[linux-2.6-block.git] / net / sunrpc / auth_gss / gss_krb5_keys.c

/*
 * COPYRIGHT (c) 2008
 * The Regents of the University of Michigan
 * ALL RIGHTS RESERVED
 *
 * Permission is granted to use, copy, create derivative works
 * and redistribute this software and such derivative works
 * for any purpose, so long as the name of The University of
 * Michigan is not used in any advertising or publicity
 * pertaining to the use of distribution of this software
 * without specific, written prior authorization.  If the
 * above copyright notice or any other identification of the
 * University of Michigan is included in any copy of any
 * portion of this software, then the disclaimer below must
 * also be included.
 *
 * THIS SOFTWARE IS PROVIDED AS IS, WITHOUT REPRESENTATION
 * FROM THE UNIVERSITY OF MICHIGAN AS TO ITS FITNESS FOR ANY
 * PURPOSE, AND WITHOUT WARRANTY BY THE UNIVERSITY OF
 * MICHIGAN OF ANY KIND, EITHER EXPRESS OR IMPLIED, INCLUDING
 * WITHOUT LIMITATION THE IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. THE
 * REGENTS OF THE UNIVERSITY OF MICHIGAN SHALL NOT BE LIABLE
 * FOR ANY DAMAGES, INCLUDING SPECIAL, INDIRECT, INCIDENTAL, OR
 * CONSEQUENTIAL DAMAGES, WITH RESPECT TO ANY CLAIM ARISING
 * OUT OF OR IN CONNECTION WITH THE USE OF THE SOFTWARE, EVEN
 * IF IT HAS BEEN OR IS HEREAFTER ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGES.
 */

/*
 * Copyright (C) 1998 by the FundsXpress, INC.
 *
 * All rights reserved.
 *
 * Export of this software from the United States of America may require
 * a specific license from the United States Government.  It is the
 * responsibility of any person or organization contemplating export to
 * obtain such a license before exporting.
 *
 * WITHIN THAT CONSTRAINT, permission to use, copy, modify, and
 * distribute this software and its documentation for any purpose and
 * without fee is hereby granted, provided that the above copyright
 * notice appear in all copies and that both that copyright notice and
 * this permission notice appear in supporting documentation, and that
 * the name of FundsXpress. not be used in advertising or publicity pertaining
 * to distribution of the software without specific, written prior
 * permission.  FundsXpress makes no representations about the suitability of
 * this software for any purpose.  It is provided "as is" without express
 * or implied warranty.
 *
 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
 * WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE.
 */

#include <linux/err.h>
#include <linux/types.h>
#include <linux/crypto.h>
#include <linux/sunrpc/gss_krb5.h>
#include <linux/sunrpc/xdr.h>

#ifdef RPC_DEBUG
# define RPCDBG_FACILITY        RPCDBG_AUTH
#endif

/*
 * This is the n-fold function as described in rfc3961, sec 5.1
 * Taken from MIT Kerberos and modified.
 */

static void krb5_nfold(u32 inbits, const u8 *in,
		       u32 outbits, u8 *out)
{
	int a, b, c, lcm;
	int byte, i, msbit;

	/* the code below is more readable if I make these bytes
	   instead of bits */

	inbits >>= 3;
	outbits >>= 3;

	/* first compute lcm(n,k) */

	a = outbits;
	b = inbits;

	while (b != 0) {
		c = b;
		b = a%b;
		a = c;
	}

	lcm = outbits*inbits/a;

	/* now do the real work */

	memset(out, 0, outbits);
	byte = 0;

	/* this will end up cycling through k lcm(k,n)/k times, which
	   is correct */
	for (i = lcm-1; i >= 0; i--) {
		/* compute the msbit in k which gets added into this byte */
		msbit = (
			/* first, start with the msbit in the first,
			 * unrotated byte */
			 ((inbits << 3) - 1)
			 /* then, for each byte, shift to the right
			  * for each repetition */
			 + (((inbits << 3) + 13) * (i/inbits))
			 /* last, pick out the correct byte within
			  * that shifted repetition */
			 + ((inbits - (i % inbits)) << 3)
			 ) % (inbits << 3);

		/* pull out the byte value itself */
		byte += (((in[((inbits - 1) - (msbit >> 3)) % inbits] << 8)|
				  (in[((inbits) - (msbit >> 3)) % inbits]))
				 >> ((msbit & 7) + 1)) & 0xff;

		/* do the addition */
		byte += out[i % outbits];
		out[i % outbits] = byte & 0xff;

		/* keep around the carry bit, if any */
		byte >>= 8;

	}

	/* if there's a carry bit left over, add it back in */
	if (byte) {
		for (i = outbits - 1; i >= 0; i--) {
			/* do the addition */
			byte += out[i];
			out[i] = byte & 0xff;

			/* keep around the carry bit, if any */
			byte >>= 8;
		}
	}
}

/*
 * This is the DK (derive_key) function as described in rfc3961, sec 5.1
 * Taken from MIT Kerberos and modified.
 */

u32 krb5_derive_key(const struct gss_krb5_enctype *gk5e,
		    const struct xdr_netobj *inkey,
		    struct xdr_netobj *outkey,
		    const struct xdr_netobj *in_constant,
		    gfp_t gfp_mask)
{
	size_t blocksize, keybytes, keylength, n;
	unsigned char *inblockdata, *outblockdata, *rawkey;
	struct xdr_netobj inblock, outblock;
	struct crypto_blkcipher *cipher;
	u32 ret = EINVAL;

	blocksize = gk5e->blocksize;
	keybytes = gk5e->keybytes;
	keylength = gk5e->keylength;

	if ((inkey->len != keylength) || (outkey->len != keylength))
		goto err_return;

	cipher = crypto_alloc_blkcipher(gk5e->encrypt_name, 0,
					CRYPTO_ALG_ASYNC);
	if (IS_ERR(cipher))
		goto err_return;
	if (crypto_blkcipher_setkey(cipher, inkey->data, inkey->len))
		goto err_return;

	/* allocate and set up buffers */

	ret = ENOMEM;
	inblockdata = kmalloc(blocksize, gfp_mask);
	if (inblockdata == NULL)
		goto err_free_cipher;

	outblockdata = kmalloc(blocksize, gfp_mask);
	if (outblockdata == NULL)
		goto err_free_in;

	rawkey = kmalloc(keybytes, gfp_mask);
	if (rawkey == NULL)
		goto err_free_out;

	inblock.data = (char *) inblockdata;
	inblock.len = blocksize;

	outblock.data = (char *) outblockdata;
	outblock.len = blocksize;

	/* initialize the input block */

	if (in_constant->len == inblock.len) {
		memcpy(inblock.data, in_constant->data, inblock.len);
	} else {
		krb5_nfold(in_constant->len * 8, in_constant->data,
			   inblock.len * 8, inblock.data);
	}

	/* loop encrypting the blocks until enough key bytes are generated */

	n = 0;
	while (n < keybytes) {
		(*(gk5e->encrypt))(cipher, NULL, inblock.data,
				   outblock.data, inblock.len);

		if ((keybytes - n) <= outblock.len) {
			memcpy(rawkey + n, outblock.data, (keybytes - n));
			break;
		}

		memcpy(rawkey + n, outblock.data, outblock.len);
		memcpy(inblock.data, outblock.data, outblock.len);
		n += outblock.len;
	}

	/* postprocess the key */

	inblock.data = (char *) rawkey;
	inblock.len = keybytes;

	BUG_ON(gk5e->mk_key == NULL);
	ret = (*(gk5e->mk_key))(gk5e, &inblock, outkey);
	if (ret) {
		dprintk("%s: got %d from mk_key function for '%s'\n",
			__func__, ret, gk5e->encrypt_name);
		goto err_free_raw;
	}

