lepu-test-platform-web/node_modules/asn1.js/lib/asn1/decoders/der.js

336 lines
7.9 KiB
JavaScript

'use strict';
const inherits = require('inherits');
const bignum = require('bn.js');
const DecoderBuffer = require('../base/buffer').DecoderBuffer;
const Node = require('../base/node');
// Import DER constants
const der = require('../constants/der');
function DERDecoder(entity) {
this.enc = 'der';
this.name = entity.name;
this.entity = entity;
// Construct base tree
this.tree = new DERNode();
this.tree._init(entity.body);
}
module.exports = DERDecoder;
DERDecoder.prototype.decode = function decode(data, options) {
if (!DecoderBuffer.isDecoderBuffer(data)) {
data = new DecoderBuffer(data, options);
}
return this.tree._decode(data, options);
};
// Tree methods
function DERNode(parent) {
Node.call(this, 'der', parent);
}
inherits(DERNode, Node);
DERNode.prototype._peekTag = function peekTag(buffer, tag, any) {
if (buffer.isEmpty())
return false;
const state = buffer.save();
const decodedTag = derDecodeTag(buffer, 'Failed to peek tag: "' + tag + '"');
if (buffer.isError(decodedTag))
return decodedTag;
buffer.restore(state);
return decodedTag.tag === tag || decodedTag.tagStr === tag ||
(decodedTag.tagStr + 'of') === tag || any;
};
DERNode.prototype._decodeTag = function decodeTag(buffer, tag, any) {
const decodedTag = derDecodeTag(buffer,
'Failed to decode tag of "' + tag + '"');
if (buffer.isError(decodedTag))
return decodedTag;
let len = derDecodeLen(buffer,
decodedTag.primitive,
'Failed to get length of "' + tag + '"');
// Failure
if (buffer.isError(len))
return len;
if (!any &&
decodedTag.tag !== tag &&
decodedTag.tagStr !== tag &&
decodedTag.tagStr + 'of' !== tag) {
return buffer.error('Failed to match tag: "' + tag + '"');
}
if (decodedTag.primitive || len !== null)
return buffer.skip(len, 'Failed to match body of: "' + tag + '"');
// Indefinite length... find END tag
const state = buffer.save();
const res = this._skipUntilEnd(
buffer,
'Failed to skip indefinite length body: "' + this.tag + '"');
if (buffer.isError(res))
return res;
len = buffer.offset - state.offset;
buffer.restore(state);
return buffer.skip(len, 'Failed to match body of: "' + tag + '"');
};
DERNode.prototype._skipUntilEnd = function skipUntilEnd(buffer, fail) {
for (;;) {
const tag = derDecodeTag(buffer, fail);
if (buffer.isError(tag))
return tag;
const len = derDecodeLen(buffer, tag.primitive, fail);
if (buffer.isError(len))
return len;
let res;
if (tag.primitive || len !== null)
res = buffer.skip(len);
else
res = this._skipUntilEnd(buffer, fail);
// Failure
if (buffer.isError(res))
return res;
if (tag.tagStr === 'end')
break;
}
};
DERNode.prototype._decodeList = function decodeList(buffer, tag, decoder,
options) {
const result = [];
while (!buffer.isEmpty()) {
const possibleEnd = this._peekTag(buffer, 'end');
if (buffer.isError(possibleEnd))
return possibleEnd;
const res = decoder.decode(buffer, 'der', options);
if (buffer.isError(res) && possibleEnd)
break;
result.push(res);
}
return result;
};
DERNode.prototype._decodeStr = function decodeStr(buffer, tag) {
if (tag === 'bitstr') {
const unused = buffer.readUInt8();
if (buffer.isError(unused))
return unused;
return { unused: unused, data: buffer.raw() };
} else if (tag === 'bmpstr') {
const raw = buffer.raw();
if (raw.length % 2 === 1)
return buffer.error('Decoding of string type: bmpstr length mismatch');
let str = '';
for (let i = 0; i < raw.length / 2; i++) {
str += String.fromCharCode(raw.readUInt16BE(i * 2));
}
return str;
} else if (tag === 'numstr') {
const numstr = buffer.raw().toString('ascii');
if (!this._isNumstr(numstr)) {
