Disallow everything by default

And update config.d/security to configure sane defaults

config.d/security.in

@@ -6,13 +6,12 @@
 # installation.
 
 # Configures which programs are allowed to use which sway features
+permit * fullscreen keyboard mouse ipc
 permit __PREFIX__/bin/swaylock lock
 permit __PREFIX__/bin/swaybar panel
 permit __PREFIX__/bin/swaybg background
 permit __PREFIX__/bin/swaygrab screenshot
 
-permit * fullscreen keyboard mouse
-
 # Configures which IPC features are enabled
 ipc {
     command enabled
@@ -36,6 +35,8 @@ ipc {
 
 # Limits the contexts from which certain commands are permitted
 commands {
+    * all
+
     fullscreen binding criteria
     bindsym config
     exit binding

sway/commands.c

@@ -524,7 +524,7 @@ struct cmd_results *config_commands_command(char *exec) {
 	}
 
 	struct cmd_handler *handler = find_handler(cmd, CMD_BLOCK_END);
-	if (!handler) {
+	if (!handler && strcmp(cmd, "*") != 0) {
 		char *input = cmd ? cmd : "(empty)";
 		results = cmd_results_new(CMD_INVALID, input, "Unknown/invalid command");
 		goto cleanup;

sway/security.c

@@ -5,16 +5,25 @@
 #include "log.h"
 
 struct feature_policy *alloc_feature_policy(const char *program) {
+	uint32_t default_policy = 0;
+	for (int i = 0; i < config->feature_policies->length; ++i) {
+		struct feature_policy *policy = config->feature_policies->items[i];
+		if (strcmp(policy->program, "*") == 0) {
+			default_policy = policy->features;
+			break;
+		}
+	}
+
 	struct feature_policy *policy = malloc(sizeof(struct feature_policy));
 	policy->program = strdup(program);
-	policy->features = FEATURE_FULLSCREEN | FEATURE_KEYBOARD | FEATURE_MOUSE | FEATURE_IPC;
+	policy->features = default_policy;
 	return policy;
 }
 
 struct command_policy *alloc_command_policy(const char *command) {
 	struct command_policy *policy = malloc(sizeof(struct command_policy));
 	policy->command = strdup(command);
-	policy->context = CONTEXT_ALL;
+	policy->context = 0;
 	return policy;
 }
 
@@ -25,8 +34,7 @@ enum secure_feature get_feature_policy(pid_t pid) {
 	snprintf(path, pathlen + 1, fmt, pid);
 	static char link[2048];
 
-	enum secure_feature default_policy =
-		FEATURE_FULLSCREEN | FEATURE_KEYBOARD | FEATURE_MOUSE;
+	uint32_t default_policy = 0;
 
 	ssize_t len = readlink(path, link, sizeof(link));
 	if (len < 0) {
@@ -53,10 +61,13 @@ enum secure_feature get_feature_policy(pid_t pid) {
 }
 
 enum command_context get_command_policy(const char *cmd) {
-	enum command_context default_policy = CONTEXT_ALL;
+	uint32_t default_policy = 0;
 
 	for (int i = 0; i < config->command_policies->length; ++i) {
 		struct command_policy *policy = config->command_policies->items[i];
+		if (strcmp(policy->command, "*") == 0) {
+			default_policy = policy->context;
+		}
 		if (strcmp(policy->command, cmd) == 0) {
 			return policy->context;
 		}

sway/sway-security.7.txt

@@ -124,8 +124,14 @@ To work correctly, sway's own programs require the following permissions:
 
 - swaybg: background
 - swaylock: lock, keyboard
-- swaybar: panel, mouse
-- swaygrab: screenshot
+- swaybar: panel, mouse, ipc
+- swaygrab: screenshot, ipc
+
+When you first declare a policy for an executable, it will inherit the default
+policy. Further changes to the default policy will not retroactively affect which
+permissions an earlier policy inherits. You must explicitly reject any features
+from the default policy that you do not want an executable to receive permission
+for.
 
 Command policies
 ----------------
@@ -145,6 +151,9 @@ contexts you can control are:
 **criteria**::
 	Can be run when evaluating window criteria.
 
+**all**::
+	Shorthand for granting permission in all contexts.
+
 By default a command is allowed to execute in any context. To configure this, open
 a commands block and fill it with policies:
 
@@ -160,13 +169,13 @@ binding and critiera:
 		focus binding criteria
 	}
 
+Setting a command policy overwrites any previous policy that was in place.
+
 IPC policies
 ------------
 
-By default all programs can connect to IPC for backwards compatability with i3.
-However, you can whitelist IPC access like so:
+You may whitelist IPC access like so:
 
-	reject * ipc
 	permit /usr/bin/swaybar ipc
 	permit /usr/bin/swaygrab ipc
 	# etc