fernet_verify_token() should do DN case insensitive compare

[mreynolds389]

Issue Description

In lib.rs fernet_verify_token() does an exact DN case comparison and in some scenarios this breaks down and returns invalid credentials when the case of the DN is different than what is in the token.

[mreynolds389]

One solution is to do:

diff --git a/src/librnsslapd/src/lib.rs b/src/librnsslapd/src/lib.rs
index 2085bb7ad..2f730f6d6 100644
--- a/src/librnsslapd/src/lib.rs
+++ b/src/librnsslapd/src/lib.rs
@@ -58,7 +58,7 @@ pub extern "C" fn fernet_verify_token(
             match slapd::fernet::decrypt(&inst, c_str_token, ttl) {
                 Ok(val) => {
                     // Finally check if the extracted dn is what we expect
-                    val.as_c_str() == c_str_dn
+                    val.as_c_str().to_str().unwrap().to_lowercase() == c_str_dn.to_str().unwrap().to_lowercase()
                 }
                 Err(_) => false,
             }

I'm not familiar enough with Rust/SSO token design to know if this is the best approach or not.

[progier389]

Not sure either but I wonder if we should perform a full dn compare rather than a case insensitive string compare