[release/10.0.1xx-preview1] Fix array length Fixes #45632 #46654
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| @@ -27,7 +27,7 @@ public static Guid Create(string name) | |||
| Array.Copy(namespaceBytes, streamToHash, namespaceBytes.Length); | |||
| Array.Copy(nameBytes, 0, streamToHash, namespaceBytes.Length, nameBytes.Length); | |||
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| var hashResult = XxHash3.Hash(streamToHash); // This is just used for generating a named pipe so we don't need a cryptographic hash | |||
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nit: Debug.Assert(hashResult.Length >= 16);
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I don't dislike this, but I'd rather keep this small. Maybe add this to the main-targeted PR?
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Fixes #45632
Description and impact
#42775 changed the hash function we used from one that generates a 64-byte hash to one that generates an 8-byte hash. We were only actually using 16 bytes of the hash, but 16 bytes of an 8-byte hash is a source array not long enough error. This upgrades to a 16-byte hash from the same hash family.
This hash function doesn't need to be cryptographically secure since it's just used for a named pipe we use for elevation. Without this change, a user with an MSI-based SDK installation who creates a non-admin command prompt then tries to run (almost) any workload command will be prompted to elevate as expected, but regardless of what they respond, it will then fail. The only workaround is to create an admin prompt or use a file-based installation.
Regression
Yes - changing a hash function to a more secure one (even though we don't use it for security) caused this.
Risk
Low – This changes which hash function we use, but we use one from the same family.
Testing
I was able to reproduce the bug first as described then using my custom-built SDK. I made this change then tried to reproduce it again and failed. Here's the side-by-side version of failure then success:
I have pushed this change to our internal repo and started a build. When that finishes, I will install it just to verify again that this problem is properly resolved.