[net-next-2.6.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/err.h>
#include <linux/types.h>
#include <linux/mm.h>
#include <linux/scatterlist.h>
#include <linux/crypto.h>
#include <linux/highmem.h>
#include <linux/pagemap.h>
#include <linux/sunrpc/gss_krb5.h>
#include <linux/sunrpc/xdr.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 };

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

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

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

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

	ret = crypto_blkcipher_encrypt_iv(&desc, sg, sg, length);
out:
	dprintk("RPC:       krb5_encrypt returns %d\n", ret);
	return ret;
}

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 };

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

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

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

	ret = crypto_blkcipher_decrypt_iv(&desc, sg, sg, length);
out:
	dprintk("RPC:       gss_k5decrypt returns %d\n",ret);
	return ret;
}

static int
checksummer(struct scatterlist *sg, void *data)
{
	struct hash_desc *desc = data;

	return crypto_hash_update(desc, sg, sg->length);
}

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

	desc.tfm = crypto_alloc_hash(cksumname, 0, CRYPTO_ALG_ASYNC);
	if (IS_ERR(desc.tfm))
		return GSS_S_FAILURE;
	cksum->len = crypto_hash_digestsize(desc.tfm);
	desc.flags = CRYPTO_TFM_REQ_MAY_SLEEP;

	err = crypto_hash_init(&desc);
	if (err)
		goto out;
	sg_init_one(sg, header, hdrlen);
	err = crypto_hash_update(&desc, sg, hdrlen);
	if (err)
		goto out;
	err = xdr_process_buf(body, body_offset, body->len - body_offset,
			      checksummer, &desc);
	if (err)
		goto out;
	err = crypto_hash_final(&desc, cksum->data);

out:
	crypto_free_hash(desc.tfm);
	return err ? GSS_S_FAILURE : 0;
}

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);

	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(sg);
	}
	sg_set_page(&desc->infrags[desc->fragno], in_page, sg->length,
		    sg->offset);
	sg_set_page(&desc->outfrags[desc->fragno], sg_page(sg), sg->length,
		    sg->offset);
	desc->fragno++;
	desc->fraglen += sg->length;
	desc->pos += sg->length;

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

	if (thislen == 0)
		return 0;

	sg_mark_end(&desc->infrags[desc->fragno - 1]);
	sg_mark_end(&desc->outfrags[desc->fragno - 1]);

	ret = crypto_blkcipher_encrypt_iv(&desc->desc, desc->outfrags,
					  desc->infrags, thislen);
	if (ret)
		return ret;

	sg_init_table(desc->infrags, 4);
	sg_init_table(desc->outfrags, 4);

	if (fraglen) {
		sg_set_page(&desc->outfrags[0], sg_page(sg), fraglen,
				sg->offset + sg->length - fraglen);
		desc->infrags[0] = desc->outfrags[0];
		sg_assign_page(&desc->infrags[0], 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;

	sg_init_table(desc.infrags, 4);
	sg_init_table(desc.outfrags, 4);

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

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);
	sg_set_page(&desc->frags[desc->fragno], sg_page(sg), sg->length,
		    sg->offset);
	desc->fragno++;
	desc->fraglen += sg->length;

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

	if (thislen == 0)
		return 0;

	sg_mark_end(&desc->frags[desc->fragno - 1]);

	ret = crypto_blkcipher_decrypt_iv(&desc->desc, desc->frags,
					  desc->frags, thislen);
	if (ret)
		return ret;

	sg_init_table(desc->frags, 4);

	if (fraglen) {
		sg_set_page(&desc->frags[0], sg_page(sg), fraglen,
				sg->offset + sg->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;

	sg_init_table(desc.frags, 4);

