CVE-2021-47105

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

ice: xsk: return xsk buffers back to pool when cleaning the ring

Currently we only NULL the xdp_buff pointer in the internal SW ring but we never give it back to the xsk buffer pool. This means that buffers can be leaked out of the buff pool and never be used again.

Add missing xsk_buff_free() call to the routine that is supposed to clean the entries that are left in the ring so that these buffers in the umem can be used by other sockets.

Also, only go through the space that is actually left to be cleaned instead of a whole ring.

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/ad6d20da2cfbe14b7b1200d15f39e65988b0b9e8
• https://git.kernel.org/stable/c/afe8a3ba85ec2a6b6849367e25c06a2f8e0ddd05
• https://git.kernel.org/stable/c/ad6d20da2cfbe14b7b1200d15f39e65988b0b9e8
• https://git.kernel.org/stable/c/afe8a3ba85ec2a6b6849367e25c06a2f8e0ddd05