Microsoft Technology Licensing, LLC

Jason Lin

Mehmet Iyigun

Jin Lin

Gregory John Colombo

Kenneth Dean Johnson

Niraj Majmudar

Eric Paul Witt

Weidong Cui

Yuenkeen Cheong

Michael Bohan

Ben Niu

Neil O'Connell

Erika Kelter

Tsitsi Kolawole

Keith Loren Mange

Daniel Frederick Cuomo, Jr

Daniel Dhondt

Sarath Madakasira

Hundraj S Gopal

Matthew John Woolman

Travis Luke

Jari Heiskanen

Shayne Daniel Hiet-Block

Young Soo Kim

Quintin Robert Morris

Scott Andrew Dallmeyer

Yevgeniy Bak

Mark Shintaro Ando

Stephen John Minarsch

Kaitlyn Schoeck

Thomas E McCue, Jr

Kevin Michael Broas

Michael Bishop Ebersol

Gregory Kim Justice

Wen Jia Liu

Ahmed Saruhan Karademir

Randal Joseph Kinser

Byung Joo Cho

Christopher Peter Kleynhans

Scott F Williams

Kok Liang Yue

Olli-Pekka Ahokas

Arto Ylikoski

Hamid-reza Shayesteh-Pour

Shawn Michael Denbow

Stephen Louis-Essman Hufnagel

Kaitlyn M Schoeck

Thomas E Mccue

A verified stack trace can be generated by utilizing information contained in a shadow stack, such as a hardware protected duplicate stack implemented for malware prevention and computer security. The shadow stack contains return addresses which are obtainable without requiring an unwinding of the traditional call stack. As such, triaging based on return address information can be performed more quickly and more efficiently, and with a reduced utilization of processing resources. Additionally, the generation of a verified stack trace can be performed, with such a verified stack trace containing return addresses that are known to be correct and not corrupted. The return addresses can either be read from the traditional call stack, or derived therefrom, and then verified by comparison to corresponding return addresses from the shadow stack, or they can be read directly from the shadow stack.

Verified stack trace generation and accelerated stack-based analysis with shadow stacks

Handling a memory fault based on detecting whether a memory pointer was invalidated by a pointer authentication (PA) failure. After an access to a memory pointer causes a memory fault, detecting that the memory pointer was invalidated by a PA failure includes creating a new memory pointer by replacing reserved bits of the memory pointer with a default value, and determining that the new memory pointer corresponds to a memory address that falls within executable memory. This determination includes determining that the memory address is within an executable memory page, determining that a call instruction is stored at a prior memory address that immediately precedes the memory address, and/or determining that the memory address corresponds to a code section of an executable file. The PA failure is handled based on logging the PA failure, terminating the application program, and/or resuming execution at an instruction stored at the memory address.

Pointer authentication failure detection

A program is executed using a call stack and shadow stack. The call stack includes frames having respective return addresses. The frames may also store variables and/or parameters. The shadow stack stores duplicates of the return addresses in the call stack. The call stack and the shadow stack are maintained by, (i) each time a function is called, adding a corresponding stack frame to the call stack and adding a corresponding return address to the shadow stack, and (ii) each time a function is exited, removing a corresponding frame from the call stack and removing a corresponding return address from the shadow stack. A backtrace of the program's current call chain is generated by accessing the return addresses in the shadow stack. The outputted backtrace includes the return addresses from the shadow stack and/or information about the traced functions that is derived from the shadow stack's return addresses.

Stack traces using shadow stack

Performing shadow stack functionality for a thread in an audit mode includes initiating execution of a thread at the processor. Execution of the thread includes initiating execution of executable code of an application binary as part of the thread and enabling shadow stack functionality for the thread in an audit mode. Based at least on the execution of the thread in the audit mode, at least a portion of the shadow stack is enabled to be a circular stack. In response to determining that usage of the shadow stack has reached the defined threshold, one or more currently used entries of the shadow stack are overwritten, preventing the shadow stack from overflowing.

