cryptenroll: refuse reading a key longer than 4 MiB

If we open this up to external processes let's tighten rules and refuse
reading more than 4 MiB as key, after all this is locked memory.

diff --git a/src/cryptenroll/cryptenroll-password.c b/src/cryptenroll/cryptenroll-password.c
index 595279c80d6b8f0b98d1c07505e1304f36451f73..22b64e3229aba7c2428f7aa25fd48469e4f63287 100644 (file)
--- a/src/cryptenroll/cryptenroll-password.c
+++ b/src/cryptenroll/cryptenroll-password.c
@@ -55,8 +55,8 @@ int load_volume_key_keyfile(
                         AT_FDCWD,
                         c->unlock_keyfile,
                         UINT64_MAX,
-                        SIZE_MAX,
-                        READ_FULL_FILE_SECURE|READ_FULL_FILE_WARN_WORLD_READABLE|READ_FULL_FILE_CONNECT_SOCKET,
+                        4U * U64_MB, /* safety net */
+                        READ_FULL_FILE_SECURE|READ_FULL_FILE_WARN_WORLD_READABLE|READ_FULL_FILE_CONNECT_SOCKET|READ_FULL_FILE_FAIL_WHEN_LARGER,
                         NULL,
                         &password,
                         &password_len);