Improved FRIDA mode scripting support (#994)

Co-authored-by: Your Name <you@example.com>

8 files changed, 422 insertions, 20 deletions

diff --git a/frida_mode/test/js/GNUmakefile b/frida_mode/test/js/GNUmakefile
index 8ea71656..af40c1c4 100644
--- a/frida_mode/test/js/GNUmakefile
+++ b/frida_mode/test/js/GNUmakefile
@@ -1,18 +1,21 @@
 PWD:=$(shell pwd)/
 ROOT:=$(shell realpath $(PWD)../../..)/
 BUILD_DIR:=$(PWD)build/
-TESTINSTR_DATA_DIR:=$(BUILD_DIR)in/
-TESTINSTR_DATA_FILE:=$(TESTINSTR_DATA_DIR)in
+TEST_DATA_DIR:=$(BUILD_DIR)in/
+TEST_DATA_FILE:=$(TEST_DATA_DIR)in
 
-TESTINSTBIN:=$(BUILD_DIR)testinstr
-TESTINSTSRC:=$(PWD)testinstr.c
+TESTINSTBIN:=$(BUILD_DIR)test
+TESTINSTSRC:=$(PWD)test.c
+
+TESTINSTBIN2:=$(BUILD_DIR)test2
+TESTINSTSRC2:=$(PWD)test2.c
 
 QEMU_OUT:=$(BUILD_DIR)qemu-out
 FRIDA_OUT:=$(BUILD_DIR)frida-out
 
 .PHONY: all 32 clean qemu frida
 
-all: $(TESTINSTBIN)
+all: $(TESTINSTBIN) $(TESTINSTBIN2)
 	make -C $(ROOT)frida_mode/
 
 32:
@@ -21,24 +24,57 @@ all: $(TESTINSTBIN)
 $(BUILD_DIR):
 	mkdir -p $@
 
-$(TESTINSTR_DATA_DIR): | $(BUILD_DIR)
+$(TEST_DATA_DIR): | $(BUILD_DIR)
 	mkdir -p $@
 
-$(TESTINSTR_DATA_FILE): | $(TESTINSTR_DATA_DIR)
+$(TEST_DATA_FILE): | $(TEST_DATA_DIR)
 	echo -n "000" > $@
 
 $(TESTINSTBIN): $(TESTINSTSRC) | $(BUILD_DIR)
 	$(CC) $(CFLAGS) $(LDFLAGS) -o $@ $<
 
+$(TESTINSTBIN2): $(TESTINSTSRC2) | $(BUILD_DIR)
+	$(CC) $(CFLAGS) $(LDFLAGS) -o $@ $<
+
 clean:
 	rm -rf $(BUILD_DIR)
 
-frida: $(TESTINSTBIN) $(TESTINSTR_DATA_FILE)
-	AFL_FRIDA_JS_SCRIPT=test.js \
+frida_js_entry: $(TESTINSTBIN) $(TEST_DATA_FILE)
+	AFL_FRIDA_JS_SCRIPT=entry.js \
 	$(ROOT)afl-fuzz \
 		-D \
 		-O \
-		-i $(TESTINSTR_DATA_DIR) \
+		-i $(TEST_DATA_DIR) \
 		-o $(FRIDA_OUT) \
 		-- \
 			$(TESTINSTBIN) @@
+
+frida_js_replace: $(TESTINSTBIN) $(TEST_DATA_FILE)
+	AFL_FRIDA_JS_SCRIPT=replace.js \
+	$(ROOT)afl-fuzz \
+		-D \
+		-O \
+		-i $(TEST_DATA_DIR) \
+		-o $(FRIDA_OUT) \
+		-- \
+			$(TESTINSTBIN) @@
+
+frida_js_patch: $(TESTINSTBIN2) $(TEST_DATA_FILE)
+	AFL_FRIDA_JS_SCRIPT=patch.js \
+	$(ROOT)afl-fuzz \
+		-D \
+		-O \
+		-i $(TEST_DATA_DIR) \
+		-o $(FRIDA_OUT) \
+		-- \
+			$(TESTINSTBIN2) @@
+
+frida_js_stalker: $(TESTINSTBIN2) $(TEST_DATA_FILE)
+	AFL_FRIDA_JS_SCRIPT=stalker.js \
+	$(ROOT)afl-fuzz \
+		-D \
+		-O \
+		-i $(TEST_DATA_DIR) \
+		-o $(FRIDA_OUT) \
+		-- \
+			$(TESTINSTBIN2) @@
diff --git a/frida_mode/test/js/Makefile b/frida_mode/test/js/Makefile
index 7a237f99..8a2b6fb0 100644
--- a/frida_mode/test/js/Makefile
+++ b/frida_mode/test/js/Makefile
@@ -9,8 +9,17 @@ all:
 clean:
 	@gmake clean
 
