proxy: credentials of an earlier request not inherited by the next

src/httpsrv.c

@@ -1598,6 +1598,14 @@ void * httpsrvchild(struct clientparam *param)
 		r.lasthost = lasthost;
 		param->res = 0;
 
+		/* What the request brought belongs to it alone. A connection
+		   can carry a client's request after another's, as a reverse
+		   proxy reuses its upstreams, so the credentials and the host
+		   of an earlier request decide nothing for this one. */
+		*param->hostname = 0;
+		*param->username = 0;
+		*param->password = 0;
+
 		answered = httpsrv_request(param, &r);
 		handoff = r.handoff;
 		param->climark = -1;

src/proxy.c

@@ -561,6 +561,15 @@ for(;;){
  hdrfree(&buf, &bufown);
  hdrsdone = 0;
 
+ /* What the request brought belongs to it alone. A connection can carry
+    a request after another's, so the credentials of an earlier request
+    decide nothing for this one. */
+ *param->username = 0;
+ *param->password = 0;
+ param->pwtype = 0;
+ *param->extusername = 0;
+ *param->extpassword = 0;
+
  if(keepalive && (param->cliinbuf == param->clioffset) && (param->remsock != INVALID_SOCKET)){
 	memset(fds, 0, sizeof(fds));
 	fds[0].fd = param->clisock;

tests/cases/httpsrv_auth.py

@@ -1,5 +1,7 @@
 """Authentication and access rules in front of the HTTP server."""
 
+import base64
+
 
 def run(t):
     if not t.skip_unless("httpsrv"):
@@ -49,3 +51,19 @@ def run(t):
 
     t.contains(t.http(url + "/echo", auth=("alice", "secret")), "path=/echo",
                "an authenticated request is dispatched")
+
+    # --- credentials do not outlive the request that carried them ------
+    # A kept connection answers a second request without credentials as
+    # unauthenticated: a reverse proxy reuses its upstreams between
+    # clients, so one client's login must not open another's way in.
+    creds = base64.b64encode(b"alice:secret").decode()
+    text, closed = t.raw_session(srv,
+        f"GET /echo HTTP/1.1\r\nHost: t\r\n"
+        f"Authorization: Basic {creds}\r\n\r\n"
+        f"GET /echo HTTP/1.1\r\nHost: t\r\nConnection: close\r\n\r\n")
+    parts = text.split("HTTP/1.")
+    t.eq(3, len(parts), "the kept connection answers both requests")
+    t.eq(True, parts[1].startswith("1 200"),
+         "the request with credentials is allowed")
+    t.eq(True, parts[2].startswith("0 401"),
+         "the request after it, without credentials, is refused")

tests/cases/proxy_http.py

@@ -4,6 +4,8 @@ Access rules accumulate until "flush", so each service section here starts
 from a clean list.
 """
 
+import base64
+
 
 def run(t):
     if not t.skip_unless("httpsrv"):
@@ -108,3 +110,18 @@ def run(t):
     t.eq(407, t.http(origin + "/echo", proxy=needs_auth,
                      proxy_auth=("alice", "wrong")).status,
          "wrong proxy credentials are refused")
+
+    # credentials do not outlive the request which carried them: a second
+    # request on the same connection, without them, is asked again
+    creds = base64.b64encode(b"alice:secret").decode()
+    text, closed = t.raw_session(auth,
+        f"GET {origin}/echo HTTP/1.1\r\nHost: 127.0.0.1:{srv}\r\n"
+        f"Proxy-Authorization: Basic {creds}\r\n\r\n"
+        f"GET {origin}/echo HTTP/1.1\r\nHost: 127.0.0.1:{srv}\r\n"
+        f"Connection: close\r\n\r\n")
+    parts = text.split("HTTP/1.")
+    t.eq(3, len(parts), "the kept connection answers both requests")
+    t.eq(True, parts[1].startswith("1 200"),
+         "the request with credentials is allowed")
+    t.eq(True, parts[2].startswith("0 407"),
+         "the request after it, without credentials, is refused")