Return to uvm_swap_encrypt.c CVS log

Up to [local] / src / sys / uvm

Convert bzero to memset(X, 0..) and bcopy to memcpy.
This is to match (make diffs smaller) the code in NetBSD.
new gcc inlines those functions, so this could also be a performance win.

/*
 * Copyright 1999 Niels Provos <provos@citi.umich.edu>
 * All rights reserved.
 *
 * 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.
 * 3. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *      This product includes software developed by Niels Provos.
 * 4. The name of the author may not be used to endorse or promote products
 *    derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``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 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.
 */

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/kernel.h>
#include <sys/malloc.h>
#include <sys/sysctl.h>
#include <sys/time.h>
#include <dev/rndvar.h>
#include <crypto/rijndael.h>

#include <vm/vm.h>
#include <vm/vm_conf.h>

#include <uvm/uvm.h>

struct swap_key *kcur = NULL;
rijndael_ctx swap_key;

int uvm_doswapencrypt = 0;
u_int uvm_swpkeyscreated = 0;
u_int uvm_swpkeysdeleted = 0;

int swap_encrypt_initalized = 0;

int
swap_encrypt_ctl(name, namelen, oldp, oldlenp, newp, newlen, p)
	int *name;
	u_int namelen;
	void *oldp;
	size_t *oldlenp;
	void *newp;
	size_t newlen;
	struct proc *p;
{
	/* all sysctl names at this level are terminal */
	if (namelen != 1)
		return (ENOTDIR);		/* overloaded */

	switch (name[0]) {
	case SWPENC_ENABLE: {
		int doencrypt = uvm_doswapencrypt;
		int result;

		result = sysctl_int(oldp, oldlenp, newp, newlen, &doencrypt);
		if (result)
			return result;

		/* Swap Encryption has been turned on, we need to
		 * initalize state for swap devices that have been
		 * added 
		 */
		if (doencrypt)
			uvm_swap_initcrypt_all();
		uvm_doswapencrypt = doencrypt;
		return (0);
	}
	case SWPENC_CREATED:
		return (sysctl_rdint(oldp, oldlenp, newp, uvm_swpkeyscreated));
	case SWPENC_DELETED:
		return (sysctl_rdint(oldp, oldlenp, newp, uvm_swpkeysdeleted));
	default:
		return (EOPNOTSUPP);
	}
	/* NOTREACHED */
}

void
swap_key_create(struct swap_key *key)
{
	int i;
	u_int32_t *p = key->key;

	key->refcount = 0;
	for (i = 0; i < sizeof(key->key) / sizeof(u_int32_t); i++)
		*p++ = arc4random();

	uvm_swpkeyscreated++;
}

void
swap_key_delete(struct swap_key *key)
{
	/* Make sure that this key gets removed if we just used it */
	swap_key_cleanup(key);

	memset(key, 0, sizeof(*key));
	uvm_swpkeysdeleted++;
}

/*
 * Encrypt the data before it goes to swap, the size should be 64-bit
 * aligned.
 */

void
swap_encrypt(struct swap_key *key, caddr_t src, caddr_t dst,
	     u_int64_t block, size_t count)
{
	u_int32_t *dsrc = (u_int32_t *)src;
	u_int32_t *ddst = (u_int32_t *)dst;
	u_int32_t iv[4];
	u_int32_t iv1, iv2, iv3, iv4;

	if (!swap_encrypt_initalized)
		swap_encrypt_initalized = 1;

	swap_key_prepare(key, 1);

	count /= sizeof(u_int32_t);

	iv[0] = block >> 32; iv[1] = block; iv[2] = ~iv[0]; iv[3] = ~iv[1];
	rijndael_encrypt(&swap_key, iv, iv); 
	iv1 = iv[0]; iv2 = iv[1]; iv3 = iv[2]; iv4 = iv[3];

	for (; count > 0; count -= 4) {
		ddst[0] = dsrc[0] ^ iv1;
		ddst[1] = dsrc[1] ^ iv2;
		ddst[2] = dsrc[2] ^ iv3;
		ddst[3] = dsrc[3] ^ iv4;
		/*
		 * Do not worry about endianess, it only needs to decrypt
		 * on this machine
		 */
		rijndael_encrypt(&swap_key, ddst, ddst);
		iv1 = ddst[0];
		iv2 = ddst[1];
		iv3 = ddst[2];
		iv4 = ddst[3];

		dsrc += 4;
		ddst += 4;
	}
}

/*
 * Decrypt the data after we retrieved it from swap, the size should be 64-bit
 * aligned.
 */

void
swap_decrypt(struct swap_key *key, caddr_t src, caddr_t dst,
	     u_int64_t block, size_t count)
{
	u_int32_t *dsrc = (u_int32_t *)src;
	u_int32_t *ddst = (u_int32_t *)dst;
	u_int32_t iv[4];
	u_int32_t iv1, iv2, iv3, iv4, niv1, niv2, niv3, niv4;

	if (!swap_encrypt_initalized)
		panic("swap_decrypt: key not initalized");

	swap_key_prepare(key, 0);

	count /= sizeof(u_int32_t);

	iv[0] = block >> 32; iv[1] = block; iv[2] = ~iv[0]; iv[3] = ~iv[1];
	rijndael_encrypt(&swap_key, iv, iv); 
	iv1 = iv[0]; iv2 = iv[1]; iv3 = iv[2]; iv4 = iv[3];

	for (; count > 0; count -= 4) {
		ddst[0] = niv1 = dsrc[0];
		ddst[1] = niv2 = dsrc[1];
		ddst[2] = niv3 = dsrc[2];
		ddst[3] = niv4 = dsrc[3];
		rijndael_decrypt(&swap_key, ddst, ddst);
		ddst[0] ^= iv1;
		ddst[1] ^= iv2;
		ddst[2] ^= iv3;
		ddst[3] ^= iv4;

		iv1 = niv1;
		iv2 = niv2;
		iv3 = niv3;
		iv4 = niv4;

		dsrc += 4;
		ddst += 4;
	}
}

void
swap_key_prepare(struct swap_key *key, int encrypt)
{
	/* Check if we have prepared for this key already,
	 * if we only have the encryption schedule, we have
	 * to recompute ang get the decryption schedule also
	 */
	if (kcur == key && (encrypt || swap_key.decrypt))
		return;

	rijndael_set_key(&swap_key, key->key,
			 sizeof(key->key) * 8,
			 encrypt);

	kcur = key;
}

/*
 * Make sure that a specific key is no longer available.
 */

void
swap_key_cleanup(struct swap_key *key)
{
	/* Check if we have a key */
	if (kcur == NULL || kcur != key)
		return;

	/* Zero out the subkeys */
       	memset(&swap_key, 0, sizeof(swap_key));

	kcur = NULL;
}