-frida:
-	@gmake frida
+frida_js_entry:
+	@gmake frida_js_entry
+
+frida_js_replace:
+	@gmake frida_js_replace
+
+frida_js_patch:
+	@gmake frida_js_patch
+
+frida_js_stalker:
+	@gmake frida_js_stalker
 
 debug:
 	@gmake debug
diff --git a/frida_mode/test/js/test.js b/frida_mode/test/js/entry.js
index f10ef2d1..f10ef2d1 100644
--- a/frida_mode/test/js/test.js
+++ b/frida_mode/test/js/entry.js
diff --git a/frida_mode/test/js/patch.js b/frida_mode/test/js/patch.js
new file mode 100644
index 00000000..485a434f
--- /dev/null
+++ b/frida_mode/test/js/patch.js
@@ -0,0 +1,34 @@
+Afl.print('******************');
+Afl.print('* AFL FRIDA MODE *');
+Afl.print('******************');
+Afl.print('');
+
+const main = DebugSymbol.fromName('main').address;
+Afl.print(`main: ${main}`);
+Afl.setEntryPoint(main);
+Afl.setPersistentAddress(main);
+Afl.setPersistentCount(10000000);
+
+const crc32_check = DebugSymbol.fromName('crc32_check').address;
+const crc32_replacement = new NativeCallback(
+    (buf, len) => {
+        Afl.print(`len: ${len}`);
+        if (len < 4) {
+            return 0;
+        }
+
+        return 1;
+    },
+    'int',
+    ['pointer', 'int']);
+Interceptor.replace(crc32_check, crc32_replacement);
+
+const some_boring_bug = DebugSymbol.fromName('some_boring_bug').address
+const boring_replacement = new NativeCallback(
+    (c) => { },
+    'void',
+    ['char']);
+Interceptor.replace(some_boring_bug, boring_replacement);
+
+Afl.done();
+Afl.print("done");
diff --git a/frida_mode/test/js/replace.js b/frida_mode/test/js/replace.js
new file mode 100644
index 00000000..4e1e7eb7
--- /dev/null
+++ b/frida_mode/test/js/replace.js
@@ -0,0 +1,43 @@
+Afl.print('******************');
+Afl.print('* AFL FRIDA MODE *');
+Afl.print('******************');
+Afl.print('');
+
+Afl.print(`PID: ${Process.id}`);
+
+const name = Process.enumerateModules()[0].name;
+Afl.print(`Name: ${name}`);
+
+new ModuleMap().values().forEach(m => {
+    Afl.print(`${m.base}-${m.base.add(m.size)} ${m.name}`);
+});
+
+const slow = DebugSymbol.fromName('slow').address;
+Afl.print(`slow: ${slow}`);
+
+const LLVMFuzzerTestOneInput = DebugSymbol.fromName('LLVMFuzzerTestOneInput').address;
+Afl.print(`LLVMFuzzerTestOneInput: ${LLVMFuzzerTestOneInput}`);
+
+const cm = new CModule(`
+
+    extern unsigned char * __afl_fuzz_ptr;
+    extern unsigned int * __afl_fuzz_len;
+    extern void LLVMFuzzerTestOneInput(char *buf, int len);
+
+    void slow(void) {
+
+      LLVMFuzzerTestOneInput(__afl_fuzz_ptr, *__afl_fuzz_len);
+    }
+    `,
+    {
+        LLVMFuzzerTestOneInput: LLVMFuzzerTestOneInput,
+        __afl_fuzz_ptr: Afl.getAflFuzzPtr(),
+        __afl_fuzz_len: Afl.getAflFuzzLen()
+    });
+
+Afl.setEntryPoint(cm.slow);
+Afl.setPersistentAddress(cm.slow);
+Afl.setInMemoryFuzzing();
+Interceptor.replace(slow, cm.slow);
+Afl.print("done");
+Afl.done();
diff --git a/frida_mode/test/js/stalker.js b/frida_mode/test/js/stalker.js
new file mode 100644
index 00000000..33f024f5
--- /dev/null
+++ b/frida_mode/test/js/stalker.js
