freebsd-dev/sys/opencrypto/xform_md5.c
Conrad Meyer 3693b18840 opencrypto: Loosen restriction on HMAC key sizes
Theoretically, HMACs do not actually have any limit on key sizes.
Transforms should compact input keys larger than the HMAC block size by
using the transform (hash) on the input key.

(Short input keys are padded out with zeros to the HMAC block size.)

Still, not all FreeBSD crypto drivers that provide HMAC functionality
handle longer-than-blocksize keys appropriately, so enforce a "maximum" key
length in the crypto API for auth_hashes that previously expressed a
requirement.  (The "maximum" is the size of a single HMAC block for the
given transform.)  Unconstrained auth_hashes are left as-is.

I believe the previous hardcoded sizes were committed in the original
import of opencrypto from OpenBSD and are due to specific protocol
details of IPSec.  Note that none of the previous sizes actually matched
the appropriate HMAC block size.

The previous hardcoded sizes made the SHA tests in cryptotest.py
useless for testing FreeBSD crypto drivers; none of the NIST-KAT example
inputs had keys sized to the previous expectations.

The following drivers were audited to check that they handled keys up to
the block size of the HMAC safely:

  Software HMAC:
    * padlock(4)
    * cesa
    * glxsb
    * safe(4)
    * ubsec(4)

  Hardware accelerated HMAC:
    * ccr(4)
    * hifn(4)
    * sec(4) (Only supports up to 64 byte keys despite claiming to
      support SHA2 HMACs, but validates input key sizes)
    * cryptocteon (MIPS)
    * nlmsec (MIPS)
    * rmisec (MIPS) (Amusingly, does not appear to use key material at
      all -- presumed broken)

Reviewed by:	jhb (previous version), rlibby (previous version)
Sponsored by:	Dell EMC Isilon
Differential Revision:	https://reviews.freebsd.org/D12437
2017-09-26 16:18:10 +00:00

82 lines
2.6 KiB
C

/* $OpenBSD: xform.c,v 1.16 2001/08/28 12:20:43 ben Exp $ */
/*-
* The authors of this code are John Ioannidis (ji@tla.org),
* Angelos D. Keromytis (kermit@csd.uch.gr),
* Niels Provos (provos@physnet.uni-hamburg.de) and
* Damien Miller (djm@mindrot.org).
*
* This code was written by John Ioannidis for BSD/OS in Athens, Greece,
* in November 1995.
*
* Ported to OpenBSD and NetBSD, with additional transforms, in December 1996,
* by Angelos D. Keromytis.
*
* Additional transforms and features in 1997 and 1998 by Angelos D. Keromytis
* and Niels Provos.
*
* Additional features in 1999 by Angelos D. Keromytis.
*
* AES XTS implementation in 2008 by Damien Miller
*
* Copyright (C) 1995, 1996, 1997, 1998, 1999 by John Ioannidis,
* Angelos D. Keromytis and Niels Provos.
*
* Copyright (C) 2001, Angelos D. Keromytis.
*
* Copyright (C) 2008, Damien Miller
* Copyright (c) 2014 The FreeBSD Foundation
* All rights reserved.
*
* Portions of this software were developed by John-Mark Gurney
* under sponsorship of the FreeBSD Foundation and
* Rubicon Communications, LLC (Netgate).
*
* Permission to use, copy, and modify this software with or without fee
* is hereby granted, provided that this entire notice is included in
* all copies of any software which is or includes a copy or
* modification of this software.
* You may use this code under the GNU public license if you so wish. Please
* contribute changes back to the authors under this freer than GPL license
* so that we may further the use of strong encryption without limitations to
* all.
*
* THIS SOFTWARE IS BEING PROVIDED "AS IS", WITHOUT ANY EXPRESS OR
* IMPLIED WARRANTY. IN PARTICULAR, NONE OF THE AUTHORS MAKES ANY
* REPRESENTATION OR WARRANTY OF ANY KIND CONCERNING THE
* MERCHANTABILITY OF THIS SOFTWARE OR ITS FITNESS FOR ANY PARTICULAR
* PURPOSE.
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include <sys/md5.h>
#include <opencrypto/xform_auth.h>
static int MD5Update_int(void *, const u_int8_t *, u_int16_t);
/* Authentication instances */
struct auth_hash auth_hash_hmac_md5 = {
CRYPTO_MD5_HMAC, "HMAC-MD5",
MD5_HMAC_BLOCK_LEN, MD5_HASH_LEN, sizeof(MD5_CTX), MD5_HMAC_BLOCK_LEN,
(void (*) (void *)) MD5Init, NULL, NULL, MD5Update_int,
(void (*) (u_int8_t *, void *)) MD5Final
};
struct auth_hash auth_hash_key_md5 = {
CRYPTO_MD5_KPDK, "Keyed MD5",
0, MD5_KPDK_HASH_LEN, sizeof(MD5_CTX), 0,
(void (*)(void *)) MD5Init, NULL, NULL, MD5Update_int,
(void (*)(u_int8_t *, void *)) MD5Final
};
/*
* And now for auth.
*/
static int
MD5Update_int(void *ctx, const u_int8_t *buf, u_int16_t len)
{
MD5Update(ctx, buf, len);
return 0;
}