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JavaScript generic ASN.1 parser (mirror)
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asn1js asn1.js
26 kB · 658 lines
JavaScript
at github-104
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// Permission to use, copy, modify, and/or distribute this software for any// purpose with or without fee is hereby granted, provided that the above// copyright notice and this permission notice appear in all copies.//// THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES// WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF// MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR// ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES// WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN// ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF// OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
import { Int10 } from './int10.js';import { oids } from './oids.js';
const ellipsis = '\u2026', reTimeS = /^(\d\d)(0[1-9]|1[0-2])(0[1-9]|[12]\d|3[01])([01]\d|2[0-3])(?:([0-5]\d)(?:([0-5]\d)(?:[.,](\d{1,3}))?)?)?(Z|(-(?:0\d|1[0-2])|[+](?:0\d|1[0-4]))([0-5]\d)?)?$/, reTimeL = /^(\d\d\d\d)(0[1-9]|1[0-2])(0[1-9]|[12]\d|3[01])([01]\d|2[0-3])(?:([0-5]\d)(?:([0-5]\d)(?:[.,](\d{1,3}))?)?)?(Z|(-(?:0\d|1[0-2])|[+](?:0\d|1[0-4]))([0-5]\d)?)?$/, hexDigits = '0123456789ABCDEF', b64Std = 'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/', b64URL = 'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789-_', tableT61 = [ ['', ''], ['AEIOUaeiou', 'ÀÈÌÒÙàèìòù'], // Grave ['ACEILNORSUYZacegilnorsuyz', 'ÁĆÉÍĹŃÓŔŚÚÝŹáćéģíĺńóŕśúýź'], // Acute ['ACEGHIJOSUWYaceghijosuwy', 'ÂĈÊĜĤÎĴÔŜÛŴŶâĉêĝĥîĵôŝûŵŷ'], // Circumflex ['AINOUainou', 'ÃĨÑÕŨãĩñõũ'], // Tilde ['AEIOUaeiou', 'ĀĒĪŌŪāēīōū'], // Macron ['AGUagu', 'ĂĞŬăğŭ'], // Breve ['CEGIZcegz', 'ĊĖĠİŻċėġż'], // Dot ['AEIOUYaeiouy', 'ÄËÏÖÜŸäëïöüÿ'], // Umlaut or diæresis ['', ''], ['AUau', 'ÅŮåů'], // Ring ['CGKLNRSTcklnrst', 'ÇĢĶĻŅŖŞŢçķļņŗşţ'], // Cedilla ['', ''], ['OUou', 'ŐŰőű'], // Double Acute ['AEIUaeiu', 'ĄĘĮŲąęįų'], // Ogonek ['CDELNRSTZcdelnrstz', 'ČĎĚĽŇŘŠŤŽčďěľňřšťž'], // Caron ];
function stringCut(str, len) { if (str.length > len) str = str.substring(0, len) + ellipsis; return str;}
function checkPrintable(s) { let i, v; for (i = 0; i < s.length; ++i) { v = s.charCodeAt(i); if (v < 32 && v != 9 && v != 10 && v != 13) // [\t\r\n] are (kinda) printable throw new Error('Unprintable character at index ' + i + ' (code ' + s.str.charCodeAt(i) + ')'); }}
/** Class to manage a stream of bytes, with a zero-copy approach. * It uses an existing array or binary string and advances a position index. */export class Stream {
/** * @param {Stream|array|string} enc data (will not be copied) * @param {?number} pos starting position (mandatory when `end` is not a Stream) */ constructor(enc, pos) { if (enc instanceof Stream) { this.enc = enc.enc; this.pos = enc.pos; } else { this.enc = enc; this.pos = pos; } if (typeof this.pos != 'number') throw new Error('"pos" must be a numeric value'); if (typeof this.enc == 'string') this.getRaw = pos => this.enc.charCodeAt(pos); else if (typeof this.enc[0] == 'number') this.getRaw = pos => this.enc[pos]; else throw new Error('"enc" must be a numeric array or a string'); } /** Get the byte at current position (and increment it) or at