[deliverable/linux.git] / net / sunrpc / auth_gss / gss_krb5_crypto.c

/*
 *  linux/net/sunrpc/gss_krb5_crypto.c
 *
 *  Copyright (c) 2000 The Regents of the University of Michigan.
 *  All rights reserved.
 *
 *  Andy Adamson   <andros@umich.edu>
 *  Bruce Fields   <bfields@umich.edu>
 */

/*
 * 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/types.h>
#include <linux/mm.h>
#include <linux/slab.h>
#include <linux/scatterlist.h>
#include <linux/crypto.h>
#include <linux/highmem.h>
#include <linux/pagemap.h>
#include <linux/sunrpc/gss_krb5.h>

#ifdef RPC_DEBUG
# define RPCDBG_FACILITY        RPCDBG_AUTH
#endif

u32
krb5_encrypt(
	struct crypto_blkcipher *tfm,
	void * iv,
	void * in,
	void * out,
	int length)
{
	u32 ret = -EINVAL;
        struct scatterlist sg[1];
	u8 local_iv[16] = {0};
	struct blkcipher_desc desc = { .tfm = tfm, .info = local_iv };

	dprintk("RPC:      krb5_encrypt: input data:\n");
	print_hexl((u32 *)in, length, 0);

	if (length % crypto_blkcipher_blocksize(tfm) != 0)
		goto out;

	if (crypto_blkcipher_ivsize(tfm) > 16) {
		dprintk("RPC:      gss_k5encrypt: tfm iv size to large %d\n",
		         crypto_blkcipher_ivsize(tfm));
		goto out;
	}

	if (iv)
		memcpy(local_iv, iv, crypto_blkcipher_ivsize(tfm));

	memcpy(out, in, length);
	sg_set_buf(sg, out, length);

	ret = crypto_blkcipher_encrypt_iv(&desc, sg, sg, length);

	dprintk("RPC:      krb5_encrypt: output data:\n");
	print_hexl((u32 *)out, length, 0);
out:
	dprintk("RPC:      krb5_encrypt returns %d\n",ret);
	return(ret);
}

EXPORT_SYMBOL(krb5_encrypt);

u32
krb5_decrypt(
     struct crypto_blkcipher *tfm,
     void * iv,
     void * in,
     void * out,
     int length)
{
	u32 ret = -EINVAL;
	struct scatterlist sg[1];
	u8 local_iv[16] = {0};
	struct blkcipher_desc desc = { .tfm = tfm, .info = local_iv };

	dprintk("RPC:      krb5_decrypt: input data:\n");
	print_hexl((u32 *)in, length, 0);

	if (length % crypto_blkcipher_blocksize(tfm) != 0)
		goto out;

	if (crypto_blkcipher_ivsize(tfm) > 16) {
		dprintk("RPC:      gss_k5decrypt: tfm iv size to large %d\n",
			crypto_blkcipher_ivsize(tfm));
		goto out;
	}
	if (iv)
		memcpy(local_iv,iv, crypto_blkcipher_ivsize(tfm));

	memcpy(out, in, length);
	sg_set_buf(sg, out, length);

	ret = crypto_blkcipher_decrypt_iv(&desc, sg, sg, length);

	dprintk("RPC:      krb5_decrypt: output_data:\n");
	print_hexl((u32 *)out, length, 0);
out:
	dprintk("RPC:      gss_k5decrypt returns %d\n",ret);
	return(ret);
}

EXPORT_SYMBOL(krb5_decrypt);

static int
process_xdr_buf(struct xdr_buf *buf, int offset, int len,
		int (*actor)(struct scatterlist *, void *), void *data)
{
	int i, page_len, thislen, page_offset, ret = 0;
	struct scatterlist	sg[1];

	if (offset >= buf->head[0].iov_len) {
		offset -= buf->head[0].iov_len;
	} else {
		thislen = buf->head[0].iov_len - offset;
		if (thislen > len)
			thislen = len;
		sg_set_buf(sg, buf->head[0].iov_base + offset, thislen);
		ret = actor(sg, data);
		if (ret)
			goto out;
		offset = 0;
		len -= thislen;
	}
	if (len == 0)
		goto out;

