radare2/libr/anal/jmptbl.c
radare 3f6fb93689
Add afj command to analyze jmptbl from the shell ##anal
$ r2 Payload/Undecimus.app/Undecimus
[0x10007e3ac]> s 0x1000081d8;af;s 0x1000082b0;afj 0x1000085fc 4
2019-07-22 04:38:26 +02:00

344 lines
11 KiB
C

/* radare - LGPL - Copyright 2010-2019 - nibble, alvaro, pancake */
#include <r_anal.h>
#include <r_parse.h>
#include <r_util.h>
#include <r_list.h>
#define JMPTBL_MAXSZ 512
static void queue_case(RAnal *anal, ut64 switch_addr, int offset_sz, ut64 case_addr, ut64 id, ut64 case_addr_loc) {
// eprintf ("** queue_case: 0x%"PFMT64x " from 0x%"PFMT64x "\n", case_addr, case_addr_loc);
anal->cmdtail = r_str_appendf (anal->cmdtail,
"Cd %d @ 0x%08"PFMT64x"\n", offset_sz, case_addr_loc);
anal->cmdtail = r_str_appendf (anal->cmdtail,
"ahi 10 @ 0x%08"PFMT64x"\n", case_addr_loc);
anal->cmdtail = r_str_appendf (anal->cmdtail,
"axc 0x%"PFMT64x " 0x%"PFMT64x "\n",
(ut64)case_addr, (ut64)switch_addr);
anal->cmdtail = r_str_appendf (anal->cmdtail,
"afbe 0x%"PFMT64x " 0x%"PFMT64x "\n",
(ut64)switch_addr, (ut64)case_addr);
// anal->cmdtail = r_str_appendf (anal->cmdtail,
// "aho case %d: from 0x%"PFMT64x " @ 0x%"PFMT64x "\n",
// id, switch_addr, case_addr_loc);
// anal->cmdtail = r_str_appendf (anal->cmdtail,
// "CCu case %d: @ 0x%"PFMT64x "\n",
// id, case_addr);
anal->cmdtail = r_str_appendf (anal->cmdtail,
"f case.0x%"PFMT64x ".%d 1 @ 0x%08"PFMT64x "\n",
(ut64)switch_addr, (int)id, (ut64)case_addr);
}
// analyze a jmptablle inside a function // maybe rename to r_anal_fcn_jmptbl() ?
R_API bool r_anal_jmptbl(RAnal *anal, RAnalFunction *fcn, ut64 jmpaddr, ut64 table, ut64 tablesize, ut64 default_addr) {
const int depth = 50;
return try_walkthrough_jmptbl (anal, fcn, depth, jmpaddr, table, table, tablesize, tablesize, default_addr, 0);
}
R_API int try_walkthrough_jmptbl(RAnal *anal, RAnalFunction *fcn, int depth, ut64 ip, ut64 jmptbl_loc, ut64 jmptbl_off, ut64 sz, int jmptbl_size, ut64 default_case, int ret0) {
int ret = ret0;
// jmptbl_size can not always be determined
if (jmptbl_size == 0) {
jmptbl_size = JMPTBL_MAXSZ;
}
if (jmptbl_loc == UT64_MAX) {
if (anal->verbose) {
eprintf ("Warning: Invalid JumpTable location 0x%08"PFMT64x"\n", jmptbl_loc);
}
return 0;
}
if (jmptbl_size < 1 || jmptbl_size > ST32_MAX) {
if (anal->verbose) {
eprintf ("Warning: Invalid JumpTable size at 0x%08"PFMT64x"\n", ip);
}
return 0;
}
ut64 jmpptr, offs;
ut8 *jmptbl = calloc (jmptbl_size, sz);
if (!jmptbl) {
return 0;
}
bool is_arm = anal->cur->arch && !strncmp (anal->cur->arch, "arm", 3);
// eprintf ("JMPTBL AT 0x%"PFMT64x"\n", jmptbl_loc);
anal->iob.read_at (anal->iob.io, jmptbl_loc, jmptbl, jmptbl_size * sz);
for (offs = 0; offs + sz - 1 < jmptbl_size * sz; offs += sz) {
switch (sz) {
case 1:
jmpptr = (ut64)(ut8)r_read_le8 (jmptbl + offs);
break;
case 2:
jmpptr = (ut64)r_read_le16 (jmptbl + offs);
break;
case 4:
jmpptr = r_read_le32 (jmptbl + offs);
break;
case 8:
jmpptr = r_read_le64 (jmptbl + offs);
break; // XXX
default:
jmpptr = r_read_le64 (jmptbl + offs);
break;
}
// eprintf ("WALKING %llx\n", jmpptr);
// if we don't check for 0 here, the next check with ptr+jmpptr
// will obviously be a good offset since it will be the start
// of the table, which is not what we want
if (jmpptr == 0 || jmpptr == UT32_MAX || jmpptr == UT64_MAX) {
break;
}
if (sz == 2 && is_arm) {
jmpptr = ip + 4 + (jmpptr * 2); // tbh [pc, r2, lsl 1] // assume lsl 1
} else if (sz == 1 && is_arm) {
