{"id":28499,"date":"2026-09-25T00:31:33","date_gmt":"2026-09-24T16:31:33","guid":{"rendered":"https:\/\/www.54iter.cn\/?vuln=cve-2026-93235"},"modified":"2026-09-25T00:31:33","modified_gmt":"2026-09-24T16:31:33","slug":"cve-2026-93235","status":"publish","type":"vuln","link":"https:\/\/www.54iter.cn\/?vuln=cve-2026-93235","title":{"rendered":"CVE-2026-93235 &#8211; In the Linux kernel, the following vulnerability has been resolved:\n\nf2fs: fix to zero pos"},"content":{"rendered":"<p>In the Linux kernel, the following vulnerability has been resolved:<\/p>\n<p>f2fs: fix to zero post-EOF data when extending file size<\/p>\n<p>generic\/794  4s &#8230; &#8211; output mismatch (see \/share\/git\/fstests\/results\/\/generic\/794.out.bad)<br \/>\n    &#8212; tests\/generic\/794.out   2026-06-12 08:46:32.766426241 +0800<br \/>\n    +++ \/share\/git\/fstests\/results\/\/generic\/794.out.bad 2026-07-05 18:32:55.000000000 +0800<br \/>\n    @@ -1,4 +1,16 @@<br \/>\n     QA output created by 794<br \/>\n     append_write<br \/>\n    +FAIL: non-zero data in gap [4080,4096) after shutdown+remount<br \/>\n    +000000 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a  &gt;ZZZZZZZZZZZZZZZZ&lt;<br \/>\n    +*<br \/>\n    +001000<br \/>\n     truncate_up<br \/>\n    &#8230;<br \/>\n    (Run &#039;diff -u \/share\/git\/fstests\/tests\/generic\/794.out \/share\/git\/fstests\/results\/\/generic\/794.out.bad&#039;  to see the entire diff)<br \/>\nRan: generic\/794<br \/>\nFailures: generic\/794<br \/>\nFailed 1 of 1 tests<\/p>\n<p>Steps of generic\/794:<br \/>\n1. write 4096 bytes to file w\/ 0x5a<br \/>\n2. use fiemap to get PBA of first block in file<br \/>\n3. truncate file to 4080<br \/>\n4. umount; write 4096 bytes to file w\/ 0x5a directly via PBA; mount<br \/>\n5. extend filesize via<br \/>\n   a) append 4096 from offset 4096, or<br \/>\n   b) truncate 8192, or<br \/>\n   c) fallocate 4096 from offset 4096<br \/>\n6. verify the gap is zeroed in memory [4080,4096)<br \/>\n7. sync range 4096 from offset 4096; shutdown -f (flush meta before shutdown)<br \/>\n8. umount; mount; verify [4080,4096) is zeroed or not.<\/p>\n<p>When extending file size (e.g. via truncate, fallocate, or write) across an<br \/>\nunaligned EOF boundary, we need to ensure that post-EOF data in the partial<br \/>\npage is zeroed out in pagecache and marked dirty, then writeback the cache to<br \/>\npersist zeroed data before committing inode w\/ updated i_size.<\/p>\n<p>This help to prevent stale disk data beyond the previous EOF from being exposed<br \/>\nafter remounting or crash recovery.<\/p>\n<p>Since f2fs is a LFS filesystem, we only support direct write via PBA in pinfile,<br \/>\nand pinfile has section-aligned filesize, so in Android, there should no problem,<br \/>\nbut for other usage in different environment, let&#039;s fix this w\/ fsync_mode=strict<br \/>\nmount option.<\/p>\n","protected":false},"excerpt":{"rendered":"<p>In the Linux kernel, the following vulnerability has been resolved:<\/p>\n<p>f2fs: fix to zero post-EOF data when extending file size<\/p>\n<p>generic\/794  4s &#8230; &#8211; output mismatch (see \/share\/git\/fstests\/results\/\/ge<\/p>\n","protected":false},"template":"","meta":[],"categories":[],"tags":[],"class_list":["post-28499","vuln","type-vuln","status-publish","hentry"],"_links":{"self":[{"href":"https:\/\/www.54iter.cn\/index.php?rest_route=\/wp\/v2\/vuln\/28499","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.54iter.cn\/index.php?rest_route=\/wp\/v2\/vuln"}],"about":[{"href":"https:\/\/www.54iter.cn\/index.php?rest_route=\/wp\/v2\/types\/vuln"}],"wp:attachment":[{"href":"https:\/\/www.54iter.cn\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=28499"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.54iter.cn\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=28499"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.54iter.cn\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=28499"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}