[mirror_ubuntu-bionic-kernel.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 <asm/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_tfm *tfm,
	void * iv,
	void * in,
	void * out,
	int length)
{
	u32 ret = -EINVAL;
        struct scatterlist sg[1];
	u8 local_iv[16] = {0};

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

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

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

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

	memcpy(out, in, length);
	sg[0].page = virt_to_page(out);
	sg[0].offset = offset_in_page(out);
	sg[0].length = length;

	ret = crypto_cipher_encrypt_iv(tfm, sg, sg, length, local_iv);

	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_tfm *tfm,
     void * iv,
     void * in,
     void * out,
     int length)
{
	u32 ret = -EINVAL;
	struct scatterlist sg[1];
	u8 local_iv[16] = {0};

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

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

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

	memcpy(out, in, length);
	sg[0].page = virt_to_page(out);
	sg[0].offset = offset_in_page(out);
	sg[0].length = length;

	ret = crypto_cipher_decrypt_iv(tfm, sg, sg, length, local_iv);

	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 void
buf_to_sg(struct scatterlist *sg, char *ptr, int len) {
	sg->page = virt_to_page(ptr);
	sg->offset = offset_in_page(ptr);
	sg->length = len;
}

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;
		buf_to_sg(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;
		buf_to_sg(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];
	u32                             code = GSS_S_FAILURE;

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

	crypto_digest_init(tfm);
	buf_to_sg(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);
	code = 0;
out:
	crypto_free_tfm(tfm);
	return code;
}

EXPORT_SYMBOL(make_checksum);

struct encryptor_desc {
	u8 iv[8]; /* XXX hard-coded blocksize */
	struct crypto_tfm *tfm;
	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_cipher_encrypt_iv(desc->tfm, desc->outfrags, desc->infrags,
					thislen, desc->iv);
	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_tfm *tfm, struct xdr_buf *buf, int offset,
		struct page **pages)
{
	int ret;
	struct encryptor_desc desc;

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

	memset(desc.iv, 0, sizeof(desc.iv));
	desc.tfm = tfm;
	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 crypto_tfm *tfm;
	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_cipher_decrypt_iv(desc->tfm, desc->frags, desc->frags,
					thislen, desc->iv);
	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_tfm *tfm, struct xdr_buf *buf, int offset)
{
	struct decryptor_desc desc;