	if (offset >= buf->page_len) {
		offset -= buf->page_len;
	} else {
		page_len = buf->page_len - offset;
		if (page_len > len)
			page_len = len;
		len -= page_len;
		page_offset = (offset + buf->page_base) & (PAGE_CACHE_SIZE - 1);
		i = (offset + buf->page_base) >> PAGE_CACHE_SHIFT;
		thislen = PAGE_CACHE_SIZE - page_offset;
		do {
			if (thislen > page_len)
				thislen = page_len;
			sg->page = buf->pages[i];
			sg->offset = page_offset;
			sg->length = thislen;
			ret = actor(sg, data);
			if (ret)
				goto out;
			page_len -= thislen;
			i++;
			page_offset = 0;
			thislen = PAGE_CACHE_SIZE;
		} while (page_len != 0);
		offset = 0;
	}
	if (len == 0)
		goto out;

	if (offset < buf->tail[0].iov_len) {
		thislen = buf->tail[0].iov_len - offset;
		if (thislen > len)
			thislen = len;
		sg_set_buf(sg, buf->tail[0].iov_base + offset, thislen);
		ret = actor(sg, data);
		len -= thislen;
	}
	if (len != 0)
		ret = -EINVAL;
out:
	return ret;
}

static int
checksummer(struct scatterlist *sg, void *data)
{
	struct crypto_tfm *tfm = (struct crypto_tfm *)data;

	crypto_digest_update(tfm, sg, 1);

	return 0;
}

/* checksum the plaintext data and hdrlen bytes of the token header */
s32
make_checksum(s32 cksumtype, char *header, int hdrlen, struct xdr_buf *body,
		   int body_offset, struct xdr_netobj *cksum)
{
	char                            *cksumname;
	struct crypto_tfm               *tfm = NULL; /* XXX add to ctx? */
	struct scatterlist              sg[1];

	switch (cksumtype) {
		case CKSUMTYPE_RSA_MD5:
			cksumname = "md5";
			break;
		default:
			dprintk("RPC:      krb5_make_checksum:"
				" unsupported checksum %d", cksumtype);
			return GSS_S_FAILURE;
	}
	if (!(tfm = crypto_alloc_tfm(cksumname, CRYPTO_TFM_REQ_MAY_SLEEP)))
		return GSS_S_FAILURE;
	cksum->len = crypto_tfm_alg_digestsize(tfm);

	crypto_digest_init(tfm);
	sg_set_buf(sg, header, hdrlen);
	crypto_digest_update(tfm, sg, 1);
	process_xdr_buf(body, body_offset, body->len - body_offset,
			checksummer, tfm);
	crypto_digest_final(tfm, cksum->data);
	crypto_free_tfm(tfm);
	return 0;
}

EXPORT_SYMBOL(make_checksum);

struct encryptor_desc {
	u8 iv[8]; /* XXX hard-coded blocksize */
	struct blkcipher_desc desc;
	int pos;
	struct xdr_buf *outbuf;
	struct page **pages;
	struct scatterlist infrags[4];
	struct scatterlist outfrags[4];
	int fragno;
	int fraglen;
};

static int
encryptor(struct scatterlist *sg, void *data)
{
	struct encryptor_desc *desc = data;
	struct xdr_buf *outbuf = desc->outbuf;
	struct page *in_page;
	int thislen = desc->fraglen + sg->length;
	int fraglen, ret;
	int page_pos;

