[deliverable/linux.git] / net / sunrpc / auth_gss / gss_krb5_wrap.c

#include <linux/types.h>
#include <linux/slab.h>
#include <linux/jiffies.h>
#include <linux/sunrpc/gss_krb5.h>
#include <linux/random.h>
#include <linux/pagemap.h>
#include <linux/crypto.h>

#ifdef RPC_DEBUG
# define RPCDBG_FACILITY	RPCDBG_AUTH
#endif

static inline int
gss_krb5_padding(int blocksize, int length)
{
	/* Most of the code is block-size independent but currently we
	 * use only 8: */
	BUG_ON(blocksize != 8);
	return 8 - (length & 7);
}

static inline void
gss_krb5_add_padding(struct xdr_buf *buf, int offset, int blocksize)
{
	int padding = gss_krb5_padding(blocksize, buf->len - offset);
	char *p;
	struct kvec *iov;

	if (buf->page_len || buf->tail[0].iov_len)
		iov = &buf->tail[0];
	else
		iov = &buf->head[0];
	p = iov->iov_base + iov->iov_len;
	iov->iov_len += padding;
	buf->len += padding;
	memset(p, padding, padding);
}

static inline int
gss_krb5_remove_padding(struct xdr_buf *buf, int blocksize)
{
	u8 *ptr;
	u8 pad;
	size_t len = buf->len;

	if (len <= buf->head[0].iov_len) {
		pad = *(u8 *)(buf->head[0].iov_base + len - 1);
		if (pad > buf->head[0].iov_len)
			return -EINVAL;
		buf->head[0].iov_len -= pad;
		goto out;
	} else
		len -= buf->head[0].iov_len;
	if (len <= buf->page_len) {
		unsigned int last = (buf->page_base + len - 1)
					>>PAGE_CACHE_SHIFT;
		unsigned int offset = (buf->page_base + len - 1)
					& (PAGE_CACHE_SIZE - 1);
		ptr = kmap_atomic(buf->pages[last], KM_USER0);
		pad = *(ptr + offset);
		kunmap_atomic(ptr, KM_USER0);
		goto out;
	} else
		len -= buf->page_len;
	BUG_ON(len > buf->tail[0].iov_len);
	pad = *(u8 *)(buf->tail[0].iov_base + len - 1);
out:
	/* XXX: NOTE: we do not adjust the page lengths--they represent
	 * a range of data in the real filesystem page cache, and we need
	 * to know that range so the xdr code can properly place read data.
	 * However adjusting the head length, as we do above, is harmless.
	 * In the case of a request that fits into a single page, the server
	 * also uses length and head length together to determine the original
	 * start of the request to copy the request for deferal; so it's
	 * easier on the server if we adjust head and tail length in tandem.
	 * It's not really a problem that we don't fool with the page and
	 * tail lengths, though--at worst badly formed xdr might lead the
	 * server to attempt to parse the padding.
	 * XXX: Document all these weird requirements for gss mechanism
	 * wrap/unwrap functions. */
	if (pad > blocksize)
		return -EINVAL;
	if (buf->len > pad)
		buf->len -= pad;
	else
		return -EINVAL;
	return 0;
}

static inline void
make_confounder(char *p, int blocksize)
{
	static u64 i = 0;
	u64 *q = (u64 *)p;

	/* rfc1964 claims this should be "random".  But all that's really
	 * necessary is that it be unique.  And not even that is necessary in
	 * our case since our "gssapi" implementation exists only to support
	 * rpcsec_gss, so we know that the only buffers we will ever encrypt
	 * already begin with a unique sequence number.  Just to hedge my bets
	 * I'll make a half-hearted attempt at something unique, but ensuring
	 * uniqueness would mean worrying about atomicity and rollover, and I
	 * don't care enough. */

	BUG_ON(blocksize != 8);
	*q = i++;
}

/* Assumptions: the head and tail of inbuf are ours to play with.
 * The pages, however, may be real pages in the page cache and we replace
 * them with scratch pages from **pages before writing to them. */
/* XXX: obviously the above should be documentation of wrap interface,
 * and shouldn't be in this kerberos-specific file. */

