[mirror_ubuntu-artful-kernel.git] / net / sunrpc / auth_gss / gss_krb5_wrap.c

#include <linux/types.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 void
make_confounder(char *p, u32 conflen)
{
	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. */

	/* initialize to random value */
	if (i == 0) {
		i = random32();
		i = (i << 32) | random32();
	}

	switch (conflen) {
	case 16:
		*q++ = i++;
		/* fall through */
	case 8:
		*q++ = i++;
		break;
	default:
		BUG();
	}
}

/* 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	1	#include <linux/types.h>
14ae162c BF	2	#include <linux/jiffies.h>
	3	#include <linux/sunrpc/gss_krb5.h>
	4	#include <linux/random.h>
	5	#include <linux/pagemap.h>
14ae162c BF	6	#include <linux/crypto.h>
	7
	8	#ifdef RPC_DEBUG
	9	# define RPCDBG_FACILITY RPCDBG_AUTH
	10	#endif
	11
	12	static inline int
	13	gss_krb5_padding(int blocksize, int length)
	14	{
	15	/* Most of the code is block-size independent but currently we
	16	* use only 8: */
	17	BUG_ON(blocksize != 8);
	18	return 8 - (length & 7);
	19	}
	20
	21	static inline void
	22	gss_krb5_add_padding(struct xdr_buf *buf, int offset, int blocksize)
	23	{
	24	int padding = gss_krb5_padding(blocksize, buf->len - offset);
	25	char *p;
	26	struct kvec *iov;
	27
	28	if (buf->page_len \|\| buf->tail[0].iov_len)
	29	iov = &buf->tail[0];
	30	else
	31	iov = &buf->head[0];
	32	p = iov->iov_base + iov->iov_len;
	33	iov->iov_len += padding;
	34	buf->len += padding;
	35	memset(p, padding, padding);
	36	}
	37
	38	static inline int
	39	gss_krb5_remove_padding(struct xdr_buf *buf, int blocksize)
	40	{
	41	u8 *ptr;
	42	u8 pad;
67f97d83	43	size_t len = buf->len;
14ae162c BF	44
	45	if (len <= buf->head[0].iov_len) {
	46	pad = (u8 )(buf->head[0].iov_base + len - 1);
	47	if (pad > buf->head[0].iov_len)
	48	return -EINVAL;
	49	buf->head[0].iov_len -= pad;
	50	goto out;
	51	} else
	52	len -= buf->head[0].iov_len;
	53	if (len <= buf->page_len) {
67f97d83	54	unsigned int last = (buf->page_base + len - 1)
14ae162c	55	>>PAGE_CACHE_SHIFT;
67f97d83	56	unsigned int offset = (buf->page_base + len - 1)
14ae162c	57	& (PAGE_CACHE_SIZE - 1);
87d918d6	58	ptr = kmap_atomic(buf->pages[last], KM_USER0);
14ae162c	59	pad = *(ptr + offset);
87d918d6	60	kunmap_atomic(ptr, KM_USER0);
14ae162c BF	61	goto out;
	62	} else
	63	len -= buf->page_len;
	64	BUG_ON(len > buf->tail[0].iov_len);
	65	pad = (u8 )(buf->tail[0].iov_base + len - 1);
	66	out:
	67	/* XXX: NOTE: we do not adjust the page lengths--they represent
	68	* a range of data in the real filesystem page cache, and we need
	69	* to know that range so the xdr code can properly place read data.
	70	* However adjusting the head length, as we do above, is harmless.
	71	* In the case of a request that fits into a single page, the server
	72	* also uses length and head length together to determine the original
	73	* start of the request to copy the request for deferal; so it's
	74	* easier on the server if we adjust head and tail length in tandem.
	75	* It's not really a problem that we don't fool with the page and
	76	* tail lengths, though--at worst badly formed xdr might lead the
	77	* server to attempt to parse the padding.