	/* Worst case is 4 fragments: head, end of page 1, start
	 * of page 2, tail.  Anything more is a bug. */
	BUG_ON(desc->fragno > 3);
	desc->infrags[desc->fragno] = *sg;
	desc->outfrags[desc->fragno] = *sg;

	page_pos = desc->pos - outbuf->head[0].iov_len;
	if (page_pos >= 0 && page_pos < outbuf->page_len) {
		/* pages are not in place: */
		int i = (page_pos + outbuf->page_base) >> PAGE_CACHE_SHIFT;
		in_page = desc->pages[i];
	} else {
		in_page = sg->page;
	}
	desc->infrags[desc->fragno].page = in_page;
	desc->fragno++;
	desc->fraglen += sg->length;
	desc->pos += sg->length;

	fraglen = thislen & 7; /* XXX hardcoded blocksize */
	thislen -= fraglen;

	if (thislen == 0)
		return 0;

	ret = crypto_blkcipher_encrypt_iv(&desc->desc, desc->outfrags,
					  desc->infrags, thislen);
	if (ret)
		return ret;
	if (fraglen) {
		desc->outfrags[0].page = sg->page;
		desc->outfrags[0].offset = sg->offset + sg->length - fraglen;
		desc->outfrags[0].length = fraglen;
		desc->infrags[0] = desc->outfrags[0];
		desc->infrags[0].page = in_page;
		desc->fragno = 1;
		desc->fraglen = fraglen;
	} else {
		desc->fragno = 0;
		desc->fraglen = 0;
	}
	return 0;
}

int
gss_encrypt_xdr_buf(struct crypto_blkcipher *tfm, struct xdr_buf *buf,
		    int offset, struct page **pages)
{
	int ret;
	struct encryptor_desc desc;

	BUG_ON((buf->len - offset) % crypto_blkcipher_blocksize(tfm) != 0);

	memset(desc.iv, 0, sizeof(desc.iv));
	desc.desc.tfm = tfm;
	desc.desc.info = desc.iv;
	desc.desc.flags = 0;
	desc.pos = offset;
	desc.outbuf = buf;
	desc.pages = pages;
	desc.fragno = 0;
	desc.fraglen = 0;

	ret = process_xdr_buf(buf, offset, buf->len - offset, encryptor, &desc);
	return ret;
}

EXPORT_SYMBOL(gss_encrypt_xdr_buf);

struct decryptor_desc {
	u8 iv[8]; /* XXX hard-coded blocksize */
	struct blkcipher_desc desc;
	struct scatterlist frags[4];
	int fragno;
	int fraglen;
};

static int
decryptor(struct scatterlist *sg, void *data)
{
	struct decryptor_desc *desc = data;
	int thislen = desc->fraglen + sg->length;
	int fraglen, ret;

	/* Worst case is 4 fragments: head, end of page 1, start
	 * of page 2, tail.  Anything more is a bug. */
	BUG_ON(desc->fragno > 3);
	desc->frags[desc->fragno] = *sg;
	desc->fragno++;
	desc->fraglen += sg->length;

	fraglen = thislen & 7; /* XXX hardcoded blocksize */
	thislen -= fraglen;

	if (thislen == 0)
		return 0;

	ret = crypto_blkcipher_decrypt_iv(&desc->desc, desc->frags,
					  desc->frags, thislen);
	if (ret)
		return ret;
	if (fraglen) {
		desc->frags[0].page = sg->page;
		desc->frags[0].offset = sg->offset + sg->length - fraglen;
		desc->frags[0].length = fraglen;
		desc->fragno = 1;
		desc->fraglen = fraglen;
	} else {
		desc->fragno = 0;
		desc->fraglen = 0;
	}
	return 0;
}

int
gss_decrypt_xdr_buf(struct crypto_blkcipher *tfm, struct xdr_buf *buf,
		    int offset)
{
	struct decryptor_desc desc;

	/* XXXJBF: */
	BUG_ON((buf->len - offset) % crypto_blkcipher_blocksize(tfm) != 0);

	memset(desc.iv, 0, sizeof(desc.iv));
	desc.desc.tfm = tfm;
	desc.desc.info = desc.iv;
	desc.desc.flags = 0;
	desc.fragno = 0;
	desc.fraglen = 0;
	return process_xdr_buf(buf, offset, buf->len - offset, decryptor, &desc);
}

