[GitHub/mt8127/android_kernel_alcatel_ttab.git] / lib / mpi / mpicoder.c

/* mpicoder.c  -  Coder for the external representation of MPIs
 * Copyright (C) 1998, 1999 Free Software Foundation, Inc.
 *
 * This file is part of GnuPG.
 *
 * GnuPG is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * GnuPG is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA
 */

#include "mpi-internal.h"

#define MAX_EXTERN_MPI_BITS 16384

MPI mpi_read_from_buffer(const void *xbuffer, unsigned *ret_nread)
{
	const uint8_t *buffer = xbuffer;
	int i, j;
	unsigned nbits, nbytes, nlimbs, nread = 0;
	mpi_limb_t a;
	MPI val = NULL;

	if (*ret_nread < 2)
		goto leave;
	nbits = buffer[0] << 8 | buffer[1];

	if (nbits > MAX_EXTERN_MPI_BITS) {
		pr_info("MPI: mpi too large (%u bits)\n", nbits);
		goto leave;
	}
	buffer += 2;
	nread = 2;

	nbytes = (nbits + 7) / 8;
	nlimbs = (nbytes + BYTES_PER_MPI_LIMB - 1) / BYTES_PER_MPI_LIMB;
	val = mpi_alloc(nlimbs);
	if (!val)
		return NULL;
	i = BYTES_PER_MPI_LIMB - nbytes % BYTES_PER_MPI_LIMB;
	i %= BYTES_PER_MPI_LIMB;
	val->nbits = nbits;
	j = val->nlimbs = nlimbs;
	val->sign = 0;
	for (; j > 0; j--) {
		a = 0;
		for (; i < BYTES_PER_MPI_LIMB; i++) {
			if (++nread > *ret_nread) {
				printk
				    ("MPI: mpi larger than buffer nread=%d ret_nread=%d\n",
				     nread, *ret_nread);
				goto leave;
			}
			a <<= 8;
			a |= *buffer++;
		}
		i = 0;
		val->d[j - 1] = a;
	}

leave:
	*ret_nread = nread;
	return val;
}
EXPORT_SYMBOL_GPL(mpi_read_from_buffer);

/****************
 * Make an mpi from a character string.
 */
int mpi_fromstr(MPI val, const char *str)
{
	int hexmode = 0, sign = 0, prepend_zero = 0, i, j, c, c1, c2;
	unsigned nbits, nbytes, nlimbs;
	mpi_limb_t a;

	if (*str == '-') {
		sign = 1;
		str++;
	}
	if (*str == '0' && str[1] == 'x')
		hexmode = 1;
	else
		return -EINVAL;	/* other bases are not yet supported */
	str += 2;

	nbits = strlen(str) * 4;
	if (nbits % 8)
		prepend_zero = 1;
	nbytes = (nbits + 7) / 8;
	nlimbs = (nbytes + BYTES_PER_MPI_LIMB - 1) / BYTES_PER_MPI_LIMB;
	if (val->alloced < nlimbs)
		if (!mpi_resize(val, nlimbs))
			return -ENOMEM;
	i = BYTES_PER_MPI_LIMB - nbytes % BYTES_PER_MPI_LIMB;
	i %= BYTES_PER_MPI_LIMB;
	j = val->nlimbs = nlimbs;
	val->sign = sign;
	for (; j > 0; j--) {
		a = 0;
		for (; i < BYTES_PER_MPI_LIMB; i++) {
			if (prepend_zero) {
				c1 = '0';
				prepend_zero = 0;
			} else
				c1 = *str++;
			assert(c1);
			c2 = *str++;
			assert(c2);
			if (c1 >= '0' && c1 <= '9')
				c = c1 - '0';
			else if (c1 >= 'a' && c1 <= 'f')
				c = c1 - 'a' + 10;
			else if (c1 >= 'A' && c1 <= 'F')
				c = c1 - 'A' + 10;
			else {
				mpi_clear(val);
				return 1;
			}
			c <<= 4;
			if (c2 >= '0' && c2 <= '9')
				c |= c2 - '0';
			else if (c2 >= 'a' && c2 <= 'f')
				c |= c2 - 'a' + 10;
			else if (c2 >= 'A' && c2 <= 'F')
				c |= c2 - 'A' + 10;
			else {
				mpi_clear(val);
				return 1;
			}
			a <<= 8;
			a |= c;
		}
		i = 0;

		val->d[j - 1] = a;
	}

	return 0;
}
EXPORT_SYMBOL_GPL(mpi_fromstr);