a specified position (and avoid moving current position). * @param {?number} pos read position if specified, else current position (and increment it) */ get(pos) { if (pos === undefined) pos = this.pos++; if (pos >= this.enc.length) throw new Error('Requesting byte offset ' + pos + ' on a stream of length ' + this.enc.length); return this.getRaw(pos); } /** Convert a single byte to an hexadcimal string (of length 2). * @param {number} b */ static hexByte(b) { return hexDigits.charAt((b >> 4) & 0xF) + hexDigits.charAt(b & 0xF); } /** Hexadecimal dump of a specified region of the stream. * @param {number} start starting position (included) * @param {number} end ending position (excluded) * @param {string} type 'raw', 'byte' or 'dump' (default) */ hexDump(start, end, type = 'dump') { let s = ''; for (let i = start; i < end; ++i) { if (type == 'byte' && i > start) s += ' '; s += Stream.hexByte(this.get(i)); if (type == 'dump') switch (i & 0xF) { case 0x7: s += ' '; break; case 0xF: s += '\n'; break; default: s += ' '; } } return s; } /** Base64url dump of a specified region of the stream (according to RFC 4648 section 5). * @param {number} start starting position (included) * @param {number} end ending position (excluded) * @param {string} type 'url' (default, section 5 without padding) or 'std' (section 4 with padding) */ b64Dump(start, end, type = 'url') { const b64 = type === 'url' ? b64URL : b64Std; let extra = (end - start) % 3, s = '', i, c; for (i = start; i + 2 < end; i += 3) { c = this.get(i) << 16 | this.get(i + 1) << 8 | this.get(i + 2); s += b64.charAt(c >> 18 & 0x3F); s += b64.charAt(c >> 12 & 0x3F); s += b64.charAt(c >> 6 & 0x3F); s += b64.charAt(c & 0x3F); } if (extra > 0) { c = this.get(i) << 16; if (extra > 1) c |= this.get(i + 1) << 8; s += b64.charAt(c >> 18 & 0x3F); s += b64.charAt(c >> 12 & 0x3F); if (extra == 2) s += b64.charAt(c >> 6 & 0x3F); if (b64 === b64Std) s += '==='.slice(0, 3 - extra); } return s; } isASCII(start, end) { for (let i = start; i < end; ++i) { let c = this.get(i); if (c < 32 || c > 176) return false; } return true; } parseStringISO(start, end, maxLength) { let s = ''; for (let i = start; i < end; ++i) s += String.fromCharCode(this.get(i)); return { size: s.length, str: stringCut(s, maxLength) }; } parseStringT61(start, end, maxLength) { // warning: this code is not very well tested so far function merge(c, d) { let t = tableT61[c - 0xC0]; let i = t[0].indexOf(String.fromCharCode(d)); return (i < 0) ? '\0' : t[1].charAt(i); } let s = '', c; for (let i = start; i < end; ++i) { c = this.get(i); if (c >= 0xA4 && c <= 0xBF) s += '$¥#§¤\0\0«\0\0\0\0°±²³×µ¶·÷\0\0»¼½¾¿'.charAt(c - 0xA4); else if (c >= 0xE0 && c <= 0xFF) s += 'ΩÆЪĦ\0IJĿŁØŒºÞŦŊʼnĸæđðħıijŀłøœßþŧŋ\0'.charAt(c - 0xE0); else if (c >= 0xC0 && c <= 0xCF) s += merge(c, this.get(++i)); else // using ISO 8859-1 for characters undefined (or equal) in T.61 s += String.fromCharCode(c); } return { size: s.length, str: stringCut(s, maxLength) }; } parseStringUTF(start, end, maxLength) { function ex(c) { // must be 10xxxxxx if ((c < 0x80) || (c >= 0xC0)) throw new Error('Invalid UTF-8 continuation byte: ' + c); return (c & 0x3F); } function surrogate(cp) { if (cp < 0x10000) throw new Error('UTF-8 overlong encoding, codepoint encoded in 4 bytes: ' + cp); // we could use