dma-direct: Leak pages on dma_set_decrypted() failure

Vulnerability Description

In the Linux kernel, the following vulnerability has been resolved: dma-direct: Leak pages on dma_set_decrypted() failure On TDX 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. DMA could free decrypted/shared pages if dma_set_decrypted() fails. This should be a rare case. Just leak the pages in this case instead of freeing them.

References

• https://git.kernel.org/stable/c/4e0cfb25d49da2e6261ad582f58ffa5b5dd8c8e9
• https://git.kernel.org/stable/c/4031b72ca747a1e6e9ae4fa729e765b43363d66a
• https://git.kernel.org/stable/c/b57326c96b7bc7638aa8c44e12afa2defe0c934c
• https://git.kernel.org/stable/c/b9fa16949d18e06bdf728a560f5c8af56d2bdcaf