In the Linux kernel, the following vulnerability has been resolved:<\/p>\n
fbdev: core: Fix pointer desynchronization in fb_io_read()<\/p>\n
In fb_io_read(), if copy_to_user() performs a partial copy (e.g., due to
\na faulty user buffer), the loop adjusts the chunk size ‘c’ and updates
\nthe remaining ‘count’. However, the hardware ‘src’ pointer has already
\nbeen eagerly advanced by the original chunk size.<\/p>\n
If the loop is allowed to continue, the read will resume from an
\nincorrect, over-advanced offset. Since the remaining ‘count’ was only
\ndecremented by the successful bytes, this desynchronization causes the
\nnext iterations to execute more hardware reads than originally bounded,
\neventually leading to out-of-bounds I\/O reads.<\/p>\n
Fix this by breaking out of the loop immediately upon a partial
\ncopy_to_user(). A partial copy indicates a faulty user buffer, making
\nsubsequent read attempts futile. Breaking out ensures we return the
\nnumber of successfully read bytes without risking out-of-bounds hardware
\naccesses in subsequent mismatched iterations.<\/p>\n","protected":false},"excerpt":{"rendered":"
In the Linux kernel, the following vulnerability has been resolved:<\/p>\n
fbdev: core: Fix pointer desynchronization in fb_io_read()<\/p>\n
In fb_io_read(), if copy_to_user() performs a partial copy (e.g., due t<\/p>\n","protected":false},"template":"","meta":[],"categories":[],"tags":[],"class_list":["post-11975","vuln","type-vuln","status-publish","hentry"],"_links":{"self":[{"href":"https:\/\/www.54iter.cn\/index.php?rest_route=\/wp\/v2\/vuln\/11975","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=11975"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.54iter.cn\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=11975"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.54iter.cn\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=11975"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}