rizin/librz/util/asn1.c

668 lines
18 KiB
C

// SPDX-FileCopyrightText: 2017-2025 deroad <deroad@kumo.xn--q9jyb4c>
// SPDX-License-Identifier: LGPL-3.0-only
#include <rz_util.h>
#include <rz_cons.h>
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
static ut64 asn1_ber_indefinite(const ut8 *buffer, ut64 length) {
if (!buffer || length < 3) {
return 0;
}
const ut8 *next = buffer + 2;
const ut8 *end = buffer + (length - 3);
while (next < end) {
if (!next[0] && !next[1]) {
break;
}
if (next[0] == 0x80 && (next[-1] & RZ_ASN1_FORM) == RZ_ASN1_FORM_CONSTRUCTED) {
next--;
st64 sz = (st64)asn1_ber_indefinite(next, end - next);
if (sz < (st64)1) {
break;
}
next += sz;
}
next++;
}
return (next - buffer) + 2;
}
static RzASN1Object *asn1_parse_header(const ut8 *buffer, ut64 length, const ut8 *start_pointer) {
ut8 head, length8, byte;
ut64 length64, remaining;
if (!buffer || length < 2) {
return NULL;
}
RzASN1Object *object = RZ_NEW0(RzASN1Object);
if (!object) {
return NULL;
}
head = buffer[0];
object->offset = buffer - start_pointer;
object->klass = head & RZ_ASN1_CLASS;
object->form = head & RZ_ASN1_FORM;
object->tag = head & RZ_ASN1_TAG;
length8 = buffer[1];
remaining = length - 2;
if (length8 & RZ_ASN1_LENLONG) {
length64 = 0;
length8 &= RZ_ASN1_LENSHORT;
object->sector = buffer + 2;
if (length8 && length8 < remaining) {
remaining -= length8;
// can overflow.
for (ut8 i8 = 0; i8 < length8; i8++) {
byte = buffer[2 + i8];
length64 <<= 8;
length64 |= byte;
if (length64 > remaining) {
// Malformed object - overflow from data ptr
goto out_error;
}
}
object->sector += length8;
} else {
length64 = asn1_ber_indefinite(object->sector, remaining);
if (length64 > remaining) {
// Malformed object - overflow from data ptr
goto out_error;
}
}
object->length = (ut32)length64;
} else {
if (length8 > remaining) {
// Malformed object - overflow from data ptr
goto out_error;
}
object->length = (ut32)length8;
object->sector = buffer + 2;
}
if (object->sector >= (buffer + length)) {
// Malformed object - overflow from data ptr
goto out_error;
}
object->total_size = (object->sector - buffer) + object->length;
if (object->tag == RZ_ASN1_TAG_BITSTRING && !object->sector[0] && object->length > 0) {
object->sector++; // real sector starts + 1
object->length--;
}
return object;
out_error:
free(object);
return NULL;
}
/**
* \brief Parse only the ASN1 DER/BER encoded header
*
* \param[in] buffer The buffer to decode
* \param[in] length The length of the buffer
*
* \return On success returns a valid pointer, otherwise NULL
*/
RZ_API RZ_OWN RzASN1Object *rz_asn1_object_parse_header(RZ_NONNULL const ut8 *buffer, ut32 length) {
rz_return_val_if_fail(buffer && length > 0, NULL);
return asn1_parse_header(buffer, length, buffer);
}
static ut32 asn1_count_objects(RzASN1Object *object) {
if (!object) {
return 0;
}
const ut8 *buffer = object->sector;
ut64 length = object->length;
ut32 counter = 0;
RzASN1Object *tmp = NULL;
const ut8 *next = buffer;
const ut8 *end = buffer + length;
while (next >= buffer && next < end) {
// i do not care about the offset now.