@@ -0,0 +1,109 @@
+Afl.print('******************');
+Afl.print('* AFL FRIDA MODE *');
+Afl.print('******************');
+Afl.print('');
+
+const main = DebugSymbol.fromName('main').address;
+Afl.print(`main: ${main}`);
+Afl.setEntryPoint(main);
+Afl.setPersistentAddress(main);
+Afl.setPersistentCount(10000000);
+
+/* Replace CRC-32 check */
+const crc32_check = DebugSymbol.fromName('crc32_check').address;
+const crc32_replacement = new NativeCallback(
+    (buf, len) => {
+        if (len < 4) {
+            return 0;
+        }
+
+        return 1;
+    },
+    'int',
+    ['pointer', 'int']);
+Interceptor.replace(crc32_check, crc32_replacement);
+
+/* Patch out the first boring bug */
+const some_boring_bug = DebugSymbol.fromName('some_boring_bug').address
+const boring_replacement = new NativeCallback(
+    (c) => { },
+    'void',
+    ['char']);
+Interceptor.replace(some_boring_bug, boring_replacement);
+
+/* Modify the instructions */
+const some_boring_bug2 = DebugSymbol.fromName('some_boring_bug2').address
+const pid = Memory.alloc(4);
+pid.writeInt(Process.id);
+
+const cm = new CModule(`
+    #include <stdio.h>
+    #include <gum/gumstalker.h>
+
+    typedef int pid_t;
+
+    #define STDERR_FILENO 2
+    #define BORING2_LEN 10
+
+    extern int dprintf(int fd, const char *format, ...);
+    extern void some_boring_bug2(char c);
+    extern pid_t getpid(void);
+    extern pid_t pid;
+
+    gboolean js_stalker_callback(const cs_insn *insn, gboolean begin,
+        gboolean excluded, GumStalkerOutput *output)
+    {
+        pid_t my_pid = getpid();
+        GumX86Writer *cw = output->writer.x86;
+
+        if (GUM_ADDRESS(insn->address) < GUM_ADDRESS(some_boring_bug2)) {
+
+            return TRUE;
+
+        }
+
+        if (GUM_ADDRESS(insn->address) >=
+            GUM_ADDRESS(some_boring_bug2) + BORING2_LEN) {
+
+            return TRUE;
+
+        }
+
+        if (my_pid == pid) {
+
+            if (begin) {
+
+                dprintf(STDERR_FILENO, "\n> 0x%016lX: %s %s\n", insn->address,
+                        insn->mnemonic, insn->op_str);
+
+            } else {
+
+                dprintf(STDERR_FILENO, "  0x%016lX: %s %s\n", insn->address,
+                        insn->mnemonic, insn->op_str);
+
+            }
+
+        }
+
+        if (insn->id == X86_INS_UD2) {
+
+            gum_x86_writer_put_nop(cw);
+            return FALSE;
+
+        } else {
+
+            return TRUE;
+
+        }
+    }
+    `,
+    {
+        dprintf: Module.getExportByName(null, 'dprintf'),
+        getpid: Module.getExportByName(null, 'getpid'),
+        some_boring_bug2: some_boring_bug2,
+        pid: pid
+    });
+Afl.setStalkerCallback(cm.js_stalker_callback)
+Afl.setStdErr("/tmp/stderr.txt");
+Afl.done();
+Afl.print("done");
diff --git a/frida_mode/test/js/testinstr.c b/frida_mode/test/js/test.c
index bd605c52..bbda5ccf 100644
--- a/frida_mode/test/js/testinstr.c
+++ b/frida_mode/test/js/test.c
@@ -16,13 +16,7 @@
 #include <stdlib.h>
 #include <unistd.h>
 