/* XXX factor out common code with seal/unseal. */

u32
gss_wrap_kerberos(struct gss_ctx *ctx, int offset,
		struct xdr_buf *buf, struct page **pages)
{
	struct krb5_ctx		*kctx = ctx->internal_ctx_id;
	char			cksumdata[16];
	struct xdr_netobj	md5cksum = {.len = 0, .data = cksumdata};
	int			blocksize = 0, plainlen;
	unsigned char		*ptr, *msg_start;
	s32			now;
	int			headlen;
	struct page		**tmp_pages;
	u32			seq_send;

	dprintk("RPC:       gss_wrap_kerberos\n");

	now = get_seconds();

	blocksize = crypto_blkcipher_blocksize(kctx->enc);
	gss_krb5_add_padding(buf, offset, blocksize);
	BUG_ON((buf->len - offset) % blocksize);
	plainlen = blocksize + buf->len - offset;

	headlen = g_token_size(&kctx->mech_used, 24 + plainlen) -
						(buf->len - offset);

	ptr = buf->head[0].iov_base + offset;
	/* shift data to make room for header. */
	/* XXX Would be cleverer to encrypt while copying. */
	/* XXX bounds checking, slack, etc. */
	memmove(ptr + headlen, ptr, buf->head[0].iov_len - offset);
	buf->head[0].iov_len += headlen;
	buf->len += headlen;
	BUG_ON((buf->len - offset - headlen) % blocksize);

	g_make_token_header(&kctx->mech_used,
				GSS_KRB5_TOK_HDR_LEN + 8 + plainlen, &ptr);


	/* ptr now at header described in rfc 1964, section 1.2.1: */
	ptr[0] = (unsigned char) ((KG_TOK_WRAP_MSG >> 8) & 0xff);
	ptr[1] = (unsigned char) (KG_TOK_WRAP_MSG & 0xff);

	msg_start = ptr + 24;

	*(__be16 *)(ptr + 2) = htons(SGN_ALG_DES_MAC_MD5);
	memset(ptr + 4, 0xff, 4);
	*(__be16 *)(ptr + 4) = htons(SEAL_ALG_DES);

	make_confounder(msg_start, blocksize);

	/* XXXJBF: UGH!: */
	tmp_pages = buf->pages;
	buf->pages = pages;
	if (make_checksum("md5", ptr, 8, buf,
				offset + headlen - blocksize, &md5cksum))
		return GSS_S_FAILURE;
	buf->pages = tmp_pages;

	if (krb5_encrypt(kctx->seq, NULL, md5cksum.data,
			  md5cksum.data, md5cksum.len))
		return GSS_S_FAILURE;
	memcpy(ptr + GSS_KRB5_TOK_HDR_LEN, md5cksum.data + md5cksum.len - 8, 8);

	spin_lock(&krb5_seq_lock);
	seq_send = kctx->seq_send++;
	spin_unlock(&krb5_seq_lock);

	/* XXX would probably be more efficient to compute checksum
	 * and encrypt at the same time: */
	if ((krb5_make_seq_num(kctx->seq, kctx->initiate ? 0 : 0xff,
			       seq_send, ptr + GSS_KRB5_TOK_HDR_LEN, ptr + 8)))
		return GSS_S_FAILURE;

	if (gss_encrypt_xdr_buf(kctx->enc, buf, offset + headlen - blocksize,
									pages))
		return GSS_S_FAILURE;

	return (kctx->endtime < now) ? GSS_S_CONTEXT_EXPIRED : GSS_S_COMPLETE;
}

u32
gss_unwrap_kerberos(struct gss_ctx *ctx, int offset, struct xdr_buf *buf)
{
	struct krb5_ctx		*kctx = ctx->internal_ctx_id;
	int			signalg;
	int			sealalg;
	char			cksumdata[16];
	struct xdr_netobj	md5cksum = {.len = 0, .data = cksumdata};
	s32			now;
	int			direction;
	s32			seqnum;
	unsigned char		*ptr;
	int			bodysize;
	void			*data_start, *orig_start;
	int			data_len;
	int			blocksize;

	dprintk("RPC:       gss_unwrap_kerberos\n");

	ptr = (u8 *)buf->head[0].iov_base + offset;
	if (g_verify_token_header(&kctx->mech_used, &bodysize, &ptr,
					buf->len - offset))
		return GSS_S_DEFECTIVE_TOKEN;

	if ((ptr[0] != ((KG_TOK_WRAP_MSG >> 8) & 0xff)) ||
	    (ptr[1] !=  (KG_TOK_WRAP_MSG & 0xff)))
		return GSS_S_DEFECTIVE_TOKEN;

