Include Content-{Length,Type} headers in signature calculation (#1267)

Signed-off-by: Bala.FA <bala@minio.io>

Author: balamurugana

api/src/main/java/io/minio/Signer.java

@@ -46,19 +46,6 @@ public class Signer {
   // URLs (that are executed by other agents) or when customers pass requests through proxies, which
   // may modify the user-agent.
   //
-  // * Content-Length
-  // This is ignored from signing because generating a pre-signed URL should not provide a
-  // content-length constraint, specifically when vending a S3 pre-signed PUT URL. The corollary to
-  // this is that when sending regular requests (non-pre-signed), the signature contains a checksum
-  // of the body, which implicitly validates the payload length (since changing the number of bytes
-  // would change the checksum) and therefore this header is not valuable in the signature.
-  //
-  // * Content-Type
-  // Signing this header causes quite a number of problems in browser environments, where browsers
-  // like to modify and normalize the content-type header in different ways. There is more
-  // information on this in https://github.com/aws/aws-sdk-js/issues/244. Avoiding this field
-  // simplifies logic and reduces the possibility of future bugs.
-  //
   // * Authorization
   // Is skipped for obvious reasons.
   //
@@ -67,14 +54,11 @@ public class Signer {
   // calculation.
   //
   private static final Set<String> IGNORED_HEADERS =
-      ImmutableSet.of(
-          "accept-encoding", "authorization", "content-type", "content-length", "user-agent");
+      ImmutableSet.of("accept-encoding", "authorization", "user-agent");
   private static final Set<String> PRESIGN_IGNORED_HEADERS =
       ImmutableSet.of(
           "accept-encoding",
           "authorization",
-          "content-type",
-          "content-length",
           "user-agent",
           "content-md5",
           "x-amz-content-sha256",