Cipher suites configured through WebPkiServerVerifier::builder_with_provider is not working. Client hello contains more cipher suites then it configured. about rustls HOT 6 CLOSED

Thanks cpu , Its working . I have added the crl support at client side also in custom_verifier below to check the revocation status of server cert chain.

let custom_verifier =
    WebPkiServerVerifier::builder_with_provider(server_auth_root.into(), provider.clone())
        **.with_crls(crls.clone())**
        .build()
        .unwrap();

let config = rustls::ClientConfig::builder_with_provider(provider)
    .with_protocol_versions(&[&rustls::version::TLS13])
    .unwrap()
    .with_webpki_verifier(custom_verifier)
    .with_no_client_auth();

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@pranaw215 you can use the custom provider for both -- it's just that you weren't customizing the CryptoProvider used for the ClientConfig (directly) previously which would cause this issue.

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Hi there,

I have configured the cipher suites using below code.
let builder = WebPkiServerVerifier::builder_with_provider(...

The crypto provider used by the WebPkiServerVerifier is not the one that determines the ciphersuites offered in the client hello of a TLS handshake. The verifier's crypto provider cipher_suites are specific to validating the signatures of presented certificate chains. Edit: Sorry, misspoke. This field would be ignored by the verifier, I was thinking of the signature_verification_algorithms.

Try using ClientConfig::builder_with_provider to ensure that the ClientConfig uses the same customized crypto provider. There's a complete example of doing this in limitedclient.rs if that's helpful.

from rustls.

Hi there,

I have configured the cipher suites using below code.
let builder = WebPkiServerVerifier::builder_with_provider(...

The crypto provider used by the WebPkiServerVerifier is not the one that determines the ciphersuites offered in the client hello of a TLS handshake. The verifier's crypto provider cipher_suites are specific to validating the signatures of presented certificate chains. Edit: Sorry, misspoke. This field would be ignored by the verifier, I was thinking of the signature_verification_algorithms.

Try using ClientConfig::builder_with_provider to ensure that the ClientConfig uses the same customized crypto provider. There's a complete example of doing this in limitedclient.rs if that's helpful.

Hi ,

I used [ClientConfig::builder_with_provider] and the configured cipher is working there , But I want the CRL support also.
Can you please point the example where CRL support is also there in the example.

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Can you please point the example where CRL support is also there in the example.

We only have an example using CRLs for verifying client certificates as a server. It looks like you're trying to do the inverse and have a client check revocation status for the server.

Something like this diff to limitedclient.rs should be a good starting point for using a custom provider for both the client config and the verifier:

diff --git a/examples/src/bin/limitedclient.rs b/examples/src/bin/limitedclient.rs
index 62443cae..fcaeafa3 100644
--- a/examples/src/bin/limitedclient.rs
+++ b/examples/src/bin/limitedclient.rs
@@ -2,6 +2,7 @@
 //! so that unused cryptography in rustls can be discarded by the linker.  You can
 //! observe using `nm` that the binary of this program does not contain any AES code.

+use rustls::client::WebPkiServerVerifier;
 use std::io::{stdout, Read, Write};
 use std::net::TcpStream;
 use std::sync::Arc;
@@ -15,18 +16,22 @@ fn main() {
             .cloned(),
     );

-    let config = rustls::ClientConfig::builder_with_provider(
-        CryptoProvider {
-            cipher_suites: vec![provider::cipher_suite::TLS13_CHACHA20_POLY1305_SHA256],
-            kx_groups: vec![provider::kx_group::X25519],
-            ..provider::default_provider()
-        }
-        .into(),
-    )
-    .with_protocol_versions(&[&rustls::version::TLS13])
-    .unwrap()
-    .with_root_certificates(root_store)
-    .with_no_client_auth();
+    let provider = Arc::new(CryptoProvider {
+        cipher_suites: vec![provider::cipher_suite::TLS13_CHACHA20_POLY1305_SHA256],
+        kx_groups: vec![provider::kx_group::X25519],
+        ..provider::default_provider()
+    });
+
+    let custom_verifier =
+        WebPkiServerVerifier::builder_with_provider(root_store.into(), provider.clone())
+            .build()
+            .unwrap();
+
+    let config = rustls::ClientConfig::builder_with_provider(provider)
+        .with_protocol_versions(&[&rustls::version::TLS13])
+        .unwrap()
+        .with_webpki_verifier(custom_verifier)
+        .with_no_client_auth();

     let server_name = "www.rust-lang.org".try_into().unwrap();
     let mut conn = rustls::ClientConnection::new(Arc::new(config), server_name).unwrap();

from rustls.

I'm going to close this since we've figured out the problem causing the unexpected cipher suites in the hello. If you have any further questions feel free to comment or open a new issue.

Thanks!

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