Gorilla Websocket Package with Go 1.24 FIPS 140-3

[juburr]

I'm leaving a quick note here for searchability in case anyone else encounters this issue.

My team reported to me that the SHA1 call from this package throws a panic when the new FIPS module from Go 1.24 is enabled. More specifically, h := sha1.New() still seems to work, as does h.Write(...), but the call to h.Sum(...) will panic.

The solution is to change GODEBUG=fips140=only to GODEBUG=fips140=on. I'm not sure if there's a better long-term solution for those with more stringent compliance requirements.

It seems that RFC-6455 requires the use of SHA-1 to calculate the Sec-Websocket-Accept header, creating a conflict if you want to disallow all functions that aren't FIPS compliant. My understanding is that its use in this context is purely a protocol requirement though, not a cryptographic security feature -- i.e., there's nothing inherently insecure about its use here in the gorilla/websocket package. However, fips140=only mode will cause a panic when SHA-1 is called, regardless of the non-security context.