guard malformed attribute in unpackAttributes

[netliomax25-code]

1. unpackAttributes indexes child.Children[1] (the vals SET) and asserts the type and each value to string for every attribute of a SearchResultEntry, without checking the server returned a well-formed PartialAttribute.
2. A non-conforming or malicious server that omits the vals element, or sends a non-string type/value, makes the attribute decode index out of range or fail the assertion, which panics the synchronous Search goroutine and the SearchAsync worker. Neither path has a recover, so the caller process crashes.

Return an error for an attribute that lacks the two expected children or whose type or value is not a string, so the caller can handle it: Search returns it to the caller, SearchAsync delivers it on the result channel as SearchSingleResult.Error. Well-formed entries decode exactly as before. Added a unit test covering the missing-vals and non-string-type cases.

[netliomax25-code]

any update?

[cpuschma]

Discarding the PartialAttribute without throwing an error because of a non-conforming result is undefined behaviour compared to the LDAPv3 RFC. I'd suggest to throw an error instead and allow the user to handle it.

[netliomax25-code]

Makes sense. Pushed a change so unpackAttributes now returns an error for a malformed attribute instead of skipping it:

1. Search returns the error to the caller; SearchAsync delivers it on the result channel as SearchSingleResult.Error.
2. Applied the same treatment to the per-value assertion, so a non-string value also reports an error rather than silently decoding as an empty string.
3. Updated the test to expect errors for the missing-vals and non-string-type cases; go build, go vet and the unit tests pass locally.

[cpuschma]

Same goes here.

[netliomax25-code]

Done here as well, this path returns an error now too.

[netliomax25-code]

gentle ping