Fchown DNS query socket with AID_DNS when sdk version < 30 am: 6a9603a187 am: 315a89ad93 (3dff1be0) · Commits · e / os / android_packages_modules_DnsResolver

resolv_callback_unit_test.cpp

+35 −12

Original line number	Diff line number	Diff line
		@@ -16,34 +16,34 @@

		#define LOG_TAG "resolv_callback_unit_test"

		#include <sys/stat.h>

		#include <android-base/file.h>
		#include <android-base/properties.h>
		#include <gtest/gtest.h>
		#include <private/android_filesystem_config.h> // AID_DNS

		#include "DnsResolver.h"
		#include "getaddrinfo.h"
		#include "resolv_cache.h"
		#include "resolv_private.h"
		#include "tests/resolv_test_utils.h"

		namespace android::net {

		using android::base::unique_fd;
		using android::net::NetworkDnsEventReported;
		using android::netdutils::ScopedAddrinfo;

		// Use maximum reserved appId for applications to avoid conflict with existing uids.
		const int TEST_UID = 99999;
		const uid_t TEST_UID = 99999;
		// Use testUid to make sure TagSocketCallback is called.
		static int testUid = 0;

		bool isApiLevelSupported(size_t requiredVersion) {
		if (android::base::GetUintProperty<uint64_t>("ro.build.version.sdk", 0) >= requiredVersion)
		return true;
		else
		return false;
		}
		static uid_t testUid = 0;

		// gApiLevel would be initialized in resolv_init().
		#define SKIP_IF_APILEVEL_LESS_THAN(version) \
		do { \
		if (!isApiLevelSupported(version)) { \
		if (android::net::gApiLevel < (version)) { \
		GTEST_LOG_(INFO) << "Skip. Required API version: " << (version) << "\n"; \
		return; \
		} \
		@@ -141,9 +141,9 @@ class CallbackTest : public ::testing::Test {
		};

		TEST_F(CallbackTest, tagSocketCallback) {
		// tagSocketCallback is used when ro.build.version.sdk >=30.
		// If ro.build.version.sdk < 30, don't run this test case.
		// tagSocketCallback is used when supported sdk version >=30.
		SKIP_IF_APILEVEL_LESS_THAN(30);

		test::DNSResponder dns;
		dns.addMapping(kHelloExampleCom, ns_type::ns_t_a, kHelloExampleComAddrV4);
		ASSERT_TRUE(dns.startServer());
		@@ -158,4 +158,27 @@ TEST_F(CallbackTest, tagSocketCallback) {
		EXPECT_EQ(testUid, TEST_UID);
		EXPECT_EQ(rv, 0);
		}

		TEST_F(CallbackTest, tagSocketFchown) {
		const uint64_t tmpApiLevel = gApiLevel;

		// Expect the given socket will be fchown() with given uid.
		gApiLevel = 30; // R
		unique_fd sk(socket(AF_INET, SOCK_DGRAM \| SOCK_CLOEXEC, 0));
		EXPECT_GE(sk, 3);
		resolv_tag_socket(sk, TEST_UID, -1);
		struct stat sb;
		EXPECT_EQ(fstat(sk, &sb), 0);
		EXPECT_EQ(sb.st_uid, TEST_UID);

		// Expect the given socket will be fchown() with AID_DNS.
		gApiLevel = 29; // Q
		resolv_tag_socket(sk, TEST_UID, -1);
		EXPECT_EQ(fstat(sk, &sb), 0);
		EXPECT_EQ(sb.st_uid, static_cast<uid_t>(AID_DNS));

		// restore API level.
		gApiLevel = tmpApiLevel;
		}

		} // end of namespace android::net

resolv_private.h

+5 −5

Original line number	Diff line number	Diff line
		@@ -50,6 +50,8 @@

		#include <android-base/logging.h>
		#include <android-base/unique_fd.h>
		#include <private/android_filesystem_config.h> // AID_DNS

		#include <net/if.h>
		#include <time.h>
		#include <string>
		@@ -176,11 +178,9 @@ inline void resolv_tag_socket(int sock, uid_t uid, pid_t pid) {
		}
		}

		// R+, since fchown() incompatible with Q's ebpf vpn isolation feature
		if (android::net::gApiLevel >= 30) {
		if (fchown(sock, uid, -1) == -1) {
		LOG(WARNING) << "Failed to chown socket: " << strerror(errno);
		}
		// fchown() apps' uid only in R+, since it's incompatible with Q's ebpf vpn isolation feature.
		if (fchown(sock, (android::net::gApiLevel >= 30) ? uid : AID_DNS, -1) == -1) {
		PLOG(WARNING) << "Failed to chown socket";
		}
		}