Merge "init: finer grained permissions for ctl. properties" into pi-dev (8b491495) · Commits · e / os / android_system_core

init/property_service.cpp

+39 −11

Original line number	Diff line number	Diff line
		@@ -95,6 +95,11 @@ uint32_t (*property_set)(const std::string& name, const std::string& value) = In

		void CreateSerializedPropertyInfo();

		struct PropertyAuditData {
		const ucred* cr;
		const char* name;
		};

		void property_init() {
		mkdir("/dev/__properties__", S_IRWXU \| S_IXGRP \| S_IXOTH);
		CreateSerializedPropertyInfo();
		@@ -111,7 +116,7 @@ static bool CheckMacPerms(const std::string& name, const char* target_context,
		return false;
		}

		property_audit_data audit_data;
		PropertyAuditData audit_data;

		audit_data.name = name.c_str();
		audit_data.cr = &cr;
		@@ -388,6 +393,35 @@ class SocketConnection {
		DISALLOW_IMPLICIT_CONSTRUCTORS(SocketConnection);
		};

		bool CheckControlPropertyPerms(const std::string& name, const std::string& value,
		const std::string& source_context, const ucred& cr) {
		// We check the legacy method first but these properties are dontaudit, so we only log an audit
		// if the newer method fails as well. We only do this with the legacy ctl. properties.
		if (name == "ctl.start" \|\| name == "ctl.stop" \|\| name == "ctl.restart") {
		// The legacy permissions model is that ctl. properties have their name ctl.<action> and
		// their value is the name of the service to apply that action to. Permissions for these
		// actions are based on the service, so we must create a fake name of ctl.<service> to
		// check permissions.
		auto control_string_legacy = "ctl." + value;
		const char* target_context_legacy = nullptr;
		const char* type_legacy = nullptr;
		property_info_area->GetPropertyInfo(control_string_legacy.c_str(), &target_context_legacy,
		&type_legacy);

		if (CheckMacPerms(control_string_legacy, target_context_legacy, source_context.c_str(), cr)) {
		return true;
		}
		}

		auto control_string_full = name + "$" + value;
		const char* target_context_full = nullptr;
		const char* type_full = nullptr;
		property_info_area->GetPropertyInfo(control_string_full.c_str(), &target_context_full,
		&type_full);

		return CheckMacPerms(control_string_full, target_context_full, source_context.c_str(), cr);
		}

		// This returns one of the enum of PROP_SUCCESS or PROP_ERROR*.
		uint32_t HandlePropertySet(const std::string& name, const std::string& value,
		const std::string& source_context, const ucred& cr, std::string* error) {
		@@ -397,15 +431,9 @@ uint32_t HandlePropertySet(const std::string& name, const std::string& value,
		}

		if (StartsWith(name, "ctl.")) {
		// ctl. properties have their name ctl.<action> and their value is the name of the service
		// to apply that action to. Permissions for these actions are based on the service, so we
		// must create a fake name of ctl.<service> to check permissions.
		auto control_string = "ctl." + value;
		const char* target_context = nullptr;
		const char* type = nullptr;
		property_info_area->GetPropertyInfo(control_string.c_str(), &target_context, &type);
		if (!CheckMacPerms(control_string, target_context, source_context.c_str(), cr)) {
		*error = StringPrintf("Unable to '%s' service %s", name.c_str() + 4, value.c_str());
		if (!CheckControlPropertyPerms(name, value, source_context, cr)) {
		*error = StringPrintf("Invalid permissions to perform '%s' on '%s'", name.c_str() + 4,
		value.c_str());
		return PROP_ERROR_HANDLE_CONTROL_MESSAGE;
		}

		@@ -737,7 +765,7 @@ void load_system_props() {
		}

		static int SelinuxAuditCallback(void* data, security_class_t /cls/, char* buf, size_t len) {
		property_audit_data* d = reinterpret_cast<property_audit_data*>(data);
		auto* d = reinterpret_cast<PropertyAuditData*>(data);

		if (!d \|\| !d->name \|\| !d->cr) {
		LOG(ERROR) << "AuditCallback invoked with null data arguments!";

init/property_service.h

+0 −5

Original line number	Diff line number	Diff line
		@@ -24,11 +24,6 @@
		namespace android {
		namespace init {

		struct property_audit_data {
		const ucred* cr;
		const char* name;
		};

		extern uint32_t (*property_set)(const std::string& name, const std::string& value);

		uint32_t HandlePropertySet(const std::string& name, const std::string& value,