id	summary	reporter	owner	description	type	status	priority	milestone	component	version	resolution	keywords	cc	uname	nginx_version
2463	ssl_reject_handshake allows some connections through	thestinger@…		"We've noticed a small number of connections somehow making it past ssl_reject_handshake.

This is an example caused by a censys.io bot scanning the whole IPv4 space:

{{{
Mar 05 14:32:59 0-network nginx[47606]: 2023/03/05 14:32:59 [error] 47606#47606: *4121615 directory index of ""/var/empty/"" is forbidden, client: 167.248.133.117, server: , request: ""GET / HTTP/1.1"", host: ""51.79.54.68:443""
Mar 05 14:32:59 0-network nginx[47606]: 4121615 167.248.133.117 - TLSv1.3 HTTP/1.1 51.79.54.68 GET ""/"" 403 41 146/304 0.000 ""-"" ""-""
}}}

We mostly see this happening with these bots scanning for vulnerabilities. I expect that it's easy enough to replicate by just having a server with a similar configuration with a public IPv4 address.

If I run `curl https://51.79.54.68/ --http1.1` myself, I get the expected `tlsv1 unrecognized name` error. I've also tried `openssl s_client -connect 51.79.54.68:443` and `gnutls-cli 51.79.54.68:443`. No luck bypassing ssl_reject_handshake myself.

    server {
        listen 443 default_server ssl backlog=4096;
        listen [::]:443 default_server ssl backlog=4096;
        ssl_reject_handshake on;
    }

This issue is happening across each of our sites. Here's one of the configurations, corresponding to the server with the logs above:

https://github.com/GrapheneOS/grapheneos.network/blob/main/nginx/nginx.conf

We have much simpler configurations without any use of proxy_pass, etc. where this is happening too.

I'm guessing that most people are not using nginx with OpenSSL 3.x yet and that it's an OpenSSL 3.x bug or compatibility issue. I don't know enough about how nginx implements this feature to know if the bug is in nginx or OpenSSL."	defect	closed	minor		nginx-core	1.21.x	invalid			Linux 0-network 6.1.14-1-lts #1 SMP PREEMPT_DYNAMIC Sat, 25 Feb 2023 11:02:38 +0000 x86_64 GNU/Linux	"nginx version: nginx/1.22.1
built with OpenSSL 3.0.7 1 Nov 2022 (running with OpenSSL 3.0.8 7 Feb 2023)
TLS SNI support enabled
configure arguments: --prefix=/etc/nginx --conf-path=/etc/nginx/nginx.conf --sbin-path=/usr/bin/nginx --pid-path=/run/nginx.pid --lock-path=/run/lock/nginx.lock --user=http --group=http --http-log-path=/var/log/nginx/access.log --error-log-path=stderr --http-client-body-temp-path=/var/lib/nginx/client-body --http-proxy-temp-path=/var/lib/nginx/proxy --http-fastcgi-temp-path=/var/lib/nginx/fastcgi --http-scgi-temp-path=/var/lib/nginx/scgi --http-uwsgi-temp-path=/var/lib/nginx/uwsgi --with-cc-opt='-march=x86-64 -mtune=generic -O2 -pipe -fno-plt -fexceptions -Wp,-D_FORTIFY_SOURCE=2 -Wformat -Werror=format-security -fstack-clash-protection -fcf-protection -flto=auto' --with-ld-opt='-Wl,-O1,--sort-common,--as-needed,-z,relro,-z,now -flto=auto' --with-compat --with-debug --with-file-aio --with-http_addition_module --with-http_auth_request_module --with-http_dav_module --with-http_degradation_module --with-http_flv_module --with-http_geoip_module --with-http_gunzip_module --with-http_gzip_static_module --with-http_mp4_module --with-http_realip_module --with-http_secure_link_module --with-http_slice_module --with-http_ssl_module --with-http_stub_status_module --with-http_sub_module --with-http_v2_module --with-mail --with-mail_ssl_module --with-pcre-jit --with-stream --with-stream_geoip_module --with-stream_realip_module --with-stream_ssl_module --with-stream_ssl_preread_module --with-threads"