	78	* XXX: Document all these weird requirements for gss mechanism
	79	* wrap/unwrap functions. */
	80	if (pad > blocksize)
	81	return -EINVAL;
	82	if (buf->len > pad)
	83	buf->len -= pad;
	84	else
	85	return -EINVAL;
	86	return 0;
	87	}
	88
863a2488 KC	89	static void
863a2488 KC	90	make_confounder(char *p, u32 conflen)
14ae162c BF	91	{
	92	static u64 i = 0;
	93	u64 q = (u64 )p;
	94
	95	/* rfc1964 claims this should be "random". But all that's really
	96	* necessary is that it be unique. And not even that is necessary in
	97	* our case since our "gssapi" implementation exists only to support
	98	* rpcsec_gss, so we know that the only buffers we will ever encrypt
	99	* already begin with a unique sequence number. Just to hedge my bets
	100	* I'll make a half-hearted attempt at something unique, but ensuring
	101	* uniqueness would mean worrying about atomicity and rollover, and I
	102	* don't care enough. */
	103
863a2488 KC	104	/* initialize to random value */
	105	if (i == 0) {
	106	i = random32();
	107	i = (i << 32) \| random32();
	108	}
	109
	110	switch (conflen) {
	111	case 16:
	112	*q++ = i++;
	113	/* fall through */
	114	case 8:
	115	*q++ = i++;
	116	break;
	117	default:
	118	BUG();
	119	}
14ae162c BF	120	}
	121
	122	/* Assumptions: the head and tail of inbuf are ours to play with.
	123	* The pages, however, may be real pages in the page cache and we replace
	124	* them with scratch pages from *pages before writing to them. /
	125	/* XXX: obviously the above should be documentation of wrap interface,
	126	* and shouldn't be in this kerberos-specific file. */
	127
	128	/* XXX factor out common code with seal/unseal. */
	129
	130	u32
00fd6e14	131	gss_wrap_kerberos(struct gss_ctx *ctx, int offset,
14ae162c BF	132	struct xdr_buf buf, struct page *pages)
	133	{
	134	struct krb5_ctx *kctx = ctx->internal_ctx_id;
9e57b302 BF	135	char cksumdata[16];
9e57b302 BF	136	struct xdr_netobj md5cksum = {.len = 0, .data = cksumdata};
14ae162c	137	int blocksize = 0, plainlen;
d00953a5	138	unsigned char ptr, msg_start;
14ae162c BF	139	s32 now;
	140	int headlen;
	141	struct page **tmp_pages;
eaa82edf	142	u32 seq_send;
14ae162c	143
8885cb36	144	dprintk("RPC: gss_wrap_kerberos\n");
14ae162c BF	145
	146	now = get_seconds();
	147
378c6697	148	blocksize = crypto_blkcipher_blocksize(kctx->enc);
14ae162c BF	149	gss_krb5_add_padding(buf, offset, blocksize);
	150	BUG_ON((buf->len - offset) % blocksize);
	151	plainlen = blocksize + buf->len - offset;
	152
4ab4b0be	153	headlen = g_token_size(&kctx->mech_used, 24 + plainlen) -
14ae162c BF	154	(buf->len - offset);
	155
	156	ptr = buf->head[0].iov_base + offset;
	157	/* shift data to make room for header. */
	158	/* XXX Would be cleverer to encrypt while copying. */