/****************
 * Return an allocated buffer with the MPI (msb first).
 * NBYTES receives the length of this buffer. Caller must free the
 * return string (This function does return a 0 byte buffer with NBYTES
 * set to zero if the value of A is zero. If sign is not NULL, it will
 * be set to the sign of the A.
 */
void *mpi_get_buffer(MPI a, unsigned *nbytes, int *sign)
{
	uint8_t *p, *buffer;
	mpi_limb_t alimb;
	int i;
	unsigned int n;

	if (sign)
		*sign = a->sign;
	*nbytes = n = a->nlimbs * BYTES_PER_MPI_LIMB;
	if (!n)
		n++;		/* avoid zero length allocation */
	p = buffer = kmalloc(n, GFP_KERNEL);
	if (!p)
		return NULL;

	for (i = a->nlimbs - 1; i >= 0; i--) {
		alimb = a->d[i];
#if BYTES_PER_MPI_LIMB == 4
		*p++ = alimb >> 24;
		*p++ = alimb >> 16;
		*p++ = alimb >> 8;
		*p++ = alimb;
#elif BYTES_PER_MPI_LIMB == 8
		*p++ = alimb >> 56;
		*p++ = alimb >> 48;
		*p++ = alimb >> 40;
		*p++ = alimb >> 32;
		*p++ = alimb >> 24;
		*p++ = alimb >> 16;
		*p++ = alimb >> 8;
		*p++ = alimb;
#else
#error please implement for this limb size.
#endif
	}

	/* this is sub-optimal but we need to do the shift operation
	 * because the caller has to free the returned buffer */
	for (p = buffer; !*p && *nbytes; p++, --*nbytes)
		;
	if (p != buffer)
		memmove(buffer, p, *nbytes);

	return buffer;
}
EXPORT_SYMBOL_GPL(mpi_get_buffer);

/****************
 * Use BUFFER to update MPI.
 */
int mpi_set_buffer(MPI a, const void *xbuffer, unsigned nbytes, int sign)
{
	const uint8_t *buffer = xbuffer, *p;
	mpi_limb_t alimb;
	int nlimbs;
	int i;

	nlimbs = (nbytes + BYTES_PER_MPI_LIMB - 1) / BYTES_PER_MPI_LIMB;
	if (RESIZE_IF_NEEDED(a, nlimbs) < 0)
		return -ENOMEM;
	a->sign = sign;

	for (i = 0, p = buffer + nbytes - 1; p >= buffer + BYTES_PER_MPI_LIMB;) {
#if BYTES_PER_MPI_LIMB == 4
		alimb = (mpi_limb_t) *p--;
		alimb |= (mpi_limb_t) *p-- << 8;
		alimb |= (mpi_limb_t) *p-- << 16;
		alimb |= (mpi_limb_t) *p-- << 24;
#elif BYTES_PER_MPI_LIMB == 8
		alimb = (mpi_limb_t) *p--;
		alimb |= (mpi_limb_t) *p-- << 8;
		alimb |= (mpi_limb_t) *p-- << 16;
		alimb |= (mpi_limb_t) *p-- << 24;
		alimb |= (mpi_limb_t) *p-- << 32;
		alimb |= (mpi_limb_t) *p-- << 40;
		alimb |= (mpi_limb_t) *p-- << 48;
		alimb |= (mpi_limb_t) *p-- << 56;
#else
#error please implement for this limb size.
#endif
		a->d[i++] = alimb;
	}
	if (p >= buffer) {
#if BYTES_PER_MPI_LIMB == 4
		alimb = *p--;
		if (p >= buffer)
			alimb |= (mpi_limb_t) *p-- << 8;
		if (p >= buffer)
			alimb |= (mpi_limb_t) *p-- << 16;
		if (p >= buffer)
			alimb |= (mpi_limb_t) *p-- << 24;
#elif BYTES_PER_MPI_LIMB == 8
		alimb = (mpi_limb_t) *p--;
		if (p >= buffer)
			alimb |= (mpi_limb_t) *p-- << 8;
		if (p >= buffer)
			alimb |= (mpi_limb_t) *p-- << 16;
		if (p >= buffer)
			alimb |= (mpi_limb_t) *p-- << 24;
		if (p >= buffer)
			alimb |= (mpi_limb_t) *p-- << 32;
		if (p >= buffer)
			alimb |= (mpi_limb_t) *p-- << 40;
		if (p >= buffer)
			alimb |= (mpi_limb_t) *p-- << 48;
		if (p >= buffer)
			alimb |= (mpi_limb_t) *p-- << 56;
#else
#error please implement for this limb size.
#endif
		a->d[i++] = alimb;
	}
	a->nlimbs = i;

