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fix: harden minidump parser against malformed inputs #150

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Merged
MarshallOfSound merged 1 commit into from
Apr 22, 2026
Merged

fix: harden minidump parser against malformed inputs #150

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22 changes: 22 additions & 0 deletions lib/format.js
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Original file line number Diff line number Diff line change
Expand Up @@ -13,6 +13,14 @@ if (!Buffer.prototype.readBigUInt64LE) {
};
}

function assertRange(buf, offset, length, label) {
if (!Number.isInteger(offset) || offset < 0 || offset + length > buf.length) {
throw new Error(
`malformed minidump: ${label} at offset ${offset} (len ${length}) is out of bounds`,
);
}
}

// MDRawHeader
// https://chromium.googlesource.com/breakpad/breakpad/+/c46151db0ffd1a8dae914e45f1212ef427f61ed3/src/google_breakpad/common/minidump_format.h#252
function readHeader(buf) {
Expand All @@ -30,6 +38,7 @@ function readHeader(buf) {
// MDRawDirectory
// https://chromium.googlesource.com/breakpad/breakpad/+/c46151db0ffd1a8dae914e45f1212ef427f61ed3/src/google_breakpad/common/minidump_format.h#305
function readDirectory(buf, rva) {
assertRange(buf, rva, 12, 'stream directory entry');
return {
type: buf.readUInt32LE(rva),
location: readLocationDescriptor(buf, rva + 4),
Expand All @@ -39,6 +48,7 @@ function readDirectory(buf, rva) {
// MDRawModule
// https://chromium.googlesource.com/breakpad/breakpad/+/c46151db0ffd1a8dae914e45f1212ef427f61ed3/src/google_breakpad/common/minidump_format.h#386
function readRawModule(buf, rva) {
assertRange(buf, rva, 24 + 13 * 4 + 8 + 8, 'module record');
const module = {
base_of_image: buf.readBigUInt64LE(rva),
size_of_image: buf.readUInt32LE(rva + 8),
Expand All @@ -63,6 +73,7 @@ function readRawModule(buf, rva) {
// MDVSFixedFileInfo
// https://chromium.googlesource.com/breakpad/breakpad/+/c46151db0ffd1a8dae914e45f1212ef427f61ed3/src/google_breakpad/common/minidump_format.h#129
function readVersionInfo(buf, base) {
assertRange(buf, base, 40, 'version info');
return {
signature: buf.readUInt32LE(base),
struct_version: buf.readUInt32LE(base + 4),
Expand All @@ -83,6 +94,7 @@ function readVersionInfo(buf, base) {
// MDLocationDescriptor
// https://chromium.googlesource.com/breakpad/breakpad/+/c46151db0ffd1a8dae914e45f1212ef427f61ed3/src/google_breakpad/common/minidump_format.h#237
function readLocationDescriptor(buf, base) {
assertRange(buf, base, 8, 'location descriptor');
return {
data_size: buf.readUInt32LE(base),
rva: buf.readUInt32LE(base + 4),
Expand Down Expand Up @@ -118,8 +130,10 @@ function debugIdFromGuidAndAge(guid, age) {
// https://chromium.googlesource.com/breakpad/breakpad/+/c46151db0ffd1a8dae914e45f1212ef427f61ed3/src/google_breakpad/common/minidump_format.h#426
function readCVRecord(buf, { rva, data_size: dataSize }) {
if (rva === 0) return;
assertRange(buf, rva, 4, 'cv record signature');
const cvSignature = buf.readUInt32LE(rva);
if (cvSignature !== 0x53445352 /* SDSR */) {
assertRange(buf, rva + 4, 16 + 4, 'cv record guid/age');
const age = buf.readUInt32LE(rva + 4 + 16);
const guid = readGUID(buf.subarray(rva + 4, rva + 4 + 16));
return {
Expand All @@ -138,6 +152,7 @@ function readCVRecord(buf, { rva, data_size: dataSize }) {
// https://chromium.googlesource.com/breakpad/breakpad/+/c46151db0ffd1a8dae914e45f1212ef427f61ed3/src/google_breakpad/common/minidump_format.h#357
function readString(buf, rva) {
if (rva === 0) return null;
assertRange(buf, rva, 4, 'string length');
const bytes = buf.readUInt32LE(rva);
return buf.subarray(rva + 4, rva + 4 + bytes).toString('utf16le');
}
Expand All @@ -150,10 +165,12 @@ export const streamTypes = {

const streamTypeProcessors = {
[streamTypes.MD_MODULE_LIST_STREAM]: (stream, buf) => {
assertRange(buf, stream.location.rva, 4, 'module list count');
const numModules = buf.readUInt32LE(stream.location.rva);
const modules = [];
const size = 8 + 4 + 4 + 4 + 4 + 13 * 4 + 8 + 8 + 8 + 8;
const base = stream.location.rva + 4;
assertRange(buf, base, numModules * size, 'module list');
for (let i = 0; i < numModules; i++) {
modules.push(readRawModule(buf, base + i * size));
}
Expand All @@ -163,11 +180,16 @@ const streamTypeProcessors = {
};

export function readMinidump(buf) {
if (!Buffer.isBuffer(buf) || buf.length < 32) {
throw new Error('minidump too small');
}
const header = readHeader(buf);
if (header.signature !== headerMagic) {
throw new Error('not a minidump file');
}

assertRange(buf, header.stream_directory_rva, header.stream_count * 12, 'stream directory');

const streams = [];
for (let i = 0; i < header.stream_count; i++) {
const stream = readDirectory(buf, header.stream_directory_rva + i * 12);
Expand Down
34 changes: 19 additions & 15 deletions lib/minidump.js
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Original file line number Diff line number Diff line change
Expand Up @@ -51,21 +51,25 @@ export const addSymbolPath = Array.prototype.push.bind(globalSymbolPaths);
export function moduleList(minidump, callback) {
fs.readFile(minidump, (err, data) => {
if (err) return callback(err);
const { streams } = format.readMinidump(data);
const moduleList = streams.find((s) => s.type === format.streamTypes.MD_MODULE_LIST_STREAM);
if (!moduleList) return callback(new Error('minidump does not contain module list'));
const modules = moduleList.modules.map((m) => {
const mod = {
version: m.version,
name: m.name,
};
if (m.cv_record) {
mod.pdb_file_name = m.cv_record.pdb_file_name;
mod.debug_identifier = m.cv_record.debug_file_id;
}
return mod;
});
callback(null, modules);
try {
const { streams } = format.readMinidump(data);
const moduleList = streams.find((s) => s.type === format.streamTypes.MD_MODULE_LIST_STREAM);
if (!moduleList) return callback(new Error('minidump does not contain module list'));
const modules = moduleList.modules.map((m) => {
const mod = {
version: m.version,
name: m.name,
};
if (m.cv_record) {
mod.pdb_file_name = m.cv_record.pdb_file_name;
mod.debug_identifier = m.cv_record.debug_file_id;
}
return mod;
});
callback(null, modules);
} catch (e) {
callback(e);
}
});
}

Expand Down
44 changes: 44 additions & 0 deletions test/minidump-test.js
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Original file line number Diff line number Diff line change
@@ -1,4 +1,5 @@
import assert from 'node:assert';
import fs from 'node:fs';
import path from 'node:path';

import * as minidump from '../lib/minidump.js';
Expand Down Expand Up @@ -150,6 +151,49 @@ describe('minidump', function () {
});
});
});

describe('on a malformed dump', () => {
function writeDump(buf) {
const dumpPath = temp.path({ suffix: '.dmp' });
fs.writeFileSync(dumpPath, buf);
return dumpPath;
}

it('returns an error for a truncated header', function (done) {
const dumpPath = writeDump(Buffer.alloc(16));
minidump.moduleList(dumpPath, (err, modules) => {
assert(err instanceof Error, 'expected an Error');
assert.match(err.message, /too small/);
assert.equal(modules, undefined);
done();
});
});

it('returns an error for an invalid magic signature', function (done) {
const dumpPath = writeDump(Buffer.alloc(32));
minidump.moduleList(dumpPath, (err, modules) => {
assert(err instanceof Error, 'expected an Error');
assert.equal(err.message, 'not a minidump file');
assert.equal(modules, undefined);
done();
});
});

it('returns an error for an out-of-bounds stream_directory_rva', function (done) {
const buf = Buffer.alloc(32);
buf.writeUInt32LE(0x504d444d, 0); // 'MDMP'
buf.writeUInt32LE(0xa793, 4); // version
buf.writeUInt32LE(1, 8); // stream_count
buf.writeUInt32LE(0x1000, 12); // stream_directory_rva — far past EOF
const dumpPath = writeDump(buf);
minidump.moduleList(dumpPath, (err, modules) => {
assert(err instanceof Error, 'expected an Error');
assert.match(err.message, /out of bounds/);
assert.equal(modules, undefined);
done();
});
});
});
});
});

Expand Down