radare2/libr/core/hack.c

264 lines
7.5 KiB
C

/* radare - LGPL - Copyright 2011-2012 - pancake */
#include <r_core.h>
/* We can not use some kind of structure type with
* a string for each case, because some architectures (like ARM)
* have several modes/alignement requirements.
*/
void r_core_hack_help(const RCore *core) {
const char* help_msg[] = {
"wao", " [op]", "performs a modification on current opcode",
"wao", " nop", "nop current opcode",
"wao", " jz", "make current opcode conditional (zero)",
"wao", " jnz", "make current opcode conditional (not zero)",
"wao", " ret1", "make the current opcode return 1",
"wao", " ret0", "make the current opcode return 0",
"wao", " retn", "make the current opcode return -1",
"wao", " nocj", "remove conditional operation from branch (make it unconditional)",
"wao", " trap", "make the current opcode a trap",
"wao", " recj", "reverse (swap) conditional branch instruction",
"NOTE:", "", "those operations are only implemented for x86 and arm atm.", //TODO
NULL
};
r_core_cmd_help (core, help_msg);
}
R_API bool r_core_hack_arm64(RCore *core, const char *op, const RAnalOp *analop) {
if (!strcmp (op, "nop")) {
r_core_cmdf (core, "wx 1f2003d5");
} else if (!strcmp (op, "ret")) {
r_core_cmdf (core, "wx c0035fd6t");
} else if (!strcmp (op, "trap")) {
r_core_cmdf (core, "wx 000020d4");
} else if (!strcmp (op, "jz")) {
eprintf ("ARM jz hack not supported\n");
return false;
} else if (!strcmp (op, "jnz")) {
eprintf ("ARM jnz hack not supported\n");
return false;
} else if (!strcmp (op, "nocj")) {
eprintf ("ARM jnz hack not supported\n");
return false;
} else if (!strcmp (op, "recj")) {
eprintf ("TODO: use jnz or jz\n");
return false;
} else if (!strcmp (op, "ret1")) {
r_core_cmdf (core, "wa mov x0, 1,,ret");
} else if (!strcmp (op, "ret0")) {
r_core_cmdf (core, "wa mov x0, 0,,ret");
} else if (!strcmp (op, "retn")) {
r_core_cmdf (core, "wa mov x0, -1,,ret");
} else {
eprintf ("Invalid operation '%s'\n", op);
return false;
}
return true;
}
R_API bool r_core_hack_arm(RCore *core, const char *op, const RAnalOp *analop) {
const int bits = core->assembler->bits;
const ut8 *b = core->block;
if (!strcmp (op, "nop")) {
const int nopsize = (bits==16)? 2: 4;
const char *nopcode = (bits==16)? "00bf":"0000a0e1";
const int len = analop->size;
char* str;
int i;
if (len % nopsize) {
eprintf ("Invalid nopcode size\n");
return false;
}
str = calloc (len + 1, 2);
if (!str) {
return false;
}
for (i=0; i < len; i+=nopsize) {
memcpy (str + i * 2, nopcode, nopsize*2);
}
str[len*2] = '\0';
r_core_cmdf (core, "wx %s\n", str);
free (str);
} else if (!strcmp (op, "trap")) {
const char* trapcode = (bits==16)? "bebe": "fedeffe7";
r_core_cmdf (core, "wx %s\n", trapcode);
} else if (!strcmp (op, "jz")) {
if (bits == 16) {
switch (b[1]) {
case 0xb9: // CBNZ
r_core_cmd0 (core, "wx b1 @@ $$+1\n"); //CBZ
break;
case 0xbb: // CBNZ
r_core_cmd0 (core, "wx b3 @@ $$+1\n"); //CBZ
break;
case 0xd1: // BNE
r_core_cmd0 (core, "wx d0 @@ $$+1\n"); //BEQ
break;
default:
eprintf ("Current opcode is not conditional\n");
return false;
}
} else {
eprintf ("ARM jz hack not supported\n");
return false;
}
} else if (!strcmp (op, "jnz")) {
if (bits == 16) {
switch (b[1]) {
case 0xb1: // CBZ
r_core_cmd0 (core, "wx b9 @@ $$+1\n"); //CBNZ
break;
case 0xb3: // CBZ
r_core_cmd0 (core, "wx bb @@ $$+1\n"); //CBNZ
break;
case 0xd0: // BEQ
r_core_cmd0 (core, "wx d1 @@ $$+1\n"); //BNE
break;
default:
eprintf ("Current opcode is not conditional\n");
return false;
}
} else {
eprintf ("ARM jnz hack not supported\n");
return false;
}
} else if (!strcmp (op, "nocj")) {