	/* XXX sanity-check bodysize?? */

	/* get the sign and seal algorithms */

	signalg = ptr[2] + (ptr[3] << 8);
	if (signalg != SGN_ALG_DES_MAC_MD5)
		return GSS_S_DEFECTIVE_TOKEN;

	sealalg = ptr[4] + (ptr[5] << 8);
	if (sealalg != SEAL_ALG_DES)
		return GSS_S_DEFECTIVE_TOKEN;

	if ((ptr[6] != 0xff) || (ptr[7] != 0xff))
		return GSS_S_DEFECTIVE_TOKEN;

	if (gss_decrypt_xdr_buf(kctx->enc, buf,
			ptr + GSS_KRB5_TOK_HDR_LEN + 8 - (unsigned char *)buf->head[0].iov_base))
		return GSS_S_DEFECTIVE_TOKEN;

	if (make_checksum("md5", ptr, 8, buf,
		 ptr + GSS_KRB5_TOK_HDR_LEN + 8 - (unsigned char *)buf->head[0].iov_base, &md5cksum))
		return GSS_S_FAILURE;

	if (krb5_encrypt(kctx->seq, NULL, md5cksum.data,
			   md5cksum.data, md5cksum.len))
		return GSS_S_FAILURE;

	if (memcmp(md5cksum.data + 8, ptr + GSS_KRB5_TOK_HDR_LEN, 8))
		return GSS_S_BAD_SIG;

	/* it got through unscathed.  Make sure the context is unexpired */

	now = get_seconds();

	if (now > kctx->endtime)
		return GSS_S_CONTEXT_EXPIRED;

	/* do sequencing checks */

	if (krb5_get_seq_num(kctx->seq, ptr + GSS_KRB5_TOK_HDR_LEN, ptr + 8,
				    &direction, &seqnum))
		return GSS_S_BAD_SIG;

	if ((kctx->initiate && direction != 0xff) ||
	    (!kctx->initiate && direction != 0))
		return GSS_S_BAD_SIG;

	/* Copy the data back to the right position.  XXX: Would probably be
	 * better to copy and encrypt at the same time. */

	blocksize = crypto_blkcipher_blocksize(kctx->enc);
	data_start = ptr + GSS_KRB5_TOK_HDR_LEN + 8 + blocksize;
	orig_start = buf->head[0].iov_base + offset;
	data_len = (buf->head[0].iov_base + buf->head[0].iov_len) - data_start;
	memmove(orig_start, data_start, data_len);
	buf->head[0].iov_len -= (data_start - orig_start);
	buf->len -= (data_start - orig_start);

	if (gss_krb5_remove_padding(buf, blocksize))
		return GSS_S_DEFECTIVE_TOKEN;