tmp = asn1_parse_header(next, end - next, buffer);
if (!tmp || next == tmp->sector) {
RZ_FREE(tmp);
break;
}
next = tmp->sector + tmp->length;
counter++;
RZ_FREE(tmp);
}
RZ_FREE(tmp);
return counter;
}
static RzASN1Object *asn1_create_object(const ut8 *buffer, ut64 length, const ut8 *start_pointer) {
RzASN1Object *object = asn1_parse_header(buffer, length, start_pointer);
if (object && (object->form == RZ_ASN1_FORM_CONSTRUCTED || object->tag == RZ_ASN1_TAG_BITSTRING || object->tag == RZ_ASN1_TAG_OCTETSTRING)) {
const ut8 *next = object->sector;
const ut8 *end = next + object->length;
if (end > buffer + length) {
free(object);
return NULL;
}
ut64 count = asn1_count_objects(object);
if (count > 0) {
object->list.length = count;
object->list.objects = RZ_NEWS0(RzASN1Object *, count);
if (!object->list.objects) {
rz_asn1_object_free(object);
return NULL;
}
for (ut32 i = 0; next >= buffer && next < end && i < count; i++) {
RzASN1Object *inner = asn1_create_object(next, end - next, start_pointer);
if (!inner || next == inner->sector) {
rz_asn1_object_free(inner);
break;
}
next = inner->sector + inner->length;
object->list.objects[i] = inner;
}
}
}
return object;
}
/**
* \brief Parse the ASN1 DER encoded buffer
*
* \param[in] buffer The buffer to decode
* \param[in] length The length of the buffer
*
* \return On success returns a valid pointer, otherwise NULL
*/
RZ_API RZ_OWN RzASN1Object *rz_asn1_object_parse(RZ_NONNULL const ut8 *buffer, ut32 length) {
rz_return_val_if_fail(buffer && length > 0, NULL);
return asn1_create_object(buffer, length, buffer);
}
/**
* \brief Allocates and initializes an RzASN1String structure
*
* \param[in] buffer The buffer to copy
* \param[in] length The length of the buffer
*
* \return On success returns a valid pointer, otherwise NULL
*/
RZ_API RZ_OWN RzASN1Binary *rz_asn1_binary_parse(RZ_NULLABLE const ut8 *buffer, ut32 length) {
if (!buffer || !length) {
return NULL;
}
ut8 *buf = (ut8 *)calloc(sizeof(*buf), length);
if (!buf) {
return NULL;
}
RzASN1Binary *bin = RZ_NEW0(RzASN1Binary);
if (!bin) {
free(buf);
return NULL;
}
memcpy(buf, buffer, length);
bin->binary = buf;
bin->length = length;
return bin;
}
static void asn1_print_hex(RzASN1Object *object, char *buffer, ut32 size, ut32 depth) {
if (!object || !object->sector) {
return;
}
char *p = buffer;
char *end = buffer + size;
for (ut32 i = 0; i < object->length && p < end; i++) {
snprintf(p, end - p, "%02x", object->sector[i]);
p += 2;
}
if (p >= end) {
p -= 4;
snprintf(p, end - p, "...");
}
}
static RzASN1String *asn1_print_hexdump_padded(RzASN1Object *object, ut32 depth) {
const char *pad = NULL;
ut32 i = 0, j = 0;
char *allocated = NULL;
char readable[20] = { 0 };
if (!object || !object->sector || object->length < 1) {
return NULL;
}
RzStrBuf *sb = rz_strbuf_new("");
pad = " : ";
for (i = 0, j = 0; i < object->length; i++, j++) {
ut8 c = object->sector[i];
if (i > 0 && (i % 16) == 0) {
rz_strbuf_appendf(sb, "|%-16s|\n%s", readable, pad);
memset(readable, 0, sizeof(readable));
j = 0;
}
rz_strbuf_appendf(sb, "%02x ", c);
readable[j] = IS_PRINTABLE(c) ? c : '.';
}
free(allocated);
while ((i % 16) != 0) {
rz_strbuf_appendf(sb, " ");
i++;
}
rz_strbuf_appendf(sb, "|%-16s|", readable);
char *text = rz_strbuf_drain(sb);
RzASN1String *asn1str = rz_asn1_string_parse(text, true, strlen(text) + 1);
if (!asn1str) {
free(text);
}
return asn1str;
}
static void asn1_to_strbuf(RzASN1Object *object, ut32 depth, RzStrBuf *sb) {
if (!object) {
return;
}
// this shall not be freed. it's a pointer into the buffer.