// TODO: drop conditional bit instead of that hack
if (bits == 16) {
switch (b[1]) {
case 0xb1: // CBZ
case 0xb3: // CBZ
case 0xd0: // BEQ
case 0xb9: // CBNZ
case 0xbb: // CBNZ
case 0xd1: // BNE
r_core_cmd0 (core, "wx e0 @@ $$+1\n"); //BEQ
break;
default:
eprintf ("Current opcode is not conditional\n");
return false;
}
} else {
eprintf ("ARM un-cjmp hack not supported\n");
return false;
}
} else if (!strcmp (op, "recj")) {
eprintf ("TODO: use jnz or jz\n");
return false;
} else if (!strcmp (op, "ret1")) {
if (bits == 16)
r_core_cmd0 (core, "wx 01207047 @@ $$+1\n"); // mov r0, 1; bx lr
else
r_core_cmd0 (core, "wx 0100b0e31eff2fe1 @@ $$+1\n"); // movs r0, 1; bx lr
} else if (!strcmp (op, "ret0")) {
if (bits == 16)
r_core_cmd0 (core, "wx 00207047 @@ $$+1\n"); // mov r0, 0; bx lr
else
r_core_cmd0 (core, "wx 0000a0e31eff2fe1 @@ $$+1\n"); // movs r0, 0; bx lr
} else if (!strcmp (op, "retn")) {
if (bits == 16)
r_core_cmd0 (core, "wx ff207047 @@ $$+1\n"); // mov r0, -1; bx lr
else
r_core_cmd0 (core, "wx ff00a0e31eff2fe1 @@ $$+1\n"); // movs r0, -1; bx lr
} else {
eprintf ("Invalid operation\n");
return false;
}
return true;
}
R_API bool r_core_hack_x86(RCore *core, const char *op, const RAnalOp *analop) {
const ut8 *b = core->block;
int i, size = analop->size;
if (!strcmp (op, "nop")) {
if (size * 2 + 1 < size) return false;
char *str = malloc (size * 2 + 1);
if (!str) {
return false;
}
for (i = 0; i < size; i++)
memcpy (str + (i * 2), "90", 2);
str[size*2] = '\0';
r_core_cmdf (core, "wx %s\n", str);
free (str);
} else if (!strcmp (op, "trap")) {
r_core_cmd0 (core, "wx cc\n");
} else if (!strcmp (op, "jz")) {
if (b[0] == 0x75) {
r_core_cmd0 (core, "wx 74\n");
} else {
eprintf ("Current opcode is not conditional\n");
return false;
}
} else if (!strcmp (op, "jnz")) {
if (b[0] == 0x74) {
r_core_cmd0 (core, "wx 75\n");
} else {
eprintf ("Current opcode is not conditional\n");
return false;
}
} else if (!strcmp (op, "nocj")) {
if (*b == 0xf) {
r_core_cmd0 (core, "wx 90e9");
} else if (b[0] >= 0x70 && b[0] <= 0x7f) {
r_core_cmd0 (core, "wx eb");
} else {
eprintf ("Current opcode is not conditional\n");
return false;
}
} else if (!strcmp (op, "recj")) {
int is_near = (*b == 0xf);
if (b[0] < 0x80 && b[0] >= 0x70) { // short jmps: jo, jno, jb, jae, je, jne, jbe, ja, js, jns
r_core_cmdf (core, "wx %x\n", (b[0]%2)? b[0] - 1: b[0] + 1);
} else if (is_near && b[1] < 0x90 && b[1] >= 0x80) { // near jmps: jo, jno, jb, jae, je, jne, jbe, ja, js, jns
r_core_cmdf (core, "wx 0f%x\n", (b[1]%2)? b[1] - 1: b[1] + 1);
} else {
eprintf ("Invalid conditional jump opcode\n");
return false;
}
} else if (!strcmp (op, "ret1")) {
r_core_cmd0 (core, "wx c20100\n");
} else if (!strcmp (op, "ret0")) {
r_core_cmd0 (core, "wx c20000\n");
} else if (!strcmp (op, "retn")) {
r_core_cmd0 (core, "wx c2ffff\n");
} else {
eprintf ("Invalid operation '%s'\n", op);
return false;
}
return true;
}
R_API int r_core_hack(RCore *core, const char *op) {
bool (*hack)(RCore *core, const char *op, const RAnalOp *analop) = NULL;
const char *asmarch = r_config_get (core->config, "asm.arch");
const int asmbits = core->assembler->bits;
if (!asmarch) {
return false;
}
if (strstr (asmarch, "x86")) {
hack = r_core_hack_x86;
} else if (strstr (asmarch, "arm")) {
if (asmbits == 64) {
hack = r_core_hack_arm64;
} else {
hack = r_core_hack_arm;
}
} else {
eprintf ("TODO: write hacks are only for x86\n");
}
if (hack) {
RAnalOp analop;
if (!r_anal_op (core->anal, &analop, core->offset, core->block, core->blocksize, R_ANAL_OP_MASK_BASIC)) {
eprintf ("anal op fail\n");
return false;
}
return hack (core, op, &analop);
}
return false;
}