Abaphandi abaphuma kwinkampani yeNCC Group epapashwe kutshanje iziphumo zophicotho lweprojekthi yeZephyr, okuyinkqubo yokusebenza ngexesha langempela (RTOS), ejoliswe ekuxhobiseni izixhobo ngokuhambelana nengcamango "ye-Intanethi yezinto" (IoT). I-Zephyr iphuhliswa ngokuthatha inxaxheba kwe-Intel.
I-Zephyr ibonelela ngesithuba sedilesi enye enenyani kuzo zonke iinkqubo. ekwabelwana ngayo kwihlabathi (i-SASOS, iNkqubo yokuSebenza iNdawo enye yeedilesi). Ikhowudi ethile yesicelo idibaniswe ne-kernel elungiselelwe isicelo esithile kwaye yenza ifayile ephunyeziweyo ye-monolithic ukukhuphela nokusebenza kwiikhomputha ezithile.
Zonke izixhobo zenkqubo zimiselwa kwinqanaba lokwakha, okunciphisa ubungakanani bekhowudi kunye nokwandisa imveliso. Kuphela ziimpawu zekernel ezifunekayo ukuqhuba usetyenziso ezinokuqukwa kumfanekiso wenkqubo.
Kuyaphawuleka ukuba phakathi kweenzuzo eziphambili UZephyr ukhankanyiwe uphuhliso ngeliso kukhuseleko. Kuyaxoxwa ukuba zonke izigaba zophuhliso zidlula kwizigaba ezinyanzelekileyo ze qinisekisa ukhuseleko lwekhowudi: uvavanyo olungenangqondo, uhlalutyo lwe-static, uvavanyo lokungena, ukuphononongwa kwekhowudi, uhlalutyo lokuthunyelwa kwe-backdoor, kunye ne-model modeling.
Malunga nokuba semngciphekweni
Uphicotho lubonakalise ubuthathaka obungama-25 eZephyr kunye nokuba sesichengeni oku-1 kwi-MCUboot. Bebonke, bachonga 6 ubuthathaka kwisitaki sothungelwano, 4 kwi-kernel, 2 kwiqokobhe lomyalelo, 5 kwisistim yokuphatha umnxeba, 5 kwi-subsystem ye-USB kunye ne-3 kwindlela yokuhlaziya i-firmware.
Iingxaki ezimbini zanikwa inqanaba lengozi ebalulekileyo, ezimbini: eziphezulu, i-9 ephakathi, i-9 - ephantsi kunye ne-4 - ukuthathela ingqalelo. Iingxaki Imiba ebalulekileyo ichaphazela i-IPv4 stack kunye ne-MQTT parser, ngelixae eziyingozi ziquka USB mass yokugcina kunye nabaqhubi USB DFU.
Ngexesha lokuvezwa kolwazi, ukulungiswa kwalungiselelwa kuphela ubuthathaka be-15 kuyingozi ngakumbi, kusekho iingxaki eziye zasonjululwa, ezikhokelela ekukhanyeni kwenkonzo okanye ezinxulumene nokungaphumeleli kwiindlela zokukhusela okongeziweyo kwe-kernel.
Ukuba semngciphekweni okusetyenziswa kude kuye kwachongwa kwisitaki se-IPv4 seqonga, esikhokelela kurhwaphilizo lwenkumbulo xa kusetyenzwa iipakethi ze-ICMP eziguqulwe ngendlela ethile.
Enye ingxaki enkulu ifunyenwe kwi-MQTT protocol analyzer, que ibangelwa kukusilela ukujonga ngokufanelekileyo ubude bemihlaba kwiheda kwaye kunokukhokelela ekuphunyezweni kwekhowudi ekude. Imiba enganeno yingozi yokwaliwa kwenkonzo ifumaneka kwisitaki se-IPv6 kunye nokuphunyezwa kweprotocol ye-CoAP.
Ezinye iingxaki zinokusetyenziswa ekuhlaleni ukwenza ukwaliwa kwenkonzo okanye ukwenziwa kwekhowudi kwinqanaba le-kernel. Uninzi lwezi buthathaka zinxulumene nokunqongophala kokutshekishwa okufanelekileyo kweengxoxo zokufowuna kwenkqubo, kwaye kunokukhokelela ekubhaleni nasekufundeni iindawo ezingafanelekanga zememori ye-kernel.
Iingxaki zikwagubungela ikhowudi yokusetyenzwa kwefowuni ngokwayo: ukufikelela kwinombolo yokufowuna yenkqubo engalunganga kukhokelela ekuphuphumeni okupheleleyo. KUNYEUndoqo uchonge iingxaki ekuphunyezweni kokhuseleko lwe-ASLR (i-address space randomization) kunye nendlela yokufaka i-canary tags kwi-stack, eyenza ezi ndlela zingasebenzi.
Imiba emininzi ichaphazela isitaki se-USB kunye nabaqhubi ngabanye. Umzekelo, umba kugcino oluninzi lwe-USB likuvumela ukuba ubangele ukuphuphuma kwebuffer kwaye wenze ikhowudi yenqanaba le-kernel xa uqhagamshela isixhobo kummkeli olawulwayo wohlaseli we-USB.
Ubuthathaka kwi-USB DFU, umqhubi wokukhuphela i-firmware entsha kwi-USB, ikuvumela ukuba ulayishe umfanekiso we-firmware olungisiweyo kwi-Flash yangaphakathi ye-microcontroller ngaphandle kokusebenzisa i-encryption kunye nokugqithisa imo ekhuselekileyo yokuqalisa kunye necandelo lokuqinisekisa utyikityo lwedijithali. Ukongeza, ikhowudi yokuvula i-MCUboot evulekileyo yafundwa, apho ubuthathaka obungeyongozi bufunyenwe obunokukhokelela ekuphuphumeni kwe-buffer xa usebenzisa i-Simple Management Protocol (SMP) phezu kwe-UART.