RzASN1String *asn1str = NULL;
char temp_name[4096] = { 0 };
const char *name = "";
const char *string = "";
switch (object->klass) {
case RZ_ASN1_CLASS_UNIVERSAL: // universal
switch (object->tag) {
case RZ_ASN1_TAG_EOC:
name = "EOC";
break;
case RZ_ASN1_TAG_BOOLEAN:
name = "BOOLEAN";
if (object->sector) {
string = (object->sector[0] != 0) ? "true" : "false";
}
break;
case RZ_ASN1_TAG_INTEGER:
name = "INTEGER";
if (object->length < 16) {
asn1_print_hex(object, temp_name, sizeof(temp_name), depth);
string = temp_name;
} else {
asn1str = asn1_print_hexdump_padded(object, depth);
}
break;
case RZ_ASN1_TAG_BITSTRING:
name = "BIT_STRING";
if (!object->list.objects) {
if (object->length < 16) {
asn1_print_hex(object, temp_name, sizeof(temp_name), depth);
string = temp_name;
} else {
asn1str = asn1_print_hexdump_padded(object, depth);
}
}
break;
case RZ_ASN1_TAG_OCTETSTRING:
name = "OCTET_STRING";
break;
case RZ_ASN1_TAG_NULL:
name = "NULL";
break;
case RZ_ASN1_TAG_OID:
name = "OBJECT_IDENTIFIER";
asn1str = rz_asn1_stringify_oid(object->sector, object->length);
break;
case RZ_ASN1_TAG_OBJDESCRIPTOR:
name = "OBJECT_DESCRIPTOR";
break;
case RZ_ASN1_TAG_EXTERNAL:
name = "EXTERNAL";
break;
case RZ_ASN1_TAG_REAL:
name = "REAL";
asn1str = asn1_print_hexdump_padded(object, depth);
break;
case RZ_ASN1_TAG_ENUMERATED:
name = "ENUMERATED";
break;
case RZ_ASN1_TAG_EMBEDDED_PDV:
name = "EMBEDDED_PDV";
break;
case RZ_ASN1_TAG_UTF8STRING:
name = "UTF8String";
asn1str = rz_asn1_stringify_string(object->sector, object->length);
break;
case RZ_ASN1_TAG_SEQUENCE:
name = "SEQUENCE";
break;
case RZ_ASN1_TAG_SET:
name = "SET";
break;
case RZ_ASN1_TAG_NUMERICSTRING:
name = "NumericString";
asn1str = rz_asn1_stringify_string(object->sector, object->length);
break;
case RZ_ASN1_TAG_PRINTABLESTRING:
name = "PrintableString"; // ASCII subset
asn1str = rz_asn1_stringify_string(object->sector, object->length);
break;
case RZ_ASN1_TAG_T61STRING:
name = "TeletexString"; // aka T61String
asn1str = rz_asn1_stringify_string(object->sector, object->length);
break;
case RZ_ASN1_TAG_VIDEOTEXSTRING:
name = "VideotexString";
asn1str = rz_asn1_stringify_string(object->sector, object->length);
break;
case RZ_ASN1_TAG_IA5STRING:
name = "IA5String"; // ASCII
asn1str = rz_asn1_stringify_string(object->sector, object->length);
break;
case RZ_ASN1_TAG_UTCTIME:
name = "UTCTime";
asn1str = rz_asn1_stringify_utctime(object->sector, object->length);
break;
case RZ_ASN1_TAG_GENERALIZEDTIME:
name = "GeneralizedTime";
asn1str = rz_asn1_stringify_time(object->sector, object->length);
break;
case RZ_ASN1_TAG_GRAPHICSTRING:
name = "GraphicString";
asn1str = rz_asn1_stringify_string(object->sector, object->length);
break;
case RZ_ASN1_TAG_VISIBLESTRING:
name = "VisibleString"; // ASCII subset
asn1str = rz_asn1_stringify_string(object->sector, object->length);
break;
case RZ_ASN1_TAG_GENERALSTRING:
name = "GeneralString";
break;
case RZ_ASN1_TAG_UNIVERSALSTRING:
name = "UniversalString";
asn1str = rz_asn1_stringify_string(object->sector, object->length);
break;
case RZ_ASN1_TAG_BMPSTRING:
name = "BMPString";
asn1str = rz_asn1_stringify_string(object->sector, object->length);
break;
default:
rz_strf(temp_name, "Universal_%u", object->tag);
name = temp_name;
break;
}
break;
case RZ_ASN1_CLASS_APPLICATION:
rz_strf(temp_name, "Application_%u", object->tag);
name = temp_name;
break;
case RZ_ASN1_CLASS_CONTEXT:
rz_strf(temp_name, "Context [%u]", object->tag); // Context
name = temp_name;
break;
case RZ_ASN1_CLASS_PRIVATE:
