +++ b/frida_mode/src/instrument/instrument.c @@ -13,6 +13,7 @@ #include "prefetch.h" #include "ranges.h" #include "stalker.h" +#include "stats.h" #include "util.h" static gboolean tracing = false; @@ -47,7 +48,7 @@ __attribute__((hot)) static void on_basic_block(GumCpuContext *context, "x, previous_pc: 0x%016" G_GINT64_MODIFIER "x\n", current_pc, previous_pc); - IGNORED_RERURN(write(STDOUT_FILENO, buffer, len + 1)); + IGNORED_RETURN(write(STDOUT_FILENO, buffer, len + 1)); } @@ -79,17 +80,52 @@ static void instr_basic_block(GumStalkerIterator *iterator, const cs_insn *instr; gboolean begin = TRUE; + gboolean excluded; + while (gum_stalker_iterator_next(iterator, &instr)) { if (instr->address == entry_start) { entry_prologue(iterator, output); } if (instr->address == persistent_start) { persistent_prologue(output); } - - if (begin) { + if (instr->address == persistent_ret) { persistent_epilogue(output); } + + /* + * Until we reach AFL_ENTRYPOINT (assumed to be main if not specified) or + * AFL_FRIDA_PERSISTENT_ADDR (if specified), we don't mark our ranges + * excluded as we wish to remain inside stalker at all times so that we can + * instrument our entry point and persistent loop (if present). This allows + * the user to exclude ranges which would be traversed between main and the + * AFL_ENTRYPOINT, but which they don't want included in their coverage + * information when fuzzing. + * + * Since we have no means to discard the instrumented copies of blocks + * (setting the trust threshold simply causes a new copy to be made on each + * execution), we instead ensure that we honour the additional + * instrumentation requested (e.g. coverage, asan and complog) when a block + * is compiled no matter where we are during initialization. We will end up + * re-using these blocks if the code under test calls a block which is also + * used during initialization. + * + * Coverage data generated during initialization isn't a problem since the + * map is zeroed each time the target is forked or each time the persistent + * loop is run. + * + * Lastly, we don't enable pre-fetching back to the parent until we reach + * our AFL_ENTRYPOINT, since it is not until then that we start the + * fork-server and thus start executing in the child. + */ + excluded = range_is_excluded(GSIZE_TO_POINTER(instr->address)); + + stats_collect(instr, begin); + + if (unlikely(begin)) { + + instrument_debug_start(instr->address, output); prefetch_write(GSIZE_TO_POINTER(instr->address)); - if (!range_is_excluded(GSIZE_TO_POINTER(instr->address))) { - if (optimize) { + if (likely(!excluded)) { + + if (likely(optimize)) { instrument_coverage_optimize(instr, output); @@ -106,7 +142,9 @@ static void instr_basic_block(GumStalkerIterator *iterator, } - if (!range_is_excluded(GSIZE_TO_POINTER(instr->address))) { + instrument_debug_instruction(instr->address, instr->size); + + if (likely(!excluded)) { asan_instrument(instr, iterator); cmplog_instrument(instr, iterator); @@ -117,6 +155,8 @@ static void instr_basic_block(GumStalkerIterator *iterator, } + instrument_debug_end(output); + } void instrument_init(void) { @@ -144,6 +184,7 @@ void instrument_init(void) { transformer = gum_stalker_transformer_make_from_callback(instr_basic_block, NULL, NULL); + instrument_debug_init(); asan_init(); cmplog_init(); diff --git a/frida_mode/src/instrument/instrument_debug.c b/frida_mode/src/instrument/instrument_debug.c new file mode 100644 index 00000000..be72ef89 --- /dev/null +++ b/frida_mode/src/instrument/instrument_debug.c @@ -0,0 +1,129 @@ +#include <fcntl.h> +#include <stdarg.h> +#include <stdio.h> +#include <unistd.h> + +#include "frida-gum.h" + +#include "debug.h" + +#include "util.h" + +static int debugging_fd = -1; +static gpointer instrument_gen_start = NULL; + +static void instrument_debug(char *format, ...) { + + va_list ap; + char buffer[4096] = {0}; + int ret; + int len; + + va_start(ap, format); + ret = vsnprintf(buffer, sizeof(buffer) - 1, format, ap); + va_end(ap); + + if (ret < 0) { return; } + + len = strnlen(buffer, sizeof(buffer)); + + IGNORED_RETURN(write(debugging_fd, buffer, len)); + +} + +static void instrument_disasm(guint8 *code, guint size) { + + csh capstone; + cs_err err; + cs_insn *insn; + size_t count, i; + + err = cs_open(GUM_DEFAULT_CS_ARCH, + GUM_DEFAULT_CS_MODE | GUM_DEFAULT_CS_ENDIAN, &capstone); + g_assert(err == CS_ERR_OK); + + count = cs_disasm(capstone, code, size, GPOINTER_TO_SIZE(code), 0, &insn); + g_assert(insn != NULL); + + for (i = 0; i != count; i++) { + + instrument_debug("\t0x%" G_GINT64_MODIFIER "x\t%s %s\n", insn[i].address, + insn[i].mnemonic, insn[i].op_str); + + } + + cs_free(insn, count); + + cs_close(&capstone); + +} + +static gpointer instrument_cur(GumStalkerOutput *output) { + +#if defined(__i386__) || defined(__x86_64__) + return gum_x86_writer_cur(output->writer.x86); +#elif defined(__aarch64__) + return gum_arm64_writer_cur(output->writer.arm64); +#elif defined(__arm__) + return gum_arm_writer_cur(output->writer.arm); +#else + #error "Unsupported architecture" +#endif + +} + +void instrument_debug_init(void) { + + char *filename = getenv("AFL_FRIDA_INST_DEBUG_FILE"); + OKF("Instrumentation debugging - enabled [%c]", filename == NULL ? ' ' : 'X'); + + if (filename == NULL) { return; } + + OKF("Instrumentation debugging - file [%s]", filename); + + if (filename == NULL) { return; } + + char *path = g_canonicalize_filename(filename, g_get_current_dir()); + + OKF("Instrumentation debugging - path [%s]", path); + + debugging_fd = open(path, O_RDWR | O_CREAT | O_TRUNC, + S_IRUSR | S_IWUSR | S_IRGRP | S_IWGRP); + + if (debugging_fd < 0) { FATAL("Failed to open stats file '%s'", path); } + + g_free(path); + +} + +void instrument_debug_start(uint64_t address, GumStalkerOutput *output) { + + if (likely(debugging_fd < 0)) { return; } + + instrument_gen_start = instrument_cur(output); + + instrument_debug("\n\n***\n\nCreating block for 0x%" G_GINT64_MODIFIER "x:\n", + address); + +} + +void instrument_debug_instruction(uint64_t address, uint16_t size) { + + if (likely(debugging_fd < 0)) { return; } + uint8_t *start = (uint8_t *)GSIZE_TO_POINTER(address); + instrument_disasm(start, size); + +} + +void instrument_debug_end(GumStalkerOutput *output) { + + if (likely(debugging_fd < 0)) { return; } + gpointer instrument_gen_end = instrument_cur(output); + uint16_t size = GPOINTER_TO_SIZE(instrument_gen_end) - + GPOINTER_TO_SIZE(instrument_gen_start); + + instrument_debug("\nGenerated block %p\n", instrument_gen_start); + instrument_disasm(instrument_gen_start, size); + +} + |