{"id":23933,"date":"2016-07-10T02:41:50","date_gmt":"2016-07-09T19:41:50","guid":{"rendered":"http:\/\/deepquest.code511.com\/blog\/2016\/07\/pax-reference-count-overflow-mitigation-bypass\/"},"modified":"2016-07-10T02:41:50","modified_gmt":"2016-07-09T19:41:50","slug":"pax-reference-count-overflow-mitigation-bypass","status":"publish","type":"post","link":"https:\/\/deepquest.code511.com\/blog\/2016\/07\/pax-reference-count-overflow-mitigation-bypass\/","title":{"rendered":"PaX Reference Count Overflow Mitigation Bypass"},"content":{"rendered":"<p>PaX contains a mitigation for reference count overflows that is intended to prevent atomic_t variables from reaching 0x80000000 and, more importantly, wrapping around to zero. A documented special case on x86 is that, because &#8220;atomically increment unless current value is X&#8221; cannot be implemented without a cmpxchg loop, the code instead increments the counter, checks for an overflow and, if an overflow happened, immediately decrements the counter back.<\/p>\n","protected":false},"excerpt":{"rendered":"<p>PaX contains a mitigation for reference count overflows that is intended to prevent atomic_t variables from reaching 0x80000000 and, more importantly, wrapping around to zero. A documented special case on&#8230;<\/p>\n","protected":false},"author":439,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_seopress_robots_primary_cat":"","_seopress_titles_title":"","_seopress_titles_desc":"","_seopress_robots_index":"","jetpack_post_was_ever_published":false,"_jetpack_newsletter_access":"","_jetpack_dont_email_post_to_subs":false,"_jetpack_newsletter_tier_id":0,"_jetpack_memberships_contains_paywalled_content":false,"_jetpack_memberships_contains_paid_content":false,"footnotes":""},"categories":[43],"tags":[],"class_list":["post-23933","post","type-post","status-publish","format-standard","hentry","category-exploit"],"jetpack_featured_media_url":"","jetpack_sharing_enabled":true,"jetpack_shortlink":"https:\/\/wp.me\/p4bBYZ-6e1","_links":{"self":[{"href":"https:\/\/deepquest.code511.com\/blog\/wp-json\/wp\/v2\/posts\/23933","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/deepquest.code511.com\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/deepquest.code511.com\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/deepquest.code511.com\/blog\/wp-json\/wp\/v2\/users\/439"}],"replies":[{"embeddable":true,"href":"https:\/\/deepquest.code511.com\/blog\/wp-json\/wp\/v2\/comments?post=23933"}],"version-history":[{"count":0,"href":"https:\/\/deepquest.code511.com\/blog\/wp-json\/wp\/v2\/posts\/23933\/revisions"}],"wp:attachment":[{"href":"https:\/\/deepquest.code511.com\/blog\/wp-json\/wp\/v2\/media?parent=23933"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/deepquest.code511.com\/blog\/wp-json\/wp\/v2\/categories?post=23933"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/deepquest.code511.com\/blog\/wp-json\/wp\/v2\/tags?post=23933"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}