	return GSS_S_COMPLETE;
}
Commit	Line	Data
14ae162c BF	1	#include <linux/types.h>
	2	#include <linux/slab.h>
	3	#include <linux/jiffies.h>
	4	#include <linux/sunrpc/gss_krb5.h>
	5	#include <linux/random.h>
	6	#include <linux/pagemap.h>
14ae162c BF	7	#include <linux/crypto.h>
	8
	9	#ifdef RPC_DEBUG
	10	# define RPCDBG_FACILITY RPCDBG_AUTH
	11	#endif
	12
	13	static inline int
	14	gss_krb5_padding(int blocksize, int length)
	15	{
	16	/* Most of the code is block-size independent but currently we
	17	* use only 8: */
	18	BUG_ON(blocksize != 8);
	19	return 8 - (length & 7);
	20	}
	21
	22	static inline void
	23	gss_krb5_add_padding(struct xdr_buf *buf, int offset, int blocksize)
	24	{
	25	int padding = gss_krb5_padding(blocksize, buf->len - offset);
	26	char *p;
	27	struct kvec *iov;
	28
	29	if (buf->page_len \|\| buf->tail[0].iov_len)
	30	iov = &buf->tail[0];
	31	else
	32	iov = &buf->head[0];
	33	p = iov->iov_base + iov->iov_len;
	34	iov->iov_len += padding;
	35	buf->len += padding;
	36	memset(p, padding, padding);
	37	}
	38
	39	static inline int
	40	gss_krb5_remove_padding(struct xdr_buf *buf, int blocksize)
	41	{
	42	u8 *ptr;
	43	u8 pad;
67f97d83	44	size_t len = buf->len;
14ae162c BF	45
	46	if (len <= buf->head[0].iov_len) {
	47	pad = (u8 )(buf->head[0].iov_base + len - 1);
	48	if (pad > buf->head[0].iov_len)
	49	return -EINVAL;
	50	buf->head[0].iov_len -= pad;
	51	goto out;
	52	} else
	53	len -= buf->head[0].iov_len;
	54	if (len <= buf->page_len) {
67f97d83	55	unsigned int last = (buf->page_base + len - 1)
14ae162c	56	>>PAGE_CACHE_SHIFT;
67f97d83	57	unsigned int offset = (buf->page_base + len - 1)
14ae162c	58	& (PAGE_CACHE_SIZE - 1);
87d918d6	59	ptr = kmap_atomic(buf->pages[last], KM_USER0);
14ae162c	60	pad = *(ptr + offset);
87d918d6	61	kunmap_atomic(ptr, KM_USER0);
14ae162c BF	62	goto out;
	63	} else
	64	len -= buf->page_len;
	65	BUG_ON(len > buf->tail[0].iov_len);
	66	pad = (u8 )(buf->tail[0].iov_base + len - 1);
	67	out:
	68	/* XXX: NOTE: we do not adjust the page lengths--they represent
	69	* a range of data in the real filesystem page cache, and we need
	70	* to know that range so the xdr code can properly place read data.
	71	* However adjusting the head length, as we do above, is harmless.
	72	* In the case of a request that fits into a single page, the server
	73	* also uses length and head length together to determine the original
	74	* start of the request to copy the request for deferal; so it's
	75	* easier on the server if we adjust head and tail length in tandem.
	76	* It's not really a problem that we don't fool with the page and
	77	* tail lengths, though--at worst badly formed xdr might lead the
	78	* server to attempt to parse the padding.
	79	* XXX: Document all these weird requirements for gss mechanism
	80	* wrap/unwrap functions. */
	81	if (pad > blocksize)
	82	return -EINVAL;
	83	if (buf->len > pad)
	84	buf->len -= pad;
	85	else
	86	return -EINVAL;
	87	return 0;
	88	}
	89
	90	static inline void
	91	make_confounder(char *p, int blocksize)
	92	{
	93	static u64 i = 0;
	94	u64 q = (u64 )p;
	95
	96	/* rfc1964 claims this should be "random". But all that's really
	97	* necessary is that it be unique. And not even that is necessary in
	98	* our case since our "gssapi" implementation exists only to support
	99	* rpcsec_gss, so we know that the only buffers we will ever encrypt
	100	* already begin with a unique sequence number. Just to hedge my bets
	101	* I'll make a half-hearted attempt at something unique, but ensuring
