krb5 commit [krb5-1.12]: Fix minor utf8-to-ucs2s read overrun bug

[Tom Yu]

https://github.com/krb5/krb5/commit/fdbac6f2bbbe4673359760f2170770aa93044882
commit fdbac6f2bbbe4673359760f2170770aa93044882
Author: Greg Hudson <ghudson at mit.edu>
Date:   Fri Sep 25 17:31:53 2015 -0400

    Fix minor utf8-to-ucs2s read overrun bug
    
    k5_utf8s_to_ucs2s() reads and ignores one extra byte from the input
    string before terminating its loop, possibly overrunning the input
    buffer of its caller.  This overrun is typically without consequence,
    but can show up in tools like asan or valgrind during RC4
    string-to-key operations.  Fix the bug by swapping the order of the
    loop conditions.
    
    (cherry picked from commit eb52da21d72faa3d00b1205a5a0fdbabc45c9e6d)
    
    ticket: 8321 (new)
    version_fixed: 1.12.5
    status: resolved

 src/util/support/utf8_conv.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)

diff --git a/src/util/support/utf8_conv.c b/src/util/support/utf8_conv.c
index b8bf989..8fa2ce0 100644
--- a/src/util/support/utf8_conv.c
+++ b/src/util/support/utf8_conv.c
@@ -85,7 +85,7 @@ k5_utf8s_to_ucs2s(krb5_ucs2 *ucs2str,
     }
 
     /* Examine next UTF-8 character.  */
-    while (*utf8str && ucs2len < count) {
+    while (ucs2len < count && *utf8str != '\0') {
         /* Get UTF-8 sequence length from 1st byte */
         utflen = KRB5_UTF8_CHARLEN2(utf8str, utflen);