Otu ndị nyocha sitere na Vrije Universiteit Amsterdam, ETH Zurich na Qualcomm ọmụmụ banyere ịdị irè nke nchebe megide mwakpo klaasị ejiri na ibe ebe nchekwa DDR4 ọgbara ọhụrụ , na-enye gị ohere ịgbanwe ọdịnaya nke ibe n'ibe nke dynamic random access memory (DRAM). Nsonaazụ a na-akụda mmụọ na ibe DDR4 sitere na ndị nrụpụta isi ka dị adịghị ike ().
Adịghị ike nke RowHammer na-enye ohere ka emebie ọdịnaya nke ebe nchekwa ibe n'otu n'otu site na ịgụ data sitere na sel ebe nchekwa dị n'akụkụ. Ebe nchekwa DRAM bụ ụdị mkpụrụ ndụ nwere akụkụ abụọ, nke ọ bụla nwere capacitor na transistor, na-eme ka agụ na-aga n'ihu nke otu mpaghara ebe nchekwa na-ebute mgbanwe voltaji na anomalies nke na-akpata obere mfu ụgwọ na sel ndị agbata obi. Ọ bụrụ na ọgụgụ ọgụgụ dị elu nke ukwuu, mgbe ahụ, cell nwere ike ịlafu nnukwu ego zuru oke na usoro mmeghari na-esote agaghị enwe oge iji weghachi ọnọdụ mbụ ya, nke ga-eduga n'ịgbanwe uru nke data echekwara na cell. .
Iji gbochie mmetụta a, ibe DDR4 ọgbara ọhụrụ na-eji teknụzụ TRR (Target Row Refresh), emebere iji gbochie emebi emebi n'oge ọgụ RowHammer. Nsogbu bụ na ọ dịghị otu ụzọ iji mejuputa TRR na onye ọ bụla na-emepụta CPU na ebe nchekwa na-akọwa TRR n'ụzọ nke ya, na-etinye nhọrọ nchebe nke ya ma ghara igosipụta nkọwa mmejuputa.
Ịmụ usoro mgbochi RowHammer nke ndị na-emepụta ihe na-eji eme ka ọ dị mfe ịchọta ụzọ iji gafere nchebe. Mgbe nyochachara, ọ tụgharịrị na ụkpụrụ nke ndị nrụpụta na-eme " (nchekwa site na nzuzo) mgbe mmejuputa TRR na-enyere aka naanị maka nchebe n'ọnọdụ pụrụ iche, na-ekpuchi ọgụ ndị a na-ahụkarị na-emegharị mgbanwe na ụgwọ nke sel na otu ma ọ bụ abụọ ahịrị dị n'akụkụ.
Akụrụngwa nke ndị nyocha ahụ mepụtara na-eme ka o kwe omume ịlele ike nke ibe na ụdị dị iche iche nke ọgụ RowHammer, nke a na-eme mgbalị iji mee ka ụgwọ ahụ maka ọtụtụ ahịrị sel ebe nchekwa ozugbo. Mwakpo ndị dị otú ahụ nwere ike gafere nchebe TRR nke ụfọdụ ndị na-emepụta ihe na-eme ma duga nrụrụ ebe nchekwa bit, ọbụlagodi na ngwaike ọhụrụ nwere ebe nchekwa DDR4.
N'ime 42 DIMM ndị a mụrụ, modul 13 tụgharịrị bụrụ ndị na-adịghị ike maka ụdị ọgụ RowHammer na-abụghị ọkọlọtọ, n'agbanyeghị nchebe ekwuputara. Ọ bụ SK Hynix, Micron na Samsung mepụtara modul nsogbu ahụ, ndị ngwaahịa ha 95% nke ahịa DRAM.
Na mgbakwunye na DDR4, a na-amụkwa ibe LPDDR4 eji na ngwaọrụ mkpanaka, nke tụgharịrị na-enwe mmetụta maka ụdị dị elu nke ọgụ RowHammer. Karịsịa, ebe nchekwa ejiri na Google Pixel, Google Pixel 3, LG G7, OnePlus 7 na Samsung Galaxy S10 smartphones metụtara nsogbu ahụ.
Ndị nyocha nwere ike imepụtaghachi ọtụtụ usoro nrigbu na ibe DDR4 nwere nsogbu. Dịka ọmụmaatụ, iji RowHammer- maka PTE (Page Table Entries) o were site na 2.3 sekọnd ruo awa atọ na sekọnd iri na ise iji nweta ihe ùgwù kernel, dabere na ibe a nwalere. maka mmebi igodo ọha echekwara na ebe nchekwa, RSA-2048 were site na 74.6 sekọnd ruo 39 nkeji 28 sekọnd. o were nkeji 54 na sekọnd iri na isii iji gafere nlele nzere site na ngbanwe ebe nchekwa nke usoro sudo.
Ebipụtala akụrụngwa iji lelee ibe ebe nchekwa DDR4 nke ndị ọrụ na-eji . Iji mee mwakpo nke ọma, achọrọ ozi gbasara nhazi adreesị anụ ahụ ejiri na njikwa ebe nchekwa gbasara ụlọ akụ na ahịrị mkpụrụ ndụ ebe nchekwa. Emebekwara ngwa ọrụ iji chọpụta nhazi ya , nke chọrọ ịgba ọsọ dị ka mgbọrọgwụ. N'ọdịnihu dị nso kwa bipụta ngwa maka ịnwale ebe nchekwa ekwentị.
Ndị ụlọ ọrụ и Maka nchekwa, ha dụrụ ọdụ ka iji ebe nchekwa na-emezi njehie (ECC), ndị na-ahụ maka ebe nchekwa nwere nkwado Maximum Activate Count (MAC), ma jiri ọnụego ume ọhụrụ na-abawanye. Ndị ọrụ nyocha kwenyere na maka ibe ewepụtaralarị, ọ nweghị ihe ngwọta maka nchebe a na-ekwe nkwa megide Rowhammer, yana iji ECC na ịbawanye ugboro nke nrụpụta ebe nchekwa wee bụrụ nke na-adịghị arụ ọrụ. Dịka ọmụmaatụ, a tụrụ ya na mbụ mwakpo na ebe nchekwa DRAM na-agafe nchebe ECC, ma gosipụtakwa ohere ịwakpo DRAM site na site na и na-agba JavaScript na ihe nchọgharị ahụ.
isi: opennet.ru