	159	/* XXX bounds checking, slack, etc. */
	160	memmove(ptr + headlen, ptr, buf->head[0].iov_len - offset);
	161	buf->head[0].iov_len += headlen;
	162	buf->len += headlen;
	163	BUG_ON((buf->len - offset - headlen) % blocksize);
	164
d00953a5 KC	165	g_make_token_header(&kctx->mech_used,
d00953a5 KC	166	GSS_KRB5_TOK_HDR_LEN + 8 + plainlen, &ptr);
14ae162c BF	167
14ae162c BF	168
d00953a5 KC	169	/* ptr now at header described in rfc 1964, section 1.2.1: */
	170	ptr[0] = (unsigned char) ((KG_TOK_WRAP_MSG >> 8) & 0xff);
	171	ptr[1] = (unsigned char) (KG_TOK_WRAP_MSG & 0xff);
14ae162c	172
d00953a5	173	msg_start = ptr + 24;
14ae162c	174
d00953a5 KC	175	(__be16 )(ptr + 2) = htons(SGN_ALG_DES_MAC_MD5);
	176	memset(ptr + 4, 0xff, 4);
	177	(__be16 )(ptr + 4) = htons(SEAL_ALG_DES);
14ae162c BF	178
	179	make_confounder(msg_start, blocksize);
	180
	181	/* XXXJBF: UGH!: */
	182	tmp_pages = buf->pages;
	183	buf->pages = pages;
d00953a5	184	if (make_checksum("md5", ptr, 8, buf,
14ae162c	185	offset + headlen - blocksize, &md5cksum))
39a21dd1	186	return GSS_S_FAILURE;
14ae162c BF	187	buf->pages = tmp_pages;
14ae162c BF	188
e678e06b BF	189	if (krb5_encrypt(kctx->seq, NULL, md5cksum.data,
e678e06b BF	190	md5cksum.data, md5cksum.len))
39a21dd1	191	return GSS_S_FAILURE;
d00953a5	192	memcpy(ptr + GSS_KRB5_TOK_HDR_LEN, md5cksum.data + md5cksum.len - 8, 8);
14ae162c	193
eaa82edf BF	194	spin_lock(&krb5_seq_lock);
	195	seq_send = kctx->seq_send++;
	196	spin_unlock(&krb5_seq_lock);
	197
14ae162c BF	198	/* XXX would probably be more efficient to compute checksum
	199	* and encrypt at the same time: */
	200	if ((krb5_make_seq_num(kctx->seq, kctx->initiate ? 0 : 0xff,
d00953a5	201	seq_send, ptr + GSS_KRB5_TOK_HDR_LEN, ptr + 8)))
39a21dd1	202	return GSS_S_FAILURE;
14ae162c BF	203
	204	if (gss_encrypt_xdr_buf(kctx->enc, buf, offset + headlen - blocksize,
	205	pages))
39a21dd1	206	return GSS_S_FAILURE;
14ae162c	207
94efa934	208	return (kctx->endtime < now) ? GSS_S_CONTEXT_EXPIRED : GSS_S_COMPLETE;
14ae162c BF	209	}
	210
	211	u32
00fd6e14	212	gss_unwrap_kerberos(struct gss_ctx ctx, int offset, struct xdr_buf buf)
14ae162c BF	213	{
	214	struct krb5_ctx *kctx = ctx->internal_ctx_id;
	215	int signalg;
	216	int sealalg;
9e57b302 BF	217	char cksumdata[16];
9e57b302 BF	218	struct xdr_netobj md5cksum = {.len = 0, .data = cksumdata};
14ae162c BF	219	s32 now;
	220	int direction;
	221	s32 seqnum;
	222	unsigned char *ptr;
	223	int bodysize;
14ae162c BF	224	void data_start, orig_start;
	225	int data_len;
	226	int blocksize;
	227
8885cb36	228	dprintk("RPC: gss_unwrap_kerberos\n");
14ae162c BF	229
	230	ptr = (u8 *)buf->head[0].iov_base + offset;
	231	if (g_verify_token_header(&kctx->mech_used, &bodysize, &ptr,
