varlink: optionally, mark all incoming message's "parameters" field as sensitive

[thirdparty/systemd.git] / src / shared / varlink.c

diff --git a/src/shared/varlink.c b/src/shared/varlink.c
index 699d21745f187eb652a638086b347aa73853a76c..96dfd8de92ac40c60413d60291c89853c83deab5 100644 (file)
--- a/src/shared/varlink.c
+++ b/src/shared/varlink.c
@@ -184,6 +184,7 @@ struct Varlink {
         bool allow_fd_passing_output:1;
 
         bool output_buffer_sensitive:1; /* whether to erase the output buffer after writing it to the socket */
+        bool input_sensitive:1; /* Whether incoming messages might be sensitive */
 
         int af; /* address family if socket; AF_UNSPEC if not socket; negative if not known */
 
@@ -703,7 +704,7 @@ static void varlink_clear(Varlink *v) {
 
         varlink_clear_current(v);
 
-        v->input_buffer = mfree(v->input_buffer);
+        v->input_buffer = v->input_sensitive ? erase_and_free(v->input_buffer) : mfree(v->input_buffer);
         v->output_buffer = v->output_buffer_sensitive ? erase_and_free(v->output_buffer) : mfree(v->output_buffer);
 
         v->input_control_buffer = mfree(v->input_control_buffer);
@@ -1022,7 +1023,8 @@ static int varlink_read(Varlink *v) {
 }
 
 static int varlink_parse_message(Varlink *v) {
-        const char *e, *begin;
+        const char *e;
+        char *begin;
         size_t sz;
         int r;
 
@@ -1047,6 +1049,8 @@ static int varlink_parse_message(Varlink *v) {
         sz = e - begin + 1;
 
         r = json_parse(begin, 0, &v->current, NULL, NULL);
+        if (v->input_sensitive)
+                explicit_bzero_safe(begin, sz);
         if (r < 0) {
                 /* If we encounter a parse failure flush all data. We cannot possibly recover from this,
                  * hence drop all buffered data now. */
@@ -1054,6 +1058,13 @@ static int varlink_parse_message(Varlink *v) {
                 return varlink_log_errno(v, r, "Failed to parse JSON: %m");
         }
 
+        if (v->input_sensitive) {
+                /* Mark the parameters subfield as sensitive right-away, if that's requested */
+                JsonVariant *parameters = json_variant_by_key(v->current, "parameters");
+                if (parameters)
+                        json_variant_sensitive(parameters);
+        }
+
         v->input_buffer_size -= sz;
 
         if (v->input_buffer_size == 0)
@@ -3097,6 +3108,13 @@ int varlink_set_allow_fd_passing_output(Varlink *v, bool b) {
         return 0;
 }
 
+int varlink_set_input_sensitive(Varlink *v) {
+        assert_return(v, -EINVAL);
+
+        v->input_sensitive = true;
+        return 0;
+}
+
 int varlink_server_new(VarlinkServer **ret, VarlinkServerFlags flags) {
         _cleanup_(varlink_server_unrefp) VarlinkServer *s = NULL;
         int r;
@@ -3325,6 +3343,9 @@ static int connect_callback(sd_event_source *source, int fd, uint32_t revents, v
 
         TAKE_FD(cfd);
 
+        if (FLAGS_SET(ss->server->flags, VARLINK_SERVER_INPUT_SENSITIVE))
+                varlink_set_input_sensitive(v);
+
         if (ss->server->connect_callback) {
                 r = ss->server->connect_callback(ss->server, v, ss->server->userdata);
                 if (r < 0) {