-#ifdef __APPLE__
-  #define TESTINSTR_SECTION
-#else
-  #define TESTINSTR_SECTION __attribute__((section(".testinstr")))
-#endif
-
-void testinstr(char *buf, int len) {
+void LLVMFuzzerTestOneInput(char *buf, int len) {
 
   if (len < 1) return;
   buf[len] = 0;
@@ -90,7 +84,7 @@ int run(char *file) {
 
     dprintf(STDERR_FILENO, "Running:    %s: (%zd bytes)\n", file, n_read);
 
-    testinstr(buf, len);
+    LLVMFuzzerTestOneInput(buf, len);
     dprintf(STDERR_FILENO, "Done:    %s: (%zd bytes)\n", file, n_read);
 
     result = 0;
diff --git a/frida_mode/test/js/test2.c b/frida_mode/test/js/test2.c
new file mode 100644
index 00000000..d16f35fc
--- /dev/null
+++ b/frida_mode/test/js/test2.c
@@ -0,0 +1,177 @@
+/*
+   american fuzzy lop++ - a trivial program to test the build
+   --------------------------------------------------------
+   Originally written by Michal Zalewski
+   Copyright 2014 Google Inc. All rights reserved.
+   Copyright 2019-2020 AFLplusplus Project. 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
+ */
+
+#include <fcntl.h>
+#include <stdarg.h>
+#include <stdbool.h>
+#include <stdio.h>
+#include <stdint.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+
+#define IGNORED_RETURN(x) (void)!(x)
+
+const uint32_t crc32_tab[] = {
+	0x00000000, 0x77073096, 0xee0e612c, 0x990951ba, 0x076dc419, 0x706af48f,
+	0xe963a535, 0x9e6495a3,	0x0edb8832, 0x79dcb8a4, 0xe0d5e91e, 0x97d2d988,
+	0x09b64c2b, 0x7eb17cbd, 0xe7b82d07, 0x90bf1d91, 0x1db71064, 0x6ab020f2,
+	0xf3b97148, 0x84be41de,	0x1adad47d, 0x6ddde4eb, 0xf4d4b551, 0x83d385c7,
+	0x136c9856, 0x646ba8c0, 0xfd62f97a, 0x8a65c9ec,	0x14015c4f, 0x63066cd9,
+	0xfa0f3d63, 0x8d080df5,	0x3b6e20c8, 0x4c69105e, 0xd56041e4, 0xa2677172,
+	0x3c03e4d1, 0x4b04d447, 0xd20d85fd, 0xa50ab56b,	0x35b5a8fa, 0x42b2986c,
+	0xdbbbc9d6, 0xacbcf940,	0x32d86ce3, 0x45df5c75, 0xdcd60dcf, 0xabd13d59,
+	0x26d930ac, 0x51de003a, 0xc8d75180, 0xbfd06116, 0x21b4f4b5, 0x56b3c423,
+	0xcfba9599, 0xb8bda50f, 0x2802b89e, 0x5f058808, 0xc60cd9b2, 0xb10be924,
+	0x2f6f7c87, 0x58684c11, 0xc1611dab, 0xb6662d3d,	0x76dc4190, 0x01db7106,
+	0x98d220bc, 0xefd5102a, 0x71b18589, 0x06b6b51f, 0x9fbfe4a5, 0xe8b8d433,
+	0x7807c9a2, 0x0f00f934, 0x9609a88e, 0xe10e9818, 0x7f6a0dbb, 0x086d3d2d,
+	0x91646c97, 0xe6635c01, 0x6b6b51f4, 0x1c6c6162, 0x856530d8, 0xf262004e,
+	0x6c0695ed, 0x1b01a57b, 0x8208f4c1, 0xf50fc457, 0x65b0d9c6, 0x12b7e950,
+	0x8bbeb8ea, 0xfcb9887c, 0x62dd1ddf, 0x15da2d49, 0x8cd37cf3, 0xfbd44c65,
