Add console support for restricted commands

This adds support for CONFIG_RESTRICTED_CONSOLE_COMMANDS. If the
appropriate options are configured, restricted commands can be
prevented from running.

Nothing in this CL actually uses that, but it works if you turn
it on.

BUG=chrome-os-partner:55322
BRANCH=none
TEST=make buildall, test on Cr50 hardware

I also tested it manually. If you add this to board.h:

  #define CONFIG_CONSOLE_COMMAND_FLAGS
  #define CONFIG_RESTRICTED_CONSOLE_COMMANDS
  #define CONFIG_CONSOLE_COMMAND_FLAGS_DEFAULT CMD_FLAG_RESTRICTED

and this to board.c:

  static int restricted_state;

  int console_is_restricted(void)
  {
         return restricted_state;
  }

  static int command_lock(int argc, char **argv)
  {
         int enabled;

         if (argc > 1) {
                 if (!parse_bool(argv[1], &enabled))
                         return EC_ERROR_PARAM1;
                 restricted_state = enabled;
         }

         ccprintf("The restricted console lock is %s\n",
                  restricted_state ? "enabled" : "disabled");

         return EC_SUCCESS;
  }
  DECLARE_CONSOLE_COMMAND_FLAGS(lock, command_lock,
                                "[<BOOLEAN>]",
                                "Get/Set the restricted console lock",
                                0);               /* no restrictions */

then you can use the "lock" command to enable and disable every
other console command except for it and "help".

Change-Id: Ic9517f9ea7a9867f15e5d14b302246070163d558
Signed-off-by: Bill Richardson <wfrichar@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/376186
Reviewed-by: Randall Spangler <rspangler@chromium.org>

2 files changed, 67 insertions, 20 deletions

diff --git a/common/console.c b/common/console.c
index 3b5524b996..785f71ce56 100644
--- a/common/console.c
+++ b/common/console.c
@@ -240,6 +240,11 @@ command_has_error:
 		return EC_ERROR_UNKNOWN;
 	}
 
+#ifdef CONFIG_RESTRICTED_CONSOLE_COMMANDS
+	if (console_is_restricted() && cmd->flags & CMD_FLAG_RESTRICTED)
+		rv = EC_ERROR_ACCESS_DENIED;
+	else
+#endif
 	rv = cmd->handler(argc, argv);
 	if (rv == EC_SUCCESS)
 		return rv;
@@ -720,12 +725,18 @@ static int command_help(int argc, char **argv)
 
 	ccputs("Known commands:\n");
 	for (i = 0; i < rows; i++) {
-		ccputs("  ");
+		ccputs(" ");
 		for (j = 0; j < cols; j++) {
 			int index = j * rows + i;
 			if (index >= ncmds)
 				break;
-			ccprintf("%-15s", __cmds[index].name);
+#ifdef CONFIG_RESTRICTED_CONSOLE_COMMANDS
+			if (console_is_restricted() &&
+			    __cmds[index].flags & CMD_FLAG_RESTRICTED)
+				ccprintf("-%-14s", __cmds[index].name);
+			else
+#endif
+				ccprintf(" %-14s", __cmds[index].name);
 		}
 		ccputs("\n");
 		cflush();
@@ -738,9 +749,9 @@ static int command_help(int argc, char **argv)
 
 	return EC_SUCCESS;
 }
-DECLARE_CONSOLE_COMMAND(help, command_help,
-			"[ list | <name> ]",
-			"Print command help");
+DECLARE_SAFE_CONSOLE_COMMAND(help, command_help,
+			     "[ list | <name> ]",
+			     "Print command help");
 
