hv_netvsc: Don't free decrypted memory

Vulnerability Description

In the Linux kernel, the following vulnerability has been resolved: hv_netvsc: Don't free decrypted memory In CoCo VMs it is possible for the untrusted host to cause set_memory_encrypted() or set_memory_decrypted() to fail such that an error is returned and the resulting memory is shared. Callers need to take care to handle these errors to avoid returning decrypted (shared) memory to the page allocator, which could lead to functional or security issues. The netvsc driver could free decrypted/shared pages if set_memory_decrypted() fails. Check the decrypted field in the gpadl to decide whether to free the memory.

References

• https://git.kernel.org/stable/c/a56fe611326332bf6b7126e5559590c57dcebad4
• https://git.kernel.org/stable/c/4aaed9dbe8acd2b6114458f0498a617283d6275b
• https://git.kernel.org/stable/c/bbf9ac34677b57506a13682b31a2a718934c0e31