Boka revaongorori kubva kuTechnical University yeGraz (Austria), yaimbozivikanwa nekugadzira nzira dzekurwisa , , ΠΈ , yakaita tsvakiridzo mune zvehardware optimizations yakanangana ne AMD processors uye nzira mbiri nyowani dzepadivi-chiteshi kurwisa dzinoshandisa kuburitswa kwedata panguva yekushanda kweLXNUMX cache chiteshi chekufungidzira magadzirirwo e AMD processors. Iwo matekiniki anogona kushandiswa kuderedza kushanda kwekuchengetedzwa kweASLR, kudzoreredza makiyi munjodzi yeAES kuita, uye kugadzirisa mashandiro eSpecter attack.
Matambudziko akaonekwa mukuitwa kwechiteshi chekufungidzira nzira (nzira yekufungidzira) muCPU yekutanga-level data cache (L1D), inoshandiswa kufanotaura kuti ndeipi chiteshi checache chine imwe kero yekurangarira. Iko optimization inoshandiswa mu AMD processors yakavakirwa pakutarisa ΞΌ-tag (ΞΌTag). ΞΌTag inoverengerwa nekushandisa chaiyo hashi basa kune chaiyo kero. Panguva yekushanda, injini yekufungidzira chiteshi inoshandisa ΞΌTag kuona cache chiteshi kubva patafura. Saka, ΞΌTag inobvumira purosesa kuti azvimise pakuwana chete chiteshi, pasina kutsvaga kuburikidza nesarudzo dzese, izvo zvinoderedza zvakanyanya CPU simba rekushandisa.
Munguva yekudzoreredza engineering yechiteshi chekufungidzira system kuitiswa muzvizvarwa zvakasiyana zve AMD processors yakaburitswa kubva 2011 kusvika 2019, maviri matsva epadivi-chiteshi kurwisa nzira akaonekwa:
- Collide + Probe - inobvumira anorwisa kuti atarise ndangariro kuwana kwemaitiro anomhanya pane imwechete inonzwisisika CPU musimboti. Izvo zvakakosha zveiyo nzira ndeye kushandisa chaiwo kero dzinokonzeresa kudhumhana muhashi basa rinoshandiswa kuverenga ΞΌTag yekutevera ndangariro kuwana. Kusiyana neFlush + Reload uye Prime + Probe kurwiswa kunoshandiswa paIntel processors, Collide + Probe haishandise ndangariro yakagovaniswa uye inoshanda pasina ruzivo rwemakero epamuviri.
- Rodha + Reload - inokutendera kuti unyatso kuona ndangariro dzekuwana zviteshi pane imwechete yemuviri CPU musimboti. Iyo nzira yakavakirwa pachokwadi chekuti sero rekurangarira remuviri rinogona kunge riri muL1D cache kamwe chete. Avo. kuwana iyo imwechete ndangariro sero pane imwe yakasarudzika kero kuchaita kuti sero ribviswe kubva kuL1D cache, zvichibvumira kuwana ndangariro kuteverwa. Kunyangwe kurwiswa kwacho kuchitsamira pane yakagovaniswa ndangariro, haibvisi mitsara yecache, ichibvumira kurwisa kwekubira kusingabvisi data kubva kune yekupedzisira-level cache.
Zvichienderana neCollide + Probe uye Load + Reload matekiniki, vaongorori vakaratidza akati wandei epadivi-chiteshi kurwisa mamiriro:
- Iko mukana wekushandisa nzira dzekuronga yakavanzika isina kunanga yekutaurirana chiteshi pakati pemaitiro maviri, ichibvumira kuendesa data nekumhanya kunosvika 588 kB pasekondi, inoratidzwa.
- Uchishandisa kudhumhana mu ΞΌTag, zvaigoneka kudzikisa entropy kune akasiyana akasiyana eASLR (Kero Space Layout Randomization) uye nekunzvenga kudzivirira kweASLR mukernel pane yakagadziridzwa Linux system. Iko mukana wekuita kurwisa kudzikisa ASLR entropy zvese kubva mushandisi application uye kushandisa JavaScript kodhi inoitwa munzvimbo yesandbox uye kodhi inomhanya mune imwe nharaunda yevaenzi inoratidzwa.
- Zvichienderana neCollide + Probe nzira, kurwiswa kwakaitwa kudzoreredza kiyi yekuvharira kubva kune isina njodzi kuita (zvichienderana ne ) AES encryption.
- Nekushandisa nzira yeCollide + Probe senzira yekutora data, iyo Specter kurwisa yakakwanisa kubvisa yakavanzika data kubva kukernel pasina kushandisa yakagovaniswa ndangariro.
Kusagadzikana kunoitika pa AMD processors zvichibva pane microarchitectures
Bulldozer, Piledriver, Steamroller, Zen (Ryzen, Epic), Zen+ uye Zen2.
AMD yakaziviswa nezvenyaya iyi muna Nyamavhuvhu 23, 2019, asi kusvika zvino neruzivo rwekuvharira kusagadzikana. Sekureva kwevatsvagiri, dambudziko rinogona kuvharika padanho rekuvandudza microcode nekupa MSR bits kuti isarudze kudzima chiteshi chekufungidzira, zvakafanana nezvakaitwa neIntel kudzora kudzikiswa kwemaitiro ekufanotaura kwebazi.
Source: opennet.ru