	return xdr_process_buf(buf, offset, buf->len - offset, decryptor, &desc);
}
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
35058687	37	#include <linux/err.h>
1da177e4 LT	38	#include <linux/types.h>
1da177e4 LT	39	#include <linux/mm.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>
37a4e6cb	45	#include <linux/sunrpc/xdr.h>
1da177e4 LT	46
	47	#ifdef RPC_DEBUG
	48	# define RPCDBG_FACILITY RPCDBG_AUTH
	49	#endif
	50
	51	u32
	52	krb5_encrypt(
378c6697	53	struct crypto_blkcipher *tfm,
1da177e4 LT	54	void * iv,
	55	void * in,
	56	void * out,
	57	int length)
	58	{
	59	u32 ret = -EINVAL;
cca5172a	60	struct scatterlist sg[1];
1da177e4	61	u8 local_iv[16] = {0};
378c6697	62	struct blkcipher_desc desc = { .tfm = tfm, .info = local_iv };
1da177e4	63
378c6697	64	if (length % crypto_blkcipher_blocksize(tfm) != 0)
1da177e4 LT	65	goto out;
1da177e4 LT	66
378c6697	67	if (crypto_blkcipher_ivsize(tfm) > 16) {
3d4a6886 KC	68	dprintk("RPC: gss_k5encrypt: tfm iv size too large %d\n",
3d4a6886 KC	69	crypto_blkcipher_ivsize(tfm));
1da177e4 LT	70	goto out;
	71	}
	72
	73	if (iv)
378c6697	74	memcpy(local_iv, iv, crypto_blkcipher_ivsize(tfm));
1da177e4 LT	75
1da177e4 LT	76	memcpy(out, in, length);
68e3f5dd	77	sg_init_one(sg, out, length);
1da177e4	78
378c6697	79	ret = crypto_blkcipher_encrypt_iv(&desc, sg, sg, length);
1da177e4	80	out:
8885cb36	81	dprintk("RPC: krb5_encrypt returns %d\n", ret);
8fc7500b	82	return ret;
1da177e4 LT	83	}
1da177e4 LT	84
1da177e4 LT	85	u32
1da177e4 LT	86	krb5_decrypt(
378c6697	87	struct crypto_blkcipher *tfm,
1da177e4 LT	88	void * iv,
	89	void * in,
	90	void * out,
	91	int length)
	92	{
	93	u32 ret = -EINVAL;
	94	struct scatterlist sg[1];
	95	u8 local_iv[16] = {0};
378c6697	96	struct blkcipher_desc desc = { .tfm = tfm, .info = local_iv };
1da177e4	97
378c6697	98	if (length % crypto_blkcipher_blocksize(tfm) != 0)
1da177e4 LT	99	goto out;
1da177e4 LT	100
378c6697	101	if (crypto_blkcipher_ivsize(tfm) > 16) {
3d4a6886	102	dprintk("RPC: gss_k5decrypt: tfm iv size too large %d\n",
378c6697	103	crypto_blkcipher_ivsize(tfm));
1da177e4 LT	104	goto out;
	105	}
	106	if (iv)
378c6697	107	memcpy(local_iv,iv, crypto_blkcipher_ivsize(tfm));
1da177e4 LT	108
1da177e4 LT	109	memcpy(out, in, length);
68e3f5dd	110	sg_init_one(sg, out, length);
1da177e4	111
378c6697	112	ret = crypto_blkcipher_decrypt_iv(&desc, sg, sg, length);
1da177e4	113	out:
8885cb36	114	dprintk("RPC: gss_k5decrypt returns %d\n",ret);
8fc7500b	115	return ret;
1da177e4 LT	116	}
1da177e4 LT	117
f7b3af64 BF	118	static int
	119	checksummer(struct scatterlist sg, void data)
	120	{
35058687	121	struct hash_desc *desc = data;
f7b3af64	122
35058687	123	return crypto_hash_update(desc, sg, sg->length);
f7b3af64 BF	124	}
f7b3af64 BF	125
1da177e4 LT	126	/* checksum the plaintext data and hdrlen bytes of the token header */
1da177e4 LT	127	s32
ca54f896	128	make_checksum(char cksumname, char header, int hdrlen, struct xdr_buf *body,
14ae162c	129	int body_offset, struct xdr_netobj *cksum)
1da177e4	130	{
35058687	131	struct hash_desc desc; /* XXX add to ctx? */