Circular shadow stack in audit mode

Enforcing shadow stack violations at module granularity, rather than at thread or process granularity. An exception is processed during execution of a thread based on code of an application binary, which is enabled for shadow stack enforcement, that calls an external module. The exception results from a mismatch between a return address popped from the thread's call stack and a return address popped from the thread's shadow stack. Processing the exception includes determining that the exception resulted from execution of an instruction in the external module, and determining whether or not the external module is enabled for shadow stack enforcement. Based at least on these determinations, execution of the thread is terminated when the external module is enabled for shadow stack enforcement, or the thread is permitted to continue executing when the external module is not enabled for shadow stack enforcement.

Shadow stack violation enforcement at module granularity

Enforcing shadow stack violations for dynamic code. A thread is executed at a processor, which includes generating a portion of dynamic code for execution by the thread, identifying a range of memory addresses where the portion of dynamic code is loaded in memory, and initiating execution of the portion of dynamic code. Based at least on execution of the thread, an exception triggered by a mismatch between a first return address popped from a call stack corresponding to the thread and a second return address popped from a shadow stack corresponding to the thread is processed. Processing the exception includes (i) determining whether the second return address popped from the shadow stack is within the identified range of addresses, and (ii) based on having determined that the second return address is within the range of addresses, initiating a shadow stack enforcement action.

Shadow stack enforcement range for dynamic code

Exposing a leap second to a plurality of applications includes identifying that a positive leap second should be added to the end of a chosen date. Based on the occurrence of the positive leap second, a first conversion component is exposed to a first application. The first conversion component presents, over a period of two seconds of actual time, a last second of the chosen date as if it is one second of system time. Based on the occurrence of the positive leap second, and based on a second application opting in to leap seconds, a second conversion component is exposed to the second application. The second conversion component presents an extra 61st second of system time at the end of a last minute of the chosen date.

Application compatible leap second support

Communicating a low-latency event across a virtual machine boundary. Based on an event signaling request by a first process running at a first virtual machine, the first virtual machine updates a shared register that is accessible by a second virtual machine. Updating the shared register includes updating a signal stored in the shared register. The first virtual machine sends an event signal message, which includes a register identifier, through a virtualization fabric to the second virtual machine. The second virtual machine receives the event signaling message and identifies the register identifier from the message. Based on the register identifier, the second virtual machine reads the shared register, identifying a value of the signal stored in the shared register. Based at least on the value of the signal comprising a first value, the second virtual machine signals a second process running at the second virtual machine.

Low-latency events across a virtual machine boundary

Exposing a leap second to a plurality of applications includes identifying a system setting enabling leap second support and that a positive leap second should be added to the end of a chosen date. Based on the system setting enabling leap second support and based on the occurrence of the positive leap second, a first conversion component is exposed to a first application. The first conversion component presents, over a period of two seconds of actual time, a last second of the chosen date as if it is one second of system time. Based on the system setting enabling leap second support, based on the occurrence of the positive leap second, and based on a second application opting in to leap seconds, a second conversion component is exposed to the second application. The second conversion component presents an extra 61st second of system time at the end of a last minute of the chosen date.

Generic adjustable in-ear monitors (IEMs) may suffer from a limited range of resilient ear plugs that may not adequately fit each user, and the user may prefer different ear plugs for different purposes (e.g., the user's interest in secure fitment may be higher when exercising, while the user's interest in comfort may be higher when the user is relaxing). The presently disclosed technology is directed to IEMs that permit a user to adjust without removing and replacing an associated ear plug. Instead, the ear plug is adjustable by the user to achieve a desired fit and may be adjusted repeatedly for different desired fits and/or different users.

Adjustable in-ear plug

A portable electronic accessory is adapted to initiate an operational mode change in a portable electronic accessory responsive to a user-initiated instruction received along a standard power line. The portable electronic accessory includes a rechargeable battery, electrical leads adapted to couple with a charging source to charge the rechargeable battery, and a polarity detection circuit configured to detect a power polarity switch of the electrical leads when the portable electronic accessory is coupled to the charging source. The portable electronic accessory further includes a controller that initiates a device mode change responsive to the power polarity switch detected by the polarity detection circuit.

Power polarity detection for accessory mode change

Earcups for a headset

Headset

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Bellevue, WA, United States of America

Jason Lin