Reject psk parameter set with invalid passphrase character

WPA/WPA2-Personal passphrase is not allowed to include control
characters. Reject a passphrase configuration attempt if that passphrase
includes an invalid passphrase.

This fixes an issue where wpa_supplicant could have updated the
configuration file psk parameter with arbitrary data from the control
interface or D-Bus interface. While those interfaces are supposed to be
accessible only for trusted users/applications, it may be possible that
an untrusted user has access to a management software component that
does not validate the passphrase value before passing it to
wpa_supplicant.

This could allow such an untrusted user to inject up to 63 characters of
almost arbitrary data into the configuration file. Such configuration
file could result in wpa_supplicant trying to load a library (e.g.,
opensc_engine_path, pkcs11_engine_path, pkcs11_module_path,
load_dynamic_eap) from user controlled location when starting again.
This would allow code from that library to be executed under the
wpa_supplicant process privileges.

Signed-off-by: Jouni Malinen <jouni@qca.qualcomm.com>

diff --git a/wpa_supplicant/config.c b/wpa_supplicant/config.c
index b1c7870..fdd9643 100644 (file)
--- a/wpa_supplicant/config.c
+++ b/wpa_supplicant/config.c
@@ -478,6 +478,12 @@ static int wpa_config_parse_psk(const struct parse_data *data,
                }
                wpa_hexdump_ascii_key(MSG_MSGDUMP, "PSK (ASCII passphrase)",
                                      (u8 *) value, len);
+               if (has_ctrl_char((u8 *) value, len)) {
+                       wpa_printf(MSG_ERROR,
+                                  "Line %d: Invalid passphrase character",
+                                  line);
+                       return -1;
+               }
                if (ssid->passphrase && os_strlen(ssid->passphrase) == len &&
                    os_memcmp(ssid->passphrase, value, len) == 0) {
                        /* No change to the previously configured value */