Search unable to handle filter strings with special characters (parenthesis, plus, etc) in the DN

[AlaricWhitney]

Search is unable to handle DN filter strings that contain special characters. Example:

searchRequest := NewSearchRequest(
	"DC=example,DC=foo,DC=bar",
        ScopeWholeSubtree, NeverDerefAliases, 0, 0, false,
	`(&(objectCategory=group)(objectClass=group)(memberOf=CN=Main\+,OU=Groups,DC=example,DC=foo,DC=bar))`,
	[]string{"dn", "cn"},
	nil,
)

(error: LDAP Result Code 201 "Filter Compile Error": ldap: invalid characters for escape in filter: encoding/hex: invalid byte: U+002B '+')

Another example:
(&(objectCategory=group)(objectClass=group)(memberOf=CN=Main (Example),OU=Groups,DC=example,DC=foo,DC=bar))
(error: LDAP Result Code 201 "Filter Compile Error": ldap: finished compiling filter with extra at end: OU=Groups,DC=example,DC=foo,DC=bar))

I have discovered that the CompileFilter does not process the filter string correctly, and requires the special characters to be converted to \xx hex values of the ascii characters first.

Example:
(&(objectCategory=group)(objectClass=group)(memberOf=CN=Main\+,OU=Groups,DC=example,DC=foo,DC=bar)) needs to be converted to (&(objectCategory=group)(objectClass=group)(memberOf=CN=Main\5c\2b,OU=Groups,DC=example,DC=foo,DC=bar))

(&(objectCategory=group)(objectClass=group)(memberOf=CN=Main (Example),OU=Groups,DC=example,DC=foo,DC=bar)) needs to be converted to (&(objectCategory=group)(objectClass=group)(memberOf=CN=Main \28Example\29,OU=Groups,DC=example,DC=foo,DC=bar))

I would suggest that a parsing method be added to convert special characters within a DN search string to hex values within the CompileFilter method.

[AlaricWhitney]

I've submitted a PR to address the issues mentioned.

[vetinari]

please check #338 (comment)