CVE-2021-46923

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

fs/mount_setattr: always cleanup mount_kattr

Make sure that finish_mount_kattr() is called after mount_kattr was succesfully built in both the success and failure case to prevent leaking any references we took when we built it. We returned early if path lookup failed thereby risking to leak an additional reference we took when building mount_kattr when an idmapped mount was requested.

Weakness

The product exposes a resource to the wrong control sphere, providing unintended actors with inappropriate access to the resource.

Affected Software

Extended Description

Resources such as files and directories may be inadvertently exposed through mechanisms such as insecure permissions, or when a program accidentally operates on the wrong object. For example, a program may intend that private files can only be provided to a specific user. This effectively defines a control sphere that is intended to prevent attackers from accessing these private files. If the file permissions are insecure, then parties other than the user will be able to access those files. A separate control sphere might effectively require that the user can only access the private files, but not any other files on the system. If the program does not ensure that the user is only requesting private files, then the user might be able to access other files on the system. In either case, the end result is that a resource has been exposed to the wrong party.

References

• https://git.kernel.org/stable/c/012e332286e2bb9f6ac77d195f17e74b2963d663
• https://git.kernel.org/stable/c/47b5d0a7532d39e42a938f81e3904268145c341d
• https://git.kernel.org/stable/c/012e332286e2bb9f6ac77d195f17e74b2963d663
• https://git.kernel.org/stable/c/47b5d0a7532d39e42a938f81e3904268145c341d