CVE-2024-57793

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

virt: tdx-guest: Just leak decrypted memory on unrecoverable errors

In CoCo VMs it is possible for the untrusted host to cause 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.

Leak the decrypted memory when set_memory_decrypted() fails, and dont need to print an error since set_memory_decrypted() will call WARN_ONCE().

Weakness

The product does not sufficiently track and release allocated memory after it has been used, making the memory unavailable for reallocation and reuse.

Affected Software

Potential Mitigations

• Choose a language or tool that provides automatic memory management, or makes manual memory management less error-prone.
• For example, glibc in Linux provides protection against free of invalid pointers.
• When using Xcode to target OS X or iOS, enable automatic reference counting (ARC) [REF-391].
• To help correctly and consistently manage memory when programming in C++, consider using a smart pointer class such as std::auto_ptr (defined by ISO/IEC ISO/IEC 14882:2003), std::shared_ptr and std::unique_ptr (specified by an upcoming revision of the C++ standard, informally referred to as C++ 1x), or equivalent solutions such as Boost.

References

• https://git.kernel.org/stable/c/1429ae7b7d4759a1e362456b8911c701bae655b4
• https://git.kernel.org/stable/c/27834971f616c5e154423c578fa95e0444444ce1