	if (i != nlimbs) {
		pr_emerg("MPI: mpi_set_buffer: Assertion failed (%d != %d)", i,
		       nlimbs);
		BUG();
	}
	return 0;
}
EXPORT_SYMBOL_GPL(mpi_set_buffer);
Commit	Line	Data
cdec9cb5 DK	1	/* mpicoder.c - Coder for the external representation of MPIs
	2	* Copyright (C) 1998, 1999 Free Software Foundation, Inc.
	3	*
	4	* This file is part of GnuPG.
	5	*
	6	* GnuPG is free software; you can redistribute it and/or modify
	7	* it under the terms of the GNU General Public License as published by
	8	* the Free Software Foundation; either version 2 of the License, or
	9	* (at your option) any later version.
	10	*
	11	* GnuPG is distributed in the hope that it will be useful,
	12	* but WITHOUT ANY WARRANTY; without even the implied warranty of
	13	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	14	* GNU General Public License for more details.
	15	*
	16	* You should have received a copy of the GNU General Public License
	17	* along with this program; if not, write to the Free Software
	18	* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA
	19	*/
	20
	21	#include "mpi-internal.h"
	22
cdec9cb5 DK	23	#define MAX_EXTERN_MPI_BITS 16384
cdec9cb5 DK	24
cdec9cb5 DK	25	MPI mpi_read_from_buffer(const void xbuffer, unsigned ret_nread)
	26	{
	27	const uint8_t *buffer = xbuffer;
	28	int i, j;
	29	unsigned nbits, nbytes, nlimbs, nread = 0;
	30	mpi_limb_t a;
3cccd154	31	MPI val = NULL;
cdec9cb5 DK	32
	33	if (*ret_nread < 2)
	34	goto leave;
	35	nbits = buffer[0] << 8 \| buffer[1];
	36
	37	if (nbits > MAX_EXTERN_MPI_BITS) {
	38	pr_info("MPI: mpi too large (%u bits)\n", nbits);
	39	goto leave;
	40	}
	41	buffer += 2;
	42	nread = 2;
	43
	44	nbytes = (nbits + 7) / 8;
	45	nlimbs = (nbytes + BYTES_PER_MPI_LIMB - 1) / BYTES_PER_MPI_LIMB;
	46	val = mpi_alloc(nlimbs);
	47	if (!val)
3cccd154	48	return NULL;
cdec9cb5 DK	49	i = BYTES_PER_MPI_LIMB - nbytes % BYTES_PER_MPI_LIMB;
	50	i %= BYTES_PER_MPI_LIMB;
	51	val->nbits = nbits;
	52	j = val->nlimbs = nlimbs;
	53	val->sign = 0;
	54	for (; j > 0; j--) {
	55	a = 0;
	56	for (; i < BYTES_PER_MPI_LIMB; i++) {
	57	if (++nread > *ret_nread) {
	58	printk
	59	("MPI: mpi larger than buffer nread=%d ret_nread=%d\n",
	60	nread, *ret_nread);
	61	goto leave;
	62	}
	63	a <<= 8;
	64	a \|= *buffer++;
	65	}
	66	i = 0;
	67	val->d[j - 1] = a;
	68	}
	69
	70	leave:
	71	*ret_nread = nread;
	72	return val;
	73	}
	74	EXPORT_SYMBOL_GPL(mpi_read_from_buffer);
	75
	76	/****************
	77	* Make an mpi from a character string.
	78	*/
	79	int mpi_fromstr(MPI val, const char *str)
	80	{
	81	int hexmode = 0, sign = 0, prepend_zero = 0, i, j, c, c1, c2;
