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fix TLV Parser BER long-form length parsing (#2289)

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Willi Ballenthin 2026-06-20 09:59:30 +02:00 committed by GitHub
parent 9a8a279b82
commit 0a0d95bcbd
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2 changed files with 57 additions and 7 deletions
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23
src/core/lib/TLVParser.mjs
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@ -33,20 +33,29 @@ export default class TLVParser {
* @returns {number}
*/
getLength() {
let bytesInLength = this.bytesInLength;
let bigEndian = false;
if (this.basicEncodingRules) {
const bit = this.input[this.location];
if (bit & 0x80) {
this.bytesInLength = bit & ~0x80;
const firstLengthByte = this.input[this.location];
this.location++;
if (firstLengthByte & 0x80) {
bytesInLength = firstLengthByte & ~0x80;
bigEndian = true;
} else {
this.location++;
return bit & ~0x80;
return firstLengthByte & ~0x80;
}
}
let length = 0;
for (let i = 0; i < this.bytesInLength; i++) {
length += this.input[this.location] * Math.pow(Math.pow(2, 8), i);
for (let i = 0; i < bytesInLength; i++) {
if (bigEndian) {
length = (length << 8) + this.input[this.location];
} else {
length += this.input[this.location] * Math.pow(Math.pow(2, 8), i);
}
this.location++;
}

41
tests/operations/tests/ParseTLV.mjs
View File

@ -52,5 +52,46 @@ TestRegister.addTests([
"args": [1, 4, true] // length value is patently wrong, should be ignored by BER.
}
]
},
{
name: "Parse TLV: BER long-form length (two-byte length encoding)",
input: "\x01\x82\x01\x00" + "A".repeat(256) + "\x02\x03\x41\x42\x43",
expectedOutput: JSON.stringify([
{"key": [1], "length": 256, "value": Array(256).fill(65)},
{"key": [2], "length": 3, "value": [65, 66, 67]}
], null, 4),
recipeConfig: [
{
"op": "Parse TLV",
"args": [1, 1, true]
}
]
},
{
name: "Parse TLV: BER long-form length (one-byte length encoding)",
input: "\x01\x81\x80" + "B".repeat(128),
expectedOutput: JSON.stringify([
{"key": [1], "length": 128, "value": Array(128).fill(66)}
], null, 4),
recipeConfig: [
{
"op": "Parse TLV",
"args": [1, 1, true]
}
]
},
{
name: "Parse TLV: BER multiple entries with mixed short and long-form lengths",
input: "\x01\x05\x48\x65\x6c\x6c\x6f\x02\x81\x05\x57\x6f\x72\x6c\x64",
expectedOutput: JSON.stringify([
{"key": [1], "length": 5, "value": [72, 101, 108, 108, 111]},
{"key": [2], "length": 5, "value": [87, 111, 114, 108, 100]}
], null, 4),
recipeConfig: [
{
"op": "Parse TLV",
"args": [1, 1, true]
}
]
}
]);