If I am using a Apache to verify the client certificate and the client certificate is invalid (e.g. revoked) than I can get the appropriate SSL/TLS alert which can be evaluated by the client:


curl -v --insecure --cert cert.pem --key key.pem --cacert ca.pem https://127.0.0.1:443/1/config
* Expire in 0 ms for 6 (transfer 0x5611097bcfb0)
* Trying 127.0.0.1...
* TCP_NODELAY set
* Expire in 200 ms for 4 (transfer 0x5611097bcfb0)
* Connected to 127.0.0.1 (127.0.0.1) port 443 (#0)
* ALPN, offering h2
* ALPN, offering http/1.1
* successfully set certificate verify locations:
* CAfile: ca.pem
CApath: /etc/ssl/certs
* TLSv1.3 (OUT), TLS handshake, Client hello (1):
* TLSv1.3 (IN), TLS handshake, Server hello (2):
* TLSv1.3 (IN), TLS handshake, Encrypted Extensions (8):
* TLSv1.3 (IN), TLS handshake, Request CERT (13):
* TLSv1.3 (IN), TLS handshake, Certificate (11):
* TLSv1.3 (IN), TLS handshake, CERT verify (15):
* TLSv1.3 (IN), TLS handshake, Finished (20):
* TLSv1.3 (OUT), TLS change cipher, Change cipher spec (1):
* TLSv1.3 (OUT), TLS handshake, Certificate (11):
* TLSv1.3 (OUT), TLS handshake, CERT verify (15):
* TLSv1.3 (OUT), TLS handshake, Finished (20):
* SSL connection using TLSv1.3 / TLS_AES_256_GCM_SHA384
* ALPN, server accepted to use http/1.1
* Server certificate:
* subject: C=ZZ; ST=YY; L=Duckburg; O=McDuck LLC.; OU=moneybin; CN=moneybin.example.com
* start date: Jan 1 01:02:03 2021 UTC
* expire date: Jan 1 01:02:03 2022 UTC
* issuer: C=ZZ; ST=YY; L=Duckburg; O=McDuck LLC.; CN=Scrooge CA
* SSL certificate verify result: unable to get local issuer certificate (20), continuing anyway.
> GET /1/config HTTP/1.1
> Host: 127.0.0.1
> User-Agent: curl/7.64.0
> Accept: */*
>
* TLSv1.3 (IN), TLS alert, certificate revoked (556):
* OpenSSL SSL_read: error:14094414:SSL routines:ssl3_read_bytes:sslv3 alert certificate revoked, errno 0
* Closing connection 0
curl: (56) OpenSSL SSL_read: error:14094414:SSL routines:ssl3_read_bytes:sslv3 alert certificate revoked, errno 0



This is awesome because the (API) client can evaluate this information and start the correct actions based on that information. But for ningx (with the default configuration), I only get a generic error when the SSL certificate is revoked:


