[geary] Heap access violation in random_string(): Bug #741842

[Jim Nelson <jnelson src gnome org>]

commit c2380abff29a7c5209c57d18bc90a960d79366ab
Author: Sergey Shnatsel Davidoff <sergey elementaryos org>
Date:   Mon Dec 22 12:28:13 2014 -0800

    Heap access violation in random_string(): Bug #741842
    
    Needed to allocate space for terminating NUL.

 src/client/util/util-random.vala |    3 ++-
 1 files changed, 2 insertions(+), 1 deletions(-)
---
diff --git a/src/client/util/util-random.vala b/src/client/util/util-random.vala
index e8939f4..2310185 100644
--- a/src/client/util/util-random.vala
+++ b/src/client/util/util-random.vala
@@ -7,9 +7,10 @@
 private string random_string(int length) {
     // No upper case letters, since request gets lower-cased.
     string chars = "abcdefghijklmnopqrstuvwxyz";
-    char[] random = new char[length];
+    char[] random = new char[length+1]; //leave room for terminating null
     for (int i = 0; i < length; i++)
         random[i] = chars[Random.int_range(0, chars.length)];
+    random[length] = '\0'; //make sure the string is null-terminated
     return (string) random;
 }