	/* clean memory, free resources and exit */

	ret = 0;

err_free_raw:
	memset(rawkey, 0, keybytes);
	kfree(rawkey);
err_free_out:
	memset(outblockdata, 0, blocksize);
	kfree(outblockdata);
err_free_in:
	memset(inblockdata, 0, blocksize);
	kfree(inblockdata);
err_free_cipher:
	crypto_free_blkcipher(cipher);
err_return:
	return ret;
}

#define smask(step) ((1<<step)-1)
#define pstep(x, step) (((x)&smask(step))^(((x)>>step)&smask(step)))
#define parity_char(x) pstep(pstep(pstep((x), 4), 2), 1)

static void mit_des_fixup_key_parity(u8 key[8])
{
	int i;
	for (i = 0; i < 8; i++) {
		key[i] &= 0xfe;
		key[i] |= 1^parity_char(key[i]);
	}
}

/*
 * This is the des3 key derivation postprocess function
 */
u32 gss_krb5_des3_make_key(const struct gss_krb5_enctype *gk5e,
			   struct xdr_netobj *randombits,
			   struct xdr_netobj *key)
{
	int i;
	u32 ret = EINVAL;

	if (key->len != 24) {
		dprintk("%s: key->len is %d\n", __func__, key->len);
		goto err_out;
	}
	if (randombits->len != 21) {
		dprintk("%s: randombits->len is %d\n",
			__func__, randombits->len);
		goto err_out;
	}

	/* take the seven bytes, move them around into the top 7 bits of the
	   8 key bytes, then compute the parity bits.  Do this three times. */

	for (i = 0; i < 3; i++) {
		memcpy(key->data + i*8, randombits->data + i*7, 7);
		key->data[i*8+7] = (((key->data[i*8]&1)<<1) |
				    ((key->data[i*8+1]&1)<<2) |
				    ((key->data[i*8+2]&1)<<3) |
				    ((key->data[i*8+3]&1)<<4) |
				    ((key->data[i*8+4]&1)<<5) |
				    ((key->data[i*8+5]&1)<<6) |
				    ((key->data[i*8+6]&1)<<7));

		mit_des_fixup_key_parity(key->data + i*8);
	}
	ret = 0;
err_out:
	return ret;
}

/*
 * This is the aes key derivation postprocess function
 */
u32 gss_krb5_aes_make_key(const struct gss_krb5_enctype *gk5e,
			  struct xdr_netobj *randombits,
			  struct xdr_netobj *key)
{
	u32 ret = EINVAL;

