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Merge "init: finer grained permissions for ctl. properties" into pi-dev

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Tom Cherry 2018-05-22 20:15:07 +00:00 committed by Android (Google) Code Review
commit 8b491495a3
2 changed files with 39 additions and 16 deletions
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50
init/property_service.cpp
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@ -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!";

5
init/property_service.h
View file

@ -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,