+	0x4db26158, 0x3ab551ce, 0xa3bc0074, 0xd4bb30e2, 0x4adfa541, 0x3dd895d7,
+	0xa4d1c46d, 0xd3d6f4fb, 0x4369e96a, 0x346ed9fc, 0xad678846, 0xda60b8d0,
+	0x44042d73, 0x33031de5, 0xaa0a4c5f, 0xdd0d7cc9, 0x5005713c, 0x270241aa,
+	0xbe0b1010, 0xc90c2086, 0x5768b525, 0x206f85b3, 0xb966d409, 0xce61e49f,
+	0x5edef90e, 0x29d9c998, 0xb0d09822, 0xc7d7a8b4, 0x59b33d17, 0x2eb40d81,
+	0xb7bd5c3b, 0xc0ba6cad, 0xedb88320, 0x9abfb3b6, 0x03b6e20c, 0x74b1d29a,
+	0xead54739, 0x9dd277af, 0x04db2615, 0x73dc1683, 0xe3630b12, 0x94643b84,
+	0x0d6d6a3e, 0x7a6a5aa8, 0xe40ecf0b, 0x9309ff9d, 0x0a00ae27, 0x7d079eb1,
+	0xf00f9344, 0x8708a3d2, 0x1e01f268, 0x6906c2fe, 0xf762575d, 0x806567cb,
+	0x196c3671, 0x6e6b06e7, 0xfed41b76, 0x89d32be0, 0x10da7a5a, 0x67dd4acc,
+	0xf9b9df6f, 0x8ebeeff9, 0x17b7be43, 0x60b08ed5, 0xd6d6a3e8, 0xa1d1937e,
+	0x38d8c2c4, 0x4fdff252, 0xd1bb67f1, 0xa6bc5767, 0x3fb506dd, 0x48b2364b,
+	0xd80d2bda, 0xaf0a1b4c, 0x36034af6, 0x41047a60, 0xdf60efc3, 0xa867df55,
+	0x316e8eef, 0x4669be79, 0xcb61b38c, 0xbc66831a, 0x256fd2a0, 0x5268e236,
+	0xcc0c7795, 0xbb0b4703, 0x220216b9, 0x5505262f, 0xc5ba3bbe, 0xb2bd0b28,
+	0x2bb45a92, 0x5cb36a04, 0xc2d7ffa7, 0xb5d0cf31, 0x2cd99e8b, 0x5bdeae1d,
+	0x9b64c2b0, 0xec63f226, 0x756aa39c, 0x026d930a, 0x9c0906a9, 0xeb0e363f,
+	0x72076785, 0x05005713, 0x95bf4a82, 0xe2b87a14, 0x7bb12bae, 0x0cb61b38,
+	0x92d28e9b, 0xe5d5be0d, 0x7cdcefb7, 0x0bdbdf21, 0x86d3d2d4, 0xf1d4e242,
+	0x68ddb3f8, 0x1fda836e, 0x81be16cd, 0xf6b9265b, 0x6fb077e1, 0x18b74777,
+	0x88085ae6, 0xff0f6a70, 0x66063bca, 0x11010b5c, 0x8f659eff, 0xf862ae69,
+	0x616bffd3, 0x166ccf45, 0xa00ae278, 0xd70dd2ee, 0x4e048354, 0x3903b3c2,
+	0xa7672661, 0xd06016f7, 0x4969474d, 0x3e6e77db, 0xaed16a4a, 0xd9d65adc,
+	0x40df0b66, 0x37d83bf0, 0xa9bcae53, 0xdebb9ec5, 0x47b2cf7f, 0x30b5ffe9,
+	0xbdbdf21c, 0xcabac28a, 0x53b39330, 0x24b4a3a6, 0xbad03605, 0xcdd70693,
+	0x54de5729, 0x23d967bf, 0xb3667a2e, 0xc4614ab8, 0x5d681b02, 0x2a6f2b94,
+	0xb40bbe37, 0xc30c8ea1, 0x5a05df1b, 0x2d02ef8d
+};
+
+uint32_t
+crc32(const void *buf, size_t size)
+{
+	const uint8_t *p = buf;
+	uint32_t crc;
+ 	crc = ~0U;
+	while (size--)
+		crc = crc32_tab[(crc ^ *p++) & 0xFF] ^ (crc >> 8);
+	return crc ^ ~0U;
+}
+
+/*
+ * Don't you hate those contrived examples which CRC their data. We can use
+ * FRIDA to patch this function out and always return success. Otherwise, we
+ * could change it to actually correct the checksum.
+ */