	if (key->len != 16 && key->len != 32) {
		dprintk("%s: key->len is %d\n", __func__, key->len);
		goto err_out;
	}
	if (randombits->len != 16 && randombits->len != 32) {
		dprintk("%s: randombits->len is %d\n",
			__func__, randombits->len);
		goto err_out;
	}
	if (randombits->len != key->len) {
		dprintk("%s: randombits->len is %d, key->len is %d\n",
			__func__, randombits->len, key->len);
		goto err_out;
	}
	memcpy(key->data, randombits->data, key->len);
	ret = 0;
err_out:
	return ret;
}
Commit	Line	Data
4891f2d0 KC	1	/*
	2	* COPYRIGHT (c) 2008
	3	* The Regents of the University of Michigan
	4	* ALL RIGHTS RESERVED
	5	*
	6	* Permission is granted to use, copy, create derivative works
	7	* and redistribute this software and such derivative works
	8	* for any purpose, so long as the name of The University of
	9	* Michigan is not used in any advertising or publicity
	10	* pertaining to the use of distribution of this software
	11	* without specific, written prior authorization. If the
	12	* above copyright notice or any other identification of the
	13	* University of Michigan is included in any copy of any
	14	* portion of this software, then the disclaimer below must
	15	* also be included.
	16	*
	17	* THIS SOFTWARE IS PROVIDED AS IS, WITHOUT REPRESENTATION
	18	* FROM THE UNIVERSITY OF MICHIGAN AS TO ITS FITNESS FOR ANY
	19	* PURPOSE, AND WITHOUT WARRANTY BY THE UNIVERSITY OF
	20	* MICHIGAN OF ANY KIND, EITHER EXPRESS OR IMPLIED, INCLUDING
	21	* WITHOUT LIMITATION THE IMPLIED WARRANTIES OF
	22	* MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. THE
	23	* REGENTS OF THE UNIVERSITY OF MICHIGAN SHALL NOT BE LIABLE
	24	* FOR ANY DAMAGES, INCLUDING SPECIAL, INDIRECT, INCIDENTAL, OR
	25	* CONSEQUENTIAL DAMAGES, WITH RESPECT TO ANY CLAIM ARISING
	26	* OUT OF OR IN CONNECTION WITH THE USE OF THE SOFTWARE, EVEN
	27	* IF IT HAS BEEN OR IS HEREAFTER ADVISED OF THE POSSIBILITY OF
	28	* SUCH DAMAGES.
	29	*/
	30
	31	/*
	32	* Copyright (C) 1998 by the FundsXpress, INC.
	33	*
	34	* All rights reserved.
	35	*
	36	* Export of this software from the United States of America may require
	37	* a specific license from the United States Government. It is the
	38	* responsibility of any person or organization contemplating export to
	39	* obtain such a license before exporting.
	40	*
	41	* WITHIN THAT CONSTRAINT, permission to use, copy, modify, and
	42	* distribute this software and its documentation for any purpose and
	43	* without fee is hereby granted, provided that the above copyright
	44	* notice appear in all copies and that both that copyright notice and
	45	* this permission notice appear in supporting documentation, and that
	46	* the name of FundsXpress. not be used in advertising or publicity pertaining
	47	* to distribution of the software without specific, written prior
	48	* permission. FundsXpress makes no representations about the suitability of
	49	* this software for any purpose. It is provided "as is" without express
	50	* or implied warranty.
	51	*
	52	* THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
	53	* IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
	54	* WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE.
	55	*/
	56
	57	#include <linux/err.h>
	58	#include <linux/types.h>
	59	#include <linux/crypto.h>
	60	#include <linux/sunrpc/gss_krb5.h>
	61	#include <linux/sunrpc/xdr.h>
	62
	63	#ifdef RPC_DEBUG
	64	# define RPCDBG_FACILITY RPCDBG_AUTH
65	#endif
66
67	/*
68	* This is the n-fold function as described in rfc3961, sec 5.1
69	* Taken from MIT Kerberos and modified.
70	*/
71
