CVE-2022-50673

*** Pendiente de traducción *** In the Linux kernel, the following vulnerability has been resolved:<br /> <br /> ext4: fix use-after-free in ext4_orphan_cleanup<br /> <br /> I caught a issue as follows:<br /> ==================================================================<br /> BUG: KASAN: use-after-free in __list_add_valid+0x28/0x1a0<br /> Read of size 8 at addr ffff88814b13f378 by task mount/710<br /> <br /> CPU: 1 PID: 710 Comm: mount Not tainted 6.1.0-rc3-next #370<br /> Call Trace:<br /> <br /> dump_stack_lvl+0x73/0x9f<br /> print_report+0x25d/0x759<br /> kasan_report+0xc0/0x120<br /> __asan_load8+0x99/0x140<br /> __list_add_valid+0x28/0x1a0<br /> ext4_orphan_cleanup+0x564/0x9d0 [ext4]<br /> __ext4_fill_super+0x48e2/0x5300 [ext4]<br /> ext4_fill_super+0x19f/0x3a0 [ext4]<br /> get_tree_bdev+0x27b/0x450<br /> ext4_get_tree+0x19/0x30 [ext4]<br /> vfs_get_tree+0x49/0x150<br /> path_mount+0xaae/0x1350<br /> do_mount+0xe2/0x110<br /> __x64_sys_mount+0xf0/0x190<br /> do_syscall_64+0x35/0x80<br /> entry_SYSCALL_64_after_hwframe+0x63/0xcd<br /> <br /> [...]<br /> ==================================================================<br /> <br /> Above issue may happen as follows:<br /> -------------------------------------<br /> ext4_fill_super<br /> ext4_orphan_cleanup<br /> --- loop1: assume last_orphan is 12 ---<br /> list_add(&amp;EXT4_I(inode)-&gt;i_orphan, &amp;EXT4_SB(sb)-&gt;s_orphan)<br /> ext4_truncate --&gt; return 0<br /> ext4_inode_attach_jinode --&gt; return -ENOMEM<br /> iput(inode) --&gt; free inode<br /> --- loop2: last_orphan is still 12 ---<br /> list_add(&amp;EXT4_I(inode)-&gt;i_orphan, &amp;EXT4_SB(sb)-&gt;s_orphan);<br /> // use inode and trigger UAF<br /> <br /> To solve this issue, we need to propagate the return value of<br /> ext4_inode_attach_jinode() appropriately.