CVE-2022-50770

In the Linux kernel, the following vulnerability has been resolved:

ocfs2: fix memory leak in ocfs2_mount_volume()

There is a memory leak reported by kmemleak:

unreferenced object 0xffff88810cc65e60 (size 32): comm "mount.ocfs2", pid 23753, jiffies 4302528942 (age 34735.105s) hex dump (first 32 bytes): 10 00 00 00 00 00 00 00 00 01 01 01 01 01 01 01 ................ 01 01 01 01 01 01 01 01 00 00 00 00 00 00 00 00 ................ backtrace: [<ffffffff8170f73d>] __kmalloc+0x4d/0x150 [<ffffffffa0ac3f51>] ocfs2_compute_replay_slots+0x121/0x330 [ocfs2] [<ffffffffa0b65165>] ocfs2_check_volume+0x485/0x900 [ocfs2] [<ffffffffa0b68129>] ocfs2_mount_volume.isra.0+0x1e9/0x650 [ocfs2] [<ffffffffa0b7160b>] ocfs2_fill_super+0xe0b/0x1740 [ocfs2] [<ffffffff818e1fe2>] mount_bdev+0x312/0x400 [<ffffffff819a086d>] legacy_get_tree+0xed/0x1d0 [<ffffffff818de82d>] vfs_get_tree+0x7d/0x230 [<ffffffff81957f92>] path_mount+0xd62/0x1760 [<ffffffff81958a5a>] do_mount+0xca/0xe0 [<ffffffff81958d3c>] __x64_sys_mount+0x12c/0x1a0 [<ffffffff82f26f15>] do_syscall_64+0x35/0x80 [<ffffffff8300006a>] entry_SYSCALL_64_after_hwframe+0x46/0xb0

This call stack is related to two problems. Firstly, the ocfs2 super uses "replay_map" to trace online/offline slots, in order to recover offline slots during recovery and mount. But when ocfs2_truncate_log_init() returns an error in ocfs2_mount_volume(), the memory of "replay_map" will not be freed in error handling path. Secondly, the memory of "replay_map" will not be freed if d_make_root() returns an error in ocfs2_fill_super(). But the memory of "replay_map" will be freed normally when completing recovery and mount in ocfs2_complete_mount_recovery().

Fix the first problem by adding error handling path to free "replay_map" when ocfs2_truncate_log_init() fails. And fix the second problem by calling ocfs2_free_replay_slots(osb) in the error handling path "out_dismount". In addition, since ocfs2_free_replay_slots() is static, it is necessary to remove its static attribute and declare it in header file.