http: Fix proxy connection reuse with basic-auth

When using basic-auth, connections and proxy connections
can be re-used with different Authorization headers since
it does not authenticate the connection (like NTLM does).

For instance, the below command should re-use the proxy
connection, but it currently doesn't:
curl -v -U alice:a -x http://localhost:8181 http://localhost/
  --next -U bob:b -x http://localhost:8181 http://localhost/

This is a regression since refactoring of ConnectionExists()
as part of: cb4e2be7c6d42ca0780f8e0a747cecf9ba45f151

Fix the above by removing the username and password compare
when re-using proxy connection at proxy_info_matches().

However, this fix brings back another bug would make curl
to re-print the old proxy-authorization header of previous
proxy basic-auth connection because it wasn't cleared.

For instance, in the below command the second request should
fail if the proxy requires authentication, but would succeed
after the above fix (and before aforementioned commit):
curl -v -U alice:a -x http://localhost:8181 http://localhost/
  --next -x http://localhost:8181 http://localhost/

Fix this by clearing conn->allocptr.proxyuserpwd after use
unconditionally, same as we do for conn->allocptr.userpwd.

Also fix test 540 to not expect digest auth header to be
resent when connection is reused.

Signed-off-by: Isaac Boukris <iboukris@gmail.com>

Closes https://github.com/curl/curl/pull/1350

3 files changed, 17 insertions, 16 deletions

diff --git a/lib/http.c b/lib/http.c
index 961c80080..0b680b2d6 100644
--- a/lib/http.c
+++ b/lib/http.c
@@ -2312,20 +2312,10 @@ CURLcode Curl_http(struct connectdata *conn, bool *done)
                      te
       );
 
-  /* clear userpwd to avoid re-using credentials from re-used connections */
+  /* clear userpwd and proxyuserpwd to avoid re-using old credentials
+   * from re-used connections */
   Curl_safefree(conn->allocptr.userpwd);
-
-  /*
-   * Free proxyuserpwd for Negotiate/NTLM. Cannot reuse as it is associated
-   * with the connection and shouldn't be repeated over it either.
-   */
-  switch(data->state.authproxy.picked) {
-  case CURLAUTH_NEGOTIATE:
-  case CURLAUTH_NTLM:
-  case CURLAUTH_NTLM_WB:
-    Curl_safefree(conn->allocptr.proxyuserpwd);
-    break;
-  }
+  Curl_safefree(conn->allocptr.proxyuserpwd);
 
   if(result)
     return result;
diff --git a/lib/url.c b/lib/url.c
index 97c88f3cd..01e02de54 100644
--- a/lib/url.c
+++ b/lib/url.c
@@ -3277,9 +3277,7 @@ proxy_info_matches(const struct proxy_info* data,
 {
   if((data->proxytype == needle->proxytype) &&
      (data->port == needle->port) &&
-     Curl_safe_strcasecompare(data->host.name, needle->host.name) &&
-     Curl_safe_strcasecompare(data->user, needle->user) &&
-     Curl_safe_strcasecompare(data->passwd, needle->passwd))
+     Curl_safe_strcasecompare(data->host.name, needle->host.name))
     return TRUE;
 
   return FALSE;
diff --git a/tests/data/test540 b/tests/data/test540
index 8decaea9d..8391cbe78 100644
--- a/tests/data/test540
+++ b/tests/data/test540
@@ -11,6 +11,9 @@ multi
 
 # Server-side
 <reply>
+<servercmd>
+connection-monitor
+</servercmd>
 
 # this is returned first since we get no proxy-auth
 <data>
@@ -40,6 +43,10 @@ Content-Length: 21
 Server: no

 

 Nice proxy auth sir!
+HTTP/1.1 407 Authorization Required to proxy me my dear

+Proxy-Authenticate: Digest realm="weirdorealm", nonce="12345"

+Content-Length: 33

+

 HTTP/1.1 200 OK

 Content-Length: 21

 Server: no

@@ -88,10 +95,16 @@ Proxy-Connection: Keep-Alive
 

 GET http://test.remote.example.com/path/540 HTTP/1.1

 Host: custom.set.host.name

+Accept: */*

+Proxy-Connection: Keep-Alive

+

+GET http://test.remote.example.com/path/540 HTTP/1.1

+Host: custom.set.host.name

 Proxy-Authorization: Digest username="silly", realm="weirdorealm", nonce="12345", uri="/path/540", response="ca507dcf189196b6a5374d3233042261"

 Accept: */*

 Proxy-Connection: Keep-Alive

 

+[DISCONNECT]
 </protocol>
 </verify>
 </testcase>