common: add support to fallback to plain SHA256
In case crypt-based hashing is enabled this will be the default mechanism
that is used. If a user wants to have support for both, the environment
variable `bootstopusesha256` can be set to `true` to allow plain SHA256
based hashing of the password.
Signed-off-by: Steffen Jaeckel <jaeckel-floss@eyet-services.de>
Reviewed-by: Simon Glass <sjg@chromium.org>
diff --git a/common/autoboot.c b/common/autoboot.c
index 35ef526..8b9e9aa 100644
--- a/common/autoboot.c
+++ b/common/autoboot.c
@@ -306,6 +306,26 @@
(void)getchar();
}
+/**
+ * fallback_to_sha256() - check whether we should fall back to sha256
+ * password checking
+ *
+ * This checks for the environment variable `bootstopusesha256` in case
+ * sha256-fallback has been enabled via the config setting
+ * `AUTOBOOT_SHA256_FALLBACK`.
+ *
+ * @return `false` if we must not fall-back, `true` if plain sha256 should be tried
+ */
+static bool fallback_to_sha256(void)
+{
+ if (IS_ENABLED(CONFIG_AUTOBOOT_SHA256_FALLBACK))
+ return env_get_yesno("bootstopusesha256") == 1;
+ else if (IS_ENABLED(CONFIG_CRYPT_PW))
+ return false;
+ else
+ return true;
+}
+
/***************************************************************************
* Watch for 'delay' seconds for autoboot stop or autoboot delay string.
* returns: 0 - no key string, allow autoboot 1 - got key string, abort
@@ -326,7 +346,7 @@
# endif
if (IS_ENABLED(CONFIG_AUTOBOOT_ENCRYPTION)) {
- if (IS_ENABLED(CONFIG_CRYPT_PW))
+ if (IS_ENABLED(CONFIG_CRYPT_PW) && !fallback_to_sha256())
abort = passwd_abort_crypt(etime);
else
abort = passwd_abort_sha256(etime);