+int crc32_check (char * buf, int len) {
+  if (len < sizeof(uint32_t)) { return 0; }
+  uint32_t expected = *(uint32_t *)&buf[len - sizeof(uint32_t)];
+  uint32_t calculated = crc32(buf, len - sizeof(uint32_t));
+  return expected == calculated;
+}
+
+/*
+ * So you've found a really boring bug in an earlier campaign which results in
+ * a NULL dereference or something like that. That bug can get in the way,
+ * causing the persistent loop to exit whenever it is triggered, and can also
+ * cloud your output unnecessarily. Again, we can use FRIDA to patch it out.
+ */
+void some_boring_bug(char c) {
+  switch (c) {
+    case 'A'...'Z':
+    case 'a'...'z':
+      __builtin_trap();
+      break;
+  }
+}
+
+extern void some_boring_bug2(char c);
+
+__asm__ (
+      ".text                                 \n"
+      "some_boring_bug2:                     \n"
+      ".global some_boring_bug2              \n"
+      ".type some_boring_bug2, @function     \n"
+      "mov %edi, %eax                        \n"
+      "cmp $0xb4, %al                        \n"
+      "jne ok                                \n"
+      "ud2                                   \n"
+      "ok:                                   \n"
+      "ret                                   \n");
+
+void LLVMFuzzerTestOneInput(char *buf, int len) {
+
+  if (!crc32_check(buf, len)) return;
+
+  some_boring_bug(buf[0]);
+  some_boring_bug2(buf[0]);
+
+  if (buf[0] == '0') {
+    printf("Looks like a zero to me!\n");
+  }
+  else if (buf[0] == '1') {
+    printf("Pretty sure that is a one!\n");
+  }
+  else if (buf[0] == '2') {
+    printf("Oh we, weren't expecting that!");
+    __builtin_trap();
+  }
+  else
+    printf("Neither one or zero? How quaint!\n");
+
+}
+
+int main(int argc, char **argv) {
+
+  int    fd = -1;
+  off_t  len;
+  char * buf = NULL;
+  size_t n_read;
+  int    result = -1;
+
+  if (argc != 2) { return 1; }
+
+  printf("Running: %s\n", argv[1]);
+
+  fd = open(argv[1], O_RDONLY);
+  if (fd < 0) { return 1; }
+
+  len = lseek(fd, 0, SEEK_END);
+  if (len < 0) { return 1; }
+
+  if (lseek(fd, 0, SEEK_SET) != 0) { return 1; }
+
+  buf = malloc(len);
+  if (buf == NULL) { return 1; }
+
+  n_read = read(fd, buf, len);
+  if (n_read != len) { return 1; }
+
+  printf("Running:    %s: (%zd bytes)\n", argv[1], n_read);
+
+  LLVMFuzzerTestOneInput(buf, len);
+  printf("Done:    %s: (%zd bytes)\n", argv[1], n_read);
+
+  return 0;
+}
+