String.fromCodePoint(cp) but let's be nice to older browsers and use surrogate pairs cp -= 0x10000; return String.fromCharCode((cp >> 10) + 0xD800, (cp & 0x3FF) + 0xDC00); } let s = ''; for (let i = start; i < end; ) { let c = this.get(i++); if (c < 0x80) // 0xxxxxxx (7 bit) s += String.fromCharCode(c); else if (c < 0xC0) throw new Error('Invalid UTF-8 starting byte: ' + c); else if (c < 0xE0) // 110xxxxx 10xxxxxx (11 bit) s += String.fromCharCode(((c & 0x1F) << 6) | ex(this.get(i++))); else if (c < 0xF0) // 1110xxxx 10xxxxxx 10xxxxxx (16 bit) s += String.fromCharCode(((c & 0x0F) << 12) | (ex(this.get(i++)) << 6) | ex(this.get(i++))); else if (c < 0xF8) // 11110xxx 10xxxxxx 10xxxxxx 10xxxxxx (21 bit) s += surrogate(((c & 0x07) << 18) | (ex(this.get(i++)) << 12) | (ex(this.get(i++)) << 6) | ex(this.get(i++))); else throw new Error('Invalid UTF-8 starting byte (since 2003 it is restricted to 4 bytes): ' + c); } return { size: s.length, str: stringCut(s, maxLength) }; } parseStringBMP(start, end, maxLength) { let s = '', hi, lo; for (let i = start; i < end; ) { hi = this.get(i++); lo = this.get(i++); s += String.fromCharCode((hi << 8) | lo); } return { size: s.length, str: stringCut(s, maxLength) }; } parseTime(start, end, shortYear) { let s = this.parseStringISO(start, end).str, m = (shortYear ? reTimeS : reTimeL).exec(s); if (!m) throw new Error('Unrecognized time: ' + s); if (shortYear) { // to avoid querying the timer, use the fixed range [1970, 2069] // it will conform with ITU X.400 [-10, +40] sliding window until 2030 m[1] = +m[1]; m[1] += (m[1] < 70) ? 2000 : 1900; } s = m[1] + '-' + m[2] + '-' + m[3] + ' ' + m[4]; if (m[5]) { s += ':' + m[5]; if (m[6]) { s += ':' + m[6]; if (m[7]) s += '.' + m[7]; } } if (m[8]) { s += ' UTC'; if (m[9]) s += m[9] + ':' + (m[10] || '00'); } return s; } parseInteger(start, end) { let v = this.get(start), neg = (v > 127), pad = neg ? 255 : 0, len, s = ''; // skip unuseful bits (not allowed in DER) while (v == pad && ++start < end) v = this.get(start); len = end - start; if (len === 0) return neg ? '-1' : '0'; // show bit length of huge integers if (len > 4) { s = v; len <<= 3; while (((s ^ pad) & 0x80) == 0) { s <<= 1; --len; } s = '(' + len + ' bit)\n'; } // decode the integer if (neg) v = v - 256; let n = new Int10(v); for (let i = start + 1; i < end; ++i) n.mulAdd(256, this.get(i)); return s + n.toString(); } parseBitString(start, end, maxLength) { let unusedBits = this.get(start); if (unusedBits > 7) throw new Error('Invalid BitString with unusedBits=' + unusedBits); let lenBit = ((end - start - 1) << 3) - unusedBits, s = ''; for (let i = start + 1; i < end; ++i) { let b = this.get(i), skip = (i == end - 1) ? unusedBits : 0; for (let j = 7; j >= skip; --j) s += (b >> j) & 1 ? '1' : '0'; if (s.length > maxLength) s = stringCut(s, maxLength); } return { size: lenBit, str: s }; } parseOctetString(start, end, maxLength) { let len = end - start, s; try { s = this.parseStringUTF(start, end, maxLength); checkPrintable(s.str); return { size: end - start, str: s.str }; } catch (ignore) { // ignore } maxLength /= 2; // we work in bytes if (len > maxLength) end = start + maxLength; s = ''; for (let i = start; i < end; ++i) s += Stream.hexByte(this.get(i)); if (len > maxLength) s += ellipsis; return { size: len, str: s }; } parseOID(start, end, maxLength, isRelative) { let s = '', n = new Int10(), bits = 0; for (let i = start; i < end; ++i) { let v = this.get(i); n.mulAdd(128, v & 0x7F); bits += 7; if (!