Sadullah Canakci

Leila Delshadtehrani, Sadullah Canakci, Manuel Egele et al.

With the continuous increase in the number of software-based attacks, there has been a growing effort towards isolating sensitive data and trusted software components from untrusted third-party components. A hardware-assisted intra-process isolation mechanism enables software developers to partition a process into isolated components and in turn secure sensitive data from untrusted components. However, most of the existing hardware-assisted intra-process isolation mechanisms in modern processors, such as ARM and IBM Power, rely on costly kernel operations for switching between trusted and untrusted domains. Recently, Intel introduced a new hardware feature for intra-process memory isolation, called Memory Protection Keys (MPK), which enables a user-space process to switch the domains in an efficient way. While the efficiency of Intel MPK enables developers to leverage it for common use cases such as Code-Pointer Integrity, the limited number of unique domains (16) prohibits its use in cases such as OpenSSL where a large number of domains are required. Moreover, Intel MPK suffers from the protection key use-after-free vulnerability. To address these shortcomings, in this paper, we propose an efficient intra-process isolation technique for the RISC-V open ISA, called SealPK, which supports up to 1024 unique domains. SealPK prevents the protection key use-after-free problem by leveraging a lazy de-allocation approach. To further strengthen SealPK, we devise three novel sealing features to protect the allocated domains, their associated pages, and their permissions from modifications or tampering by an attacker. To demonstrate the feasibility of our design, we implement SealPK on a RISC-V Rocket processor, provide the OS support for it, and prototype our design on an FPGA. We demonstrate the efficiency of SealPK by leveraging it to implement an isolated shadow stack on our FPGA prototype.

Furkan Eris, Sadullah Canakci, Cansu Demirkiran et al.

To close the gap between memory and processors, and in turn improve performance, there has been an abundance of work in the area of data/instruction prefetcher designs. Prefetchers are deployed in each level of the memory hierarchy, but typically, each prefetcher gets designed without comprehensively accounting for other prefetchers in the system. As a result, these individual prefetcher designs do not always complement each other, and that leads to low average performance gains and/or many negative outliers. In this work, we propose SuitAP (Suite of random forests for Adaptation of Prefetcher system configuration), which is a hardware prefetcher adapter that uses a suite of random forests to determine at runtime which prefetcher should be ON at each memory level, such that they complement each other. Compared to a design with no prefetchers, using SuitAP we improve IPC by 46% on average across traces generated from SPEC2017 suite with 12KB overhead. Moreover, we also reduce negative outliers using SuitAP.