diff options
| author | Colin Walters <walters@verbum.org> | 2013-08-22 13:55:21 -0400 |
|---|---|---|
| committer | Zbigniew Jędrzejewski-Szmek <zbyszek@in.waw.pl> | 2013-09-18 11:06:04 -0500 |
| commit | 72fd713962ca2c2450e23b01d9e22017a7e28fd4 (patch) | |
| tree | 81549ab1c80eb0bfff2ee15aa1fa5cd3d1a0cd41 | |
| parent | 00f117a59973f9c4e1a966252d668949f62a9265 (diff) | |
polkit: Avoid race condition in scraping /proc
If a calling process execve()s a setuid program, it can appear to be
uid 0. Since we're receiving requests over DBus, avoid this by simply
passing system-bus-name as a subject.
| -rw-r--r-- | src/shared/polkit.c | 31 |
1 files changed, 5 insertions, 26 deletions
diff --git a/src/shared/polkit.c b/src/shared/polkit.c index cea7074ad3..1c5e9e3e0f 100644 --- a/src/shared/polkit.c +++ b/src/shared/polkit.c @@ -38,12 +38,8 @@ int verify_polkit( #ifdef ENABLE_POLKIT DBusMessage *m = NULL, *reply = NULL; - const char *unix_process = "unix-process", *pid = "pid", *starttime = "start-time", *cancel_id = ""; + const char *system_bus_name = "system-bus-name", *name = "name", *cancel_id = ""; uint32_t flags = interactive ? 1 : 0; - pid_t pid_raw; - uint32_t pid_u32; - unsigned long long starttime_raw; - uint64_t starttime_u64; DBusMessageIter iter_msg, iter_struct, iter_array, iter_dict, iter_variant; int r; dbus_bool_t authorized = FALSE, challenge = FALSE; @@ -68,14 +64,6 @@ int verify_polkit( #ifdef ENABLE_POLKIT - pid_raw = bus_get_unix_process_id(c, sender, error); - if (pid_raw == 0) - return -EINVAL; - - r = get_starttime_of_pid(pid_raw, &starttime_raw); - if (r < 0) - return r; - m = dbus_message_new_method_call( "org.freedesktop.PolicyKit1", "/org/freedesktop/PolicyKit1/Authority", @@ -86,22 +74,13 @@ int verify_polkit( dbus_message_iter_init_append(m, &iter_msg); - pid_u32 = (uint32_t) pid_raw; - starttime_u64 = (uint64_t) starttime_raw; - if (!dbus_message_iter_open_container(&iter_msg, DBUS_TYPE_STRUCT, NULL, &iter_struct) || - !dbus_message_iter_append_basic(&iter_struct, DBUS_TYPE_STRING, &unix_process) || + !dbus_message_iter_append_basic(&iter_struct, DBUS_TYPE_STRING, &system_bus_name) || !dbus_message_iter_open_container(&iter_struct, DBUS_TYPE_ARRAY, "{sv}", &iter_array) || !dbus_message_iter_open_container(&iter_array, DBUS_TYPE_DICT_ENTRY, NULL, &iter_dict) || - !dbus_message_iter_append_basic(&iter_dict, DBUS_TYPE_STRING, &pid) || - !dbus_message_iter_open_container(&iter_dict, DBUS_TYPE_VARIANT, "u", &iter_variant) || - !dbus_message_iter_append_basic(&iter_variant, DBUS_TYPE_UINT32, &pid_u32) || - !dbus_message_iter_close_container(&iter_dict, &iter_variant) || - !dbus_message_iter_close_container(&iter_array, &iter_dict) || - !dbus_message_iter_open_container(&iter_array, DBUS_TYPE_DICT_ENTRY, NULL, &iter_dict) || - !dbus_message_iter_append_basic(&iter_dict, DBUS_TYPE_STRING, &starttime) || - !dbus_message_iter_open_container(&iter_dict, DBUS_TYPE_VARIANT, "t", &iter_variant) || - !dbus_message_iter_append_basic(&iter_variant, DBUS_TYPE_UINT64, &starttime_u64) || + !dbus_message_iter_append_basic(&iter_dict, DBUS_TYPE_STRING, &name) || + !dbus_message_iter_open_container(&iter_dict, DBUS_TYPE_VARIANT, "s", &iter_variant) || + !dbus_message_iter_append_basic(&iter_variant, DBUS_TYPE_STRING, &sender) || !dbus_message_iter_close_container(&iter_dict, &iter_variant) || !dbus_message_iter_close_container(&iter_array, &iter_dict) || !dbus_message_iter_close_container(&iter_struct, &iter_array) || |