Return None when ipv6 has too many segments

Comcast · Jun 5, 2024 · 15a101a · 15a101a
1 parent 70c0632
commit 15a101a
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Showing 2 changed files with 33 additions and 18 deletions.
diff --git a/shared/src/main/scala/com/comcast/ip4s/Host.scala b/shared/src/main/scala/com/comcast/ip4s/Host.scala
@@ -773,6 +773,7 @@ object Ipv6Address extends Ipv6AddressCompanionPlatform {
       }
       idx += 1
     }
+
     if (result ne null) {
       result
     } else if (fields.isEmpty && (trimmed.isEmpty || trimmed != "::")) {
@@ -781,26 +782,34 @@ object Ipv6Address extends Ipv6AddressCompanionPlatform {
       val bytes = new Array[Byte](16)
       idx = 0
       val prefixSize = prefix.size
-      var prefixIdx = prefixSize - 1
-      while (prefixIdx >= 0) {
-        val value = prefix(prefixIdx)
-        bytes(idx) = (value >> 8).toByte
-        bytes(idx + 1) = value.toByte
-        prefixIdx -= 1
-        idx += 2
-      }
       val suffixSize = suffix.size
-      val numCondensedZeroes = bytes.size - idx - (suffixSize * 2)
-      idx += numCondensedZeroes
-      var suffixIdx = suffixSize - 1
-      while (suffixIdx >= 0) {
-        val value = suffix(suffixIdx)
-        bytes(idx) = (value >> 8).toByte
-        bytes(idx + 1) = value.toByte
-        suffixIdx -= 1
-        idx += 2
+      val numCondensedZeroes = 8 - (prefixSize + suffixSize)
+
+      if (numCondensedZeroes < 0) {
+        None
+      } else {
+        var prefixIdx = prefixSize - 1
+        while (prefixIdx >= 0) {
+          val value = prefix(prefixIdx)
+          bytes(idx) = (value >> 8).toByte
+          bytes(idx + 1) = value.toByte
+          prefixIdx -= 1
+          idx += 2
+        }
+
+        idx += numCondensedZeroes * 2
+
+        var suffixIdx = suffixSize - 1
+        while (suffixIdx >= 0) {
+          val value = suffix(suffixIdx)
+          bytes(idx) = (value >> 8).toByte
+          bytes(idx + 1) = value.toByte
+          suffixIdx -= 1
+          idx += 2
+        }
+
+        Some(unsafeFromBytes(bytes))
       }
-      Some(unsafeFromBytes(bytes))
     }
   }
 

diff --git a/test-kit/shared/src/test/scala/com/comcast/ip4s/Ipv6AddressTest.scala b/test-kit/shared/src/test/scala/com/comcast/ip4s/Ipv6AddressTest.scala
@@ -35,6 +35,11 @@ class Ipv6AddressTest extends BaseTestSuite {
     assertEquals(Ipv6Address.fromString(" : "), None)
   }
 
+  test("parsing from string - does not parse invalid number of sections in ipv6") {
+    assertEquals(Ipv6Address.fromString("::1:1:1:1:1:1:2:1:3"), None)
+    assertEquals(Ipv6Address.fromString("1:1:1:1:1:1:2:1:3"), None)
+  }
+
   test("parsing from string - does parse ::") {
     assertEquals(Ipv6Address.fromString("::").isDefined, true)
     assertEquals(Ipv6Address.fromString(" :: ").isDefined, true)
@@ -150,4 +155,5 @@ class Ipv6AddressTest extends BaseTestSuite {
     assert(ipv6"fe80::1".isLinkLocal)
     assert(ipv6"::ffff:169.254.0.0".isLinkLocal)
   }
+
 }