Skip go content

CET shadow stacks

Architecture referenceFeex

Dem still dey call am CET-SS

CET shadow stacks dey provide protected return-address state to help detect corrupted control-flow return dem. Di processor im shadow-stack capability na only one prerequisite for process wey get active protection.

Wetin you need know

CET shadow stacks dey provide protected return-address state to help detect corrupted control-flow return dem. Di processor im shadow-stack capability na only one prerequisite for process wey get active protection.

How e dey work

Shadow stack dey hold protected copy of return information alongside di normal execution stack. Protected return dey check consistency according to di architecture im rule dem. Di OS dey manage enablement, memory permission dem and thread state, while runtime dem must correctly handle exception dem and context transition dem.

Where e dey useful

Stack overwrite wey change normal return address fit produce control-protection exception wen e no agree with di protected return state. Debugger or runtime must understand di shadow-stack environment instead of treating am as ordinary writable stack.

How to check support and enablement

CPUID.07H.00H:ECX bit 7 dey enumerate shadow-stack capability. Use di OS im documented per-process or per-thread status interface to establish enablement. Crash wey nobody fit explain dey warrant checking supported software update dem and compatibility before changing protection policy.

Capability, enablement and enforcement na different ting dem wey person must check separately. Processor fit support protection while di OS, application or virtual-machine policy no turn am on. Database support field no be attestation say running system dey secure.

Wetin di feature no dey guarantee

Shadow stack dem no dey establish IBT support, protect all application data or eliminate every control-flow attack. CPU label no dey prove say every executable and loaded library dey covered under di OS im compatibility policy.

Compatibility and performance inside real life

Keep di OS, firmware and affected runtime current. If protection show compatibility problem, make you use vendor diagnostics and supported update dem first. Broad protection toggle fit affect oda application dem wey no concern am, so e suppose follow clear deployment and recovery policy.

Practical verification checklist

  1. Record di exact processor or platform model plus di application, OS and runtime version dem wey dey involve. Make you keep di exact word dem wey di error or requirement use.
  2. Check di manufacturer reference for dat exact model, den inspect di real capability and enabled state inside di environment where di program dey run.
  3. Compare every single requirement of di binary or backend wey you choose. Name wey resemble am, alias, or broad technology label no reach.
  4. Confirm say di application select di implementation wey dem intend. Use di diagnostics wey dem document and supported fallback if requirement dem no complete.
  5. Make only one supported change at a time, den run di same workload again. Keep di original configuration and recovery way ready.

If dem list di feature but software no fit use am

Start from di exact component wey dey fail. Hardware database dey describe capability wey dem record; di operating system or hypervisor fit show different real environment. If illegal-instruction error happen, you still need to check di exact instruction wey cause di fault and di binary build, because corrupt file or anoda instruction wey no dey supported fit give di same kind problem.

Install di application, driver or runtime version wey get support for dat exact platform, and use di vendor documented baseline or fallback build if e need am. Software update no fit create instruction wey di processor no get. Firmware and security-policy change dem suppose follow di system manufacturer procedure and recovery plan, no be just any common optimization advice.

Sources and scope of dis explanation

Intel 64 and IA-32 Architectures Software Developer's Manual · Linux kernel: Control-flow Enforcement Technology shadow stack

Dis reference dem establish architectural behavior and software requirement dem. Dem no dey independently verify every feature value for any linked hardware model page. For model support, use dat page manufacturer evidence and check di active system configuration. Dis article no supply benchmark, certification or independent review date.

Sources and verification

Editorial ownership: Feex. No independent review date dey recorded. How we dey do research.

Dis article make sense to you?

Yes or no dey enough. Choose reason if you want, or add short note.

Dis article make sense to you?