72	static void krb5_nfold(u32 inbits, const u8 *in,
73	u32 outbits, u8 *out)
74	{
75	int a, b, c, lcm;
76	int byte, i, msbit;
77
78	/* the code below is more readable if I make these bytes
79	instead of bits */
80
81	inbits >>= 3;
82	outbits >>= 3;
83
84	/* first compute lcm(n,k) */
85
86	a = outbits;
87	b = inbits;
88
89	while (b != 0) {
90	c = b;
91	b = a%b;
92	a = c;
93	}
94
95	lcm = outbits*inbits/a;
96
97	/* now do the real work */
98
99	memset(out, 0, outbits);
100	byte = 0;
101
102	/* this will end up cycling through k lcm(k,n)/k times, which
103	is correct */
104	for (i = lcm-1; i >= 0; i--) {
105	/* compute the msbit in k which gets added into this byte */
106	msbit = (
107	/* first, start with the msbit in the first,
108	* unrotated byte */
109	((inbits << 3) - 1)
110	/* then, for each byte, shift to the right
111	* for each repetition */
112	+ (((inbits << 3) + 13) * (i/inbits))
113	/* last, pick out the correct byte within
114	* that shifted repetition */
115	+ ((inbits - (i % inbits)) << 3)
116	) % (inbits << 3);
117
118	/* pull out the byte value itself */
119	byte += (((in[((inbits - 1) - (msbit >> 3)) % inbits] << 8)\|
120	(in[((inbits) - (msbit >> 3)) % inbits]))
121	>> ((msbit & 7) + 1)) & 0xff;
122
123	/* do the addition */
124	byte += out[i % outbits];
125	out[i % outbits] = byte & 0xff;
126
127	/* keep around the carry bit, if any */
128	byte >>= 8;
129
130	}
131
132	/* if there's a carry bit left over, add it back in */
133	if (byte) {
134	for (i = outbits - 1; i >= 0; i--) {
135	/* do the addition */
136	byte += out[i];
137	out[i] = byte & 0xff;
138
139	/* keep around the carry bit, if any */
140	byte >>= 8;
141	}
142	}
143	}
144
145	/*
146	* This is the DK (derive_key) function as described in rfc3961, sec 5.1
147	* Taken from MIT Kerberos and modified.
148	*/
149
47d84807	150	u32 krb5_derive_key(const struct gss_krb5_enctype *gk5e,
4891f2d0 KC	151	const struct xdr_netobj *inkey,
4891f2d0 KC	152	struct xdr_netobj *outkey,
1f4c86c0 TM	153	const struct xdr_netobj *in_constant,
1f4c86c0 TM	154	gfp_t gfp_mask)
4891f2d0 KC	155	{
	156	size_t blocksize, keybytes, keylength, n;
	157	unsigned char inblockdata, outblockdata, *rawkey;
	158	struct xdr_netobj inblock, outblock;
	159	struct crypto_blkcipher *cipher;
	160	u32 ret = EINVAL;
	161
	162	blocksize = gk5e->blocksize;
	163	keybytes = gk5e->keybytes;
	164	keylength = gk5e->keylength;
	165
	166	if ((inkey->len != keylength) \|\| (outkey->len != keylength))
	167	goto err_return;
	168
	169	cipher = crypto_alloc_blkcipher(gk5e->encrypt_name, 0,
	170	CRYPTO_ALG_ASYNC);
	171	if (IS_ERR(cipher))
	172	goto err_return;
	173	if (crypto_blkcipher_setkey(cipher, inkey->data, inkey->len))
	174	goto err_return;
	175
	176	/* allocate and set up buffers */
	177
	178	ret = ENOMEM;
1f4c86c0	179	inblockdata = kmalloc(blocksize, gfp_mask);
4891f2d0 KC	180	if (inblockdata == NULL)
	181	goto err_free_cipher;
	182
1f4c86c0	183	outblockdata = kmalloc(blocksize, gfp_mask);
4891f2d0 KC	184	if (outblockdata == NULL)
	185	goto err_free_in;
	186
1f4c86c0	187	rawkey = kmalloc(keybytes, gfp_mask);
4891f2d0 KC	188	if (rawkey == NULL)
	189	goto err_free_out;
	190
	191	inblock.data = (char *) inblockdata;
	192	inblock.len = blocksize;
	193
	194	outblock.data = (char *) outblockdata;
	195	outblock.len = blocksize;
	196
	197	/* initialize the input block */
	198
	199	if (in_constant->len == inblock.len) {
	200	memcpy(inblock.data, in_constant->data, inblock.len);
	201	} else {
	202	krb5_nfold(in_constant->len * 8, in_constant->data,
	203	inblock.len * 8, inblock.data);