EXPORT_SYMBOL(gss_decrypt_xdr_buf);
Commit	Line	Data
1da177e4 LT	1	/*
	2	* linux/net/sunrpc/gss_krb5_crypto.c
	3	*
	4	* Copyright (c) 2000 The Regents of the University of Michigan.
	5	* All rights reserved.
	6	*
	7	* Andy Adamson <andros@umich.edu>
	8	* Bruce Fields <bfields@umich.edu>
	9	*/
	10
	11	/*
	12	* Copyright (C) 1998 by the FundsXpress, INC.
	13	*
	14	* All rights reserved.
	15	*
	16	* Export of this software from the United States of America may require
	17	* a specific license from the United States Government. It is the
	18	* responsibility of any person or organization contemplating export to
	19	* obtain such a license before exporting.
	20	*
	21	* WITHIN THAT CONSTRAINT, permission to use, copy, modify, and
	22	* distribute this software and its documentation for any purpose and
	23	* without fee is hereby granted, provided that the above copyright
	24	* notice appear in all copies and that both that copyright notice and
	25	* this permission notice appear in supporting documentation, and that
	26	* the name of FundsXpress. not be used in advertising or publicity pertaining
	27	* to distribution of the software without specific, written prior
	28	* permission. FundsXpress makes no representations about the suitability of
	29	* this software for any purpose. It is provided "as is" without express
	30	* or implied warranty.
	31	*
	32	* THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
	33	* IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
	34	* WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE.
	35	*/
	36
	37	#include <linux/types.h>
	38	#include <linux/mm.h>
	39	#include <linux/slab.h>
378f058c	40	#include <linux/scatterlist.h>
1da177e4 LT	41	#include <linux/crypto.h>
	42	#include <linux/highmem.h>
	43	#include <linux/pagemap.h>
	44	#include <linux/sunrpc/gss_krb5.h>
	45
	46	#ifdef RPC_DEBUG
	47	# define RPCDBG_FACILITY RPCDBG_AUTH
	48	#endif
	49
	50	u32
	51	krb5_encrypt(
378c6697	52	struct crypto_blkcipher *tfm,
1da177e4 LT	53	void * iv,
	54	void * in,
	55	void * out,
	56	int length)
	57	{
	58	u32 ret = -EINVAL;
	59	struct scatterlist sg[1];
	60	u8 local_iv[16] = {0};
378c6697	61	struct blkcipher_desc desc = { .tfm = tfm, .info = local_iv };
1da177e4 LT	62
	63	dprintk("RPC: krb5_encrypt: input data:\n");
	64	print_hexl((u32 *)in, length, 0);
	65
378c6697	66	if (length % crypto_blkcipher_blocksize(tfm) != 0)
1da177e4 LT	67	goto out;
1da177e4 LT	68
378c6697	69	if (crypto_blkcipher_ivsize(tfm) > 16) {
1da177e4	70	dprintk("RPC: gss_k5encrypt: tfm iv size to large %d\n",
378c6697	71	crypto_blkcipher_ivsize(tfm));
1da177e4 LT	72	goto out;
	73	}
	74
	75	if (iv)
378c6697	76	memcpy(local_iv, iv, crypto_blkcipher_ivsize(tfm));
1da177e4 LT	77
1da177e4 LT	78	memcpy(out, in, length);
6df5b9f4	79	sg_set_buf(sg, out, length);
1da177e4	80
378c6697	81	ret = crypto_blkcipher_encrypt_iv(&desc, sg, sg, length);
1da177e4 LT	82
	83	dprintk("RPC: krb5_encrypt: output data:\n");
	84	print_hexl((u32 *)out, length, 0);
	85	out:
