Check result of snprintf() in basicauth.c and digestauth.c, log more errors

2 files changed, 35 insertions, 11 deletions

diff --git a/src/microhttpd/basicauth.c b/src/microhttpd/basicauth.c
index 51f9cf93..bb9e1ea4 100644
--- a/src/microhttpd/basicauth.c
+++ b/src/microhttpd/basicauth.c
@@ -117,7 +117,7 @@ MHD_queue_basic_auth_fail_response (struct MHD_Connection *connection,
                                     const char *realm, 
                                     struct MHD_Response *response) 
 {
-  int ret;
+  int ret, res;
   size_t hlen = strlen(realm) + strlen("Basic realm=\"\"") + 1;
   char *header;
   
@@ -130,18 +130,29 @@ MHD_queue_basic_auth_fail_response (struct MHD_Connection *connection,
 #endif /* HAVE_MESSAGES */
     return MHD_NO;
   }
-  MHD_snprintf_ (header, 
-            hlen, 
-            "Basic realm=\"%s\"", 
-            realm);
-  ret = MHD_add_response_header (response,
-                                 MHD_HTTP_HEADER_WWW_AUTHENTICATE,
-                                 header);
+  res = MHD_snprintf_ (header, 
+                       hlen, 
+                       "Basic realm=\"%s\"", 
+                       realm);
+  if (res > 0 && res < hlen)
+    ret = MHD_add_response_header (response,
+                                   MHD_HTTP_HEADER_WWW_AUTHENTICATE,
+                                   header);
+  else
+    ret = MHD_NO;
+
   free(header);
   if (MHD_YES == ret)
     ret = MHD_queue_response (connection, 
                               MHD_HTTP_UNAUTHORIZED, 
                               response);
+  else
+    {
+#ifdef HAVE_MESSAGES
+      MHD_DLOG (connection->daemon,
+                "Failed to add Basic auth header\n");
+#endif /* HAVE_MESSAGES */
+    }
   return ret;
 }
 
diff --git a/src/microhttpd/digestauth.c b/src/microhttpd/digestauth.c
index 8e38dc41..851eaa3f 100644
--- a/src/microhttpd/digestauth.c
+++ b/src/microhttpd/digestauth.c
@@ -822,6 +822,7 @@ MHD_queue_auth_fail_response (struct MHD_Connection *connection,
                    signal_stale
                    ? ",stale=\"true\""
                    : "");
+  if (hlen > 0)
   {
     char *header;
 
@@ -835,7 +836,7 @@ MHD_queue_auth_fail_response (struct MHD_Connection *connection,
       return MHD_NO;
     }
 
-    MHD_snprintf_(header,
+    if (MHD_snprintf_(header,
               hlen + 1,
               "Digest realm=\"%s\",qop=\"auth\",nonce=\"%s\",opaque=\"%s\"%s",
               realm,
@@ -843,16 +844,28 @@ MHD_queue_auth_fail_response (struct MHD_Connection *connection,
               opaque,
               signal_stale
               ? ",stale=\"true\""
-              : "");
-    ret = MHD_add_response_header(response,
+              : "") == hlen)
+      ret = MHD_add_response_header(response,
                                   MHD_HTTP_HEADER_WWW_AUTHENTICATE,
                                   header);
+    else
+      ret = MHD_NO;
     free(header);
   }
+  else
+    ret = MHD_NO;
+
   if (MHD_YES == ret)
     ret = MHD_queue_response(connection,
                              MHD_HTTP_UNAUTHORIZED,
                              response);
+  else
+    {
+#ifdef HAVE_MESSAGES
+      MHD_DLOG (connection->daemon,
+                "Failed to add Digest auth header\n");
+#endif /* HAVE_MESSAGES */
+    }
   return ret;
 }