CVE-2022-50421

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

rpmsg: char: Avoid double destroy of default endpoint

The rpmsg_dev_remove() in rpmsg_core is the place for releasing this default endpoint.

So need to avoid destroying the default endpoint in rpmsg_chrdev_eptdev_destroy(), this should be the same as rpmsg_eptdev_release(). Otherwise there will be double destroy issue that ept->refcount report warning:

refcount_t: underflow; use-after-free.

Call trace: refcount_warn_saturate+0xf8/0x150 virtio_rpmsg_destroy_ept+0xd4/0xec rpmsg_dev_remove+0x60/0x70

The issue can be reproduced by stopping remoteproc before closing the /dev/rpmsgX.

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 Any operations using the original pointer are no longer valid because the memory “belongs” to the code that operates on the new pointer.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/3f20ef7a845c2c8d7ec82ecffa20d95cab5ecfeb
• https://git.kernel.org/stable/c/467233a4ac29b215d492843d067a9f091e6bf0c5
• https://git.kernel.org/stable/c/ef828a39d6a7028836eaf37df3ad568c8c2dd6f9