Single threaded CRYPTO_secure_malloc implementation is bottleneck in busy servers
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- Dominant language
- C
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Description
On OpenSSL 3.1.4, 2.90% of context switches in our HTTP server are due to locking and freeing the secure_memory_lock, as this is used by all the HMAC operations in deriving the TLS keys. This measurement is for TLS 1.2.
It might be worth considering if secure_malloc, vs telling people to use encrypted swap, is worth it. Alternatively an implementation that doesn't require a single global lock should be considered, or reexamining the use in the tls1_PRF function.
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Research direction
Start by tracing CRYPTO_secure_malloc, secure_memory_lock, and the tls1_PRF use described in the report, then measure their locking and freeing behavior under busy TLS 1.2 server workloads. Done would require a decided approach to avoid the single global-lock bottleneck and benchmark evidence showing whether it improves the reported context-switch overhead without weakening secure-memory behavior.
Written by the indexing model from the issue text.
Assessment
- Tech stack
- c
- Domain
- cryptography, performance
- Issue type
- Refactor
- Difficulty
- 5/5
- Estimated time
- Over a week
- Activity status
- Stale
- Clarity
- Needs clarification
- Newbie friendliness
- 25/100