(v & 0x80)) { // finished if (s === '') { n = n.simplify(); if (isRelative) { s = (n instanceof Int10) ? n.toString() : '' + n; } else if (n instanceof Int10) { n.sub(80); s = '2.' + n.toString(); } else { let m = n < 80 ? n < 40 ? 0 : 1 : 2; s = m + '.' + (n - m * 40); } } else s += '.' + n.toString(); if (s.length > maxLength) return stringCut(s, maxLength); n = new Int10(); bits = 0; } } if (bits > 0) s += '.incomplete'; if (typeof oids === 'object' && !isRelative) { let oid = oids[s]; if (oid) { if (oid.d) s += '\n' + oid.d; if (oid.c) s += '\n' + oid.c; if (oid.w) s += '\n(warning!)'; } } return s; } parseRelativeOID(start, end, maxLength) { return this.parseOID(start, end, maxLength, true); }}
function recurse(el, parser, maxLength) { let avoidRecurse = true; if (el.tag.tagConstructed && el.sub) { avoidRecurse = false; el.sub.forEach(function (e1) { if (e1.tag.tagClass != el.tag.tagClass || e1.tag.tagNumber != el.tag.tagNumber) avoidRecurse = true; }); } if (avoidRecurse) return el.stream[parser](el.posContent(), el.posContent() + Math.abs(el.length), maxLength); let d = { size: 0, str: '' }; el.sub.forEach(function (el) { let d1 = recurse(el, parser, maxLength - d.str.length); d.size += d1.size; d.str += d1.str; }); return d;}
class ASN1Tag { constructor(stream) { let buf = stream.get(); this.tagClass = buf >> 6; this.tagConstructed = ((buf & 0x20) !== 0); this.tagNumber = buf & 0x1F; if (this.tagNumber == 0x1F) { // long tag let n = new Int10(); do { buf = stream.get(); n.mulAdd(128, buf & 0x7F); } while (buf & 0x80); this.tagNumber = n.simplify(); } } isUniversal() { return this.tagClass === 0x00; } isEOC() { return this.tagClass === 0x00 && this.tagNumber === 0x00; }}
export class ASN1 { constructor(stream, header, length, tag, tagLen, sub) { if (!(tag instanceof ASN1Tag)) throw new Error('Invalid tag value.'); this.stream = stream; this.header = header; this.length = length; this.tag = tag; this.tagLen = tagLen; this.sub = sub; } typeName() { switch (this.tag.tagClass) { case 0: // universal switch (this.tag.tagNumber) { case 0x00: return 'EOC'; case 0x01: return 'BOOLEAN'; case 0x02: return 'INTEGER'; case 0x03: return 'BIT_STRING'; case 0x04: return 'OCTET_STRING'; case 0x05: return 'NULL'; case 0x06: return 'OBJECT_IDENTIFIER'; case 0x07: return 'ObjectDescriptor'; case 0x08: return 'EXTERNAL'; case 0x09: return 'REAL'; case 0x0A: return 'ENUMERATED'; case 0x0B: return 'EMBEDDED_PDV'; case 0x0C: return 'UTF8String'; case 0x0D: return 'RELATIVE_OID'; case 0x10: return 'SEQUENCE'; case 0x11: return 'SET'; case 0x12: return 'NumericString'; case 0x13: return 'PrintableString'; // ASCII subset case 0x14: return 'TeletexString'; // aka T61String case 0x15: return 'VideotexString'; case 0x16: return 'IA5String'; // ASCII case 0x17: return 'UTCTime'; case 0x18: return 'GeneralizedTime'; case 0x19: return 'GraphicString'; case 0x1A: return 'VisibleString'; // ASCII subset case 0x1B: return 'GeneralString'; case 0x1C: return 'UniversalString'; case 0x1E: return 'BMPString'; } return 'Universal_' + this.tag.tagNumber.toString(); case 1: return 'Application_' + this.tag.tagNumber.toString(); case 2: return '[' + this.tag.tagNumber.toString() + ']'; // Context case 3: return 'Private_' + this.tag.tagNumber.toString(); } } /** A string preview of the content (intended for humans). */ content(maxLength) { if (this.tag === undefined) return null; if (maxLength === undefined) maxLength = Infinity; let content = this.posContent(), len = Math.abs(this.length); if (!this.tag.isUniversal()) { if (this.sub !