vtls: fix CURLOPT_CAPATH use

A regression in curl 8.17.0 led to a customer CAPATH set by the
application (or the curl command) to be ignored unless licurl was built
with a default CAPATH.

Add test cases using `--capath` on the custom pytest CA, generated with
the help of the openssl command when available.

Fixes #19401
Reported-by: Brad King
Closes #19308

lib/vtls/vtls.c

@@ -310,7 +310,6 @@ CURLcode Curl_ssl_easy_config_complete(struct Curl_easy *data)
       if(result)
         return result;
     }
-    sslc->primary.CApath = data->set.str[STRING_SSL_CAPATH];
 #endif
 #ifdef CURL_CA_BUNDLE
     if(!sslc->custom_cafile && !set->str[STRING_SSL_CAFILE]) {
@@ -322,6 +321,7 @@ CURLcode Curl_ssl_easy_config_complete(struct Curl_easy *data)
   }
   sslc->primary.CAfile = data->set.str[STRING_SSL_CAFILE];
   sslc->primary.CRLfile = data->set.str[STRING_SSL_CRLFILE];
+  sslc->primary.CApath = data->set.str[STRING_SSL_CAPATH];
   sslc->primary.issuercert = data->set.str[STRING_SSL_ISSUERCERT];
   sslc->primary.issuercert_blob = data->set.blobs[BLOB_SSL_ISSUERCERT];
   sslc->primary.cipher_list = data->set.str[STRING_SSL_CIPHER_LIST];
@@ -358,7 +358,6 @@ CURLcode Curl_ssl_easy_config_complete(struct Curl_easy *data)
       if(result)
         return result;
     }
-    sslc->primary.CApath = data->set.str[STRING_SSL_CAPATH_PROXY];
 #endif
 #ifdef CURL_CA_BUNDLE
     if(!sslc->custom_cafile && !set->str[STRING_SSL_CAFILE_PROXY]) {
@@ -370,6 +369,7 @@ CURLcode Curl_ssl_easy_config_complete(struct Curl_easy *data)
 #endif
   }
   sslc->primary.CAfile = data->set.str[STRING_SSL_CAFILE_PROXY];
+  sslc->primary.CApath = data->set.str[STRING_SSL_CAPATH_PROXY];
   sslc->primary.cipher_list = data->set.str[STRING_SSL_CIPHER_LIST_PROXY];
   sslc->primary.cipher_list13 = data->set.str[STRING_SSL_CIPHER13_LIST_PROXY];
   sslc->primary.pinned_key = data->set.str[STRING_SSL_PINNEDPUBLICKEY_PROXY];

tests/http/test_17_ssl_use.py

@@ -597,3 +597,29 @@ class TestSSLUse:
         ])
         # expect NOT_IMPLEMENTED or OK
         assert r.exit_code in [0, 2], f'{r.dump_logs()}'
+
+    @pytest.mark.skipif(condition=not Env.have_openssl(), reason="needs openssl command")
+    def test_17_21_capath_valid(self, env: Env, httpd):
+        if env.curl_uses_lib('rustls-ffi'):
+            pytest.skip('rustls does not support CURLOPT_CAPATH')
+        proto = 'http/1.1'
+        curl = CurlClient(env=env)
+        url = f'https://{env.authority_for(env.domain1, proto)}/curltest/sslinfo'
+        r = curl.http_get(url=url, alpn_proto=proto, extra_args=[
+            '--capath', env.ca.hashdir
+        ])
+        assert r.exit_code == 0, f'{r.dump_logs()}'
+        assert r.json['HTTPS'] == 'on', f'{r.json}'
+
+    @pytest.mark.skipif(condition=not Env.have_openssl(), reason="needs openssl command")
+    def test_17_22_capath_invalid(self, env: Env, httpd):
+        # we can test all TLS backends here. the ones not supporting CAPATH
+        # need to fail as well as the ones which do, but get an invalid path.
+        proto = 'http/1.1'
+        curl = CurlClient(env=env)
+        url = f'https://{env.authority_for(env.domain1, proto)}/curltest/sslinfo'
+        r = curl.http_get(url=url, alpn_proto=proto, extra_args=[
+            '--capath', os.path.join(env.gen_dir, 'ca/invalid')
+        ])
+        # CURLE_PEER_FAILED_VERIFICATION or CURLE_SSL_CACERT_BADFILE
+        assert r.exit_code in [60, 77], f'{r.dump_logs()}'

