IDN: Fix handling of long domain names.android-6.0.1_r73marshmallow-mr1-release

Fix merge conflict into mnc-mr1-release
We were incorrectly using sizeof() to calculate the size of the
output array. Note that this change also changes the output size
to 512 to minimize behavioural differences (especially wrt. ICU
checks on sizes).

bug: 30765246
Change-Id: I5d28ddc45d2d6d2bed3e479ca195ed2779b906ed
(cherry picked from commit a1e0873bd8ab79f64296d1103a4e9e7ee6a5bbb7)

2 files changed, 16 insertions, 4 deletions

diff --git a/luni/src/main/native/libcore_icu_NativeIDN.cpp b/luni/src/main/native/libcore_icu_NativeIDN.cpp
index 43f3ce5d3d6..9786b9dbf79 100644
--- a/luni/src/main/native/libcore_icu_NativeIDN.cpp
+++ b/luni/src/main/native/libcore_icu_NativeIDN.cpp
@@ -37,7 +37,8 @@ static jstring NativeIDN_convertImpl(JNIEnv* env, jclass, jstring javaSrc, jint
     if (src.get() == NULL) {
         return NULL;
     }
-    UChar dst[256];
+    static const size_t kDstSize = 512;
+    UChar dst[kDstSize];
     UErrorCode status = U_ZERO_ERROR;
 
     // We're stuck implementing IDNA-2003 for now since that's what we specify.
@@ -47,10 +48,10 @@ static jstring NativeIDN_convertImpl(JNIEnv* env, jclass, jstring javaSrc, jint
 #pragma GCC diagnostic push
 #pragma GCC diagnostic ignored "-Wdeprecated-declarations"
     size_t resultLength = toAscii
-        ? uidna_IDNToASCII(src.get(), src.size(), &dst[0], sizeof(dst), flags, NULL, &status)
-        : uidna_IDNToUnicode(src.get(), src.size(), &dst[0], sizeof(dst), flags, NULL, &status);
+        ? uidna_IDNToASCII(src.get(), src.size(), &dst[0], kDstSize, flags, NULL, &status)
+        : uidna_IDNToUnicode(src.get(), src.size(), &dst[0], kDstSize, flags, NULL, &status);
 #pragma GCC diagnostic pop
-
+    
     if (U_FAILURE(status)) {
         jniThrowException(env, "java/lang/IllegalArgumentException", u_errorName(status));
         return NULL;
diff --git a/luni/src/test/java/libcore/java/net/IDNTest.java b/luni/src/test/java/libcore/java/net/IDNTest.java
index f01eca36cf7..37f3505a310 100644
--- a/luni/src/test/java/libcore/java/net/IDNTest.java
+++ b/luni/src/test/java/libcore/java/net/IDNTest.java
@@ -37,4 +37,15 @@ public class IDNTest extends TestCase {
         String longInput = makePunyString(512);
         assertEquals(longInput, IDN.toUnicode(longInput));
     }
+
+    // http://b/30765246
+    public void testLongDomainName() {
+        String label63 = "123456789-123456789-123456789-123456789-123456789-123456789-123";
+        String host255 = label63 + "." + label63 + "." + label63 + "." + label63;
+        try {
+            IDN.toASCII(host255.substring(3) + ".com");
+            fail();
+        } catch (IllegalArgumentException expected) {
+        }
+    }
 }