== null) return '(' + this.sub.length + ' elem)'; let d1 = this.stream.parseOctetString(content, content + len, maxLength); return '(' + d1.size + ' byte)\n' + d1.str; } switch (this.tag.tagNumber) { case 0x01: // BOOLEAN if (len === 0) return 'invalid length 0'; return (this.stream.get(content) === 0) ? 'false' : 'true'; case 0x02: // INTEGER if (len === 0) return 'invalid length 0'; return this.stream.parseInteger(content, content + len); case 0x03: { // BIT_STRING let d = recurse(this, 'parseBitString', maxLength); return '(' + d.size + ' bit)\n' + d.str; } case 0x04: { // OCTET_STRING if (len === 0) return 'invalid length 0'; let d = recurse(this, 'parseOctetString', maxLength); return '(' + d.size + ' byte)\n' + d.str; } //case 0x05: // NULL case 0x06: // OBJECT_IDENTIFIER return this.stream.parseOID(content, content + len, maxLength); //case 0x07: // ObjectDescriptor //case 0x08: // EXTERNAL //case 0x09: // REAL case 0x0A: // ENUMERATED return this.stream.parseInteger(content, content + len); //case 0x0B: // EMBEDDED_PDV case 0x0D: // RELATIVE-OID return this.stream.parseRelativeOID(content, content + len, maxLength); case 0x10: // SEQUENCE case 0x11: // SET if (this.sub !== null) return '(' + this.sub.length + ' elem)'; else return '(no elem)'; case 0x0C: // UTF8String return recurse(this, 'parseStringUTF', maxLength).str; case 0x14: // TeletexString return recurse(this, 'parseStringT61', maxLength).str; case 0x12: // NumericString case 0x13: // PrintableString case 0x15: // VideotexString case 0x16: // IA5String case 0x1A: // VisibleString case 0x1B: // GeneralString //case 0x19: // GraphicString //case 0x1C: // UniversalString return recurse(this, 'parseStringISO', maxLength).str; case 0x1E: // BMPString return recurse(this, 'parseStringBMP', maxLength).str; case 0x17: // UTCTime case 0x18: // GeneralizedTime return this.stream.parseTime(content, content + len, (this.tag.tagNumber == 0x17)); } return null; } toString() { return this.typeName() + '@' + this.stream.pos + '[header:' + this.header + ',length:' + this.length + ',sub:' + ((this.sub === null) ? 'null' : this.sub.length) + ']'; } toPrettyString(indent) { if (indent === undefined) indent = ''; let s = indent; if (this.def) { if (this.def.id) s += this.def.id + ' '; if (this.def.name && this.def.name != this.typeName().replace(/_/g, ' ')) s+= this.def.name + ' '; if (this.def.mismatch) s += '[?] '; } s += this.typeName() + ' @' + this.stream.pos; if (this.length >= 0) s += '+'; s += this.length; if (this.tag.tagConstructed) s += ' (constructed)'; else if ((this.tag.isUniversal() && ((this.tag.tagNumber == 0x03) || (this.tag.tagNumber == 0x04))) && (this.sub !== null)) s += ' (encapsulates)'; let content = this.content(); if (content) s += ': ' + content.replace(/\n/g, '|'); s += '\n'; if (this.sub !