	86	dprintk("RPC: krb5_encrypt returns %d\n",ret);
	87	return(ret);
	88	}
	89
	90	EXPORT_SYMBOL(krb5_encrypt);
	91
	92	u32
	93	krb5_decrypt(
378c6697	94	struct crypto_blkcipher *tfm,
1da177e4 LT	95	void * iv,
	96	void * in,
	97	void * out,
	98	int length)
	99	{
	100	u32 ret = -EINVAL;
	101	struct scatterlist sg[1];
	102	u8 local_iv[16] = {0};
378c6697	103	struct blkcipher_desc desc = { .tfm = tfm, .info = local_iv };
1da177e4 LT	104
	105	dprintk("RPC: krb5_decrypt: input data:\n");
	106	print_hexl((u32 *)in, length, 0);
	107
378c6697	108	if (length % crypto_blkcipher_blocksize(tfm) != 0)
1da177e4 LT	109	goto out;
1da177e4 LT	110
378c6697	111	if (crypto_blkcipher_ivsize(tfm) > 16) {
1da177e4	112	dprintk("RPC: gss_k5decrypt: tfm iv size to large %d\n",
378c6697	113	crypto_blkcipher_ivsize(tfm));
1da177e4 LT	114	goto out;
	115	}
	116	if (iv)
378c6697	117	memcpy(local_iv,iv, crypto_blkcipher_ivsize(tfm));
1da177e4 LT	118
1da177e4 LT	119	memcpy(out, in, length);
6df5b9f4	120	sg_set_buf(sg, out, length);
1da177e4	121
378c6697	122	ret = crypto_blkcipher_decrypt_iv(&desc, sg, sg, length);
1da177e4 LT	123
	124	dprintk("RPC: krb5_decrypt: output_data:\n");
	125	print_hexl((u32 *)out, length, 0);
	126	out:
	127	dprintk("RPC: gss_k5decrypt returns %d\n",ret);
	128	return(ret);
	129	}
	130
	131	EXPORT_SYMBOL(krb5_decrypt);
	132
f7b3af64 BF	133	static int
	134	process_xdr_buf(struct xdr_buf *buf, int offset, int len,
	135	int (actor)(struct scatterlist , void ), void data)
	136	{
	137	int i, page_len, thislen, page_offset, ret = 0;
	138	struct scatterlist sg[1];
	139
	140	if (offset >= buf->head[0].iov_len) {
	141	offset -= buf->head[0].iov_len;
	142	} else {
	143	thislen = buf->head[0].iov_len - offset;
	144	if (thislen > len)
	145	thislen = len;
378f058c	146	sg_set_buf(sg, buf->head[0].iov_base + offset, thislen);
f7b3af64 BF	147	ret = actor(sg, data);
	148	if (ret)
	149	goto out;
	150	offset = 0;
	151	len -= thislen;
	152	}
	153	if (len == 0)
	154	goto out;
	155
	156	if (offset >= buf->page_len) {
	157	offset -= buf->page_len;
	158	} else {
	159	page_len = buf->page_len - offset;
	160	if (page_len > len)
	161	page_len = len;
	162	len -= page_len;
	163	page_offset = (offset + buf->page_base) & (PAGE_CACHE_SIZE - 1);
	164	i = (offset + buf->page_base) >> PAGE_CACHE_SHIFT;
	165	thislen = PAGE_CACHE_SIZE - page_offset;
	166	do {
	167	if (thislen > page_len)
	168	thislen = page_len;
	169	sg->page = buf->pages[i];
	170	sg->offset = page_offset;
	171	sg->length = thislen;
	172	ret = actor(sg, data);
	173	if (ret)
	174	goto out;
	175	page_len -= thislen;
	176	i++;
	177	page_offset = 0;
	178	thislen = PAGE_CACHE_SIZE;
	179	} while (page_len != 0);
	180	offset = 0;
	181	}
	182	if (len == 0)
	183	goto out;
	184
	185	if (offset < buf->tail[0].iov_len) {
	186	thislen = buf->tail[0].iov_len - offset;
	187	if (thislen > len)
	188	thislen = len;
378f058c	189	sg_set_buf(sg, buf->tail[0].iov_base + offset, thislen);
f7b3af64 BF	190	ret = actor(sg, data);
	191	len -= thislen;
	192	}
	193	if (len != 0)
	194	ret = -EINVAL;
