init: Ignore "ro." restrictions when reading prop files
"ro." properties do not make sense for prop files, especially with the
way that the system/product and vendor/odm partitions are meant to
override each other. To fix this, we ignore the fact that "ro."
properties are "write once" when first loading in property files.
We then adjust the order of property file loading, such that we read
partitions from least to most specific, reading in order: system,
vendor, odm, product, product_services.
Bug: 122864654
Test: ro. properties can override when reading build props with
appropriate permissions
Test: ro. properties do not override when lacking permissions to
be set by a given partition
Change-Id: Ib9a5f77e95d9df647cdde7a5c937bb3425c066fa
diff --git a/init/property_service.cpp b/init/property_service.cpp
index 46e5e12..d60b654 100644
--- a/init/property_service.cpp
+++ b/init/property_service.cpp
@@ -39,6 +39,7 @@
#define _REALLY_INCLUDE_SYS__SYSTEM_PROPERTIES_H_
#include <sys/_system_properties.h>
+#include <map>
#include <memory>
#include <queue>
#include <vector>
@@ -442,8 +443,8 @@
}
// 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) {
+uint32_t CheckPermissions(const std::string& name, const std::string& value,
+ const std::string& source_context, const ucred& cr, std::string* error) {
if (!IsLegalPropertyName(name)) {
*error = "Illegal property name";
return PROP_ERROR_INVALID_NAME;
@@ -456,7 +457,6 @@
return PROP_ERROR_HANDLE_CONTROL_MESSAGE;
}
- HandleControlMessage(name.c_str() + 4, value, cr.pid);
return PROP_SUCCESS;
}
@@ -475,6 +475,21 @@
return PROP_ERROR_INVALID_VALUE;
}
+ return PROP_SUCCESS;
+}
+
+// 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) {
+ if (auto ret = CheckPermissions(name, value, source_context, cr, error); ret != PROP_SUCCESS) {
+ return ret;
+ }
+
+ if (StartsWith(name, "ctl.")) {
+ HandleControlMessage(name.c_str() + 4, value, cr.pid);
+ return PROP_SUCCESS;
+ }
+
// sys.powerctl is a special property that is used to make the device reboot. We want to log
// any process that sets this property to be able to accurately blame the cause of a shutdown.
if (name == "sys.powerctl") {
@@ -579,13 +594,15 @@
}
}
-static bool load_properties_from_file(const char *, const char *);
+static bool load_properties_from_file(const char*, const char*,
+ std::map<std::string, std::string>*);
/*
* Filter is used to decide which properties to load: NULL loads all keys,
* "ro.foo.*" is a prefix match, and "ro.foo.bar" is an exact match.
*/
-static void LoadProperties(char* data, const char* filter, const char* filename) {
+static void LoadProperties(char* data, const char* filter, const char* filename,
+ std::map<std::string, std::string>* properties) {
char *key, *value, *eol, *sol, *tmp, *fn;
size_t flen = 0;
@@ -624,7 +641,7 @@
while (isspace(*key)) key++;
}
- load_properties_from_file(fn, key);
+ load_properties_from_file(fn, key, properties);
} else {
value = strchr(key, '=');
@@ -651,12 +668,19 @@
continue;
}
- uint32_t result = 0;
ucred cr = {.pid = 1, .uid = 0, .gid = 0};
std::string error;
- result = HandlePropertySet(key, value, context, cr, &error);
- if (result != PROP_SUCCESS) {
- LOG(ERROR) << "Unable to set property '" << key << "' to '" << value
+ if (CheckPermissions(key, value, context, cr, &error) == PROP_SUCCESS) {
+ auto it = properties->find(key);
+ if (it == properties->end()) {
+ (*properties)[key] = value;
+ } else if (it->second != value) {
+ LOG(WARNING) << "Overriding previous 'ro.' property '" << key << "':'"
+ << it->second << "' with new value '" << value << "'";
+ it->second = value;
+ }
+ } else {
+ LOG(ERROR) << "Do not have permissions to set '" << key << "' to '" << value
<< "' in property file '" << filename << "': " << error;
}
}
@@ -665,7 +689,8 @@
// Filter is used to decide which properties to load: NULL loads all keys,
// "ro.foo.*" is a prefix match, and "ro.foo.bar" is an exact match.
