Skip to content
New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

fs: harden options typecheck in reading methods #42772

Closed
Closed
Show file tree
Hide file tree
Changes from all commits
Commits
File filter

Filter by extension

Filter by extension

Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
19 changes: 12 additions & 7 deletions lib/fs.js
Original file line number Diff line number Diff line change
Expand Up @@ -639,6 +639,9 @@ function read(fd, buffer, offsetOrOptions, length, position, callback) {
buffer = Buffer.alloc(16384);
}

if (params !== undefined) {
validateObject(params, 'options', { nullable: true });
}
({
offset = 0,
length = buffer.byteLength - offset,
Expand Down Expand Up @@ -698,26 +701,28 @@ ObjectDefineProperty(read, kCustomPromisifyArgsSymbol,
* offset?: number;
* length?: number;
* position?: number | bigint | null;
* }} [offset]
* }} [offsetOrOptions]
* @returns {number}
*/
function readSync(fd, buffer, offset, length, position) {
function readSync(fd, buffer, offsetOrOptions, length, position) {
fd = getValidatedFd(fd);

validateBuffer(buffer);

if (arguments.length <= 3) {
// Assume fs.readSync(fd, buffer, options)
const options = offset || kEmptyObject;
let offset = offsetOrOptions;
if (arguments.length <= 3 || typeof offsetOrOptions === 'object') {
if (offsetOrOptions !== undefined) {
validateObject(offsetOrOptions, 'options', { nullable: true });
}

({
offset = 0,
length = buffer.byteLength - offset,
position = null,
} = options);
} = offsetOrOptions ?? kEmptyObject);
}

if (offset == null) {
if (offset === undefined) {
offset = 0;
} else {
validateInteger(offset, 'offset', 0);
Expand Down
4 changes: 4 additions & 0 deletions lib/internal/fs/promises.js
Original file line number Diff line number Diff line change
Expand Up @@ -77,6 +77,7 @@ const {
validateBuffer,
validateEncoding,
validateInteger,
validateObject,
validateString,
} = require('internal/validators');
const pathModule = require('path');
Expand Down Expand Up @@ -517,6 +518,9 @@ async function read(handle, bufferOrParams, offset, length, position) {
let buffer = bufferOrParams;
if (!isArrayBufferView(buffer)) {
// This is fh.read(params)
if (bufferOrParams !== undefined) {
validateObject(bufferOrParams, 'options', { nullable: true });
}
({
buffer = Buffer.alloc(16384),
offset = 0,
Expand Down
14 changes: 12 additions & 2 deletions test/parallel/test-fs-promises.js
Original file line number Diff line number Diff line change
Expand Up @@ -153,14 +153,24 @@ async function executeOnHandle(dest, func) {
});
}

// Use fallback buffer allocation when input not buffer
// Use fallback buffer allocation when first argument is null
{
await executeOnHandle(dest, async (handle) => {
const ret = await handle.read(0, 0, 0, 0);
const ret = await handle.read(null, 0, 0, 0);
assert.strictEqual(ret.buffer.length, 16384);
});
}

// TypeError if buffer is not ArrayBufferView or nullable object
{
await executeOnHandle(dest, async (handle) => {
await assert.rejects(
async () => handle.read(0, 0, 0, 0),
{ code: 'ERR_INVALID_ARG_TYPE' }
);
});
}

// Bytes written to file match buffer
{
await executeOnHandle(dest, async (handle) => {
Expand Down
34 changes: 25 additions & 9 deletions test/parallel/test-fs-readSync-optional-params.js
Original file line number Diff line number Diff line change
Expand Up @@ -8,13 +8,20 @@ const filepath = fixtures.path('x.txt');

const expected = Buffer.from('xyz\n');

function runTest(defaultBuffer, options) {
function runTest(defaultBuffer, options, errorCode = false) {
let fd;
try {
fd = fs.openSync(filepath, 'r');
const result = fs.readSync(fd, defaultBuffer, options);
assert.strictEqual(result, expected.length);
assert.deepStrictEqual(defaultBuffer, expected);
if (errorCode) {
assert.throws(
() => fs.readSync(fd, defaultBuffer, options),
{ code: errorCode }
);
} else {
const result = fs.readSync(fd, defaultBuffer, options);
assert.strictEqual(result, expected.length);
assert.deepStrictEqual(defaultBuffer, expected);
}
} finally {
if (fd != null) fs.closeSync(fd);
}
Expand All @@ -31,7 +38,6 @@ for (const options of [
{ length: expected.length, position: 0 },
{ offset: 0, length: expected.length, position: 0 },

{ offset: null },
{ position: null },
{ position: -1 },
{ position: 0n },
Expand All @@ -41,17 +47,27 @@ for (const options of [
null,
undefined,

// Test if bad params are interpreted as default (not mandatory)
// Test malicious corner case: it works as {length: 4} but not intentionally
new String('4444'),
]) {
runTest(Buffer.allocUnsafe(expected.length), options);
}

for (const options of [

// Test various invalid options
false,
true,
Infinity,
42n,
Symbol(),
'amString',
[],
() => {},

// Test even more malicious corner cases
// Test if arbitrary entity with expected .length is not mistaken for options
'4'.repeat(expected.length),
new String('4444'),
[4, 4, 4, 4],
]) {
runTest(Buffer.allocUnsafe(expected.length), mustNotMutateObjectDeep(options));
runTest(Buffer.allocUnsafe(expected.length), mustNotMutateObjectDeep(options), 'ERR_INVALID_ARG_TYPE');
}