freebsd-nq/sys/crypto/aesni/aesni_ccm.c
Conrad Meyer 6fe286ed83 aesni(4): Fix trivial type typo
This fixes the kernel build with xtoolchain-gcc (6.4.0).

X-MFC-With:	r348268
2019-05-27 00:47:51 +00:00

440 lines
13 KiB
C

/*-
* Copyright (c) 2014 The FreeBSD Foundation
* Copyright (c) 2018 iXsystems, Inc
* All rights reserved.
*
* This software was developed by John-Mark Gurney under
* the sponsorship of the FreeBSD Foundation and
* Rubicon Communications, LLC (Netgate).
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
*
* $FreeBSD$
*
* This file implements AES-CCM+CBC-MAC, as described
* at https://tools.ietf.org/html/rfc3610, using Intel's
* AES-NI instructions.
*
*/
#include <sys/types.h>
#include <sys/endian.h>
#include <sys/param.h>
#include <sys/systm.h>
#include <crypto/aesni/aesni.h>
#include <crypto/aesni/aesni_os.h>
#include <crypto/aesni/aesencdec.h>
#define AESNI_ENC(d, k, nr) aesni_enc(nr-1, (const __m128i*)k, d)
#include <wmmintrin.h>
#include <emmintrin.h>
#include <smmintrin.h>
/*
* Encrypt a single 128-bit block after
* doing an xor. This is also used to
* decrypt (yay symmetric encryption).
*/
static inline __m128i
xor_and_encrypt(__m128i a, __m128i b, const unsigned char *k, int nr)
{
__m128i retval = _mm_xor_si128(a, b);
retval = AESNI_ENC(retval, k, nr);
return (retval);
}
/*
* Put value at the end of block, starting at offset.
* (This goes backwards, putting bytes in *until* it
* reaches offset.)
*/
static void
append_int(size_t value, __m128i *block, size_t offset)
{
int indx = sizeof(*block) - 1;
uint8_t *bp = (uint8_t*)block;
while (indx > (sizeof(*block) - offset)) {
bp[indx] = value & 0xff;
indx--;
value >>= 8;
}
}
/*
* Start the CBC-MAC process. This handles the auth data.
*/
static __m128i
cbc_mac_start(const unsigned char *auth_data, size_t auth_len,
const unsigned char *nonce, size_t nonce_len,
const unsigned char *key, int nr,
size_t data_len, size_t tag_len)
{
__m128i cbc_block, staging_block;
uint8_t *byte_ptr;
/* This defines where the message length goes */
int L = sizeof(__m128i) - 1 - nonce_len;
/*
* Set up B0 here. This has the flags byte,
* followed by the nonce, followed by the
* length of the message.
*/
cbc_block = _mm_setzero_si128();
byte_ptr = (uint8_t*)&cbc_block;
byte_ptr[0] = ((auth_len > 0) ? 1 : 0) * 64 |
(((tag_len - 2) / 2) * 8) |
(L - 1);
bcopy(nonce, byte_ptr + 1, nonce_len);
append_int(data_len, &cbc_block, L+1);
cbc_block = AESNI_ENC(cbc_block, key, nr);
if (auth_len != 0) {
/*
* We need to start by appending the length descriptor.
*/
uint32_t auth_amt;
size_t copy_amt;
const uint8_t *auth_ptr = auth_data;
staging_block = _mm_setzero_si128();
/*
* The current OCF calling convention means that
* there can never be more than 4g of authentication
* data, so we don't handle the 0xffff case.
*/
KASSERT(auth_len < (1ULL << 32),
("%s: auth_len (%zu) larger than 4GB",
__FUNCTION__, auth_len));
if (auth_len < ((1 << 16) - (1 << 8))) {
/*
* If the auth data length is less than
* 0xff00, we don't need to encode a length
* specifier, just the length of the auth
* data.
*/
be16enc(&staging_block, auth_len);
auth_amt = 2;
} else if (auth_len < (1ULL << 32)) {
/*
* Two bytes for the length prefix, and then
* four bytes for the length. This makes a total
* of 6 bytes to describe the auth data length.
*/
be16enc(&staging_block, 0xfffe);
be32enc((char*)&staging_block + 2, auth_len);
auth_amt = 6;
} else
panic("%s: auth len too large", __FUNCTION__);
/*
* Need to copy abytes into blocks. The first block is
* already partially filled, by auth_amt, so we need
* to handle that. The last block needs to be zero padded.
