CVE-2024-35939
CriticalCVSS 9.3Exploitation Probability (EPSS)
Low risk12th percentile - higher than 12% of all known CVEs
Summary
In the Linux kernel, the dma-direct function has a page leak issue when dma_set_decrypted() fails. In TDX environments, an untrusted host can cause set_memory_encrypted() or set_memory_decrypted() to fail, returning shared memory to the page allocator. The fix leaks the pages in such cases instead of freeing them.
Risk Assessment
Freeing decrypted (shared) memory to the allocator could lead to data confidentiality breaches or other security issues, especially in TDX environments.
Recommendation
Update the Linux kernel to a patched version. Also monitor TDX environments for unusual behavior.
Original NVD description (English source)
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.