curl -v --insecure --cert cert.pem --key key.pem --cacert ca.pem https://127.0.0.1:443/1/config
* Expire in 0 ms for 6 (transfer 0x5611097bcfb0)
* Trying 127.0.0.1...
* TCP_NODELAY set
* Expire in 200 ms for 4 (transfer 0x5611097bcfb0)
* Connected to 127.0.0.1 (127.0.0.1) port 443 (#0)
* ALPN, offering h2
* ALPN, offering http/1.1
* successfully set certificate verify locations:
* CAfile: ca.pem
CApath: /etc/ssl/certs
* TLSv1.3 (OUT), TLS handshake, Client hello (1):
* TLSv1.3 (IN), TLS handshake, Server hello (2):
* TLSv1.3 (IN), TLS handshake, Encrypted Extensions (8):
* TLSv1.3 (IN), TLS handshake, Request CERT (13):
* TLSv1.3 (IN), TLS handshake, Certificate (11):
* TLSv1.3 (IN), TLS handshake, CERT verify (15):
* TLSv1.3 (IN), TLS handshake, Finished (20):
* TLSv1.3 (OUT), TLS change cipher, Change cipher spec (1):
* TLSv1.3 (OUT), TLS handshake, Certificate (11):
* TLSv1.3 (OUT), TLS handshake, CERT verify (15):
* TLSv1.3 (OUT), TLS handshake, Finished (20):
* SSL connection using TLSv1.3 / TLS_AES_256_GCM_SHA384
* ALPN, server accepted to use h2
* Server certificate:
* subject: C=ZZ; ST=YY; L=Duckburg; O=McDuck LLC.; OU=moneybin; CN=moneybin.example.com
* start date: Jan 1 01:02:03 2021 UTC
* expire date: Jan 1 01:02:03 2022 UTC
* issuer: C=ZZ; ST=YY; L=Duckburg; O=McDuck LLC.; CN=Scrooge CA
* SSL certificate verify result: unable to get local issuer certificate (20), continuing anyway.
* Using HTTP2, server supports multi-use
* Connection state changed (HTTP/2 confirmed)
* Copying HTTP/2 data in stream buffer to connection buffer after upgrade: len=0
* Using Stream ID: 1 (easy handle 0x5611097bcfb0)
> GET /1/config HTTP/2
> Host: 127.0.0.1:443
> User-Agent: curl/7.64.0
> Accept: */*
>
* TLSv1.3 (IN), TLS handshake, Newsession Ticket (4):
* TLSv1.3 (IN), TLS handshake, Newsession Ticket (4):
* old SSL session ID is stale, removing
* Connection state changed (MAX_CONCURRENT_STREAMS == 128)!
< HTTP/2 400
< server: nginx
< date: Tue, 02 Mar 2021 07:54:36 GMT
< content-type: text/html
< content-length: 224
< strict-transport-security: max-age=63072000; includeSubDomains; preload
<
<html>
<head><title>400 The SSL certificate error</title></head>
<body bgcolor="white">
<center><h1>400 Bad Request</h1></center>
<center>The SSL certificate error</center>
<hr><center>nginx</center>
</body>
</html>
* Connection #0 to host 127.0.0.1 left intact



How can I force nginx also to report the client certificate error via the TLS alert mechanisms instead of this useless HTML page?

---

Here is the nginx site configuration as reference:

server {
listen 443 ssl http2 default_server;

error_log /var/log/nginx/moneybin_error.log;
access_log /var/log/nginx/moneybin_access.log;

ssl_certificate /some/path/to/certs/fullchain.pem;
ssl_certificate_key /some/path/to/certs/privkey.pem;
ssl_client_certificate /some/path/to/certs/ca.pem;
ssl_trusted_certificate /some/path/to/certs/ca.pem;
ssl_crl /some/path/to/certs/crl.pem;
ssl_session_timeout 1d;
ssl_session_cache off;
ssl_session_tickets off;

# intermediate configuration
ssl_protocols TLSv1.2 TLSv1.3;
ssl_ciphers ECDHE-ECDSA-AES128-GCM-SHA256:ECDHE-RSA-AES128-GCM-SHA256:ECDHE-ECDSA-AES256-GCM-SHA384:ECDHE-RSA-AES256-GCM-SHA384:ECDHE-ECDSA-CHACHA20-POLY1305:ECDHE-RSA-CHACHA20-POLY1305:DHE-RSA-AES128-GCM-SHA256:DHE-RSA-AES256-GCM-SHA384;
ssl_prefer_server_ciphers off;
ssl_verify_client optional;
ssl_verify_depth 2;

root /var/www/moneybin;

server_name _;

location / {
fastcgi_param HTTP_PROXY "";
fastcgi_pass unix:/var/run/php/php7.3-fpm.sock;
fastcgi_index index.php;
include fastcgi_params;
fastcgi_param SCRIPT_FILENAME /var/www/moneybin/index.php;
}
}