[PATCH v8 5/7] common: bootm: add policy to commandline

[Fabian Pflug <f.pflug@pengutronix.de>]

If security policies are used, then the variable bootm.provide_policy
can be set to automatically append the currently selected security
policy to the kernel commandline with the prefix
barebox.security.policy=
This allows the system to behave differently based on the selected
security policy.

Signed-off-by: Fabian Pflug <f.pflug@pengutronix.de>
---
 common/bootm.c  | 24 ++++++++++++++++++++++++
 include/bootm.h |  5 +++++
 2 files changed, 29 insertions(+)

diff --git a/common/bootm.c b/common/bootm.c
index 371d86ae0b..703b55a38f 100644
--- a/common/bootm.c
+++ b/common/bootm.c
@@ -20,6 +20,7 @@
 #include <magicvar.h>
 #include <zero_page.h>
 #include <security/config.h>
+#include <security/policy.h>
 
 static LIST_HEAD(handler_list);
 static struct sconfig_notifier_block sconfig_notifier;
@@ -71,6 +72,7 @@ static int bootm_dryrun;
 static int bootm_earlycon;
 static int bootm_provide_machine_id;
 static int bootm_provide_hostname;
+static int bootm_provide_policy;
 static int bootm_verbosity;
 static int bootm_efi_mode = BOOTM_EFI_AVAILABLE;
 
@@ -93,6 +95,7 @@ void bootm_data_init_defaults(struct bootm_data *data)
 	data->appendroot = bootm_appendroot;
 	data->provide_machine_id = bootm_provide_machine_id;
 	data->provide_hostname = bootm_provide_hostname;
+	data->provide_policy = bootm_provide_policy;
 	data->verbose = bootm_verbosity;
 	data->dryrun = bootm_dryrun;
 	data->efi_boot = bootm_efi_mode;
@@ -114,6 +117,7 @@ void bootm_data_restore_defaults(const struct bootm_data *data)
 	bootm_appendroot = data->appendroot;
 	bootm_provide_machine_id = data->provide_machine_id;
 	bootm_provide_hostname = data->provide_hostname;
+	bootm_provide_policy = data->provide_policy;
 	bootm_verbosity = data->verbose;
 	bootm_dryrun = data->dryrun;
 	bootm_efi_mode = data->efi_boot;
@@ -715,6 +719,21 @@ struct image_data *bootm_boot_prep(const struct bootm_data *bootm_data)
 		free(hostname_bootarg);
 	}
 
+	if (IS_ENABLED(CONFIG_SECURITY_POLICY) && bootm_data->provide_policy) {
+		char *policy_bootargs;
+		const struct security_policy *active_policy = security_policy_get_active();
+
+		if (!active_policy) {
+			pr_err("Providing policy is enabled but no policy is selected\n");
+			ret = -EINVAL;
+			goto err_out;
+		}
+
+		policy_bootargs = basprintf("barebox.security.policy=%s", active_policy->name);
+		globalvar_add_simple("linux.bootargs.dyn.policy", policy_bootargs);
+		free(policy_bootargs);
+	}
+
 	return data;
 err_out:
 	bootm_boot_cleanup(data);
@@ -846,6 +865,8 @@ static int bootm_init(void)
 	globalvar_add_simple_bool("bootm.earlycon", &bootm_earlycon);
 	globalvar_add_simple_bool("bootm.provide_machine_id", &bootm_provide_machine_id);
 	globalvar_add_simple_bool("bootm.provide_hostname", &bootm_provide_hostname);
+	if (IS_ENABLED(CONFIG_SECURITY_POLICY))
+		globalvar_add_simple_bool("bootm.provide_policy", &bootm_provide_policy);
 	if (IS_ENABLED(CONFIG_BOOTM_INITRD)) {
 		globalvar_add_simple("bootm.initrd", NULL);
 		globalvar_add_simple("bootm.initrd.loadaddr", NULL);
@@ -896,3 +917,6 @@ BAREBOX_MAGICVAR(global.bootm.root_dev, "bootm default root device (overrides de
 BAREBOX_MAGICVAR(global.bootm.root_param, "bootm root parameter name (normally 'root' for root=/dev/...)");
 BAREBOX_MAGICVAR(global.bootm.provide_machine_id, "If true, append systemd.machine_id=$global.machine_id to Kernel command line");
 BAREBOX_MAGICVAR(global.bootm.provide_hostname, "If true, append systemd.hostname=$global.hostname to Kernel command line");
+#ifdef CONFIG_SECURITY_POLICY
+BAREBOX_MAGICVAR(global.bootm.provide_policy, "Add barebox.security.policy= option to Kernel");
+#endif
diff --git a/include/bootm.h b/include/bootm.h
index 85199fc702..1a556e1e95 100644
--- a/include/bootm.h
+++ b/include/bootm.h
@@ -47,6 +47,11 @@ struct bootm_data {
 	 * of global.hostname to Kernel.
 	 */
 	bool provide_hostname;
+	/*
+	 * provide_policy - if true, try to add barebox.security.policy= with
+	 * with value of currently selected policy
+	 */
+	bool provide_policy;
 	enum bootm_efi_mode efi_boot;
 	unsigned long initrd_address;
 	unsigned long os_address;

-- 
2.47.3