LDAP Bad search filter (-7) error when CN has a comma in it (fix included)

[drewferagen]

So I ran into an issue with this auth module. When the user logging in has a CN with a comma aka CN="Lastname, Firstname" the result returns it escaped like CN="Lastname\, Firstname"

Now when the group filter is created it has a slash in there, but to work it needs a \5c instead, which is the ascii for \, I modified the source to change that character in the userdn and it started working for me.

I attached my code change, you will probably want to rewrite it, I am not very experienced in C.
diff.txt

[nskalis]

Thank you for this. I tried your way, but unfortunately it didn't work for me.
Do you mind checking for any diff between my version and yours ?
Please find it attached.
ngx_http_auth_ldap_module.c.zip

[drewferagen]

I checked and that code matches the changes that I had made. I compiled my nginx with debug turned on and set up the error_log to debug.

Before I Would get the search error and now with the changes I made I get this:
2019/10/24 09:24:57 [debug] 3386#0: *58 http_auth_ldap: Search group filter is "(&(cn=ldapgroup)(member=CN=Feragen\5c, Andrew,OU=Users,OU=User Accounts,DC=domain,DC=org))"
2019/10/24 09:24:57 [debug] 3386#0: *58 http_auth_ldap: ldap_search_ext() -> msgid=3

Before at the group search phase it would have a \ instead of \5c and fail with a -7 error.

When testing I did a ldapsearch command with that same filter. I suggest turning on debugging and see what filter it was using when it fails and try to replicate the search with ldapsearch and see what is broken with it?