radare2/libr/anal/jmptbl.c
2022-08-01 16:46:46 +02:00

556 lines
17 KiB
C

/* radare - LGPL - Copyright 2010-2022 - nibble, alvaro, pancake, th3str4ng3r */
#include <r_anal.h>
#include <r_parse.h>
#include <r_util.h>
#include <r_list.h>
#define aprintf(format, ...) if (anal->verbose) eprintf (format, __VA_ARGS__)
#define JMPTBL_MAXSZ 512
static void apply_case(RAnal *anal, RAnalBlock *block, ut64 switch_addr, ut64 offset_sz, ut64 case_addr, ut64 id, ut64 case_addr_loc) {
// eprintf ("** apply_case: 0x%"PFMT64x " from 0x%"PFMT64x "\n", case_addr, case_addr_loc);
r_meta_set_data_at (anal, case_addr_loc, offset_sz);
r_anal_hint_set_immbase (anal, case_addr_loc, 10);
r_anal_xrefs_set (anal, switch_addr, case_addr, R_ANAL_REF_TYPE_CODE | R_ANAL_REF_TYPE_EXEC);
if (block) {
r_anal_block_add_switch_case (block, switch_addr, id, case_addr);
}
if (anal->flb.set) {
char flagname[0x30];
int iid = R_ABS ((int)id);
snprintf (flagname, sizeof (flagname), "case.0x%"PFMT64x ".%d", (ut64)switch_addr, iid);
anal->flb.set (anal->flb.f, flagname, case_addr, 1);
}
}
static void apply_switch(RAnal *anal, ut64 switch_addr, ut64 jmptbl_addr, ut64 cases_count, ut64 default_case_addr) {
char tmp[0x30];
snprintf (tmp, sizeof (tmp), "switch table (%"PFMT64u" cases) at 0x%"PFMT64x, cases_count, jmptbl_addr);
r_meta_set_string (anal, R_META_TYPE_COMMENT, switch_addr, tmp);
if (anal->flb.set) {
snprintf (tmp, sizeof (tmp), "switch.0x%08"PFMT64x, switch_addr);
anal->flb.set (anal->flb.f, tmp, switch_addr, 1);
if (default_case_addr != UT64_MAX) {
r_anal_xrefs_set (anal, switch_addr, default_case_addr, R_ANAL_REF_TYPE_CODE | R_ANAL_REF_TYPE_EXEC);
snprintf (tmp, sizeof (tmp), "case.default.0x%"PFMT64x, switch_addr);
anal->flb.set (anal->flb.f, tmp, default_case_addr, 1);
}
}
}
// analyze a jmptablle inside a function // maybe rename to r_anal_function_jmptbl() ?
R_API bool r_anal_jmptbl(RAnal *anal, RAnalFunction *fcn, RAnalBlock *block, ut64 jmpaddr, ut64 table, ut64 tablesize, ut64 default_addr) {
const int depth = 50;
return try_walkthrough_jmptbl (anal, fcn, block, depth, jmpaddr, 0, table, table, tablesize, tablesize, default_addr, false);
}
static inline void analyze_new_case(RAnal *anal, RAnalFunction *fcn, RAnalBlock *block, ut64 ip, ut64 jmpptr, int depth) {
const ut64 block_size = block->size;
(void)r_anal_function_bb (anal, fcn, jmpptr, depth - 1);
if (block->size != block_size) {
// block was be split during anal and does not contain the
// jmp instruction anymore, so we need to search for it and get it again
RAnalSwitchOp *sop = block->switch_op;
block = r_anal_get_block_at (anal, ip);
if (!block) {
block = r_anal_bb_from_offset (anal, ip);
if (block) {
if (block->addr != ip) {
st64 d = block->addr - ip;
R_LOG_ERROR ("Cannot find basic block for switch case at 0x%08"PFMT64x" bbdelta = %d", ip, (int)R_ABS (d));
block = NULL;
return;
} else {
R_LOG_ERROR ("Inconsistent basicblock storage issue at 0x%08"PFMT64x, ip);
}
} else {
R_LOG_ERROR ("Major disaster at 0x%08"PFMT64x, ip);