 #ifdef CONFIG_CONSOLE_HISTORY
 static int command_history(int argc, char **argv)
diff --git a/include/console.h b/include/console.h
index e82cd128cb..3f8935a525 100644
--- a/include/console.h
+++ b/include/console.h
@@ -123,22 +123,33 @@ void console_has_input(void);
  * @param flags         Per-command flags, if needed.
  */
 #ifndef HAS_TASK_CONSOLE
-#define DECLARE_CONSOLE_COMMAND(NAME, ROUTINE, ARGDESC, HELP)	\
+#define DECLARE_CONSOLE_COMMAND(NAME, ROUTINE, ARGDESC, HELP)		\
+	int (ROUTINE)(int argc, char **argv) __attribute__((unused))
+#define DECLARE_SAFE_CONSOLE_COMMAND(NAME, ROUTINE, ARGDESC, HELP)	\
+	int (ROUTINE)(int argc, char **argv) __attribute__((unused))
+#define DECLARE_CONSOLE_COMMAND_FLAGS(NAME, ROUTINE, ARGDESC, HELP, FLAGS) \
 	int (ROUTINE)(int argc, char **argv) __attribute__((unused))
-#elif defined(CONFIG_CONSOLE_CMDHELP)
-#define DECLARE_CONSOLE_COMMAND(NAME, ROUTINE, ARGDESC, HELP)	\
-	static const char __con_cmd_label_##NAME[] = #NAME;		\
-	struct size_check##NAME {					\
-		int field[2 * (sizeof(__con_cmd_label_##NAME) < 16) - 1]; }; \
-	const struct console_command __keep __con_cmd_##NAME		\
-	__attribute__((section(".rodata.cmds." #NAME)))	=		\
-	{ .name = __con_cmd_label_##NAME,				\
-	  .handler = ROUTINE,						\
-	  .argdesc = ARGDESC,						\
-	  .help = HELP					\
-	}
 #else
-#define DECLARE_CONSOLE_COMMAND(NAME, ROUTINE, ARGDESC, HELP)	\
+
+/* We always provde help args, but we may discard them to save space. */
+#if defined(CONFIG_CONSOLE_CMDHELP)
+#define _HELP_ARGS(A, H)						\
+	.argdesc = A,							\
+	.help = H,
+#else
+#define _HELP_ARGS(A, H)
+#endif
+
+/* We may or may not have a .flags field */
+#ifdef CONFIG_CONSOLE_COMMAND_FLAGS
+#define _FLAG_ARGS(F)							\
+	.flags = F,
+#else
+#define _FLAG_ARGS(F)
+#endif
+
+/* This macro takes all possible args and discards the ones we don't use */
+#define _DCL_CON_CMD_ALL(NAME, ROUTINE, ARGDESC, HELP, FLAGS)		\
 	static const char __con_cmd_label_##NAME[] = #NAME;		\
 	struct size_check##NAME {					\
 		int field[2 * (sizeof(__con_cmd_label_##NAME) < 16) - 1]; }; \
@@ -146,7 +157,32 @@ void console_has_input(void);
 	__attribute__((section(".rodata.cmds." #NAME))) =		\
 	{ .name = __con_cmd_label_##NAME,				\
 	  .handler = ROUTINE,						\
+	  _HELP_ARGS(ARGDESC, HELP)					\
+	  _FLAG_ARGS(FLAGS)						\
 	}
-#endif
+
+/*
+ * If the .flags field exists, we can use this to specify its value. If not,
+ * the value will be discarded so it doesn't matter.
+ */
+#define DECLARE_CONSOLE_COMMAND_FLAGS(NAME, ROUTINE, ARGDESC, HELP, FLAGS) \
+	_DCL_CON_CMD_ALL(NAME, ROUTINE, ARGDESC, HELP, FLAGS)
+
+/* This works as before, for the same reason. */
+#define DECLARE_CONSOLE_COMMAND(NAME, ROUTINE, ARGDESC, HELP)	\
+	_DCL_CON_CMD_ALL(NAME, ROUTINE, ARGDESC, HELP,		\
+			 CONFIG_CONSOLE_COMMAND_FLAGS_DEFAULT)
+
+/*
+ * This can be used to ensure that whatever default flag bits are set (if any),
+ * the command is never restricted. BE CAREFUL! You should only use this for
+ * commands that either do nothing or that do only safe things.
+ */
+#define DECLARE_SAFE_CONSOLE_COMMAND(NAME, ROUTINE, ARGDESC, HELP)	\
+	_DCL_CON_CMD_ALL(NAME, ROUTINE, ARGDESC, HELP,			\
+			 (CONFIG_CONSOLE_COMMAND_FLAGS_DEFAULT &	\
+			  ~CMD_FLAG_RESTRICTED))
+
+#endif	/* HAS_TASK_CONSOLE */
 
 #endif  /* __CROS_EC_CONSOLE_H */