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

	memset(desc.iv, 0, sizeof(desc.iv));
	desc.tfm = tfm;
	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>
	40	#include <asm/scatterlist.h>
	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(
	52	struct crypto_tfm *tfm,
	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};
	61
	62	dprintk("RPC: krb5_encrypt: input data:\n");
	63	print_hexl((u32 *)in, length, 0);
	64
65	if (length % crypto_tfm_alg_blocksize(tfm) != 0)
66	goto out;
67
68	if (crypto_tfm_alg_ivsize(tfm) > 16) {
69	dprintk("RPC: gss_k5encrypt: tfm iv size to large %d\n",
70	crypto_tfm_alg_ivsize(tfm));
71	goto out;
72	}
73
74	if (iv)
75	memcpy(local_iv, iv, crypto_tfm_alg_ivsize(tfm));
76
77	memcpy(out, in, length);
78	sg[0].page = virt_to_page(out);
79	sg[0].offset = offset_in_page(out);
80	sg[0].length = length;
81
82	ret = crypto_cipher_encrypt_iv(tfm, sg, sg, length, local_iv);
83
84	dprintk("RPC: krb5_encrypt: output data:\n");
85	print_hexl((u32 *)out, length, 0);
86	out:
87	dprintk("RPC: krb5_encrypt returns %d\n",ret);
88	return(ret);
89	}
90
91	EXPORT_SYMBOL(krb5_encrypt);
92
93	u32
94	krb5_decrypt(
95	struct crypto_tfm *tfm,
96	void * iv,
97	void * in,
98	void * out,
99	int length)
100	{
101	u32 ret = -EINVAL;
102	struct scatterlist sg[1];
103	u8 local_iv[16] = {0};
104
105	dprintk("RPC: krb5_decrypt: input data:\n");
106	print_hexl((u32 *)in, length, 0);
107
108	if (length % crypto_tfm_alg_blocksize(tfm) != 0)
109	goto out;
110
111	if (crypto_tfm_alg_ivsize(tfm) > 16) {
112	dprintk("RPC: gss_k5decrypt: tfm iv size to large %d\n",
113	crypto_tfm_alg_ivsize(tfm));
114	goto out;
115	}
116	if (iv)
117	memcpy(local_iv,iv, crypto_tfm_alg_ivsize(tfm));
118
119	memcpy(out, in, length);
120	sg[0].page = virt_to_page(out);
121	sg[0].offset = offset_in_page(out);
122	sg[0].length = length;
123
124	ret = crypto_cipher_decrypt_iv(tfm, sg, sg, length, local_iv);
125
126	dprintk("RPC: krb5_decrypt: output_data:\n");
127	print_hexl((u32 *)out, length, 0);
128	out:
129	dprintk("RPC: gss_k5decrypt returns %d\n",ret);
130	return(ret);
131	}
132
133	EXPORT_SYMBOL(krb5_decrypt);
134
135	static void
136	buf_to_sg(struct scatterlist sg, char ptr, int len) {
137	sg->page = virt_to_page(ptr);
138	sg->offset = offset_in_page(ptr);
139	sg->length = len;
140	}
141
f7b3af64 BF	142	static int
	143	process_xdr_buf(struct xdr_buf *buf, int offset, int len,
	144	int (actor)(struct scatterlist , void ), void data)
	145	{
	146	int i, page_len, thislen, page_offset, ret = 0;
	147	struct scatterlist sg[1];
	148
	149	if (offset >= buf->head[0].iov_len) {
	150	offset -= buf->head[0].iov_len;
	151	} else {
	152	thislen = buf->head[0].iov_len - offset;
	153	if (thislen > len)
	154	thislen = len;
	155	buf_to_sg(sg, buf->head[0].iov_base + offset, thislen);
	156	ret = actor(sg, data);
	157	if (ret)
	158	goto out;
	159	offset = 0;
	160	len -= thislen;
	161	}
	162	if (len == 0)
	163	goto out;
	164
	165	if (offset >= buf->page_len) {
	166	offset -= buf->page_len;
	167	} else {
	168	page_len = buf->page_len - offset;
	169	if (page_len > len)
	170	page_len = len;
	171	len -= page_len;
	172	page_offset = (offset + buf->page_base) & (PAGE_CACHE_SIZE - 1);
	173	i = (offset + buf->page_base) >> PAGE_CACHE_SHIFT;
	174	thislen = PAGE_CACHE_SIZE - page_offset;
	175	do {
	176	if (thislen > page_len)
	177	thislen = page_len;
	178	sg->page = buf->pages[i];
	179	sg->offset = page_offset;
	180	sg->length = thislen;
	181	ret = actor(sg, data);
	182	if (ret)
	183	goto out;
	184	page_len -= thislen;
	185	i++;
	186	page_offset = 0;
	187	thislen = PAGE_CACHE_SIZE;
	188	} while (page_len != 0);
	189	offset = 0;
	190	}
	191	if (len == 0)
	192	goto out;
	193
	194	if (offset < buf->tail[0].iov_len) {
	195	thislen = buf->tail[0].iov_len - offset;
	196	if (thislen > len)
	197	thislen = len;
	198	buf_to_sg(sg, buf->tail[0].iov_base + offset, thislen);
	199	ret = actor(sg, data);
	200	len -= thislen;
	201	}
	202	if (len != 0)
	203	ret = -EINVAL;
	204	out:
	205	return ret;
206	}
207
208	static int
209	checksummer(struct scatterlist sg, void data)
210	{
211	struct crypto_tfm tfm = (struct crypto_tfm )data;
212
213	crypto_digest_update(tfm, sg, 1);
214
215	return 0;
216	}
217
1da177e4 LT	218	/* checksum the plaintext data and hdrlen bytes of the token header */
	219	s32
	220	make_checksum(s32 cksumtype, char header, int hdrlen, struct xdr_buf body,
14ae162c	221	int body_offset, struct xdr_netobj *cksum)
1da177e4 LT	222	{
	223	char *cksumname;
	224	struct crypto_tfm tfm = NULL; / XXX add to ctx? */
	225	struct scatterlist sg[1];
	226	u32 code = GSS_S_FAILURE;
1da177e4 LT	227
	228	switch (cksumtype) {
	229	case CKSUMTYPE_RSA_MD5:
	230	cksumname = "md5";
	231	break;
	232	default:
	233	dprintk("RPC: krb5_make_checksum:"
