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: [] __kmalloc+0x4d/0x150 [] ocfs2_compute_replay_slots+0x121/0x330 [ocfs2] [] ocfs2_check_volume+0x485/0x900 [ocfs2] [] ocfs2_mount_volume.isra.0+0x1e9/0x650 [ocfs2] [] ocfs2_fill_super+0xe0b/0x1740 [ocfs2] [] mount_bdev+0x312/0x400 [] legacy_get_tree+0xed/0x1d0 [] vfs_get_tree+0x7d/0x230 [] path_mount+0xd62/0x1760 [] do_mount+0xca/0xe0 [] __x64_sys_mount+0x12c/0x1a0 [] do_syscall_64+0x35/0x80 [] 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.

Affected Software

References

• https://git.kernel.org/stable/c/2b7e59ed2e77136e9360274f8f0fc208a003e95c
• https://git.kernel.org/stable/c/4efe1d2db731bad19891e2fb9b338724b1f598cc
• https://git.kernel.org/stable/c/50ab0ca3aff4da26037113d69f5a756d8c1a92cd
• https://git.kernel.org/stable/c/7ef516888c4d30ae41bfcd79e7077d86d92794c5
• https://git.kernel.org/stable/c/8059e200259e9c483d715fc2df6340c227c3e196
• https://git.kernel.org/stable/c/ce2fcf1516d674a174d9b34d1e1024d64de9fba3