[PATCH v1 5/6] cmd: allow disabling of timeout for password entry

[Steffen Jaeckel <jaeckel-floss@eyet-services.de>]

In case a user has to enter a complicated password it is sometimes
desireable to give the user more time than the default timeout.
Enabling this feature will disable the timeout entirely in case the user
presses the <Enter> key before entering any other character.

Signed-off-by: Steffen Jaeckel <jaeckel-floss@eyet-services.de>
Reviewed-by: Simon Glass <sjg@chromium.org>
---

 cmd/Kconfig       |  8 ++++++++
 common/autoboot.c | 12 +++++++++++-
 2 files changed, 19 insertions(+), 1 deletion(-)

diff --git a/cmd/Kconfig b/cmd/Kconfig
index 9e8b69258f..860605e8c2 100644
--- a/cmd/Kconfig
+++ b/cmd/Kconfig
@@ -177,6 +177,14 @@ config CMD_SBI
 	help
 	  Display information about the SBI implementation.
 
+config AUTOBOOT_NEVER_TIMEOUT
+	bool "Make the password entry never time-out"
+	depends on AUTOBOOT_KEYED && AUTOBOOT_ENCRYPTION
+	help
+	  This option removes the timeout from the password entry
+	  when the user first presses the <Enter> key before entering
+	  any other character.
+
 endmenu
 
 menu "Boot commands"
diff --git a/common/autoboot.c b/common/autoboot.c
index c28d93049b..e88d23dabf 100644
--- a/common/autoboot.c
+++ b/common/autoboot.c
@@ -67,6 +67,10 @@ static int menukey;
  * or
  *   the config value CONFIG_AUTOBOOT_STOP_STR_CRYPT
  *
+ * In case the config value CONFIG_AUTOBOOT_NEVER_TIMEOUT has been enabled
+ * this function never times out if the user presses the <Enter> key
+ * before starting to enter the password.
+ *
  * @etime: Timeout value ticks (stop when get_ticks() reachs this)
  * @return 0 if autoboot should continue, 1 if it should stop
  */
@@ -76,6 +80,7 @@ static int passwd_abort_crypt(uint64_t etime)
 	char presskey[DELAY_STOP_STR_MAX_LENGTH];
 	u_int presskey_len = 0;
 	int abort = 0;
+	int never_timeout = 0;
 	int err;
 
 	if (IS_ENABLED(HAS_STOP_STR_CRYPT) && !crypt_env_str)
@@ -95,6 +100,11 @@ static int passwd_abort_crypt(uint64_t etime)
 
 			if ((presskey[presskey_len] == '\r') ||
 			    (presskey[presskey_len] == '\n')) {
+				if (IS_ENABLED(CONFIG_AUTOBOOT_NEVER_TIMEOUT) &&
+				    !presskey_len) {
+					never_timeout = 1;
+					continue;
+				}
 				presskey[presskey_len] = '\0';
 				err = crypt_compare(crypt_env_str, presskey,
 						    &abort);
@@ -108,7 +118,7 @@ static int passwd_abort_crypt(uint64_t etime)
 				presskey_len++;
 			}
 		}
-	} while (get_ticks() <= etime);
+	} while (never_timeout || get_ticks() <= etime);
 
 	return abort;
 }
-- 
2.31.1