http://bugs.gentoo.org/106152

--- src/magic.c
+++ src/magic.c
@@ -316,12 +316,18 @@ magic_buffer(struct magic_set *ms, const
 {
 	if (file_reset(ms) == -1)
 		return NULL;
-	/*
-	 * The main work is done here!
-	 * We have the file name and/or the data buffer to be identified. 
-	 */
-	if (file_buffer(ms, -1, buf, nb) == -1) {
-		return NULL;
+	if (nb == 0) {
+		if (file_printf(ms, (ms->flags & MAGIC_MIME) ?
+		    "application/x-empty" : "empty") == -1)
+			return NULL;
+	} else {
+		/*
+		 * The main work is done here!
+		 * We have the file name and/or the data buffer to be identified. 
+		 */
+		if (file_buffer(ms, -1, buf, nb) == -1) {
+			return NULL;
+		}
 	}
 	return file_getbuffer(ms);
 }