CVE-2023-53613

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

dax: Fix dax_mapping_release() use after free

A CONFIG_DEBUG_KOBJECT_RELEASE test of removing a device-dax region provider (like modprobe -r dax_hmem) yields:

kobject: mapping0 (ffff93eb460e8800): kobject_release, parent 0000000000000000 (delayed 2000) [..] DEBUG_LOCKS_WARN_ON(1) WARNING: CPU: 23 PID: 282 at kernel/locking/lockdep.c:232 __lock_acquire+0x9fc/0x2260 [..] RIP: 0010:__lock_acquire+0x9fc/0x2260 [..] Call Trace: [..] lock_acquire+0xd4/0x2c0 ? ida_free+0x62/0x130 _raw_spin_lock_irqsave+0x47/0x70 ? ida_free+0x62/0x130 ida_free+0x62/0x130 dax_mapping_release+0x1f/0x30 device_release+0x36/0x90 kobject_delayed_cleanup+0x46/0x150

Due to attempting ida_free() on an ida object that has already been freed. Devices typically only hold a reference on their parent while registered. If a child needs a parent object to complete its release it needs to hold a reference that it drops from its release callback. Arrange for a dax_mapping to pin its parent dev_dax instance until dax_mapping_release().

Weakness

The product reuses or references memory after it has been freed. At some point afterward, the memory may be allocated again and saved in another pointer, while the original pointer references a location somewhere within the new allocation. Any operations using the original pointer are no longer valid because the memory “belongs” to the code that operates on the new pointer.

Affected Software

Potential Mitigations

References

• https://git.kernel.org/stable/c/03859868ab82d57bfdd0cea1bf31f9319a5dded0
• https://git.kernel.org/stable/c/6d24b170a9db0456f577b1ab01226a2254c016a8
• https://git.kernel.org/stable/c/7310b84821f043dcf77d5e6aa0ad55dc1e10a11d
• https://git.kernel.org/stable/c/94a85474f5e3e518bdbf8c9f51cb343d734a04f7
• https://git.kernel.org/stable/c/9c2f993b6ca903c030d58451b5bf9ea27d0d17fa
• https://git.kernel.org/stable/c/f76db6781d76d8464ec2faa9752cc3fb2e4f6923