CVE-2024-57947

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

netfilter: nf_set_pipapo: fix initial map fill

The initial buffer has to be inited to all-ones, but it must restrict it to the size of the first field, not the total field size.

After each round in the map search step, the result and the fill map are swapped, so if we have a set where f->bsize of the first element is smaller than m->bsize_max, those one-bits are leaked into future rounds result map.

This makes pipapo find an incorrect matching results for sets where first field size is not the largest.

Followup patch adds a test case to nft_concat_range.sh selftest script.

Thanks to Stefano Brivio for pointing out that we need to zero out the remainder explicitly, only correcting memset() argument isnt enough.

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/69b6a67f7052905e928d75a0c5871de50e686986
• https://git.kernel.org/stable/c/791a615b7ad2258c560f91852be54b0480837c93
• https://git.kernel.org/stable/c/8058c88ac0df21239daee54b5934d5c80ca9685f
• https://git.kernel.org/stable/c/957a4d1c4c5849e4515c9fb4db21bf85318103dc
• https://git.kernel.org/stable/c/9625c46ce6fd4f922595a4b32b1de5066d70464f