IPFS go-unixfsnode subject to DOS via HAMT Decoding Panics

Impact

Trying to read malformed HAMT sharded directories can cause panics and virtual memory leaks.
If you are reading untrusted user input, an attacker can then trigger a panic.

This is caused by a bogus fanout parameter in the HAMT directory nodes.
This includes checks returned in ipfs/go-bitfield GHSA-2h6c-j3gf-xp9r, as well as limiting the fanout to <= 1024 (to avoid attempts of arbitrary sized allocations).

Patches

• https://github.com/ipfs/go-unixfsnode/commit/91b3d39d33ef0cd2aff2c95d50b2329350944b68
• https://github.com/ipfs/go-unixfsnode/commit/a4ed723727e0bdc2277158337c2fc0d82802d122

References

• https://github.com/ipfs/go-unixfs/security/advisories/GHSA-q264-w97q-q778
• https://github.com/ipfs/go-bitfield/security/advisories/GHSA-2h6c-j3gf-xp9r