1da177e4	132	struct scatterlist sg[1];
35058687	133	int err;
1da177e4	134
35058687 HX	135	desc.tfm = crypto_alloc_hash(cksumname, 0, CRYPTO_ALG_ASYNC);
35058687 HX	136	if (IS_ERR(desc.tfm))
d4a30e7e	137	return GSS_S_FAILURE;
35058687 HX	138	cksum->len = crypto_hash_digestsize(desc.tfm);
35058687 HX	139	desc.flags = CRYPTO_TFM_REQ_MAY_SLEEP;
1da177e4	140
35058687 HX	141	err = crypto_hash_init(&desc);
	142	if (err)
	143	goto out;
68e3f5dd	144	sg_init_one(sg, header, hdrlen);
35058687 HX	145	err = crypto_hash_update(&desc, sg, hdrlen);
	146	if (err)
	147	goto out;
37a4e6cb	148	err = xdr_process_buf(body, body_offset, body->len - body_offset,
35058687 HX	149	checksummer, &desc);
	150	if (err)
	151	goto out;
	152	err = crypto_hash_final(&desc, cksum->data);
	153
	154	out:
	155	crypto_free_hash(desc.tfm);
	156	return err ? GSS_S_FAILURE : 0;
1da177e4 LT	157	}
1da177e4 LT	158
14ae162c BF	159	struct encryptor_desc {
14ae162c BF	160	u8 iv[8]; /* XXX hard-coded blocksize */
378c6697	161	struct blkcipher_desc desc;
14ae162c BF	162	int pos;
	163	struct xdr_buf *outbuf;
	164	struct page **pages;
	165	struct scatterlist infrags[4];
	166	struct scatterlist outfrags[4];
	167	int fragno;
	168	int fraglen;
	169	};
	170
	171	static int
	172	encryptor(struct scatterlist sg, void data)
	173	{
	174	struct encryptor_desc *desc = data;
	175	struct xdr_buf *outbuf = desc->outbuf;
	176	struct page *in_page;
	177	int thislen = desc->fraglen + sg->length;
	178	int fraglen, ret;
	179	int page_pos;
	180
	181	/* Worst case is 4 fragments: head, end of page 1, start
	182	* of page 2, tail. Anything more is a bug. */
	183	BUG_ON(desc->fragno > 3);
14ae162c BF	184
	185	page_pos = desc->pos - outbuf->head[0].iov_len;
	186	if (page_pos >= 0 && page_pos < outbuf->page_len) {
	187	/* pages are not in place: */
	188	int i = (page_pos + outbuf->page_base) >> PAGE_CACHE_SHIFT;
	189	in_page = desc->pages[i];
	190	} else {
fa05f128	191	in_page = sg_page(sg);
14ae162c	192	}
68e3f5dd HX	193	sg_set_page(&desc->infrags[desc->fragno], in_page, sg->length,
	194	sg->offset);
	195	sg_set_page(&desc->outfrags[desc->fragno], sg_page(sg), sg->length,
	196	sg->offset);
14ae162c BF	197	desc->fragno++;
	198	desc->fraglen += sg->length;
	199	desc->pos += sg->length;
	200
	201	fraglen = thislen & 7; /* XXX hardcoded blocksize */
	202	thislen -= fraglen;
	203
	204	if (thislen == 0)
	205	return 0;
	206
c46f2334 JA	207	sg_mark_end(&desc->infrags[desc->fragno - 1]);
c46f2334 JA	208	sg_mark_end(&desc->outfrags[desc->fragno - 1]);
68e3f5dd	209
378c6697 HX	210	ret = crypto_blkcipher_encrypt_iv(&desc->desc, desc->outfrags,
378c6697 HX	211	desc->infrags, thislen);
14ae162c BF	212	if (ret)
14ae162c BF	213	return ret;
68e3f5dd HX	214
	215	sg_init_table(desc->infrags, 4);
	216	sg_init_table(desc->outfrags, 4);
	217
14ae162c	218	if (fraglen) {
642f1490 JA	219	sg_set_page(&desc->outfrags[0], sg_page(sg), fraglen,
642f1490 JA	220	sg->offset + sg->length - fraglen);
14ae162c	221	desc->infrags[0] = desc->outfrags[0];
642f1490	222	sg_assign_page(&desc->infrags[0], in_page);
14ae162c BF	223	desc->fragno = 1;