	232	buf->len - offset))
39a21dd1	233	return GSS_S_DEFECTIVE_TOKEN;
14ae162c	234
d00953a5 KC	235	if ((ptr[0] != ((KG_TOK_WRAP_MSG >> 8) & 0xff)) \|\|
d00953a5 KC	236	(ptr[1] != (KG_TOK_WRAP_MSG & 0xff)))
39a21dd1	237	return GSS_S_DEFECTIVE_TOKEN;
14ae162c BF	238
	239	/* XXX sanity-check bodysize?? */
	240
	241	/* get the sign and seal algorithms */
	242
d00953a5	243	signalg = ptr[2] + (ptr[3] << 8);
94efa934	244	if (signalg != SGN_ALG_DES_MAC_MD5)
39a21dd1	245	return GSS_S_DEFECTIVE_TOKEN;
14ae162c	246
d00953a5	247	sealalg = ptr[4] + (ptr[5] << 8);
d922a84a	248	if (sealalg != SEAL_ALG_DES)
39a21dd1	249	return GSS_S_DEFECTIVE_TOKEN;
94efa934	250
d00953a5	251	if ((ptr[6] != 0xff) \|\| (ptr[7] != 0xff))
39a21dd1	252	return GSS_S_DEFECTIVE_TOKEN;
14ae162c	253
14ae162c	254	if (gss_decrypt_xdr_buf(kctx->enc, buf,
d00953a5	255	ptr + GSS_KRB5_TOK_HDR_LEN + 8 - (unsigned char *)buf->head[0].iov_base))
39a21dd1	256	return GSS_S_DEFECTIVE_TOKEN;
14ae162c	257
d00953a5 KC	258	if (make_checksum("md5", ptr, 8, buf,
d00953a5 KC	259	ptr + GSS_KRB5_TOK_HDR_LEN + 8 - (unsigned char *)buf->head[0].iov_base, &md5cksum))
39a21dd1	260	return GSS_S_FAILURE;
5eb064f9	261
39a21dd1 BF	262	if (krb5_encrypt(kctx->seq, NULL, md5cksum.data,
	263	md5cksum.data, md5cksum.len))
	264	return GSS_S_FAILURE;
14ae162c	265
d00953a5	266	if (memcmp(md5cksum.data + 8, ptr + GSS_KRB5_TOK_HDR_LEN, 8))
39a21dd1	267	return GSS_S_BAD_SIG;
14ae162c BF	268
	269	/* it got through unscathed. Make sure the context is unexpired */
	270
14ae162c BF	271	now = get_seconds();
14ae162c BF	272
14ae162c	273	if (now > kctx->endtime)
39a21dd1	274	return GSS_S_CONTEXT_EXPIRED;
14ae162c BF	275
	276	/* do sequencing checks */
	277
d00953a5 KC	278	if (krb5_get_seq_num(kctx->seq, ptr + GSS_KRB5_TOK_HDR_LEN, ptr + 8,
d00953a5 KC	279	&direction, &seqnum))
39a21dd1	280	return GSS_S_BAD_SIG;
14ae162c BF	281
	282	if ((kctx->initiate && direction != 0xff) \|\|
	283	(!kctx->initiate && direction != 0))
39a21dd1	284	return GSS_S_BAD_SIG;
14ae162c BF	285
	286	/* Copy the data back to the right position. XXX: Would probably be
	287	* better to copy and encrypt at the same time. */
	288
378c6697	289	blocksize = crypto_blkcipher_blocksize(kctx->enc);
d00953a5	290	data_start = ptr + GSS_KRB5_TOK_HDR_LEN + 8 + blocksize;
14ae162c BF	291	orig_start = buf->head[0].iov_base + offset;
	292	data_len = (buf->head[0].iov_base + buf->head[0].iov_len) - data_start;
	293	memmove(orig_start, data_start, data_len);
	294	buf->head[0].iov_len -= (data_start - orig_start);
	295	buf->len -= (data_start - orig_start);
	296
14ae162c	297	if (gss_krb5_remove_padding(buf, blocksize))
39a21dd1	298	return GSS_S_DEFECTIVE_TOKEN;
14ae162c	299
39a21dd1	300	return GSS_S_COMPLETE;
14ae162c	301	}