rz_strf(temp_name, "Private_%u", object->tag);
name = temp_name;
break;
}
if (!object->list.objects && !asn1str && RZ_STR_ISEMPTY(string)) {
if (rz_str_is_printable_limited((const char *)object->sector, object->length)) {
asn1str = rz_asn1_stringify_string(object->sector, object->length);
} else {
asn1str = asn1_print_hexdump_padded(object, depth);
}
}
if (asn1str) {
string = asn1str->string;
}
rz_strbuf_appendf(sb, "%4" PFMT64d " ", object->offset);
rz_strbuf_appendf(sb, "%4u:%2d: %s %-20s: %s\n", object->length,
depth, object->form ? "cons" : "prim", name, string);
rz_asn1_string_free(asn1str);
if (object->list.objects) {
for (ut32 i = 0; i < object->list.length; i++) {
asn1_to_strbuf(object->list.objects[i], depth + 1, sb);
}
}
}
/**
* \brief Converts an the ASN1 structure to a human readable string
*
* \param object The ASN1 object
*
* \return On success returns a valid pointer, otherwise NULL
*/
RZ_API RZ_OWN char *rz_asn1_to_string(RZ_NULLABLE RzASN1Object *object) {
if (!object) {
return NULL;
}
RzStrBuf *sb = rz_strbuf_new("");
if (!sb) {
return NULL;
}
asn1_to_strbuf(object, 0, sb);
return rz_strbuf_drain(sb);
}
static void asn1_to_structure(RzASN1Object *object, RzStructuredData *parent, bool simplified) {
if (!object || !parent) {
return;
}
// this shall not be freed. it's a pointer into the buffer.
RzASN1String *asn1str = NULL;
char temp_name[4096] = { 0 };
const char *name = "";
const char *string = "";
switch (object->klass) {
case RZ_ASN1_CLASS_UNIVERSAL: // universal
switch (object->tag) {
case RZ_ASN1_TAG_EOC:
name = "EOC";
break;
case RZ_ASN1_TAG_BOOLEAN:
name = "BOOLEAN";
if (object->sector) {
string = (object->sector[0] != 0) ? "true" : "false";
}
break;
case RZ_ASN1_TAG_INTEGER:
name = "INTEGER";
if (object->length < 20) {
asn1str = rz_asn1_stringify_integer(object->sector, object->length);
} else {
asn1str = rz_asn1_stringify_bytes(object->sector, object->length);
}
break;
case RZ_ASN1_TAG_BITSTRING:
name = "BIT_STRING";
if (!object->list.objects) {
if (object->length > 0 && object->length < 20) {
asn1str = rz_asn1_stringify_bits(object->sector, object->length);
} else {
asn1str = rz_asn1_stringify_bytes(object->sector, object->length);
}
}
break;
case RZ_ASN1_TAG_OCTETSTRING:
name = "OCTET_STRING";
break;
case RZ_ASN1_TAG_NULL:
name = "NULL";
break;
case RZ_ASN1_TAG_OID:
name = "OBJECT_IDENTIFIER";
asn1str = rz_asn1_stringify_oid(object->sector, object->length);
break;
case RZ_ASN1_TAG_OBJDESCRIPTOR:
name = "OBJECT_DESCRIPTOR";
break;
case RZ_ASN1_TAG_EXTERNAL:
name = "EXTERNAL";
break;
case RZ_ASN1_TAG_REAL:
name = "REAL";
asn1str = rz_asn1_stringify_bytes(object->sector, object->length);
break;
case RZ_ASN1_TAG_ENUMERATED:
name = "ENUMERATED";
break;
case RZ_ASN1_TAG_EMBEDDED_PDV:
name = "EMBEDDED_PDV";
break;
case RZ_ASN1_TAG_UTF8STRING:
name = "UTF8String";
asn1str = rz_asn1_stringify_string(object->sector, object->length);
break;
case RZ_ASN1_TAG_SEQUENCE:
name = "SEQUENCE";
break;
case RZ_ASN1_TAG_SET:
name = "SET";
break;
case RZ_ASN1_TAG_NUMERICSTRING:
name = "NumericString";
asn1str = rz_asn1_stringify_string(object->sector, object->length);
break;
case RZ_ASN1_TAG_PRINTABLESTRING:
name = "PrintableString"; // ASCII subset
asn1str = rz_asn1_stringify_string(object->sector, object->length);
break;
case RZ_ASN1_TAG_T61STRING:
name = "TeletexString"; // aka T61String
asn1str = rz_asn1_stringify_string(object->sector, object->length);
break;
case RZ_ASN1_TAG_VIDEOTEXSTRING:
name = "VideotexString";
asn1str = rz_asn1_stringify_string(object->sector, object->length);
