Improve HTTP status handling. Allow 203 as an alternative to 200 OK.

Most other 2xx status codes are still not expected and therefor considered
an error. The GET requests issued by this code should not result in other
2xx result codes.
Also handle and ignore the 1xx Informational headers but again only 100
and 103 are handled and 101 Switching Protocols and 102 Processing are
not expected and are considered an error.
OK deraadt@

1 files changed, 27 insertions, 11 deletions

diff --git a/usr.sbin/rpki-client/http.c b/usr.sbin/rpki-client/http.c
index 314e9e1793f..fc12a7719c7 100644
--- a/usr.sbin/rpki-client/http.c
+++ b/usr.sbin/rpki-client/http.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: http.c,v 1.34 2021/07/23 16:03:47 job Exp $  */
+/*	$OpenBSD: http.c,v 1.35 2021/08/04 16:10:03 claudio Exp $  */
 /*
  * Copyright (c) 2020 Nils Fisher <nils_fisher@hotmail.com>
  * Copyright (c) 2020 Claudio Jeker <claudio@openbsd.org>
@@ -865,7 +865,9 @@ http_request(struct http_connection *conn)
 
 /*
  * Parse the HTTP status line.
- * Return 0 for status codes 200, 301-304, 307-308.
+ * Return 0 for status codes 100, 103, 200, 203, 301-304, 307-308.
+ * The other 1xx and 2xx status codes are explicitly not handled and are
+ * considered an error.
  * Failure codes and other errors return -1.
  * The redirect loop limit is enforced here.
  */
@@ -885,7 +887,7 @@ http_parse_status(struct http_connection *conn, char *buf)
 		cp++;
 
 	strlcpy(ststr, cp, sizeof(ststr));
-	status = strtonum(ststr, 200, 599, &errstr);
+	status = strtonum(ststr, 100, 599, &errstr);
 	if (errstr != NULL) {
 		strnvis(gerror, cp, sizeof gerror, VIS_SAFE);
 		warnx("Error retrieving %s: %s", http_info(conn->host),
@@ -894,19 +896,23 @@ http_parse_status(struct http_connection *conn, char *buf)
 	}
 
 	switch (status) {
-	case 301:
-	case 302:
-	case 303:
-	case 307:
-	case 308:
+	case 301:	/* Redirect: moved permanently */
+	case 302:	/* Redirect: found / moved temporarily */
+	case 303:	/* Redirect: see other */
+	case 307:	/* Redirect: temporary redirect */
+	case 308:	/* Redirect: permanent redirect */
 		if (conn->req->redirect_loop++ > 10) {
 			warnx("%s: Too many redirections requested",
 			    http_info(conn->host));
 			return -1;
 		}
 		/* FALLTHROUGH */
-	case 200:
-	case 304:
+	case 100:	/* Informational: continue (ignored) */
+	case 103:	/* Informational: early hints (ignored) */
+		/* FALLTHROUGH */
+	case 200:	/* Success: OK */
+	case 203:	/* Success: non-authoritative information (proxy) */
+	case 304:	/* Redirect: not modified */
 		conn->status = status;
 		break;
 	default:
@@ -931,6 +937,14 @@ http_isredirect(struct http_connection *conn)
 	return 0;
 }
 
+static inline int
+http_isok(struct http_connection *conn)
+{
+	if (conn->status >= 200 && conn->status < 300)
+		return 1;
+	return 0;
+}
+
 static void
 http_redirect(struct http_connection *conn)
 {
@@ -1165,7 +1179,7 @@ again:
 		}
 
 		/* Check status header and decide what to do next */
-		if (conn->status == 200 || http_isredirect(conn)) {
+		if (http_isok(conn) || http_isredirect(conn)) {
 			if (http_isredirect(conn))
 				http_redirect(conn);
 
@@ -1174,6 +1188,8 @@ again:
 			else
 				conn->state = STATE_RESPONSE_DATA;
 			goto again;
+		} else if (conn->status == 100 || conn->status == 103) {
+			conn->state = STATE_RESPONSE_STATUS;
 		} else if (conn->status == 304) {
 			return http_done(conn, HTTP_NOT_MOD);
 		}