return buffer.error('Decoding of string type: ' +
'numstr unsupported characters');
}
return numstr;
} else if (tag === 'octstr') {
return buffer.raw();
} else if (tag === 'objDesc') {
return buffer.raw();
} else if (tag === 'printstr') {
const printstr = buffer.raw().toString('ascii');
if (!this._isPrintstr(printstr)) {
return buffer.error('Decoding of string type: ' +
'printstr unsupported characters');
}
return printstr;
} else if (/str$/.test(tag)) {
return buffer.raw().toString();
} else {
return buffer.error('Decoding of string type: ' + tag + ' unsupported');
}
};
DERNode.prototype._decodeObjid = function decodeObjid(buffer, values, relative) {
let result;
const identifiers = [];
let ident = 0;
let subident = 0;
while (!buffer.isEmpty()) {
subident = buffer.readUInt8();
ident <<= 7;
ident |= subident & 0x7f;
if ((subident & 0x80) === 0) {
identifiers.push(ident);
ident = 0;
}
}
if (subident & 0x80)
identifiers.push(ident);
const first = (identifiers[0] / 40) | 0;
const second = identifiers[0] % 40;
if (relative)
result = identifiers;
else
result = [first, second].concat(identifiers.slice(1));
if (values) {
let tmp = values[result.join(' ')];
if (tmp === undefined)
tmp = values[result.join('.')];
if (tmp !== undefined)
result = tmp;
}
return result;
};
DERNode.prototype._decodeTime = function decodeTime(buffer, tag) {
const str = buffer.raw().toString();
let year;
let mon;
let day;
let hour;
let min;
let sec;
if (tag === 'gentime') {
year = str.slice(0, 4) | 0;
mon = str.slice(4, 6) | 0;
day = str.slice(6, 8) | 0;
hour = str.slice(8, 10) | 0;
min = str.slice(10, 12) | 0;
sec = str.slice(12, 14) | 0;
} else if (tag === 'utctime') {
year = str.slice(0, 2) | 0;
mon = str.slice(2, 4) | 0;
day = str.slice(4, 6) | 0;
hour = str.slice(6, 8) | 0;
min = str.slice(8, 10) | 0;
sec = str.slice(10, 12) | 0;
if (year < 70)
year = 2000 + year;
else
year = 1900 + year;
} else {
return buffer.error('Decoding ' + tag + ' time is not supported yet');
}
return Date.UTC(year, mon - 1, day, hour, min, sec, 0);
};
DERNode.prototype._decodeNull = function decodeNull() {
return null;
};
DERNode.prototype._decodeBool = function decodeBool(buffer) {
const res = buffer.readUInt8();
if (buffer.isError(res))
return res;
else
return res !== 0;
};
DERNode.prototype._decodeInt = function decodeInt(buffer, values) {
// Bigint, return as it is (assume big endian)
const raw = buffer.raw();
let res = new bignum(raw);
if (values)
res = values[res.toString(10)] || res;
return res;
};
DERNode.prototype._use = function use(entity, obj) {
if (typeof entity === 'function')
entity = entity(obj);
return entity._getDecoder('der').tree;
};
// Utility methods
function derDecodeTag(buf, fail) {
let tag = buf.readUInt8(fail);
if (buf.isError(tag))
return tag;
const cls = der.tagClass[tag >> 6];
const primitive = (tag & 0x20) === 0;
// Multi-octet tag - load
if ((tag & 0x1f) === 0x1f) {
let oct = tag;
tag = 0;
while ((oct & 0x80) === 0x80) {
oct = buf.readUInt8(fail);
if (buf.isError(oct))
return oct;
tag <<= 7;
tag |= oct & 0x7f;
}
} else {
tag &= 0x1f;
}
const tagStr = der.tag[tag];
return {
cls: cls,
primitive: primitive,
tag: tag,
tagStr: tagStr
};
}
function derDecodeLen(buf, primitive, fail) {
let len = buf.readUInt8(fail);
if (buf.isError(len))
return len;
// Indefinite form
if (!primitive && len === 0x80)
return null;
// Definite form
if ((len & 0x80) === 0) {
// Short form
return len;
}
// Long form
const num = len & 0x7f;
if (num > 4)
return buf.error('length octect is too long');
len = 0;
for (let i = 0; i < num; i++) {
len <<= 8;
const j = buf.readUInt8(fail);
if (buf.isError(j))
return j;
len |= j;
}
return len;
}