break;
case RZ_ASN1_TAG_IA5STRING:
name = "IA5String"; // ASCII
asn1str = rz_asn1_stringify_string(object->sector, object->length);
break;
case RZ_ASN1_TAG_UTCTIME:
name = "UTCTime";
asn1str = rz_asn1_stringify_utctime(object->sector, object->length);
break;
case RZ_ASN1_TAG_GENERALIZEDTIME:
name = "GeneralizedTime";
asn1str = rz_asn1_stringify_time(object->sector, object->length);
break;
case RZ_ASN1_TAG_GRAPHICSTRING:
name = "GraphicString";
asn1str = rz_asn1_stringify_string(object->sector, object->length);
break;
case RZ_ASN1_TAG_VISIBLESTRING:
name = "VisibleString"; // ASCII subset
asn1str = rz_asn1_stringify_string(object->sector, object->length);
break;
case RZ_ASN1_TAG_GENERALSTRING:
name = "GeneralString";
break;
case RZ_ASN1_TAG_UNIVERSALSTRING:
name = "UniversalString";
asn1str = rz_asn1_stringify_string(object->sector, object->length);
break;
case RZ_ASN1_TAG_BMPSTRING:
name = "BMPString";
asn1str = rz_asn1_stringify_string(object->sector, object->length);
break;
default:
rz_strf(temp_name, "Universal_%u", object->tag);
name = temp_name;
break;
}
break;
case RZ_ASN1_CLASS_APPLICATION:
rz_strf(temp_name, "Application_%u", object->tag);
name = temp_name;
break;
case RZ_ASN1_CLASS_CONTEXT:
rz_strf(temp_name, "Context [%u]", object->tag); // Context
name = temp_name;
break;
case RZ_ASN1_CLASS_PRIVATE:
rz_strf(temp_name, "Private_%u", object->tag);
name = temp_name;
break;
}
if (!object->list.objects && !asn1str && RZ_STR_ISEMPTY(string)) {
if (rz_str_is_printable_limited((const char *)object->sector, object->length)) {
asn1str = rz_asn1_stringify_string(object->sector, object->length);
} else {
asn1str = rz_asn1_stringify_bytes(object->sector, object->length);
}
}
if (asn1str) {
string = asn1str->string;
}
if (!simplified) {
rz_structured_data_map_add_unsigned(parent, "offset", object->offset, true);
rz_structured_data_map_add_unsigned(parent, "length", object->length, false);
rz_structured_data_map_add_string(parent, "form", object->form ? "cons" : "prim");
}
rz_structured_data_map_add_string(parent, "type", name);
if (!object->list.objects) {
if (RZ_STR_ISNOTEMPTY(string)) {
rz_structured_data_map_add_string(parent, "value", string);
}
rz_asn1_string_free(asn1str);
return;
}
rz_asn1_string_free(asn1str);
RzStructuredData *children = rz_structured_data_map_add_array(parent, "value");
for (ut32 i = 0; i < object->list.length; i++) {
RzStructuredData *child = rz_structured_data_array_add_map(children);
asn1_to_structure(object->list.objects[i], child, simplified);
}
}
RZ_API RZ_OWN RzStructuredData *rz_asn1_to_structure(RZ_NULLABLE RzASN1Object *object, bool simplified) {
if (!object) {
return NULL;
}
RzStructuredData *root = rz_structured_data_new_map();
if (!root) {
return NULL;
}
asn1_to_structure(object, root, simplified);
return root;
}
/**
* \brief Frees an RzASN1Object structure
*
* \param object The ASN1 object to be freed
*/
RZ_API void rz_asn1_object_free(RZ_NULLABLE RzASN1Object *object) {
if (!object) {
return;
}
// This shall not be freed. it's a pointer into the buffer.
object->sector = NULL;
if (object->list.objects) {
for (ut32 i = 0; i < object->list.length; i++) {
rz_asn1_object_free(object->list.objects[i]);
}
RZ_FREE(object->list.objects);
}
object->list.objects = NULL;
object->list.length = 0;
free(object);
}
/**
* \brief Frees an RzASN1Binary structure
*
* \param bin The ASN1 binary to be freed
*/
RZ_API void rz_asn1_binary_free(RZ_NULLABLE RzASN1Binary *bin) {
if (!bin) {
return;
}
free(bin->binary);
free(bin);
}