	102	* uniqueness would mean worrying about atomicity and rollover, and I
	103	* don't care enough. */
	104
	105	BUG_ON(blocksize != 8);
	106	*q = i++;
	107	}
	108
	109	/* Assumptions: the head and tail of inbuf are ours to play with.
	110	* The pages, however, may be real pages in the page cache and we replace
	111	* them with scratch pages from *pages before writing to them. /
	112	/* XXX: obviously the above should be documentation of wrap interface,
	113	* and shouldn't be in this kerberos-specific file. */
	114
	115	/* XXX factor out common code with seal/unseal. */
	116
	117	u32
00fd6e14	118	gss_wrap_kerberos(struct gss_ctx *ctx, int offset,
14ae162c BF	119	struct xdr_buf buf, struct page *pages)
	120	{
	121	struct krb5_ctx *kctx = ctx->internal_ctx_id;
9e57b302 BF	122	char cksumdata[16];
9e57b302 BF	123	struct xdr_netobj md5cksum = {.len = 0, .data = cksumdata};
14ae162c	124	int blocksize = 0, plainlen;
d00953a5	125	unsigned char ptr, msg_start;
14ae162c BF	126	s32 now;
	127	int headlen;
	128	struct page **tmp_pages;
eaa82edf	129	u32 seq_send;
14ae162c	130
8885cb36	131	dprintk("RPC: gss_wrap_kerberos\n");
14ae162c BF	132
	133	now = get_seconds();
	134
378c6697	135	blocksize = crypto_blkcipher_blocksize(kctx->enc);
14ae162c BF	136	gss_krb5_add_padding(buf, offset, blocksize);
	137	BUG_ON((buf->len - offset) % blocksize);
	138	plainlen = blocksize + buf->len - offset;
	139
4ab4b0be	140	headlen = g_token_size(&kctx->mech_used, 24 + plainlen) -
14ae162c BF	141	(buf->len - offset);
	142
	143	ptr = buf->head[0].iov_base + offset;
	144	/* shift data to make room for header. */
	145	/* XXX Would be cleverer to encrypt while copying. */
	146	/* XXX bounds checking, slack, etc. */
	147	memmove(ptr + headlen, ptr, buf->head[0].iov_len - offset);
	148	buf->head[0].iov_len += headlen;
	149	buf->len += headlen;
	150	BUG_ON((buf->len - offset - headlen) % blocksize);
	151
d00953a5 KC	152	g_make_token_header(&kctx->mech_used,
d00953a5 KC	153	GSS_KRB5_TOK_HDR_LEN + 8 + plainlen, &ptr);
14ae162c BF	154
14ae162c BF	155
d00953a5 KC	156	/* ptr now at header described in rfc 1964, section 1.2.1: */
	157	ptr[0] = (unsigned char) ((KG_TOK_WRAP_MSG >> 8) & 0xff);
	158	ptr[1] = (unsigned char) (KG_TOK_WRAP_MSG & 0xff);
14ae162c	159
d00953a5	160	msg_start = ptr + 24;
14ae162c	161
d00953a5 KC	162	(__be16 )(ptr + 2) = htons(SGN_ALG_DES_MAC_MD5);
	163	memset(ptr + 4, 0xff, 4);
	164	(__be16 )(ptr + 4) = htons(SEAL_ALG_DES);
14ae162c BF	165
	166	make_confounder(msg_start, blocksize);
	167
	168	/* XXXJBF: UGH!: */
	169	tmp_pages = buf->pages;
	170	buf->pages = pages;
d00953a5	171	if (make_checksum("md5", ptr, 8, buf,
14ae162c	172	offset + headlen - blocksize, &md5cksum))
39a21dd1	173	return GSS_S_FAILURE;
14ae162c BF	174	buf->pages = tmp_pages;
14ae162c BF	175
e678e06b BF	176	if (krb5_encrypt(kctx->seq, NULL, md5cksum.data,
e678e06b BF	177	md5cksum.data, md5cksum.len))
39a21dd1	178	return GSS_S_FAILURE;
d00953a5	179	memcpy(ptr + GSS_KRB5_TOK_HDR_LEN, md5cksum.data + md5cksum.len - 8, 8);
14ae162c	180
eaa82edf BF	181	spin_lock(&krb5_seq_lock);
	182	seq_send = kctx->seq_send++;
	183	spin_unlock(&krb5_seq_lock);
	184
14ae162c BF	185	/* XXX would probably be more efficient to compute checksum
	186	* and encrypt at the same time: */
	187	if ((krb5_make_seq_num(kctx->seq, kctx->initiate ? 0 : 0xff,
d00953a5	188	seq_send, ptr + GSS_KRB5_TOK_HDR_LEN, ptr + 8)))
39a21dd1	189	return GSS_S_FAILURE;
14ae162c BF	190
	191	if (gss_encrypt_xdr_buf(kctx->enc, buf, offset + headlen - blocksize,
	192	pages))
39a21dd1	193	return GSS_S_FAILURE;
14ae162c	194
