Deprecate AcceptInvalidHostnames option

Rustls does not offer a documented way to accept valid certificates with
invalid hostnames. Implementation of certificate verification in Rustls
does not have a public API and reimplementing it is error-prone.

deltachat-ffi/deltachat.h

@@ -4050,11 +4050,6 @@ int64_t          dc_lot_get_timestamp     (const dc_lot_t* lot);
  */
 #define DC_CERTCK_STRICT 1
 
-/**
- * Accept invalid hostnames, but not invalid certificates.
- */
-#define DC_CERTCK_ACCEPT_INVALID_HOSTNAMES 2
-
 /**
  * Accept invalid certificates, including self-signed ones
  * or having incorrect hostname.

python/src/deltachat/const.py

@@ -68,7 +68,6 @@ DC_LP_SMTP_SOCKET_SSL = 0x20000
 DC_LP_SMTP_SOCKET_PLAIN = 0x40000
 DC_CERTCK_AUTO = 0
 DC_CERTCK_STRICT = 1
-DC_CERTCK_ACCEPT_INVALID_HOSTNAMES = 2
 DC_CERTCK_ACCEPT_INVALID_CERTIFICATES = 3
 DC_EMPTY_MVBOX = 0x01
 DC_EMPTY_INBOX = 0x02

src/login_param.rs

@@ -16,7 +16,11 @@ use webpki_roots;
 pub enum CertificateChecks {
     Automatic = 0,
     Strict = 1,
-    AcceptInvalidHostnames = 2,
+
+    /// Same as AcceptInvalidCertificates
+    /// Previously known as AcceptInvalidHostnames, now deprecated.
+    AcceptInvalidCertificates2 = 2,
+
     AcceptInvalidCertificates = 3,
 }
 
@@ -288,14 +292,8 @@ pub fn dc_build_tls_config(certificate_checks: CertificateChecks) -> rustls::Cli
                 .dangerous()
                 .set_certificate_verifier(Arc::new(NoCertificateVerification {}));
         }
-        CertificateChecks::AcceptInvalidCertificates => {
+        CertificateChecks::AcceptInvalidCertificates
-            // TODO: only accept invalid certs
+        | CertificateChecks::AcceptInvalidCertificates2 => {
-            config
-                .dangerous()
-                .set_certificate_verifier(Arc::new(NoCertificateVerification {}));
-        }
-        CertificateChecks::AcceptInvalidHostnames => {
-            // TODO: only accept invalid hostnames
             config
                 .dangerous()
                 .set_certificate_verifier(Arc::new(NoCertificateVerification {}));
@@ -313,8 +311,8 @@ mod tests {
         use std::string::ToString;
 
         assert_eq!(
-            "accept_invalid_hostnames".to_string(),
+            "accept_invalid_certificates".to_string(),
-            CertificateChecks::AcceptInvalidHostnames.to_string()
+            CertificateChecks::AcceptInvalidCertificates.to_string()
         );
     }
 }