CVE-2023-53511

*** Pendiente de traducción *** In the Linux kernel, the following vulnerability has been resolved:<br /> <br /> io_uring: fix fget leak when fs don&amp;#39;t support nowait buffered read<br /> <br /> Heming reported a BUG when using io_uring doing link-cp on ocfs2. [1]<br /> <br /> Do the following steps can reproduce this BUG:<br /> mount -t ocfs2 /dev/vdc /mnt/ocfs2<br /> cp testfile /mnt/ocfs2/<br /> ./link-cp /mnt/ocfs2/testfile /mnt/ocfs2/testfile.1<br /> umount /mnt/ocfs2<br /> <br /> Then umount will fail, and it outputs:<br /> umount: /mnt/ocfs2: target is busy.<br /> <br /> While tracing umount, it blames mnt_get_count() not return as expected.<br /> Do a deep investigation for fget()/fput() on related code flow, I&amp;#39;ve<br /> finally found that fget() leaks since ocfs2 doesn&amp;#39;t support nowait<br /> buffered read.<br /> <br /> io_issue_sqe<br /> |-io_assign_file // do fget() first<br /> |-io_read<br /> |-io_iter_do_read<br /> |-ocfs2_file_read_iter // return -EOPNOTSUPP<br /> |-kiocb_done<br /> |-io_rw_done<br /> |-__io_complete_rw_common // set REQ_F_REISSUE<br /> |-io_resubmit_prep<br /> |-io_req_prep_async // override req-&gt;file, leak happens<br /> <br /> This was introduced by commit a196c78b5443 in v5.18. Fix it by don&amp;#39;t<br /> re-assign req-&gt;file if it has already been assigned.<br /> <br /> [1] https://lore.kernel.org/ocfs2-devel/ab580a75-91c8-d68a-3455-40361be1bfa8@linux.alibaba.com/T/#t