	224	desc->fraglen = fraglen;
	225	} else {
	226	desc->fragno = 0;
	227	desc->fraglen = 0;
	228	}
	229	return 0;
	230	}
	231
	232	int
378c6697 HX	233	gss_encrypt_xdr_buf(struct crypto_blkcipher tfm, struct xdr_buf buf,
378c6697 HX	234	int offset, struct page **pages)
14ae162c BF	235	{
	236	int ret;
	237	struct encryptor_desc desc;
	238
378c6697	239	BUG_ON((buf->len - offset) % crypto_blkcipher_blocksize(tfm) != 0);
14ae162c BF	240
14ae162c BF	241	memset(desc.iv, 0, sizeof(desc.iv));
378c6697 HX	242	desc.desc.tfm = tfm;
	243	desc.desc.info = desc.iv;
	244	desc.desc.flags = 0;
14ae162c BF	245	desc.pos = offset;
	246	desc.outbuf = buf;
	247	desc.pages = pages;
	248	desc.fragno = 0;
	249	desc.fraglen = 0;
	250
68e3f5dd HX	251	sg_init_table(desc.infrags, 4);
	252	sg_init_table(desc.outfrags, 4);
	253
37a4e6cb	254	ret = xdr_process_buf(buf, offset, buf->len - offset, encryptor, &desc);
14ae162c BF	255	return ret;
	256	}
	257
14ae162c BF	258	struct decryptor_desc {
14ae162c BF	259	u8 iv[8]; /* XXX hard-coded blocksize */
378c6697	260	struct blkcipher_desc desc;
14ae162c BF	261	struct scatterlist frags[4];
	262	int fragno;
	263	int fraglen;
	264	};
	265
	266	static int
	267	decryptor(struct scatterlist sg, void data)
	268	{
	269	struct decryptor_desc *desc = data;
	270	int thislen = desc->fraglen + sg->length;
	271	int fraglen, ret;
	272
	273	/* Worst case is 4 fragments: head, end of page 1, start
	274	* of page 2, tail. Anything more is a bug. */
	275	BUG_ON(desc->fragno > 3);
68e3f5dd HX	276	sg_set_page(&desc->frags[desc->fragno], sg_page(sg), sg->length,
68e3f5dd HX	277	sg->offset);
14ae162c BF	278	desc->fragno++;
	279	desc->fraglen += sg->length;
	280
	281	fraglen = thislen & 7; /* XXX hardcoded blocksize */
	282	thislen -= fraglen;
	283
	284	if (thislen == 0)
	285	return 0;
	286
c46f2334	287	sg_mark_end(&desc->frags[desc->fragno - 1]);
68e3f5dd	288
378c6697 HX	289	ret = crypto_blkcipher_decrypt_iv(&desc->desc, desc->frags,
378c6697 HX	290	desc->frags, thislen);
14ae162c BF	291	if (ret)
14ae162c BF	292	return ret;
68e3f5dd HX	293
	294	sg_init_table(desc->frags, 4);
	295
14ae162c	296	if (fraglen) {
642f1490 JA	297	sg_set_page(&desc->frags[0], sg_page(sg), fraglen,
642f1490 JA	298	sg->offset + sg->length - fraglen);
14ae162c BF	299	desc->fragno = 1;
	300	desc->fraglen = fraglen;
	301	} else {
	302	desc->fragno = 0;
	303	desc->fraglen = 0;
	304	}
	305	return 0;
	306	}
	307
	308	int
378c6697 HX	309	gss_decrypt_xdr_buf(struct crypto_blkcipher tfm, struct xdr_buf buf,
378c6697 HX	310	int offset)
14ae162c BF	311	{
	312	struct decryptor_desc desc;
	313
	314	/* XXXJBF: */
378c6697	315	BUG_ON((buf->len - offset) % crypto_blkcipher_blocksize(tfm) != 0);
14ae162c BF	316
14ae162c BF	317	memset(desc.iv, 0, sizeof(desc.iv));
378c6697 HX	318	desc.desc.tfm = tfm;
	319	desc.desc.info = desc.iv;
	320	desc.desc.flags = 0;
14ae162c BF	321	desc.fragno = 0;
14ae162c BF	322	desc.fraglen = 0;
68e3f5dd HX	323
	324	sg_init_table(desc.frags, 4);
	325
37a4e6cb	326	return xdr_process_buf(buf, offset, buf->len - offset, decryptor, &desc);
14ae162c	327	}