return;
}
// analyze at given address
// block = r_anal_create_block(RAnal *anal, ut64 addr, ut64 size) {
}
block->switch_op = sop;
}
}
R_API bool try_walkthrough_casetbl(RAnal *anal, RAnalFunction *fcn, RAnalBlock *block, int depth, ut64 ip, st64 start_casenum_shift, ut64 jmptbl_loc, ut64 casetbl_loc, ut64 jmptbl_off, ut64 sz, ut64 jmptbl_size, ut64 default_case, bool ret0) {
bool ret = ret0;
if (jmptbl_size == 0) {
jmptbl_size = JMPTBL_MAXSZ;
}
if (jmptbl_loc == UT64_MAX) {
aprintf ("Warning: Invalid JumpTable location 0x%08" PFMT64x "\n", jmptbl_loc);
return false;
}
if (casetbl_loc == UT64_MAX) {
aprintf ("Warning: Invalid CaseTable location 0x%08" PFMT64x "\n", jmptbl_loc);
return false;
}
if (jmptbl_size < 1 || jmptbl_size > ST32_MAX) {
aprintf ("Warning: Invalid JumpTable size at 0x%08" PFMT64x "\n", ip);
return false;
}
ut64 jmpptr, case_idx, jmpptr_idx;
ut8 *jmptbl = calloc (jmptbl_size, sz);
if (!jmptbl || !anal->iob.read_at (anal->iob.io, jmptbl_loc, jmptbl, jmptbl_size * sz)) {
free (jmptbl);
return false;
}
ut8 *casetbl = calloc (jmptbl_size, sizeof (ut8));
if (!casetbl || !anal->iob.read_at (anal->iob.io, casetbl_loc, casetbl, jmptbl_size)) {
free (jmptbl);
free (casetbl);
return false;
}
for (case_idx = 0; case_idx < jmptbl_size; case_idx++) {
jmpptr_idx = casetbl[case_idx];
if (jmpptr_idx >= jmptbl_size) {
ret = false;
break;
}
switch (sz) {
case 1:
jmpptr = r_read_le8 (jmptbl + jmpptr_idx);
break;
case 2:
jmpptr = r_read_le16 (jmptbl + jmpptr_idx * 2);
break;
case 4:
jmpptr = r_read_le32 (jmptbl + jmpptr_idx * 4);
break;
default:
jmpptr = r_read_le64 (jmptbl + jmpptr_idx * 8);
break;
}
if (jmpptr == 0 || jmpptr == UT32_MAX || jmpptr == UT64_MAX) {
break;
}
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;
}
}
const ut64 jmpptr_idx_off = casetbl_loc + case_idx;
r_meta_set_data_at (anal, jmpptr_idx_off, 1);
r_anal_hint_set_immbase (anal, jmpptr_idx_off, 10);
int casenum = case_idx + start_casenum_shift;
apply_case (anal, block, ip, sz, jmpptr, casenum, jmptbl_loc + jmpptr_idx * sz);
analyze_new_case (anal, fcn, block, ip, jmpptr, depth);
}
if (case_idx > 0) {
if (default_case == 0) {
default_case = UT64_MAX;
}
apply_switch (anal, ip, jmptbl_loc, case_idx, default_case);
}
free (jmptbl);
free (casetbl);
return ret;
}
R_API bool try_walkthrough_jmptbl(RAnal *anal, RAnalFunction *fcn, RAnalBlock *block, int depth, ut64 ip, st64 start_casenum_shift, ut64 jmptbl_loc, ut64 jmptbl_off, ut64 sz, ut64 jmptbl_size, ut64 default_case, bool ret0) {
bool ret = ret0;
// jmptbl_size can not always be determined
if (jmptbl_size == 0) {
jmptbl_size = JMPTBL_MAXSZ;
}
if (jmptbl_loc == UT64_MAX) {
aprintf ("Warning: Invalid JumpTable location 0x%08"PFMT64x"\n", jmptbl_loc);
return false;
}
if (jmptbl_size < 1 || jmptbl_size > ST32_MAX) {
aprintf ("Warning: Invalid JumpTable size at 0x%08"PFMT64x"\n", ip);
return false;
}
ut64 jmpptr, offs;
int jmptblsz = jmptbl_size * sz;
if (jmptblsz < 1) {
if (anal->verbose) {
eprintf ("Invalid jump table size\n");