	195	out:
	196	return ret;
	197	}
	198
	199	static int
	200	checksummer(struct scatterlist sg, void data)
	201	{
	202	struct crypto_tfm tfm = (struct crypto_tfm )data;
	203
	204	crypto_digest_update(tfm, sg, 1);
	205
	206	return 0;
	207	}
	208
1da177e4 LT	209	/* checksum the plaintext data and hdrlen bytes of the token header */
	210	s32
	211	make_checksum(s32 cksumtype, char header, int hdrlen, struct xdr_buf body,
14ae162c	212	int body_offset, struct xdr_netobj *cksum)
1da177e4 LT	213	{
	214	char *cksumname;
	215	struct crypto_tfm tfm = NULL; / XXX add to ctx? */
	216	struct scatterlist sg[1];
1da177e4 LT	217
	218	switch (cksumtype) {
	219	case CKSUMTYPE_RSA_MD5:
	220	cksumname = "md5";
	221	break;
	222	default:
	223	dprintk("RPC: krb5_make_checksum:"
	224	" unsupported checksum %d", cksumtype);
d4a30e7e	225	return GSS_S_FAILURE;
1da177e4	226	}
eb6f1160	227	if (!(tfm = crypto_alloc_tfm(cksumname, CRYPTO_TFM_REQ_MAY_SLEEP)))
d4a30e7e	228	return GSS_S_FAILURE;
1da177e4	229	cksum->len = crypto_tfm_alg_digestsize(tfm);
1da177e4 LT	230
1da177e4 LT	231	crypto_digest_init(tfm);
378f058c	232	sg_set_buf(sg, header, hdrlen);
1da177e4	233	crypto_digest_update(tfm, sg, 1);
14ae162c BF	234	process_xdr_buf(body, body_offset, body->len - body_offset,
14ae162c BF	235	checksummer, tfm);
1da177e4	236	crypto_digest_final(tfm, cksum->data);
573dbd95	237	crypto_free_tfm(tfm);
d4a30e7e	238	return 0;
1da177e4 LT	239	}
	240
	241	EXPORT_SYMBOL(make_checksum);
14ae162c BF	242
	243	struct encryptor_desc {
	244	u8 iv[8]; /* XXX hard-coded blocksize */
378c6697	245	struct blkcipher_desc desc;
14ae162c BF	246	int pos;
	247	struct xdr_buf *outbuf;
	248	struct page **pages;
	249	struct scatterlist infrags[4];
	250	struct scatterlist outfrags[4];
	251	int fragno;
	252	int fraglen;
	253	};
	254
	255	static int
	256	encryptor(struct scatterlist sg, void data)
	257	{
	258	struct encryptor_desc *desc = data;
	259	struct xdr_buf *outbuf = desc->outbuf;
	260	struct page *in_page;
	261	int thislen = desc->fraglen + sg->length;
	262	int fraglen, ret;
	263	int page_pos;
	264
	265	/* Worst case is 4 fragments: head, end of page 1, start
	266	* of page 2, tail. Anything more is a bug. */
	267	BUG_ON(desc->fragno > 3);
	268	desc->infrags[desc->fragno] = *sg;
	269	desc->outfrags[desc->fragno] = *sg;
	270
	271	page_pos = desc->pos - outbuf->head[0].iov_len;
	272	if (page_pos >= 0 && page_pos < outbuf->page_len) {
	273	/* pages are not in place: */
	274	int i = (page_pos + outbuf->page_base) >> PAGE_CACHE_SHIFT;
	275	in_page = desc->pages[i];
	276	} else {
	277	in_page = sg->page;
	278	}
	279	desc->infrags[desc->fragno].page = in_page;
	280	desc->fragno++;
	281	desc->fraglen += sg->length;
	282	desc->pos += sg->length;
	283
	284	fraglen = thislen & 7; /* XXX hardcoded blocksize */
	285	thislen -= fraglen;
	286
	287	if (thislen == 0)
	288	return 0;
	289
378c6697 HX	290	ret = crypto_blkcipher_encrypt_iv(&desc->desc, desc->outfrags,
378c6697 HX	291	desc->infrags, thislen);
14ae162c BF	292	if (ret)
