{"id":46270,"date":"2021-07-22T04:37:38","date_gmt":"2021-07-21T21:37:38","guid":{"rendered":"https:\/\/deepquest.code511.com\/blog\/2021\/07\/sequoia-a-deep-root-in-linuxs-filesystem-layer\/"},"modified":"2021-07-22T04:37:38","modified_gmt":"2021-07-21T21:37:38","slug":"sequoia-a-deep-root-in-linuxs-filesystem-layer","status":"publish","type":"post","link":"https:\/\/deepquest.code511.com\/blog\/2021\/07\/sequoia-a-deep-root-in-linuxs-filesystem-layer\/","title":{"rendered":"Sequoia: A Deep Root In Linux&#039;s Filesystem Layer"},"content":{"rendered":"<p>Qualys discovered a size_t-to-int conversion vulnerability in the Linux kernel&#8217;s filesystem layer: by creating, mounting, and deleting a deep directory structure whose total path length exceeds 1GB, an unprivileged local attacker can write the 10-byte string &#8220;\/\/deleted&#8221; to an offset of exactly -2GB-10B below the beginning of a vmalloc()ated kernel buffer. They successfully exploited this uncontrolled out-of-bounds write, and obtained full root privileges on default installations of Ubuntu 20.04, Ubuntu 20.10, Ubuntu 21.04, Debian 11, and Fedora 34 Workstation; other Linux distributions are certainly vulnerable, and probably exploitable. A basic proof of concept (a crasher) is attached to this advisory.<\/p>\n","protected":false},"excerpt":{"rendered":"<p>Qualys discovered a size_t-to-int conversion vulnerability in the Linux kernel&#8217;s filesystem layer: by creating, mounting, and deleting a deep directory structure whose total path length exceeds 1GB, an unprivileged local&#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-46270","post","type-post","status-publish","format-standard","hentry","category-exploit"],"jetpack_featured_media_url":"","jetpack_sharing_enabled":true,"jetpack_shortlink":"https:\/\/wp.me\/p4bBYZ-c2i","_links":{"self":[{"href":"https:\/\/deepquest.code511.com\/blog\/wp-json\/wp\/v2\/posts\/46270","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=46270"}],"version-history":[{"count":0,"href":"https:\/\/deepquest.code511.com\/blog\/wp-json\/wp\/v2\/posts\/46270\/revisions"}],"wp:attachment":[{"href":"https:\/\/deepquest.code511.com\/blog\/wp-json\/wp\/v2\/media?parent=46270"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/deepquest.code511.com\/blog\/wp-json\/wp\/v2\/categories?post=46270"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/deepquest.code511.com\/blog\/wp-json\/wp\/v2\/tags?post=46270"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}