tequilaOS/platform_system_core
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Restrict setting platform properties from vendor .prop files

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We should only allow vendor-init-settable properties to be set from
.prop files on /vendor and /odm.

Bug: 73905119
Test: test on walleye that disallowed properties are rejected
Change-Id: I2a5d244fdc71060ddda3e3d87442e831e6b97831
This commit is contained in:
Tom Cherry 2018-02-28 10:39:01 -08:00
parent 69d47aa829
commit dc375869ab
3 changed files with 34 additions and 7 deletions
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32
init/property_service.cpp
View file

@ -59,8 +59,11 @@
#include "init.h"
#include "persistent_properties.h"
#include "property_type.h"
#include "subcontext.h"
#include "util.h"
using namespace std::literals;
using android::base::ReadFileToString;
using android::base::Split;
using android::base::StartsWith;
@ -533,11 +536,17 @@ static bool load_properties_from_file(const char *, const char *);
* 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 load_properties(char *data, const char *filter)
{
static void LoadProperties(char* data, const char* filter, const char* filename) {
char *key, *value, *eol, *sol, *tmp, *fn;
size_t flen = 0;
const char* context = kInitContext.c_str();
for (const auto& [path_prefix, secontext] : paths_and_secontexts) {
if (StartsWith(filename, path_prefix)) {
context = secontext;
}
}
if (filter) {
flen = strlen(filter);
}
@ -584,7 +593,21 @@ static void load_properties(char *data, const char *filter)
}
}
property_set(key, value);
if (StartsWith(key, "ctl.") || key == "sys.powerctl"s ||
key == "selinux.restorecon_recursive"s) {
LOG(ERROR) << "Ignoring disallowed property '" << key
<< "' with special meaning in prop file '" << filename << "'";
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
<< "' in property file '" << filename << "': " << error;
}
}
}
}
@ -600,7 +623,8 @@ static bool load_properties_from_file(const char* filename, const char* filter)
return false;
}
file_contents->push_back('\n');
load_properties(file_contents->data(), filter);
LoadProperties(file_contents->data(), filter, filename);
LOG(VERBOSE) << "(Loading properties from " << filename << " took " << t << ".)";
return true;
}

8
init/subcontext.cpp
View file

@ -49,6 +49,11 @@ namespace init {
const std::string kInitContext = "u:r:init:s0";
const std::string kVendorContext = "u:r:vendor_init:s0";
const char* const paths_and_secontexts[2][2] = {
{"/vendor", kVendorContext.c_str()},
{"/odm", kVendorContext.c_str()},
};
namespace {
constexpr size_t kBufferSize = 4096;
@ -349,9 +354,6 @@ Result<std::vector<std::string>> Subcontext::ExpandArgs(const std::vector<std::s
static std::vector<Subcontext> subcontexts;
std::vector<Subcontext>* InitializeSubcontexts() {
static const char* const paths_and_secontexts[][2] = {
{"/vendor", kVendorContext.c_str()},
};
for (const auto& [path_prefix, secontext] : paths_and_secontexts) {
subcontexts.emplace_back(path_prefix, secontext);
}

1
init/subcontext.h
View file

@ -33,6 +33,7 @@ namespace init {
extern const std::string kInitContext;
extern const std::string kVendorContext;
extern const char* const paths_and_secontexts[2][2];
class Subcontext {
public: