Limit OpenSSL TLS Session cache for client SSL_CTX instances #110154
+9
−3
Conversation
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
|
@wfurt we've talked about this recently, so I put it up lest I forget, but this change might not be as useful once we figure out the bug causing the "leak" in the linked issue. |
wfurt
reviewed
Nov 25, 2024
| private const string TlsCacheSizeCtxName = "System.Net.Security.TlsCacheSize"; | ||
| private const string TlsCacheSizeEnvironmentVariable = "DOTNET_SYSTEM_NET_SECURITY_TLSCACHESIZE"; | ||
| private const int DefaultTlsCacheSizeClient = 500; // since we keep only one TLS Session per hostname, 500 should be enough to cover most scenarios | ||
| private const int DefaultTlsCacheSizeServer = -1; // use implementation default |
There was a problem hiding this comment.
if we have two different values I'm wondering if we should also split the variables...? The 500 for client seems like good default to me.
There was a problem hiding this comment.
I thought about that as well, but we either would have to
- rename the existing configuration knob (which could be argued to be a breaking change)
- introduce two more knobs to kontrol client/server separately
- introduce one new with a server/client suffix and reuse the existing one for the other role
and neither of the above is a clear winner so I wanted to not complicate things needlessly.
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
Add this suggestion to a batch that can be applied as a single commit.
This suggestion is invalid because no changes were made to the code.
Suggestions cannot be applied while the pull request is closed.
Suggestions cannot be applied while viewing a subset of changes.
Only one suggestion per line can be applied in a batch.
Add this suggestion to a batch that can be applied as a single commit.
Applying suggestions on deleted lines is not supported.
You must change the existing code in this line in order to create a valid suggestion.
Outdated suggestions cannot be applied.
This suggestion has been applied or marked resolved.
Suggestions cannot be applied from pending reviews.
Suggestions cannot be applied on multi-line comments.
Suggestions cannot be applied while the pull request is queued to merge.
Suggestion cannot be applied right now. Please check back later.
This pull request limits the OpenSSL TLS Session cache for client SSL_CTX instances to 500, which should be enough for most use cases and should save some memory resources for clients.
Exceptional use cases (web scrapers?) can increase the cache size via AppCtx switch or environmental variable.
We should still investigate issues like #109600 to make sure we are not needlessly overpopulating the sessions cache.