jmpptr = ip + 4 + (jmpptr * 2); // lbb [pc, r2] // assume lsl 1
} else if (!anal->iob.is_valid_offset (anal->iob.io, jmpptr, 0)) {
st32 jmpdelta = (st32)jmpptr;
// jump tables where sign extended movs are used
jmpptr = jmptbl_off + jmpdelta;
if (!anal->iob.is_valid_offset (anal->iob.io, jmpptr, 0)) {
break;
}
}
if (anal->limit) {
if (jmpptr < anal->limit->from || jmpptr > anal->limit->to) {
break;
}
}
queue_case (anal, ip, sz, jmpptr, offs / sz, jmptbl_loc + offs);
(void)r_anal_fcn_bb (anal, fcn, jmpptr, depth - 1);
}
if (offs > 0) {
// eprintf("\n\nSwitch statement at 0x%llx:\n", ip);
anal->cmdtail = r_str_appendf (anal->cmdtail,
"CCu switch table (%d cases) at 0x%"PFMT64x " @ 0x%"PFMT64x "\n",
(int)(offs/sz), jmptbl_loc, ip);
anal->cmdtail = r_str_appendf (anal->cmdtail,
"f switch.0x%08"PFMT64x" 1 @ 0x%08"PFMT64x"\n",
ip, ip);
if (default_case != 0 && default_case != UT64_MAX) {
anal->cmdtail = r_str_appendf (anal->cmdtail,
"f case.default.0x%"PFMT64x " 1 @ 0x%08"PFMT64x "\n",
default_case, default_case);
}
}
free (jmptbl);
return ret;
}
// TODO: RENAME
R_API bool try_get_delta_jmptbl_info(RAnal *anal, RAnalFunction *fcn, ut64 jmp_addr, ut64 lea_addr, ut64 *table_size, ut64 *default_case) {
bool isValid = false;
bool foundCmp = false;
int i;
RAnalOp tmp_aop = {0};
if (lea_addr > jmp_addr) {
return false;
}
int search_sz = jmp_addr - lea_addr;
ut8 *buf = malloc (search_sz);
if (!buf) {
return false;
}
// search for a cmp register with a reasonable size
anal->iob.read_at (anal->iob.io, lea_addr, (ut8 *)buf, search_sz);
for (i = 0; i + 8 < search_sz; i++) {
int len = r_anal_op (anal, &tmp_aop, lea_addr + i, buf + i, search_sz - i, R_ANAL_OP_MASK_BASIC);
if (len < 1) {
len = 1;
}
if (foundCmp) {
if (tmp_aop.type != R_ANAL_OP_TYPE_CJMP) {
continue;
}
*default_case = tmp_aop.jump == tmp_aop.jump + len ? tmp_aop.fail : tmp_aop.jump;
break;
}
ut32 type = tmp_aop.type & R_ANAL_OP_TYPE_MASK;
if (type != R_ANAL_OP_TYPE_CMP) {
continue;
}
// get the value of the cmp
// for operands in op, check if type is immediate and val is sane
// TODO: How? opex?
// for the time being, this seems to work
// might not actually have a value, let the next step figure out the size then
if (tmp_aop.val == UT64_MAX && tmp_aop.refptr == 0) {
isValid = true;
*table_size = 0;
} else if (tmp_aop.refptr == 0) {
isValid = tmp_aop.val < 0x200;
*table_size = tmp_aop.val + 1;
} else {
isValid = tmp_aop.refptr < 0x200;
*table_size = tmp_aop.refptr + 1;
}
// TODO: check the jmp for whether val is included in valid range or not (ja vs jae)
foundCmp = true;
}
free (buf);
return isValid;
}
// TODO: find a better function name
R_API int walkthrough_arm_jmptbl_style(RAnal *anal, RAnalFunction *fcn, int depth, ut64 ip, ut64 jmptbl_loc, ut64 sz, ut64 jmptbl_size, ut64 default_case, int ret0) {
/*
* Example about arm jump table
*
* 0x000105b4 060050e3 cmp r0, 3
* 0x000105b8 00f18f90 addls pc, pc, r0, lsl 2
* 0x000105bc 0d0000ea b loc.000105f8
* 0x000105c0 050000ea b 0x105dc
* 0x000105c4 050000ea b 0x105e0
* 0x000105c8 060000ea b 0x105e8
* ; CODE XREF from loc._a_7 (+0x10)
* 0x000105dc b6ffffea b sym.input_1
* ; CODE XREF from loc._a_7 (+0x14)
* 0x000105e0 b9ffffea b sym.input_2
* ; CODE XREF from loc._a_7 (+0x28)
* 0x000105e4 ccffffea b sym.input_7
* ; CODE XREF from loc._a_7 (+0x18)
* 0x000105e8 bbffffea b sym.input_3
*/
ut64 offs, jmpptr;
int ret = ret0;
if (jmptbl_size == 0) {
jmptbl_size = JMPTBL_MAXSZ;
}
for (offs = 0; offs + sz - 1 < jmptbl_size * sz; offs += sz) {
