Commit a44d2447 authored Feb 02, 2021 by Edwin Wong

[RESTRICT AUTOMERGE] Fix potential decrypt destPtr overflow.

There is a potential integer overflow to bypass the
destination base size check in decrypt. The destPtr
can then point to the outside of the destination buffer.

Test: sts-tradefed
  sts-tradefed run sts-engbuild-no-spl-lock -m StsHostTestCases --test android.security.sts.Bug_176444622#testPocBug_176444622

Test: push to device with target_hwasan-userdebug build
  adb shell /data/local/tmp/Bug-17644462264

Bug: 176444622
Bug: 176496353
Change-Id: I38e25c63c67b8acfa69649cc906483430da2ead6

parent eb95e3ce

drm/mediadrm/plugins/clearkey/hidl/CryptoPlugin.cpp

+5 −3

Original line number	Diff line number	Diff line
		@@ -111,8 +111,10 @@ Return<void> CryptoPlugin::decrypt(
		}

		base = static_cast<uint8_t >(static_cast<void >(destBase->getPointer()));

		if (destBuffer.offset + destBuffer.size > destBase->getSize()) {
		totalSize = 0;
		if (__builtin_add_overflow(destBuffer.offset, destBuffer.size, &totalSize) \|\|
		totalSize > destBase->getSize()) {
		android_errorWriteLog(0x534e4554, "176444622");
		_hidl_cb(Status::ERROR_DRM_CANNOT_HANDLE, 0, "invalid buffer size");
		return Void();
		}