init: finer grained permissions for ctl. properties
Currently, permissions for ctl. property apply to each action verb, so
if a domain has permissions for controlling service 'foo', then it can
start, stop, and restart foo.
This change implements finer grainer permissions such that permission
can be given to strictly start a given service, but not stop or
restart it. This new permission scheme is mandatory for the new
control functions, sigstop_on, sigstop_off, interface_start,
interface_stop, interface_restart.
Bug: 78511553
Test: see appropriate successes and failures based on permissions
Merged-In: I6ce915ae39954a67eb6fe1795a93cf715c352ae4
Change-Id: I6ce915ae39954a67eb6fe1795a93cf715c352ae4
(cherry picked from commit 1debdcf1cf3d45ba9185ab47a265995c676280d8)
diff --git a/init/property_service.cpp b/init/property_service.cpp
index 741fde0..d1c427d 100644
--- a/init/property_service.cpp
+++ b/init/property_service.cpp
@@ -95,6 +95,11 @@
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 @@
return false;
}
- property_audit_data audit_data;
+ PropertyAuditData audit_data;
audit_data.name = name.c_str();
audit_data.cr = &cr;
@@ -393,6 +398,35 @@
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) {
@@ -402,15 +436,9 @@
}
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;
}
@@ -742,7 +770,7 @@
}
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!";