fix: canonical header computation for multi-spaced header values (#1025)

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

@@ -29,6 +29,7 @@
 import java.util.Map;
 import java.util.Set;
 import java.util.TreeMap;
+import java.util.stream.Collectors;
 import javax.crypto.Mac;
 import javax.crypto.spec.SecretKeySpec;
 import okhttp3.Headers;
@@ -142,7 +143,18 @@ private void setCanonicalHeaders() {
     for (String name : headers.names()) {
       String signedHeader = name.toLowerCase(Locale.US);
       if (!IGNORED_HEADERS.contains(signedHeader)) {
-        this.canonicalHeaders.put(signedHeader, headers.get(name));
+        // Convert and add header values as per
+        // https://docs.aws.amazon.com/general/latest/gr/sigv4-create-canonical-request.html
+        // * Header having multiple values should be converted to comma separated values.
+        // * Multi-spaced value of header should be trimmed to single spaced value.
+        this.canonicalHeaders.put(
+            signedHeader,
+            headers.values(name).stream()
+                .map(
+                    value -> {
+                      return value.replaceAll("( +)", " ");
+                    })
+                .collect(Collectors.joining(",")));
       }
     }
 

functional/FunctionalTest.java

@@ -846,6 +846,8 @@ public static void putObject_test() throws Exception {
 
     Map<String, String> userMetadata = new HashMap<>();
     userMetadata.put("My-Project", "Project One");
+    userMetadata.put("My-header1", "    a   b   c  ");
+    userMetadata.put("My-Header2", "\"a   b   c\"");
 
     testPutObject(
         "[user metadata]",