DO NOT MERGE Add null check for hp in DnsProxyListener::GetHostByNameHandler

Bug: 32399924
Bug: 29748723
Test: runtest -x netd_integration_test.cpp

(cherry picked from commit 7a8a601190f948f18b1cc8c043f3a265c1ed183e)

Change-Id: I8e47c2461dc7e8bf34128a2d56ba936e2535c262

3 files changed, 33 insertions, 4 deletions

diff --git a/server/DnsProxyListener.cpp b/server/DnsProxyListener.cpp
index dc31b1aa..861f9c18 100644
--- a/server/DnsProxyListener.cpp
+++ b/server/DnsProxyListener.cpp
@@ -434,14 +434,14 @@ void DnsProxyListener::GetHostByNameHandler::run() {
         std::vector<String16> ip_addrs;
         int total_ip_addr_count = 0;
         if (mReportingLevel == INetdEventListener::REPORTING_LEVEL_FULL) {
-            if (hp->h_addrtype == AF_INET) {
+            if (hp != nullptr && hp->h_addrtype == AF_INET) {
                 in_addr** list = (in_addr**) hp->h_addr_list;
                 for (int i = 0; list[i] != NULL; i++) {
                     sockaddr_in sin = { .sin_family = AF_INET, .sin_addr = *list[i] };
                     addIpAddrWithinLimit(ip_addrs, (sockaddr*) &sin, sizeof(sin));
                     total_ip_addr_count++;
                 }
-            } else if (hp->h_addrtype == AF_INET6) {
+            } else if (hp != nullptr && hp->h_addrtype == AF_INET6) {
                 in6_addr** list = (in6_addr**) hp->h_addr_list;
                 for (int i = 0; list[i] != NULL; i++) {
                     sockaddr_in6 sin6 = { .sin6_family = AF_INET6, .sin6_addr = *list[i] };
diff --git a/tests/Android.mk b/tests/Android.mk
index b58b78ef..bf696929 100644
--- a/tests/Android.mk
+++ b/tests/Android.mk
@@ -35,7 +35,8 @@ LOCAL_SRC_FILES := binder_test.cpp \
                    dns_responder/dns_responder.cpp \
                    netd_integration_test.cpp \
                    netd_test.cpp \
-                   ../server/NetdConstants.cpp
+                   ../server/NetdConstants.cpp \
+                   ../server/binder/android/net/metrics/INetdEventListener.aidl
 LOCAL_MODULE_TAGS := eng tests
 include $(BUILD_NATIVE_TEST)
 
diff --git a/tests/netd_test.cpp b/tests/netd_test.cpp
index 6c7fdac0..a958cd90 100644
--- a/tests/netd_test.cpp
+++ b/tests/netd_test.cpp
@@ -52,11 +52,13 @@
 #include "ResolverStats.h"
 
 #include "android/net/INetd.h"
+#include "android/net/metrics/INetdEventListener.h"
 #include "binder/IServiceManager.h"
 
 using android::base::StringPrintf;
 using android::base::StringAppendF;
 using android::net::ResolverStats;
+using android::net::metrics::INetdEventListener;
 
 // Emulates the behavior of UnorderedElementsAreArray, which currently cannot be used.
 // TODO: Use UnorderedElementsAreArray, which depends on being able to compile libgmock_host,
@@ -125,13 +127,29 @@ class AddrInfo {
 };
 
 class ResolverTest : public ::testing::Test, public DnsResponderClient {
+private:
+    int mOriginalMetricsLevel;
+
 protected:
     virtual void SetUp() {
         // Ensure resolutions go via proxy.
         DnsResponderClient::SetUp();
+
+        // If DNS reporting is off: turn it on so we run through everything.
+        auto rv = mNetdSrv->getMetricsReportingLevel(&mOriginalMetricsLevel);
+        ASSERT_TRUE(rv.isOk());
+        if (mOriginalMetricsLevel != INetdEventListener::REPORTING_LEVEL_FULL) {
+            rv = mNetdSrv->setMetricsReportingLevel(INetdEventListener::REPORTING_LEVEL_FULL);
+            ASSERT_TRUE(rv.isOk());
+        }
     }
 
     virtual void TearDown() {
+        if (mOriginalMetricsLevel != INetdEventListener::REPORTING_LEVEL_FULL) {
+            auto rv = mNetdSrv->setMetricsReportingLevel(mOriginalMetricsLevel);
+            ASSERT_TRUE(rv.isOk());
+        }
+
         DnsResponderClient::TearDown();
     }
 
@@ -257,20 +275,30 @@ TEST_F(ResolverTest, GetHostByName) {
     const char* listen_addr = "127.0.0.3";
     const char* listen_srv = "53";
     const char* host_name = "hello.example.com.";
+    const char *nonexistent_host_name = "nonexistent.example.com.";
     test::DNSResponder dns(listen_addr, listen_srv, 250, ns_rcode::ns_r_servfail, 1.0);
     dns.addMapping(host_name, ns_type::ns_t_a, "1.2.3.3");
     ASSERT_TRUE(dns.startServer());
     std::vector<std::string> servers = { listen_addr };
     ASSERT_TRUE(SetResolversForNetwork(mDefaultSearchDomains, servers, mDefaultParams));
 
+    const hostent* result;
+
+    dns.clearQueries();
+    result = gethostbyname("nonexistent");
+    EXPECT_EQ(1U, GetNumQueriesForType(dns, ns_type::ns_t_a, nonexistent_host_name));
+    ASSERT_TRUE(result == nullptr);
+    ASSERT_EQ(HOST_NOT_FOUND, h_errno);
+
     dns.clearQueries();
-    const hostent* result = gethostbyname("hello");
+    result = gethostbyname("hello");
     EXPECT_EQ(1U, GetNumQueriesForType(dns, ns_type::ns_t_a, host_name));
     ASSERT_FALSE(result == nullptr);
     ASSERT_EQ(4, result->h_length);
     ASSERT_FALSE(result->h_addr_list[0] == nullptr);
     EXPECT_EQ("1.2.3.3", ToString(result));
     EXPECT_TRUE(result->h_addr_list[1] == nullptr);
+
     dns.stopServer();
 }