TLDRVuln - Cybersecurity Vulnerabilities Made Simple

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.