== null) { indent += ' '; for (let i = 0, max = this.sub.length; i < max; ++i) s += this.sub[i].toPrettyString(indent); } return s; } posStart() { return this.stream.pos; } posContent() { return this.stream.pos + this.header; } posEnd() { return this.stream.pos + this.header + Math.abs(this.length); } /** Position of the length. */ posLen() { return this.stream.pos + this.tagLen; } /** Hexadecimal dump of the node. * @param type 'raw', 'byte' or 'dump' */ toHexString(type = 'raw') { return this.stream.hexDump(this.posStart(), this.posEnd(), type); } /** Base64url dump of the node (according to RFC 4648 section 5). * @param {string} type 'url' (default, section 5 without padding) or 'std' (section 4 with padding) */ toB64String(type = 'url') { return this.stream.b64Dump(this.posStart(), this.posEnd(), type); } static decodeLength(stream) { let buf = stream.get(), len = buf & 0x7F; if (len == buf) // first bit was 0, short form return len; if (len === 0) // long form with length 0 is a special case return null; // undefined length if (len > 6) // no reason to use Int10, as it would be a huge buffer anyways throw new Error('Length over 48 bits not supported at position ' + (stream.pos - 1)); buf = 0; for (let i = 0; i < len; ++i) buf = (buf * 256) + stream.get(); return buf; } static decode(stream, offset, type = ASN1) { if (!(type == ASN1 || type.prototype instanceof ASN1)) throw new Error('Must pass a class that extends ASN1'); if (!(stream instanceof Stream)) stream = new Stream(stream, offset || 0); let streamStart = new Stream(stream), tag = new ASN1Tag(stream), tagLen = stream.pos - streamStart.pos, len = ASN1.decodeLength(stream), start = stream.pos, header = start - streamStart.pos, sub = null, getSub = function () { sub = []; if (len !== null) { // definite length let end = start + len; if (end > stream.enc.length) throw new Error('Container at offset ' + start + ' has a length of ' + len + ', which is past the end of the stream'); while (stream.pos < end) sub[sub.length] = type.decode(stream); if (stream.pos != end) throw new Error('Content size is not correct for container at offset ' + start); } else { // undefined length try { for (;;) { let s = type.decode(stream); if (s.tag.isEOC()) break; sub[sub.length] = s; } len = start - stream.pos; // undefined lengths are represented as negative values } catch (e) { throw new Error('Exception while decoding undefined length content at offset ' + start + ': ' + e); } } }; if (tag.tagConstructed) { // must have valid content getSub(); } else if (tag.isUniversal() && ((tag.tagNumber == 0x03) || (tag.tagNumber == 0x04))) { // sometimes BitString and OctetString are used to encapsulate ASN.1 try { if (tag.tagNumber == 0x03) if (stream.get() != 0) throw new Error('BIT STRINGs with unused bits cannot encapsulate.'); getSub(); for (let s of sub) { if (s.tag.isEOC()) throw new Error('EOC is not supposed to be actual content.'); try { s.content(); } catch (e) { throw new Error('Unable to parse content: ' + e); } } } catch (ignore) { // but silently ignore when they don't sub = null; //DEBUG console.log('Could not decode structure at ' + start + ':', e); } } if (sub === null) { if (len === null) throw new Error("We can't skip over an invalid tag with undefined length at offset " + start); stream.pos = start + Math.abs(len); } return new type(streamStart, header, len, tag, tagLen, sub); }
}