CVE-2024-36966 Information

Description

In the Linux kernel the following vulnerability has been resolved:

erofs: reliably distinguish block based and fscache mode

When erofs_kill_sb() is called in block dev based mode s_bdev may not have been initialised yet and if CONFIG_EROFS_FS_ONDEMAND is enabled it will be mistaken for fscache mode and then attempt to free an anon_dev that has never been allocated triggering the following warning:

============================================ ida_free called for id=0 which is not allocated. WARNING: CPU: 14 PID: 926 at lib/idr.c:525 ida_free+0x134/0x140 Modules linked in: CPU: 14 PID: 926 Comm: mount Not tainted 6.9.0-rc3-dirty 630 RIP: 0010:ida_free+0x134/0x140 Call Trace: erofs_kill_sb+0x81/0x90 deactivate_locked_super+0x35/0x80 get_tree_bdev+0x136/0x1e0 vfs_get_tree+0x2c/0xf0 do_new_mount+0x190/0x2f0 […]

Now when erofs_kill_sb() is called erofs_sb_info must have been initialised so use sbi->fsid to distinguish between the two modes.

Reference

https://git.kernel.org/stable/c/f9b877a7ee312ec8ce17598a7ef85cb820d7c371 https://git.kernel.org/stable/c/dcdd49701e429c55b3644fd70fc58d85745f8cfe https://git.kernel.org/stable/c/7af2ae1b1531feab5d38ec9c8f472dc6cceb4606