	204	}
	205
	206	/* loop encrypting the blocks until enough key bytes are generated */
	207
	208	n = 0;
	209	while (n < keybytes) {
	210	(*(gk5e->encrypt))(cipher, NULL, inblock.data,
	211	outblock.data, inblock.len);
	212
	213	if ((keybytes - n) <= outblock.len) {
	214	memcpy(rawkey + n, outblock.data, (keybytes - n));
	215	break;
	216	}
	217
	218	memcpy(rawkey + n, outblock.data, outblock.len);
	219	memcpy(inblock.data, outblock.data, outblock.len);
	220	n += outblock.len;
	221	}
	222
	223	/* postprocess the key */
	224
	225	inblock.data = (char *) rawkey;
	226	inblock.len = keybytes;
	227
	228	BUG_ON(gk5e->mk_key == NULL);
	229	ret = (*(gk5e->mk_key))(gk5e, &inblock, outkey);
	230	if (ret) {
	231	dprintk("%s: got %d from mk_key function for '%s'\n",
	232	__func__, ret, gk5e->encrypt_name);
	233	goto err_free_raw;
	234	}
	235
	236	/* clean memory, free resources and exit */
	237
	238	ret = 0;
	239
	240	err_free_raw:
	241	memset(rawkey, 0, keybytes);
	242	kfree(rawkey);
	243	err_free_out:
	244	memset(outblockdata, 0, blocksize);
	245	kfree(outblockdata);
	246	err_free_in:
	247	memset(inblockdata, 0, blocksize);
	248	kfree(inblockdata);
	249	err_free_cipher:
	250	crypto_free_blkcipher(cipher);
	251	err_return:
252	return ret;
253	}
958142e9 KC	254
	255	#define smask(step) ((1<<step)-1)
	256	#define pstep(x, step) (((x)&smask(step))^(((x)>>step)&smask(step)))
	257	#define parity_char(x) pstep(pstep(pstep((x), 4), 2), 1)
	258
	259	static void mit_des_fixup_key_parity(u8 key[8])
	260	{
	261	int i;
	262	for (i = 0; i < 8; i++) {
	263	key[i] &= 0xfe;
	264	key[i] \|= 1^parity_char(key[i]);
	265	}
	266	}
	267
	268	/*
	269	* This is the des3 key derivation postprocess function
	270	*/
	271	u32 gss_krb5_des3_make_key(const struct gss_krb5_enctype *gk5e,
	272	struct xdr_netobj *randombits,
	273	struct xdr_netobj *key)
	274	{
	275	int i;
	276	u32 ret = EINVAL;
	277
	278	if (key->len != 24) {
	279	dprintk("%s: key->len is %d\n", __func__, key->len);
	280	goto err_out;
	281	}
	282	if (randombits->len != 21) {
	283	dprintk("%s: randombits->len is %d\n",
	284	__func__, randombits->len);
	285	goto err_out;
	286	}
	287
	288	/* take the seven bytes, move them around into the top 7 bits of the
	289	8 key bytes, then compute the parity bits. Do this three times. */
	290
	291	for (i = 0; i < 3; i++) {
	292	memcpy(key->data + i8, randombits->data + i7, 7);
	293	key->data[i8+7] = (((key->data[i8]&1)<<1) \|
	294	((key->data[i*8+1]&1)<<2) \|
	295	((key->data[i*8+2]&1)<<3) \|
	296	((key->data[i*8+3]&1)<<4) \|
	297	((key->data[i*8+4]&1)<<5) \|
	298	((key->data[i*8+5]&1)<<6) \|
	299	((key->data[i*8+6]&1)<<7));
	300
	301	mit_des_fixup_key_parity(key->data + i*8);
	302	}
	303	ret = 0;
	304	err_out:
	305	return ret;
	306	}
934a95aa KC	307
	308	/*
	309	* This is the aes key derivation postprocess function
	310	*/
	311	u32 gss_krb5_aes_make_key(const struct gss_krb5_enctype *gk5e,
	312	struct xdr_netobj *randombits,
	313	struct xdr_netobj *key)
	314	{
	315	u32 ret = EINVAL;
	316
	317	if (key->len != 16 && key->len != 32) {
	318	dprintk("%s: key->len is %d\n", __func__, key->len);
	319	goto err_out;
	320	}
	321	if (randombits->len != 16 && randombits->len != 32) {
	322	dprintk("%s: randombits->len is %d\n",
	323	__func__, randombits->len);
	324	goto err_out;
	325	}
	326	if (randombits->len != key->len) {
	327	dprintk("%s: randombits->len is %d, key->len is %d\n",
	328	__func__, randombits->len, key->len);
	329	goto err_out;
	330	}
	331	memcpy(key->data, randombits->data, key->len);
	332	ret = 0;
	333	err_out:
	334	return ret;
	335	}
	336