}
return false;
}
ut8 *jmptbl = calloc (jmptbl_size, sz);
if (!jmptbl) {
return false;
}
bool is_arm = anal->cur->arch && r_str_startswith (anal->cur->arch, "arm");
bool is_x86 = !is_arm && anal->cur->arch && r_str_startswith (anal->cur->arch, "x86");
const bool is_v850 = !is_arm && !is_x86 && ((anal->cur->arch && !strncmp (anal->cur->arch, "v850", 4)) || !strncmp (anal->coreb.cfgGet (anal->coreb.core, "asm.cpu"), "v850", 4));
// eprintf ("JMPTBL AT 0x%"PFMT64x"\n", jmptbl_loc);
anal->iob.read_at (anal->iob.io, jmptbl_loc, jmptbl, jmptblsz);
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;
}
if (is_arm && anal->config->bits == 64 && ip > 4096 && jmpptr < 4096 && jmpptr < ip) {
jmpptr += ip;
}
// 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 || is_v850)) {
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;
}
} else if (sz == 2 && is_x86) {
st32 jmpdelta = (st32)jmpptr;
// jump tables where sign extended movs are used
jmpptr = jmptbl_off + jmpdelta;
}
if (anal->limit) {
if (jmpptr < anal->limit->from || jmpptr > anal->limit->to) {
break;
}
}
//apply_case (anal, block, ip, sz, jmpptr, offs / sz, jmptbl_loc + offs);
//(void)r_anal_function_bb (anal, fcn, jmpptr, depth - 1);
int case_idx = offs / sz;
int casenum = case_idx + start_casenum_shift;
apply_case (anal, block, ip, sz, jmpptr, casenum, jmptbl_loc + offs);
analyze_new_case (anal, fcn, block, ip, jmpptr, depth);
}
if (offs > 0) {
if (default_case == 0) {
default_case = UT64_MAX;
}
apply_switch (anal, ip, jmptbl_loc, offs / sz, default_case);
}
free (jmptbl);
return ret;
}
static bool detect_casenum_shift(RAnalOp *op, RRegItem **cmp_reg, st64 *start_casenum_shift) {
if (!*cmp_reg) {
return true;
}
if (op->dst && op->dst->reg && op->dst->reg->offset == (*cmp_reg)->offset) {
if (op->type == R_ANAL_OP_TYPE_LEA && op->ptr == UT64_MAX) {
*start_casenum_shift = -(st64)op->disp;
} else if (op->val != UT64_MAX) {
if (op->type == R_ANAL_OP_TYPE_ADD) {
*start_casenum_shift = -(st64)op->val;
} else if (op->type == R_ANAL_OP_TYPE_SUB) {
*start_casenum_shift = op->val;
}
} else if (op->type == R_ANAL_OP_TYPE_MOV) {
*cmp_reg = op->src[0]->reg;
return false;
}
return true;
}
return false;
}
R_API bool try_get_delta_jmptbl_info(RAnal *anal, RAnalFunction *fcn, ut64 jmp_addr, ut64 lea_addr, ut64 *table_size, ut64 *default_case, st64 *start_casenum_shift) {
bool isValid = false;
bool foundCmp = false;
ut64 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);
RVector v;
r_vector_init (&v, sizeof (ut64), NULL, NULL);
int len = 0;
RRegItem *cmp_reg = NULL;
for (i = 0; i + 8 < search_sz; i += len) {
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;
}
r_vector_push (&v, &i);
r_anal_op (anal, &tmp_aop, lea_addr + i, buf + i, search_sz - i, R_ANAL_OP_MASK_VAL);
if (tmp_aop.dst && tmp_aop.dst->reg) {
cmp_reg = tmp_aop.dst->reg;
} else if (tmp_aop.reg) {
cmp_reg = r_reg_get (anal->reg, tmp_aop.reg, R_REG_TYPE_ALL);
} else if (tmp_aop.src[0] && tmp_aop.src[0]->reg) {
cmp_reg = tmp_aop.src[0]->reg;