-static bool load_properties_from_file(const char* filename, const char* filter) {
+static bool load_properties_from_file(const char* filename, const char* filter,
+ std::map<std::string, std::string>* properties) {
Timer t;
auto file_contents = ReadFile(filename);
if (!file_contents) {
@@ -675,7 +700,7 @@
}
file_contents->push_back('\n');
- LoadProperties(file_contents->data(), filter, filename);
+ LoadProperties(file_contents->data(), filter, filename, properties);
LOG(VERBOSE) << "(Loading properties from " << filename << " took " << t << ".)";
return true;
}
@@ -698,7 +723,15 @@
static void load_override_properties() {
if (ALLOW_LOCAL_PROP_OVERRIDE) {
- load_properties_from_file("/data/local.prop", NULL);
+ std::map<std::string, std::string> properties;
+ load_properties_from_file("/data/local.prop", nullptr, &properties);
+ for (const auto& [name, value] : properties) {
+ std::string error;
+ if (PropertySet(name, value, &error) != PROP_SUCCESS) {
+ LOG(ERROR) << "Could not set '" << name << "' to '" << value
+ << "' in /data/local.prop: " << error;
+ }
+ }
}
}
@@ -835,24 +868,33 @@
void property_load_boot_defaults() {
// TODO(b/117892318): merge prop.default and build.prop files into one
- // TODO(b/122864654): read the prop files from all partitions and then
- // resolve the duplication by their origin so that RO and non-RO properties
- // have a consistent overriding order.
- if (!load_properties_from_file("/system/etc/prop.default", NULL)) {
+ // We read the properties and their values into a map, in order to always allow properties
+ // loaded in the later property files to override the properties in loaded in the earlier
+ // property files, regardless of if they are "ro." properties or not.
+ std::map<std::string, std::string> properties;
+ if (!load_properties_from_file("/system/etc/prop.default", nullptr, &properties)) {
// Try recovery path
- if (!load_properties_from_file("/prop.default", NULL)) {
+ if (!load_properties_from_file("/prop.default", nullptr, &properties)) {
// Try legacy path
- load_properties_from_file("/default.prop", NULL);
+ load_properties_from_file("/default.prop", nullptr, &properties);
}
}
- load_properties_from_file("/product/build.prop", NULL);
- load_properties_from_file("/product_services/build.prop", NULL);
- load_properties_from_file("/odm/default.prop", NULL);
- load_properties_from_file("/vendor/default.prop", NULL);
- load_properties_from_file("/system/build.prop", NULL);
- load_properties_from_file("/odm/build.prop", NULL);
- load_properties_from_file("/vendor/build.prop", NULL);
- load_properties_from_file("/factory/factory.prop", "ro.*");
+ load_properties_from_file("/system/build.prop", nullptr, &properties);
+ load_properties_from_file("/vendor/default.prop", nullptr, &properties);
+ load_properties_from_file("/vendor/build.prop", nullptr, &properties);
+ load_properties_from_file("/odm/default.prop", nullptr, &properties);
+ load_properties_from_file("/odm/build.prop", nullptr, &properties);
+ load_properties_from_file("/product/build.prop", nullptr, &properties);
+ load_properties_from_file("/product_services/build.prop", nullptr, &properties);
+ load_properties_from_file("/factory/factory.prop", "ro.*", &properties);
+
+ for (const auto& [name, value] : properties) {
+ std::string error;
+ if (PropertySet(name, value, &error) != PROP_SUCCESS) {
+ LOG(ERROR) << "Could not set '" << name << "' to '" << value
+ << "' while loading .prop files" << error;
+ }
+ }
property_initialize_ro_product_props();
property_derive_build_fingerprint();