From 352d8c5bf02303a60cc6f5abc5e4e183354540d4 Mon Sep 17 00:00:00 2001
From: stsp <>
Date: Fri, 30 Nov 2012 13:51:11 +0000
Subject: [PATCH] Document a known bug in the DES crypt cipher implementation
 which we're not going to fix in order to stay compatible with legacy password
 data. Nobody should use DES crypt anyway these days. See
 http://www.freebsd.org/security/advisories/FreeBSD-SA-12:02.crypt.asc for
 details about this bug.

Discussed with deraadt and beck about half a year ago (I'm pruning Ms
from my tree).
---
 src/lib/libc/crypt/crypt.3 | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/src/lib/libc/crypt/crypt.3 b/src/lib/libc/crypt/crypt.3
index 8415f28b..3d9785fc 100644
--- a/src/lib/libc/crypt/crypt.3
+++ b/src/lib/libc/crypt/crypt.3
@@ -1,4 +1,4 @@
-.\" $OpenBSD: crypt.3,v 1.28 2012/06/02 00:14:16 guenther Exp $
+.\" $OpenBSD: crypt.3,v 1.29 2012/11/30 13:51:11 stsp Exp $
 .\"
 .\" FreeSec: libcrypt
 .\"
@@ -31,7 +31,7 @@
 .\"
 .\" Manual page, using -mandoc macros
 .\"
-.Dd $Mdocdate: June 2 2012 $
+.Dd $Mdocdate: November 30 2012 $
 .Dt CRYPT 3
 .Os
 .Sh NAME
@@ -323,3 +323,7 @@ The
 function returns a pointer to static data, and subsequent calls to
 .Fn crypt
 will modify the same object.
+.Pp
+With DES hashing, passwords containing the byte 0x80 use less key entropy
+than other passwords.
+This is an implementation bug, not a bug in the DES cipher.