jmpptr = jmptbl_loc + offs;
queue_case (anal, ip, sz, jmpptr, offs / sz, jmptbl_loc + offs);
(void)r_anal_fcn_bb (anal, fcn, jmpptr, depth - 1);
}
if (offs > 0) {
// eprintf("\n\nSwitch statement at 0x%llx:\n", ip);
anal->cmdtail = r_str_appendf (anal->cmdtail,
"CCu switch table (%d cases) at 0x%"PFMT64x " @ 0x%"PFMT64x "\n",
offs / sz, jmptbl_loc, ip);
anal->cmdtail = r_str_appendf (anal->cmdtail,
"f switch.0x%08"PFMT64x" 1 @ 0x%08"PFMT64x"\n",
ip, ip);
if (default_case != 0 && default_case != UT64_MAX && default_case != UT32_MAX) {
anal->cmdtail = r_str_appendf (anal->cmdtail,
"f case.default.0x%"PFMT64x " 1 @ 0x%08"PFMT64x "\n",
default_case, default_case);
}
}
return ret;
}
R_API bool try_get_jmptbl_info(RAnal *anal, RAnalFunction *fcn, ut64 addr, RAnalBlock *my_bb, ut64 *table_size, ut64 *default_case) {
bool isValid = false;
int i;
RListIter *iter;
RAnalBlock *tmp_bb, *prev_bb;
prev_bb = 0;
if (!fcn->bbs) {
return false;
}
/* if UJMP is in .plt section just skip it */
RBinSection *s = anal->binb.get_vsect_at (anal->binb.bin, addr);
if (s && s->name[0]) {
bool in_plt = strstr (s->name, ".plt") != NULL;
if (!in_plt && strstr (s->name, "_stubs") != NULL) {
/* for mach0 */
in_plt = true;
}
if (in_plt) {
return false;
}
}
// search for the predecessor bb
r_list_foreach (fcn->bbs, iter, tmp_bb) {
if (tmp_bb->jump == my_bb->addr || tmp_bb->fail == my_bb->addr) {
prev_bb = tmp_bb;
break;
}
}
// predecessor must be a conditional jump
if (!prev_bb || !prev_bb->jump || !prev_bb->fail) {
if (anal->verbose) {
eprintf ("Warning: [anal.jmp.tbl] Missing predecesessor cjmp bb at 0x%08"PFMT64x"\n", addr);
}
return false;
}
// default case is the jump target of the unconditional jump
*default_case = prev_bb->jump == my_bb->addr ? prev_bb->fail : prev_bb->jump;
RAnalOp tmp_aop = {0};
ut8 *bb_buf = calloc (1, prev_bb->size);
if (!bb_buf) {
return false;
}
// search for a cmp register with a reasonable size
anal->iob.read_at (anal->iob.io, prev_bb->addr, (ut8 *) bb_buf, prev_bb->size);
isValid = false;
RAnalHint *hint = r_anal_hint_get (anal, addr);
if (hint) {
if (hint->val != UT64_MAX) {
*table_size = hint->val;
}
eprintf ("TMPAPVAL %llx, %llx\n", addr, tmp_aop.val);
r_anal_hint_free (hint);
return true;
}
for (i = 0; i < prev_bb->op_pos_size; i++) {
ut64 prev_pos = prev_bb->op_pos[i];
ut64 op_addr = prev_bb->addr + prev_pos;
if (prev_pos >= prev_bb->size) {
continue;
}
int buflen = prev_bb->size - prev_pos;
int len = r_anal_op (anal, &tmp_aop, op_addr,
bb_buf + prev_pos, buflen,
R_ANAL_OP_MASK_BASIC | R_ANAL_OP_MASK_HINT);
ut32 type = tmp_aop.type & R_ANAL_OP_TYPE_MASK;
if (len < 1 || type != R_ANAL_OP_TYPE_CMP) {
r_anal_op_fini (&tmp_aop);
continue;
}
// get the value of the cmp
// for operands in op, check if type is immediate and val is sane
// TODO: How? opex?
// for the time being, this seems to work
// might not actually have a value, let the next step figure out the size then
if (tmp_aop.val == UT64_MAX && tmp_aop.refptr == 0) {
isValid = true;
*table_size = 0;
} else if (tmp_aop.refptr == 0) {
isValid = tmp_aop.val < 0x200;
*table_size = tmp_aop.val + 1;
} else {
isValid = tmp_aop.refptr < 0x200;
*table_size = tmp_aop.refptr + 1;
}
r_anal_op_fini (&tmp_aop);
// TODO: check the jmp for whether val is included in valid range or not (ja vs jae)
break;
}
free (bb_buf);
// eprintf ("switch at 0x%" PFMT64x "\n\tdefault case 0x%" PFMT64x "\n\t#cases: %d\n",
// addr,
// *default_case,
// *table_size);
return isValid;
}