Description:
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Per RFC 4514, leading/trailing spaces should be escaped for a DN. Additionally, carriage returns should also be escaped. Currently the ldap_escape method does not doe this. I verified (in Active Directory anyway) that this really is the case, as LDAP refuses to add a LDAP object with a DN passed through the ldap_escape method with a DN flag set when it contains any of the mentioned cases.

https://www.ietf.org/rfc/rfc4514.txt

Test script:
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var_dump(ldap_escape(" Joe,= \rSmith ", null, LDAP_ESCAPE_DN));

Expected result:
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It should output:

'\20Joe\2c\3d \0dSmith\20'

Actual result:
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Currently outputs:

" Joe\2c\3d \rSmith "