Synchronize on NetBSD-CVS (2013/12/1 12:00:00 UTC)

- Fix for possible unset uid/gid in toproto
 - Fix for default mtree style
 - Update libelf
 - Importing libexecinfo
 - Resynchronize GCC, mpc, gmp, mpfr
 - build.sh: Replace params with show-params.
     This has been done as the make target has been renamed in the same
     way, while a new target named params has been added. This new
     target generates a file containing all the parameters, instead of
     printing it on the console.
 - Update test48 with new etc/services (Fix by Ben Gras <ben@minix3.org)
     get getservbyport() out of the inner loop

Change-Id: Ie6ad5226fa2621ff9f0dee8782ea48f9443d2091

lib/libc/string/memcmp.3

@@ -30,9 +30,9 @@
 .\" SUCH DAMAGE.
 .\"
 .\"     from: @(#)memcmp.3	8.1 (Berkeley) 6/4/93
-.\"	$NetBSD: memcmp.3,v 1.9 2003/08/07 16:43:48 agc Exp $
+.\"	$NetBSD: memcmp.3,v 1.11 2013/06/24 04:21:20 riastradh Exp $
 .\"
-.Dd June 4, 1993
+.Dd June 23, 2013
 .Dt MEMCMP 3
 .Os
 .Sh NAME
@@ -67,8 +67,18 @@ is greater than
 .Sq Li \&\e0 ,
 for example).
 Zero-length strings are always identical.
+.Pp
+Do not use
+.Fn memcmp
+to compare cryptographic secrets, because the time it takes varies
+depending on how many bytes are the same, and thus leaks information
+about the two strings by a timing side channel.
+To compare secrets, hashes, message authentication codes, etc., use
+.Xr consttime_memequal 3
+instead.
 .Sh SEE ALSO
 .Xr bcmp 3 ,
+.Xr consttime_memequal 3 ,
 .Xr strcasecmp 3 ,
 .Xr strcmp 3 ,
 .Xr strcoll 3 ,