	293	return ret;
	294	if (fraglen) {
	295	desc->outfrags[0].page = sg->page;
	296	desc->outfrags[0].offset = sg->offset + sg->length - fraglen;
	297	desc->outfrags[0].length = fraglen;
	298	desc->infrags[0] = desc->outfrags[0];
	299	desc->infrags[0].page = in_page;
	300	desc->fragno = 1;
	301	desc->fraglen = fraglen;
	302	} else {
	303	desc->fragno = 0;
	304	desc->fraglen = 0;
	305	}
	306	return 0;
	307	}
	308
	309	int
378c6697 HX	310	gss_encrypt_xdr_buf(struct crypto_blkcipher tfm, struct xdr_buf buf,
378c6697 HX	311	int offset, struct page **pages)
14ae162c BF	312	{
	313	int ret;
	314	struct encryptor_desc desc;
	315
378c6697	316	BUG_ON((buf->len - offset) % crypto_blkcipher_blocksize(tfm) != 0);
14ae162c BF	317
14ae162c BF	318	memset(desc.iv, 0, sizeof(desc.iv));
378c6697 HX	319	desc.desc.tfm = tfm;
	320	desc.desc.info = desc.iv;
	321	desc.desc.flags = 0;
14ae162c BF	322	desc.pos = offset;
	323	desc.outbuf = buf;
	324	desc.pages = pages;
	325	desc.fragno = 0;
	326	desc.fraglen = 0;
	327
	328	ret = process_xdr_buf(buf, offset, buf->len - offset, encryptor, &desc);
	329	return ret;
	330	}
	331
	332	EXPORT_SYMBOL(gss_encrypt_xdr_buf);
	333
	334	struct decryptor_desc {
	335	u8 iv[8]; /* XXX hard-coded blocksize */
378c6697	336	struct blkcipher_desc desc;
14ae162c BF	337	struct scatterlist frags[4];
	338	int fragno;
	339	int fraglen;
	340	};
	341
	342	static int
	343	decryptor(struct scatterlist sg, void data)
	344	{
	345	struct decryptor_desc *desc = data;
	346	int thislen = desc->fraglen + sg->length;
	347	int fraglen, ret;
	348
	349	/* Worst case is 4 fragments: head, end of page 1, start
	350	* of page 2, tail. Anything more is a bug. */
	351	BUG_ON(desc->fragno > 3);
	352	desc->frags[desc->fragno] = *sg;
	353	desc->fragno++;
	354	desc->fraglen += sg->length;
	355
	356	fraglen = thislen & 7; /* XXX hardcoded blocksize */
	357	thislen -= fraglen;
	358
	359	if (thislen == 0)
	360	return 0;
	361
378c6697 HX	362	ret = crypto_blkcipher_decrypt_iv(&desc->desc, desc->frags,
378c6697 HX	363	desc->frags, thislen);
14ae162c BF	364	if (ret)
	365	return ret;
	366	if (fraglen) {
	367	desc->frags[0].page = sg->page;
	368	desc->frags[0].offset = sg->offset + sg->length - fraglen;
	369	desc->frags[0].length = fraglen;
	370	desc->fragno = 1;
	371	desc->fraglen = fraglen;
	372	} else {
	373	desc->fragno = 0;
	374	desc->fraglen = 0;
	375	}
	376	return 0;
	377	}
	378
	379	int
378c6697 HX	380	gss_decrypt_xdr_buf(struct crypto_blkcipher tfm, struct xdr_buf buf,
378c6697 HX	381	int offset)
14ae162c BF	382	{
	383	struct decryptor_desc desc;
	384
	385	/* XXXJBF: */
378c6697	386	BUG_ON((buf->len - offset) % crypto_blkcipher_blocksize(tfm) != 0);
14ae162c BF	387
14ae162c BF	388	memset(desc.iv, 0, sizeof(desc.iv));
378c6697 HX	389	desc.desc.tfm = tfm;
	390	desc.desc.info = desc.iv;
	391	desc.desc.flags = 0;
14ae162c BF	392	desc.fragno = 0;
	393	desc.fraglen = 0;
	394	return process_xdr_buf(buf, offset, buf->len - offset, decryptor, &desc);
	395	}
	396
	397	EXPORT_SYMBOL(gss_decrypt_xdr_buf);