{"id":246703,"date":"2018-01-29T14:29:39","date_gmt":"2018-01-29T12:29:39","guid":{"rendered":"https:\/\/mybroadband.co.za\/news\/?p=246703"},"modified":"2018-01-29T14:31:26","modified_gmt":"2018-01-29T12:31:26","slug":"retpoline-googles-fix-for-spectre","status":"publish","type":"post","link":"https:\/\/mybroadband.co.za\/news\/security\/246703-retpoline-googles-fix-for-spectre.html","title":{"rendered":"Retpoline &#8211; Google\u2019s fix for Spectre"},"content":{"rendered":"<p><a href=\"https:\/\/mybroadband.co.za\/news\/software\/246635-linux-4-15-released.html\"><strong>Linux 4.15 has been released<\/strong><\/a>\u00a0with an implementation of Google\u2019s \u201cretpoline\u201d fix.<\/p>\n<p>The fix addresses the Spectre security vulnerability.<\/p>\n<p><a href=\"https:\/\/mybroadband.co.za\/news\/hardware\/243486-meltdown-vs-spectre-what-you-need-to-know.html\"><strong>Spectre<\/strong><\/a>, and its related vulnerability <a href=\"https:\/\/mybroadband.co.za\/news\/hardware\/243486-meltdown-vs-spectre-what-you-need-to-know.html\"><strong>Meltdown<\/strong><\/a>, allow a feature in all modern CPUs called speculative execution to be exploited to gain access to sensitive data.<\/p>\n<p>\u201cRetpoline\u201d is a portmanteau of \u201creturn\u201d and \u201ctrampoline\u201d, and refers to a software construct that allows indirect branches of a program to be isolated from speculative execution.<\/p>\n<p>Google said its fix aims to address only the second variant of Spectre, which its Project Zero team described as <strong><a href=\"https:\/\/googleprojectzero.blogspot.co.za\/2018\/01\/reading-privileged-memory-with-side.html\" target=\"_blank\" rel=\"noopener\">branch target injection<\/a><\/strong>.<\/p>\n<p>\u201cNaturally, protecting an indirect branch means that no prediction can occur,\u201d said Google, suggesting a performance impact.<\/p>\n<p>The performance impact was insignificant, however.<\/p>\n<p>\u201cThere has been speculation that the deployment of kernel page table isolation (KPTI) causes significant performance slowdowns,\u201d said\u00a0<strong><a href=\"https:\/\/security.googleblog.com\/2018\/01\/more-details-about-mitigations-for-cpu_4.html\" target=\"_blank\" rel=\"noopener\">Google<\/a><\/strong>.<\/p>\n<p>\u201cPerformance can vary, as the impact of the KPTI mitigations depends on the rate of system calls made by an application. On most of our workloads, including our cloud infrastructure, we see negligible impact on performance.\u201d<\/p>\n<p><strong><a href=\"https:\/\/www.phoronix.com\/scan.php?page=article&amp;item=gcc8-mindirect-thunk&amp;num=2\" target=\"_blank\" rel=\"noopener\">Benchmarks by Phoronix<\/a><\/strong>\u00a0corroborate Google\u2019s statement.<\/p>\n<h3 class=\"my-4\">Now read: <a href=\"https:\/\/mybroadband.co.za\/news\/security\/245694-intel-patch-for-spectre-and-meltdown-causing-problems.html\">Intel patch for Spectre and Meltdown causing problems<\/a><\/h3>\n","protected":false},"excerpt":{"rendered":"<p>Linux 4.15 has released with an implementation of Google\u2019s \u201cretpoline\u201d fix.<\/p>\n","protected":false},"author":23,"featured_media":243648,"comment_status":"open","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_sma_x_autopost_status":"idle","_sma_x_autopost_error":"","_sma_x_post_id":"","_sma_facebook_post_id":"","_sma_instagram_post_id":"","_sma_threads_post_id":"","_sma_x_attempts":0,"footnotes":""},"categories":[27],"tags":[48591,167,48589,48076],"class_list":["post-246703","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-security","tag-branch-target-injection","tag-google","tag-retpoline","tag-spectre"],"_links":{"self":[{"href":"https:\/\/mybroadband.co.za\/news\/wp-json\/wp\/v2\/posts\/246703"}],"collection":[{"href":"https:\/\/mybroadband.co.za\/news\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/mybroadband.co.za\/news\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/mybroadband.co.za\/news\/wp-json\/wp\/v2\/users\/23"}],"replies":[{"embeddable":true,"href":"https:\/\/mybroadband.co.za\/news\/wp-json\/wp\/v2\/comments?post=246703"}],"version-history":[{"count":1,"href":"https:\/\/mybroadband.co.za\/news\/wp-json\/wp\/v2\/posts\/246703\/revisions"}],"predecessor-version":[{"id":246717,"href":"https:\/\/mybroadband.co.za\/news\/wp-json\/wp\/v2\/posts\/246703\/revisions\/246717"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/mybroadband.co.za\/news\/wp-json\/wp\/v2\/media\/243648"}],"wp:attachment":[{"href":"https:\/\/mybroadband.co.za\/news\/wp-json\/wp\/v2\/media?parent=246703"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/mybroadband.co.za\/news\/wp-json\/wp\/v2\/categories?post=246703"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/mybroadband.co.za\/news\/wp-json\/wp\/v2\/tags?post=246703"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}