freebsd-dev/sys/libkern/timingsafe_bcmp.c
John-Mark Gurney 08fca7a56b Add some new modes to OpenCrypto. These modes are AES-ICM (can be used
for counter mode), and AES-GCM.  Both of these modes have been added to
the aesni module.

Included is a set of tests to validate that the software and aesni
module calculate the correct values.  These use the NIST KAT test
vectors.  To run the test, you will need to install a soon to be
committed port, nist-kat that will install the vectors.  Using a port
is necessary as the test vectors are around 25MB.

All the man pages were updated.  I have added a new man page, crypto.7,
which includes a description of how to use each mode.  All the new modes
and some other AES modes are present.  It would be good for someone
else to go through and document the other modes.

A new ioctl was added to support AEAD modes which AES-GCM is one of them.
Without this ioctl, it is not possible to test AEAD modes from userland.

Add a timing safe bcmp for use to compare MACs.  Previously we were using
bcmp which could leak timing info and result in the ability to forge
messages.

Add a minor optimization to the aesni module so that single segment
mbufs don't get copied and instead are updated in place.  The aesni
module needs to be updated to support blocked IO so segmented mbufs
don't have to be copied.

We require that the IV be specified for all calls for both GCM and ICM.
This is to ensure proper use of these functions.

Obtained from:	p4: //depot/projects/opencrypto
Relnotes:	yes
Sponsored by:	FreeBSD Foundation
Sponsored by:	NetGate
2014-12-12 19:56:36 +00:00

33 lines
1.1 KiB
C

/* $OpenBSD: timingsafe_bcmp.c,v 1.2 2014/06/10 04:16:57 deraadt Exp $ */
/*
* Copyright (c) 2010 Damien Miller. All rights reserved.
*
* Permission to use, copy, modify, and distribute this software for any
* purpose with or without fee is hereby granted, provided that the above
* copyright notice and this permission notice appear in all copies.
*
* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
* OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
*
* $FreeBSD$
*
*/
#include <sys/libkern.h>
int
timingsafe_bcmp(const void *b1, const void *b2, size_t n)
{
const unsigned char *p1 = b1, *p2 = b2;
int ret = 0;
for (; n > 0; n--)
ret |= *p1++ ^ *p2++;
return (ret != 0);
}