}
r_anal_op_fini (&tmp_aop);
// TODO: check the jmp for whether val is included in valid range or not (ja vs jae)
foundCmp = true;
}
if (isValid) {
*start_casenum_shift = 0;
void **it;
r_vector_foreach_prev (&v, it) {
const ut64 op_off = *(ut64 *)it;
ut64 op_addr = lea_addr + op_off;
r_anal_op (anal, &tmp_aop, op_addr,
buf + op_off, search_sz - op_off,
R_ANAL_OP_MASK_VAL);
if (detect_casenum_shift (&tmp_aop, &cmp_reg, start_casenum_shift)) {
r_anal_op_fini (&tmp_aop);
break;
}
r_anal_op_fini (&tmp_aop);
}
}
r_vector_fini (&v);
free (buf);
return isValid;
}
// TODO: find a better function name
R_API int walkthrough_arm_jmptbl_style(RAnal *anal, RAnalFunction *fcn, RAnalBlock *block, 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;
apply_case (anal, block, ip, sz, jmpptr, offs / sz, jmptbl_loc + offs);
analyze_new_case (anal, fcn, block, ip, jmpptr, depth);
}
if (offs > 0) {
if (default_case == 0 || default_case == UT32_MAX) {
default_case = UT64_MAX;
}
apply_switch (anal, ip, jmptbl_loc, offs / sz, 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, st64 *start_casenum_shift) {
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");
if (!in_plt && strstr (s->name, "_stubs")) {
/* 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) {
aprintf ("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;
RAnalHint *hint = r_anal_hint_get (anal, addr);
if (hint) {
ut64 val = hint->val;
r_anal_hint_free (hint);
if (val != UT64_MAX) {
*table_size = val;
return true;
}
}
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;
RRegItem *cmp_reg = NULL;
for (i = prev_bb->ninstr - 1; i >= 0; i--) {
const ut64 prev_pos = r_anal_bb_offset_inst (prev_bb, i);
const ut64 op_addr = r_anal_bb_opaddr_i (prev_bb, i);
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 || tmp_aop.val != UT64_MAX) {
isValid = tmp_aop.val < 0x200;
*table_size = tmp_aop.val + 1;
} else {
isValid = tmp_aop.refptr < 0x200;
*table_size = tmp_aop.refptr + 1;
}
if (isValid) {
r_anal_op_fini (&tmp_aop);
r_anal_op (anal, &tmp_aop, op_addr,
bb_buf + prev_pos, buflen,
R_ANAL_OP_MASK_VAL);
if (tmp_aop.dst && tmp_aop.dst->reg) {
cmp_reg = tmp_aop.dst->reg;
} else if (tmp_aop.reg) {
cmp_reg = r_reg_get (anal->reg, tmp_aop.reg, R_REG_TYPE_ALL);
} else if (tmp_aop.src[0] && tmp_aop.src[0]->reg) {
cmp_reg = tmp_aop.src[0]->reg;
}
}
r_anal_op_fini (&tmp_aop);
// TODO: check the jmp for whether val is included in valid range or not (ja vs jae)
break;
}
if (isValid) {
*start_casenum_shift = 0;
for (i--; i >= 0; i--) {
const ut64 prev_pos = r_anal_bb_offset_inst (prev_bb, i);
const ut64 op_addr = r_anal_bb_opaddr_i (prev_bb, i);
if (prev_pos >= prev_bb->size) {
continue;
}
int buflen = prev_bb->size - prev_pos;
r_anal_op (anal, &tmp_aop, op_addr,
bb_buf + prev_pos, buflen,
R_ANAL_OP_MASK_VAL);
if (detect_casenum_shift (&tmp_aop, &cmp_reg, start_casenum_shift)) {
r_anal_op_fini (&tmp_aop);
break;
}
r_anal_op_fini (&tmp_aop);
}
}
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;
}