*/
copy_amt = MIN(auth_len - auth_amt,
sizeof(staging_block) - auth_amt);
byte_ptr = (uint8_t*)&staging_block;
bcopy(auth_ptr, &byte_ptr[auth_amt], copy_amt);
auth_ptr += copy_amt;
cbc_block = xor_and_encrypt(cbc_block, staging_block, key, nr);
while (auth_ptr < auth_data + auth_len) {
copy_amt = MIN((auth_data + auth_len) - auth_ptr,
sizeof(staging_block));
if (copy_amt < sizeof(staging_block))
bzero(&staging_block, sizeof(staging_block));
bcopy(auth_ptr, &staging_block, copy_amt);
cbc_block = xor_and_encrypt(cbc_block, staging_block,
key, nr);
auth_ptr += copy_amt;
}
}
return (cbc_block);
}
/*
* Implement AES CCM+CBC-MAC encryption and authentication.
*
* A couple of notes:
* The specification allows for a different number of tag lengths;
* however, they're always truncated from 16 bytes, and the tag
* length isn't passed in. (This could be fixed by changing the
* code in aesni.c:aesni_cipher_crypt().)
* Similarly, although the nonce length is passed in, the
* OpenCrypto API that calls us doesn't have a way to set the nonce
* other than by having different crypto algorithm types. As a result,
* this is currently always called with nlen=12; this means that we
* also have a maximum message length of 16 megabytes. And similarly,
* since abytes is limited to a 32 bit value here, the AAD is
* limited to 4 gigabytes or less.
*/
void
AES_CCM_encrypt(const unsigned char *in, unsigned char *out,
const unsigned char *addt, const unsigned char *nonce,
unsigned char *tag, uint32_t nbytes, uint32_t abytes, int nlen,
const unsigned char *key, int nr)
{
static const int tag_length = 16; /* 128 bits */
int L;
int counter = 1; /* S0 has 0, S1 has 1 */
size_t copy_amt, total = 0;
uint8_t *byte_ptr;
__m128i s0, rolling_mac, s_x, staging_block;
if (nbytes == 0 && abytes == 0)
return;
/* NIST 800-38c section A.1 says n is [7, 13]. */
if (nlen < 7 || nlen > 13)
panic("%s: bad nonce length %d", __FUNCTION__, nlen);
/*
* We need to know how many bytes to use to describe
* the length of the data. Normally, nlen should be
* 12, which leaves us 3 bytes to do that -- 16mbytes of
* data to encrypt. But it can be longer or shorter;
* this impacts the length of the message.
*/
L = sizeof(__m128i) - 1 - nlen;
/*
* Now, this shouldn't happen, but let's make sure that
* the data length isn't too big.
*/
KASSERT(nbytes <= ((1 << (8 * L)) - 1),
("%s: nbytes is %u, but length field is %d bytes",
__FUNCTION__, nbytes, L));
/*
* Clear out the blocks
*/
s0 = _mm_setzero_si128();
rolling_mac = cbc_mac_start(addt, abytes, nonce, nlen,
key, nr, nbytes, tag_length);
/* s0 has flags, nonce, and then 0 */
byte_ptr = (uint8_t*)&s0;
byte_ptr[0] = L - 1; /* but the flags byte only has L' */
bcopy(nonce, &byte_ptr[1], nlen);
/*
* Now to cycle through the rest of the data.
*/
bcopy(&s0, &s_x, sizeof(s0));
while (total < nbytes) {
/*
* Copy the plain-text data into staging_block.
* This may need to be zero-padded.
*/
copy_amt = MIN(nbytes - total, sizeof(staging_block));
bcopy(in+total, &staging_block, copy_amt);
if (copy_amt < sizeof(staging_block)) {
byte_ptr = (uint8_t*)&staging_block;
bzero(&byte_ptr[copy_amt],
sizeof(staging_block) - copy_amt);
}
rolling_mac = xor_and_encrypt(rolling_mac, staging_block,
key, nr);
/* Put the counter into the s_x block */
append_int(counter++, &s_x, L+1);
/* Encrypt that */
__m128i X = AESNI_ENC(s_x, key, nr);
/* XOR the plain-text with the encrypted counter block */
staging_block = _mm_xor_si128(staging_block, X);
/* And copy it out */
bcopy(&staging_block, out+total, copy_amt);
total += copy_amt;
}
/*
* Allegedly done with it! Except for the tag.
*/
s0 = AESNI_ENC(s0, key, nr);
staging_block = _mm_xor_si128(s0, rolling_mac);
bcopy(&staging_block, tag, tag_length);
explicit_bzero(&s0, sizeof(s0));
explicit_bzero(&staging_block, sizeof(staging_block));
explicit_bzero(&s_x, sizeof(s_x));
explicit_bzero(&rolling_mac, sizeof(rolling_mac));
}
/*
* Implement AES CCM+CBC-MAC decryption and authentication.
* Returns 0 on failure, 1 on success.