	234	" unsupported checksum %d", cksumtype);
	235	goto out;
	236	}
eb6f1160	237	if (!(tfm = crypto_alloc_tfm(cksumname, CRYPTO_TFM_REQ_MAY_SLEEP)))
1da177e4 LT	238	goto out;
	239	cksum->len = crypto_tfm_alg_digestsize(tfm);
	240	if ((cksum->data = kmalloc(cksum->len, GFP_KERNEL)) == NULL)
	241	goto out;
	242
	243	crypto_digest_init(tfm);
	244	buf_to_sg(sg, header, hdrlen);
	245	crypto_digest_update(tfm, sg, 1);
14ae162c BF	246	process_xdr_buf(body, body_offset, body->len - body_offset,
14ae162c BF	247	checksummer, tfm);
1da177e4 LT	248	crypto_digest_final(tfm, cksum->data);
	249	code = 0;
	250	out:
573dbd95	251	crypto_free_tfm(tfm);
1da177e4 LT	252	return code;
	253	}
	254
	255	EXPORT_SYMBOL(make_checksum);
14ae162c BF	256
	257	struct encryptor_desc {
	258	u8 iv[8]; /* XXX hard-coded blocksize */
	259	struct crypto_tfm *tfm;
	260	int pos;
	261	struct xdr_buf *outbuf;
	262	struct page **pages;
	263	struct scatterlist infrags[4];
	264	struct scatterlist outfrags[4];
	265	int fragno;
	266	int fraglen;
	267	};
	268
	269	static int
	270	encryptor(struct scatterlist sg, void data)
	271	{
	272	struct encryptor_desc *desc = data;
	273	struct xdr_buf *outbuf = desc->outbuf;
	274	struct page *in_page;
	275	int thislen = desc->fraglen + sg->length;
	276	int fraglen, ret;
	277	int page_pos;
	278
	279	/* Worst case is 4 fragments: head, end of page 1, start
	280	* of page 2, tail. Anything more is a bug. */
	281	BUG_ON(desc->fragno > 3);
	282	desc->infrags[desc->fragno] = *sg;
	283	desc->outfrags[desc->fragno] = *sg;
	284
	285	page_pos = desc->pos - outbuf->head[0].iov_len;
	286	if (page_pos >= 0 && page_pos < outbuf->page_len) {
	287	/* pages are not in place: */
	288	int i = (page_pos + outbuf->page_base) >> PAGE_CACHE_SHIFT;
	289	in_page = desc->pages[i];
	290	} else {
	291	in_page = sg->page;
	292	}
	293	desc->infrags[desc->fragno].page = in_page;
	294	desc->fragno++;
	295	desc->fraglen += sg->length;
	296	desc->pos += sg->length;
	297
	298	fraglen = thislen & 7; /* XXX hardcoded blocksize */
	299	thislen -= fraglen;
	300
	301	if (thislen == 0)
	302	return 0;
	303
	304	ret = crypto_cipher_encrypt_iv(desc->tfm, desc->outfrags, desc->infrags,
	305	thislen, desc->iv);
	306	if (ret)
	307	return ret;
	308	if (fraglen) {
	309	desc->outfrags[0].page = sg->page;
	310	desc->outfrags[0].offset = sg->offset + sg->length - fraglen;
	311	desc->outfrags[0].length = fraglen;
	312	desc->infrags[0] = desc->outfrags[0];
	313	desc->infrags[0].page = in_page;
	314	desc->fragno = 1;
	315	desc->fraglen = fraglen;
	316	} else {
	317	desc->fragno = 0;
	318	desc->fraglen = 0;
	319	}
320	return 0;
321	}
322
323	int
324	gss_encrypt_xdr_buf(struct crypto_tfm tfm, struct xdr_buf buf, int offset,
325	struct page **pages)
326	{
327	int ret;
328	struct encryptor_desc desc;
329
330	BUG_ON((buf->len - offset) % crypto_tfm_alg_blocksize(tfm) != 0);
331
332	memset(desc.iv, 0, sizeof(desc.iv));
333	desc.tfm = tfm;
334	desc.pos = offset;
335	desc.outbuf = buf;
336	desc.pages = pages;
337	desc.fragno = 0;
338	desc.fraglen = 0;
339
340	ret = process_xdr_buf(buf, offset, buf->len - offset, encryptor, &desc);
341	return ret;
342	}
343
344	EXPORT_SYMBOL(gss_encrypt_xdr_buf);
345
346	struct decryptor_desc {
347	u8 iv[8]; /* XXX hard-coded blocksize */
348	struct crypto_tfm *tfm;
349	struct scatterlist frags[4];
350	int fragno;
351	int fraglen;
352	};
353
354	static int
355	decryptor(struct scatterlist sg, void data)
356	{
357	struct decryptor_desc *desc = data;
358	int thislen = desc->fraglen + sg->length;
359	int fraglen, ret;
360
361	/* Worst case is 4 fragments: head, end of page 1, start
362	* of page 2, tail. Anything more is a bug. */
363	BUG_ON(desc->fragno > 3);
364	desc->frags[desc->fragno] = *sg;
365	desc->fragno++;
366	desc->fraglen += sg->length;
367
368	fraglen = thislen & 7; /* XXX hardcoded blocksize */
369	thislen -= fraglen;
370
371	if (thislen == 0)
372	return 0;
373
374	ret = crypto_cipher_decrypt_iv(desc->tfm, desc->frags, desc->frags,
375	thislen, desc->iv);
376	if (ret)
377	return ret;
378	if (fraglen) {
379	desc->frags[0].page = sg->page;
380	desc->frags[0].offset = sg->offset + sg->length - fraglen;
381	desc->frags[0].length = fraglen;
382	desc->fragno = 1;
383	desc->fraglen = fraglen;
384	} else {
385	desc->fragno = 0;
386	desc->fraglen = 0;
387	}
388	return 0;
389	}
390
391	int
392	gss_decrypt_xdr_buf(struct crypto_tfm tfm, struct xdr_buf buf, int offset)
393	{
394	struct decryptor_desc desc;
395
396	/* XXXJBF: */
397	BUG_ON((buf->len - offset) % crypto_tfm_alg_blocksize(tfm) != 0);
398
399	memset(desc.iv, 0, sizeof(desc.iv));
400	desc.tfm = tfm;
401	desc.fragno = 0;
402	desc.fraglen = 0;
403	return process_xdr_buf(buf, offset, buf->len - offset, decryptor, &desc);
404	}
405
406	EXPORT_SYMBOL(gss_decrypt_xdr_buf);