Critical What were you trying to do that didn't work?
curl doesn't follow system-wide crypto policy regarding allowed TLS version.
What is the impact of this issue to you?
The issue affects RHEL 10.0 Common Criteria certification.
Please provide the package NVR for which the bug is seen:
RHEL 10.0 RPMs:
libcurl-8.9.1-5.el10.x86_64 curl-8.9.1-5.el10.x86_64
The same issue also impacts RHEL 10.1:
libcurl-8.12.1-2.el10.x86_64 curl-8.12.1-2.el10.x86_64
RHEL 9.6:
libcurl-7.76.1-31.el9.x86_64 curl-7.76.1-31.el9.x86_64
and RHEL 9.7:
libcurl-7.76.1-34.el9.x86_64 curl-7.76.1-34.el9.x86_64
On RHEL 9.4 this is not an issue and it has the following curl versions:
libcurl-7.76.1-29.el9_4.x86_64 curl-7.76.1-29.el9_4.x86_64
How reproducible is this bug?:
deterministic
Steps to reproduce
- Modify system-wide crypto policy to FIPS:OSPP (which only allows TLS 1.2 connections):
# update-crypto-policies --set FIPS:OSPP # grep -E "^TLS\.(Min|Max)Protocol" /etc/crypto-policies/back-ends/opensslcnf.config TLS.MinProtocol = TLSv1.2 TLS.MaxProtocol = TLSv1.2
- Generate certificates and run openssl s_server to test TLS connections:
# openssl req -x509 -newkey rsa:3072 -nodes -keyout key.pem -out cert.pem -days 1 -subj "/CN=localhost" # openssl s_server -accept 8443 -cert cert.pem -key key.pem -cipher 'DHE-RSA-AES256-GCM-SHA384' -www
- In other terminal window on the same system try to connect to the s_server and observe that curl performs TLS 1.3 connection and then errors out since there are no TLS 1.3 ciphersuites enabled:
# curl -vk https://localhost:8443 * Host localhost:8443 was resolved. * IPv6: ::1 * IPv4: 127.0.0.1 * Trying [::1]:8443... * Connected to localhost (::1) port 8443 * ALPN: curl offers h2,http/1.1 * TLSv1.3 (OUT), TLS alert, internal error (592): * OpenSSL/3.2.2: error:0A0000B5:SSL routines::no ciphers available * closing connection #0 curl: (35) OpenSSL/3.2.2: error:0A0000B5:SSL routines::no ciphers available # echo $? 35Note: Forcing curl to use TLS 1.2 or using DEFAULT crypto policy works, e.g.:
# curl -vk --tlsv1.2 --tls-max 1.2 https://localhost:8443 * Host localhost:8443 was resolved. * IPv6: ::1 * IPv4: 127.0.0.1 * Trying [::1]:8443... * Connected to localhost (::1) port 8443 * ALPN: curl offers h2,http/1.1 * TLSv1.2 (OUT), TLS handshake, Client hello (1): * TLSv1.2 (IN), TLS handshake, Server hello (2): * TLSv1.2 (IN), TLS handshake, Certificate (11): * TLSv1.2 (IN), TLS handshake, Server key exchange (12): * TLSv1.2 (IN), TLS handshake, Server finished (14): * TLSv1.2 (OUT), TLS handshake, Client key exchange (16): * TLSv1.2 (OUT), TLS change cipher, Change cipher spec (1): * TLSv1.2 (OUT), TLS handshake, Finished (20): * TLSv1.2 (IN), TLS handshake, Finished (20): * SSL connection using TLSv1.2 / DHE-RSA-AES256-GCM-SHA384 / [blank] / RSASSA-PSS * ALPN: server did not agree on a protocol. Uses default. * Server certificate: * subject: CN=localhost * start date: Oct 8 07:47:08 2025 GMT * expire date: Oct 9 07:47:08 2025 GMT * issuer: CN=localhost * SSL certificate verify result: self-signed certificate (18), continuing anyway. * Certificate level 0: Public key type RSA (3072/128 Bits/secBits), signed using sha256WithRSAEncryption * using HTTP/1.x > GET / HTTP/1.1 > Host: localhost:8443 > User-Agent: curl/8.9.1 > Accept: */* > * Request completely sent off * HTTP 1.0, assume close after body < HTTP/1.0 200 ok < Content-type: text/html < <HTML><BODY BGCOLOR="#ffffff"> <pre> s_server -accept 8443 -cert cert.pem -key key.pem -cipher DHE-RSA-AES256-GCM-SHA384 -www Secure Renegotiation IS supported Ciphers supported in s_server binary TLSv1.2 :DHE-RSA-AES256-GCM-SHA384 — Ciphers common between both SSL end points: DHE-RSA-AES256-GCM-SHA384 Signature Algorithms: ECDSA+SHA384:ECDSA+SHA512:RSA-PSS+SHA256:RSA-PSS+SHA384:RSA-PSS+SHA512:RSA-PSS+SHA256:RSA-PSS+SHA384:RSA-PSS+SHA512:RSA+SHA256:RSA+SHA384:RSA+SHA512 Shared Signature Algorithms: ECDSA+SHA384:ECDSA+SHA512:RSA-PSS+SHA256:RSA-PSS+SHA384:RSA-PSS+SHA512:RSA-PSS+SHA256:RSA-PSS+SHA384:RSA-PSS+SHA512:RSA+SHA256:RSA+SHA384:RSA+SHA512 Supported groups: secp521r1:secp384r1 Shared groups: secp521r1:secp384r1 — New, TLSv1.2, Cipher is DHE-RSA-AES256-GCM-SHA384 SSL-Session: Protocol : TLSv1.2 Cipher : DHE-RSA-AES256-GCM-SHA384 Session-ID: 90E5C366E895D31A9AEE0EF514980097FEFA6CB05355E4487E596B4D0C021D11 Session-ID-ctx: 01000000 Master-Key: 2366F7A7B4DC96F19CB6F9B03E990BE936E8301BA2807AA441483319677FBA9A554324A76140DE3E3A061C13AB8950E1 PSK identity: None PSK identity hint: None SRP username: None Start Time: 1759916424 Timeout : 7200 (sec) Verify return code: 0 (ok) Extended master secret: yes — 1 items in the session cache 0 client connects (SSL_connect()) 0 client renegotiates (SSL_connect()) 0 client connects that finished 2 server accepts (SSL_accept()) 0 server renegotiates (SSL_accept()) 1 server accepts that finished 0 session cache hits 0 session cache misses 0 session cache timeouts 0 callback cache hits 0 cache full overflows (128 allowed) — no client certificate available </pre></BODY></HTML> * TLSv1.2 (IN), TLS alert, close notify (256): * shutting down connection #0 * TLSv1.2 (OUT), TLS alert, close notify (256): # echo $? 0
Also using s_client works without any issues:
# openssl s_client -connect localhost:8443
Expected results
curl connects to the server and uses TLS 1.2 protocol as required by the system-wide crypto policy.
Actual results
curl fails to connect to the server and uses TLS 1.3 protocol even though the system-wide crypto policy requires TLS 1.2 to be used.
