International Conference on. We conclude our evaluation by looking at the thermal envelope of the SoC. Leading the IoT Gartner Insights on How to Lead in a Connected Its working principle is very similar to a hypervisor, the main difference being that no emulation is performed and that all isolation is offered at the hardware level. Well-known information security expert Cesare Garlati is the main member of the RISC-V Foundation security working group and the co-founder of Hex Five Security. It enables physical separation of different execution environments, namely TEE and REE. In the same file, __NR_syscalls must be incremented by three. Specifically, we benchmark the cost of creating, writing, reading and closing objects inside the secure storage area, for two different object sizes (100KB and 1MB), although current memory allocator limitations prevented to cover some cases [35, 19, 20, 39]. Once the maximal temperature is reached, recovery time is around 8 minutes when passively cooled and less than a minute with active cooling. HARDWARE AND SOFTWARE ARM TrustZone [1] has been proposed since ARMv6 architecture, which includes security extensions to ARM System-On-Chip (SoC) covering the processor, memory and peripherals. Figure 2. This section provides some background on TrustZone. The family of TrustZone technologies can be integrated into any Arm Cortex-A and the latest Cortex-M23 and Cortex-M33 based systems, from the smallest of microcontrollers, with TrustZone for Cortex-M processors, to high-performance application… The differentiation is done by the Non-secure TLB ID (NSTID) [12], an extra bit of the TLB. Evaluation Settings. The __NR_syscalls value must be modified to account for the new syscalls: These functions can now be invoked from any REE user-mode application. These values are set at very low values by default, 2kB and 32kB respectively [25]. To support multiple sessions, the TA must be compiled with the TA_FLAG_MULTI_SESSION flag set. To benchmark the raw performance of the Arm processors of our units, we implemented and deployed a single-threaded TA that executes a CPU-bound task, e.g., computes the first 20000 prime numbers. of the 26th USENIX Security Symposium. This is different from a hardware thermal throttling, which tries to prevent damage caused by excessive heat. ∙ ∙ These markers are monitored by a custom program (on a separate node) that pilot the Windows binary (Figure 5). Volatile Memory. It effectively provides hardware-isolated areas of the processor for sensitive data and code, i.e., a trusted execution environment (TEE). There are various other questions on TrustZone interrupts and another answer could be give on the configuration options and performance implications, etc. Due to emulation costs, the Qemu results are the worst ones. The block diagram below details the TrustZone implementation. §2.1 describes TrustZone’s main mechanisms and limitations, while §2.2 introduces Op-Tee. ∙ However, since kernel threads executing the TAs have a higher priority, the userland threads were starved and thus did not produce enough data points. Hardware checks performed by the Tzasc (TrustZone Address Space Controller) [42, 50] determines, if the access is authorized based on this NS-bit. shows average and standard deviation over 10k executions. Cortex-based cores are used in everything from microcontrollers (MCUs) to high-performance processors. A single session can be used to call TEEC_InvokeCommand any number of times. To keep our devices secure, Knox leverages a processor architecture known as ARM TrustZone. (2015), Reddy, A.K., Paramasivam, P., Vemula, P.B. The memory management unit (MMU) is secure-world aware, and secure and non-secure descriptors are stored alongside each other. Being relatively new, Op-Tee is improving rapidly. Park, C.-H. Lee, Z. Zhao, A. Doupé, and G.-J. The secure world has unrestricted access to memory regions, hardware and devices. Note that the Raspberry Pi 3B lacks support for secure boot and hardware separation of memory and peripherals [27], hence these aspects of the TrustZone ecosystem could not be evaluated and are left for future work. Several options exist: powersave and performance for minimum and maximum operating frequency; ondemand toggles between the previous two, and a more conservative mode that operates less aggressively; userspace, to manually set the CPU frequency; and schedutil, where the frequency is set by the scheduler. IEEE (2015), G-Technology: GlobalPlatform TEE Client API Specification v1.0 (2019), G-Technology: TEE Internal Core API Specification Version 1.1.2.50 (2018), © IFIP International Federation for Information Processing 2019, Distributed Applications and Interoperable Systems, IFIP International Conference on Distributed Applications and Interoperable Systems, http://infocenter.arm.com/help/index.jsp?topic=/com.arm.doc.den0024a/ch10s02s04.html, https://source.android.com/security/trusty, https://www.arm.com/company/investors/financial-results, https://community.arm.com/processors/b/blog/posts/inside-the-numbers-100-billion-arm-based-chips-1345571105, https://developer.arm.com/technologies/trustzone, http://infocenter.arm.com/help/index.jsp?topic=/com.arm.doc.ddi0301h/ch02s12s13.html, https://github.com/OP-TEE/optee_os/blob/master/documentation/benchmark.md, https://linux.die.net/man/3/clock_gettime, https://docs.microsoft.com/en-us/dotnet/framework/interop/consuming-unmanaged-dll-functions, http://infocenter.arm.com/help/index.jsp?topic=/com.arm.doc.ddi0388f/Ciheiecd.html, https://nvd.nist.gov/vuln/detail/CVE-2017-5715, https://nvd.nist.gov/vuln/detail/CVE-2017-5753, https://nvd.nist.gov/vuln/detail/CVE-2017-5754, https://nvd.nist.gov/vuln/detail/CVE-2018-3639, https://github.com/OP-TEE/optee_os/issues/1396, https://github.com/OP-TEE/optee_os/issues/2090, https://www.kingston.com/en/embedded/emmc, https://github.com/OP-TEE/OP-TEE_website/tree/master/faq, https://github.com/OP-TEE/optee_os/blob/master/core/arch/arm/kernel/generic_entry_a64.S, https://github.com/OP-TEE/optee_client/tree/master/tee-supplicant, https://github.com/OP-TEE/optee_os/blob/master/core/arch/arm/kernel/thread.c#L150, http://www.chargerlab.com/archives/536.html, https://git.linaro.org/virtualization/qemu-tz.git, https://github.com/OP-TEE/optee_os/issues/1523, https://kernel.ubuntu.com/~cking/stress-ng/, https://github.com/OP-TEE/optee_os/issues/2577, https://www.trustonic.com/solutions/trustonic-solutions-iot, https://github.com/OP-TEE/optee_os/issues/2178, https://www.vmware.com/products/esxi-and-esx.html, https://www.ibm.com/developerworks/library/l-cpufreq-3/, https://doi.org/10.1007/978-3-030-22496-7_9. It is of paramount importance to ensure that only trustworthy applications are deployed to the secure world. For instance, Figure 1 reports the sales for Arm processors in the last 20 years. This section reports on a few lessons learned during this experimental work. Interrupts. Measurements start 60 seconds after the benchmark instances. First, a new file containing the syscall used to retrieve the processor temperature getcputemp is created. As expected, it is more time-consuming to switch from the REE to the TEE (110µs with the performance-oriented governors) than the opposite (47µs). TEE Internal Core API Specification Version 1.1.2.50. memcpy((void*)&ktraceadd_d[ktrace_entries].id. The publish-subscribe paradigm is an efficient communication scheme with... TEE_GetCpuTemperature, sys_ktraceadd, sys_ktraceget, /sys/class/thermal/thermal_zone[0-9]+/temp, The research leading to these results has received funding from the European Union’s Horizon 2020 research and innovation programme under the LEGaTO Project (. These descriptions are given in Appendix A. 51.68.123.177. Arm devices are often battery-powered and must therefore make optimal use of their limited energy capacity.