94efa934	195	return (kctx->endtime < now) ? GSS_S_CONTEXT_EXPIRED : GSS_S_COMPLETE;
14ae162c BF	196	}
	197
	198	u32
00fd6e14	199	gss_unwrap_kerberos(struct gss_ctx ctx, int offset, struct xdr_buf buf)
14ae162c BF	200	{
	201	struct krb5_ctx *kctx = ctx->internal_ctx_id;
	202	int signalg;
	203	int sealalg;
9e57b302 BF	204	char cksumdata[16];
9e57b302 BF	205	struct xdr_netobj md5cksum = {.len = 0, .data = cksumdata};
14ae162c BF	206	s32 now;
	207	int direction;
	208	s32 seqnum;
	209	unsigned char *ptr;
	210	int bodysize;
14ae162c BF	211	void data_start, orig_start;
	212	int data_len;
	213	int blocksize;
	214
8885cb36	215	dprintk("RPC: gss_unwrap_kerberos\n");
14ae162c BF	216
	217	ptr = (u8 *)buf->head[0].iov_base + offset;
	218	if (g_verify_token_header(&kctx->mech_used, &bodysize, &ptr,
	219	buf->len - offset))
39a21dd1	220	return GSS_S_DEFECTIVE_TOKEN;
14ae162c	221
d00953a5 KC	222	if ((ptr[0] != ((KG_TOK_WRAP_MSG >> 8) & 0xff)) \|\|
d00953a5 KC	223	(ptr[1] != (KG_TOK_WRAP_MSG & 0xff)))
39a21dd1	224	return GSS_S_DEFECTIVE_TOKEN;
14ae162c BF	225
	226	/* XXX sanity-check bodysize?? */
	227
	228	/* get the sign and seal algorithms */
	229
d00953a5	230	signalg = ptr[2] + (ptr[3] << 8);
94efa934	231	if (signalg != SGN_ALG_DES_MAC_MD5)
39a21dd1	232	return GSS_S_DEFECTIVE_TOKEN;
14ae162c	233
d00953a5	234	sealalg = ptr[4] + (ptr[5] << 8);
d922a84a	235	if (sealalg != SEAL_ALG_DES)
39a21dd1	236	return GSS_S_DEFECTIVE_TOKEN;
94efa934	237
d00953a5	238	if ((ptr[6] != 0xff) \|\| (ptr[7] != 0xff))
39a21dd1	239	return GSS_S_DEFECTIVE_TOKEN;
14ae162c	240
14ae162c	241	if (gss_decrypt_xdr_buf(kctx->enc, buf,
d00953a5	242	ptr + GSS_KRB5_TOK_HDR_LEN + 8 - (unsigned char *)buf->head[0].iov_base))
39a21dd1	243	return GSS_S_DEFECTIVE_TOKEN;
14ae162c	244
d00953a5 KC	245	if (make_checksum("md5", ptr, 8, buf,
d00953a5 KC	246	ptr + GSS_KRB5_TOK_HDR_LEN + 8 - (unsigned char *)buf->head[0].iov_base, &md5cksum))
39a21dd1	247	return GSS_S_FAILURE;
5eb064f9	248
39a21dd1 BF	249	if (krb5_encrypt(kctx->seq, NULL, md5cksum.data,
	250	md5cksum.data, md5cksum.len))
	251	return GSS_S_FAILURE;
14ae162c	252
d00953a5	253	if (memcmp(md5cksum.data + 8, ptr + GSS_KRB5_TOK_HDR_LEN, 8))
39a21dd1	254	return GSS_S_BAD_SIG;
14ae162c BF	255
	256	/* it got through unscathed. Make sure the context is unexpired */
	257
14ae162c BF	258	now = get_seconds();
14ae162c BF	259
14ae162c	260	if (now > kctx->endtime)
39a21dd1	261	return GSS_S_CONTEXT_EXPIRED;
14ae162c BF	262
	263	/* do sequencing checks */
	264
d00953a5 KC	265	if (krb5_get_seq_num(kctx->seq, ptr + GSS_KRB5_TOK_HDR_LEN, ptr + 8,
d00953a5 KC	266	&direction, &seqnum))
39a21dd1	267	return GSS_S_BAD_SIG;
14ae162c BF	268
	269	if ((kctx->initiate && direction != 0xff) \|\|
	270	(!kctx->initiate && direction != 0))
39a21dd1	271	return GSS_S_BAD_SIG;
14ae162c BF	272
	273	/* Copy the data back to the right position. XXX: Would probably be
	274	* better to copy and encrypt at the same time. */
	275
378c6697	276	blocksize = crypto_blkcipher_blocksize(kctx->enc);
d00953a5	277	data_start = ptr + GSS_KRB5_TOK_HDR_LEN + 8 + blocksize;
14ae162c BF	278	orig_start = buf->head[0].iov_base + offset;
	279	data_len = (buf->head[0].iov_base + buf->head[0].iov_len) - data_start;
	280	memmove(orig_start, data_start, data_len);
	281	buf->head[0].iov_len -= (data_start - orig_start);
	282	buf->len -= (data_start - orig_start);
	283
14ae162c	284	if (gss_krb5_remove_padding(buf, blocksize))
39a21dd1	285	return GSS_S_DEFECTIVE_TOKEN;
14ae162c	286
39a21dd1	287	return GSS_S_COMPLETE;
14ae162c	288	}