tests/http/testenv/certs.py

@@ -28,6 +28,8 @@ import base64
 import ipaddress
 import os
 import re
+import shutil
+import subprocess
 from datetime import timedelta, datetime, timezone
 from typing import List, Any, Optional
 
@@ -200,6 +202,10 @@ class Credentials:
     def combined_file(self) -> Optional[str]:
         return self._combined_file
 
+    @property
+    def hashdir(self) -> Optional[str]:
+        return os.path.join(self._store.path, 'hashdir')
+
     def get_first(self, name) -> Optional['Credentials']:
         creds = self._store.get_credentials_for_name(name) if self._store else []
         return creds[0] if len(creds) else None
@@ -236,6 +242,16 @@ class Credentials:
             creds.issue_certs(spec.sub_specs, chain=subchain)
         return creds
 
+    def create_hashdir(self, openssl):
+        os.makedirs(self.hashdir, exist_ok=True)
+        p = subprocess.run(args=[
+            openssl, 'x509', '-hash', '-noout', '-in', self.cert_file
+        ], capture_output=True, text=True)
+        if p.returncode != 0:
+            raise Exception(f'openssl failed to compute cert hash: {p}')
+        cert_hname = f'{p.stdout.strip()}.0'
+        shutil.copy(self.cert_file, os.path.join(self.hashdir, cert_hname))
+
 
 class CertStore:
 

tests/http/testenv/curl.py

@@ -987,7 +987,8 @@ class CurlClient:
                 pass
             elif insecure:
                 args.append('--insecure')
-            elif active_options and "--cacert" in active_options:
+            elif active_options and ("--cacert" in active_options or \
+                    "--capath" in active_options):
                 pass
             elif u.hostname:
                 args.extend(["--cacert", self.env.ca.cert_file])

tests/http/testenv/env.py

@@ -199,6 +199,16 @@ class EnvConfig:
             ]),
         ]
 
+        self.openssl = 'openssl'
+        p = subprocess.run(args=[self.openssl, 'version'],
+                           capture_output=True, text=True)
+        if p.returncode != 0:
+            # no openssl in path
+            self.openssl = None
+            self.openssl_version = None
+        else:
+            self.openssl_version = p.stdout.strip()
+
         self.nghttpx = self.config['nghttpx']['nghttpx']
         if len(self.nghttpx.strip()) == 0:
             self.nghttpx = None
@@ -372,6 +382,10 @@ class Env:
     def incomplete_reason() -> Optional[str]:
         return Env.CONFIG.get_incomplete_reason()
 
+    @staticmethod
+    def have_openssl() -> bool:
+        return Env.CONFIG.openssl is not None
+
     @staticmethod
     def have_nghttpx() -> bool:
         return Env.CONFIG.nghttpx is not None
@@ -548,6 +562,8 @@ class Env:
                                               store_dir=ca_dir,
                                               key_type="rsa2048")
                 self._ca.issue_certs(self.CONFIG.cert_specs)
+                if self.have_openssl():
+                    self._ca.create_hashdir(self.openssl)
 
     def setup(self):
         os.makedirs(self.gen_dir, exist_ok=True)
@@ -703,6 +719,10 @@ class Env:
     def curl(self) -> str:
         return self.CONFIG.curl
 
+    @property
+    def openssl(self) -> Optional[str]:
+        return self.CONFIG.openssl
+
     @property
     def httpd(self) -> str:
         return self.CONFIG.httpd