*
* The primary difference here is that each encrypted block
* needs to be hashed&encrypted after it is decrypted (since
* the CBC-MAC is based on the plain text). This means that
* we do the decryption twice -- first to verify the tag,
* and second to decrypt and copy it out.
*
* To avoid annoying code copying, we implement the main
* loop as a separate function.
*
* Call with out as NULL to not store the decrypted results;
* call with hashp as NULL to not run the authentication.
* Calling with neither as NULL does the decryption and
* authentication as a single pass (which is not allowed
* per the specification, really).
*
* If hashp is non-NULL, it points to the post-AAD computed
* checksum.
*/
static void
decrypt_loop(const unsigned char *in, unsigned char *out, size_t nbytes,
__m128i s0, size_t nonce_length, __m128i *macp,
const unsigned char *key, int nr)
{
size_t total = 0;
__m128i s_x = s0, mac_block;
int counter = 1;
const size_t L = sizeof(__m128i) - 1 - nonce_length;
__m128i pad_block, staging_block;
/*
* The starting mac (post AAD, if any).
*/
if (macp != NULL)
mac_block = *macp;
while (total < nbytes) {
size_t copy_amt = MIN(nbytes - total, sizeof(staging_block));
if (copy_amt < sizeof(staging_block)) {
staging_block = _mm_setzero_si128();
}
bcopy(in+total, &staging_block, copy_amt);
/*
* staging_block has the current block of input data,
* zero-padded if necessary. This is used in computing
* both the decrypted data, and the authentication tag.
*/
append_int(counter++, &s_x, L+1);
/*
* The tag is computed based on the decrypted data.
*/
pad_block = AESNI_ENC(s_x, key, nr);
if (copy_amt < sizeof(staging_block)) {
/*
* Need to pad out pad_block with 0.
* (staging_block was set to 0's above.)
*/
uint8_t *end_of_buffer = (uint8_t*)&pad_block;
bzero(end_of_buffer + copy_amt,
sizeof(pad_block) - copy_amt);
}
staging_block = _mm_xor_si128(staging_block, pad_block);
if (out)
bcopy(&staging_block, out+total, copy_amt);
if (macp)
mac_block = xor_and_encrypt(mac_block, staging_block,
key, nr);
total += copy_amt;
}
if (macp)
*macp = mac_block;
explicit_bzero(&pad_block, sizeof(pad_block));
explicit_bzero(&staging_block, sizeof(staging_block));
explicit_bzero(&mac_block, sizeof(mac_block));
}
/*
* The exposed decryption routine. This is practically a
* copy of the encryption routine, except that the order
* in which the tag is created is changed.
* XXX combine the two functions at some point!
*/
int
AES_CCM_decrypt(const unsigned char *in, unsigned char *out,
const unsigned char *addt, const unsigned char *nonce,
const unsigned char *tag, uint32_t nbytes, uint32_t abytes, int nlen,
const unsigned char *key, int nr)
{
static const int tag_length = 16; /* 128 bits */
int L;
__m128i s0, rolling_mac, staging_block;
uint8_t *byte_ptr;
if (nbytes == 0 && abytes == 0)
return (1); // No message means no decryption!
if (nlen < 0 || nlen > 15)
panic("%s: bad nonce length %d", __FUNCTION__, nlen);
/*
* We need to know how many bytes to use to describe
* the length of the data. Normally, nlen should be
* 12, which leaves us 3 bytes to do that -- 16mbytes of
* data to encrypt. But it can be longer or shorter.
*/
L = sizeof(__m128i) - 1 - nlen;
/*
* Now, this shouldn't happen, but let's make sure that
* the data length isn't too big.
*/
if (nbytes > ((1 << (8 * L)) - 1))
panic("%s: nbytes is %u, but length field is %d bytes",
__FUNCTION__, nbytes, L);
/*
* Clear out the blocks
*/
s0 = _mm_setzero_si128();
rolling_mac = cbc_mac_start(addt, abytes, nonce, nlen,
key, nr, nbytes, tag_length);
/* s0 has flags, nonce, and then 0 */
byte_ptr = (uint8_t*)&s0;
byte_ptr[0] = L-1; /* but the flags byte only has L' */
bcopy(nonce, &byte_ptr[1], nlen);
/*
* Now to cycle through the rest of the data.
*/
decrypt_loop(in, NULL, nbytes, s0, nlen, &rolling_mac, key, nr);
/*
* Compare the tag.
*/
staging_block = _mm_xor_si128(AESNI_ENC(s0, key, nr), rolling_mac);
if (timingsafe_bcmp(&staging_block, tag, tag_length) != 0) {
return (0);
}
/*
* Push out the decryption results this time.
*/
decrypt_loop(in, out, nbytes, s0, nlen, NULL, key, nr);
return (1);
}