	82	unsigned nbits, nbytes, nlimbs;
	83	mpi_limb_t a;
	84
	85	if (*str == '-') {
	86	sign = 1;
	87	str++;
	88	}
	89	if (*str == '0' && str[1] == 'x')
	90	hexmode = 1;
	91	else
	92	return -EINVAL; /* other bases are not yet supported */
	93	str += 2;
	94
	95	nbits = strlen(str) * 4;
	96	if (nbits % 8)
	97	prepend_zero = 1;
	98	nbytes = (nbits + 7) / 8;
	99	nlimbs = (nbytes + BYTES_PER_MPI_LIMB - 1) / BYTES_PER_MPI_LIMB;
	100	if (val->alloced < nlimbs)
	101	if (!mpi_resize(val, nlimbs))
	102	return -ENOMEM;
	103	i = BYTES_PER_MPI_LIMB - nbytes % BYTES_PER_MPI_LIMB;
	104	i %= BYTES_PER_MPI_LIMB;
	105	j = val->nlimbs = nlimbs;
	106	val->sign = sign;
	107	for (; j > 0; j--) {
	108	a = 0;
	109	for (; i < BYTES_PER_MPI_LIMB; i++) {
	110	if (prepend_zero) {
	111	c1 = '0';
	112	prepend_zero = 0;
113	} else
114	c1 = *str++;
115	assert(c1);
116	c2 = *str++;
117	assert(c2);
118	if (c1 >= '0' && c1 <= '9')
119	c = c1 - '0';
120	else if (c1 >= 'a' && c1 <= 'f')
121	c = c1 - 'a' + 10;
122	else if (c1 >= 'A' && c1 <= 'F')
123	c = c1 - 'A' + 10;
124	else {
125	mpi_clear(val);
126	return 1;
127	}
128	c <<= 4;
129	if (c2 >= '0' && c2 <= '9')
130	c \|= c2 - '0';
131	else if (c2 >= 'a' && c2 <= 'f')
132	c \|= c2 - 'a' + 10;
133	else if (c2 >= 'A' && c2 <= 'F')
134	c \|= c2 - 'A' + 10;
135	else {
136	mpi_clear(val);
137	return 1;
138	}
139	a <<= 8;
140	a \|= c;
141	}
142	i = 0;
143
144	val->d[j - 1] = a;
145	}
146
147	return 0;
148	}
149	EXPORT_SYMBOL_GPL(mpi_fromstr);
150
cdec9cb5 DK	151	/****************
	152	* Return an allocated buffer with the MPI (msb first).
	153	* NBYTES receives the length of this buffer. Caller must free the
	154	* return string (This function does return a 0 byte buffer with NBYTES
	155	* set to zero if the value of A is zero. If sign is not NULL, it will
	156	* be set to the sign of the A.
	157	*/
	158	void mpi_get_buffer(MPI a, unsigned nbytes, int *sign)
	159	{
	160	uint8_t p, buffer;
	161	mpi_limb_t alimb;
	162	int i;
	163	unsigned int n;
	164
	165	if (sign)
	166	*sign = a->sign;
	167	nbytes = n = a->nlimbs BYTES_PER_MPI_LIMB;
	168	if (!n)
	169	n++; /* avoid zero length allocation */
	170	p = buffer = kmalloc(n, GFP_KERNEL);
4bf1924c DH	171	if (!p)
4bf1924c DH	172	return NULL;
cdec9cb5 DK	173
	174	for (i = a->nlimbs - 1; i >= 0; i--) {
	175	alimb = a->d[i];
	176	#if BYTES_PER_MPI_LIMB == 4
	177	*p++ = alimb >> 24;
	178	*p++ = alimb >> 16;
	179	*p++ = alimb >> 8;
	180	*p++ = alimb;
	181	#elif BYTES_PER_MPI_LIMB == 8
	182	*p++ = alimb >> 56;
	183	*p++ = alimb >> 48;
	184	*p++ = alimb >> 40;
	185	*p++ = alimb >> 32;
	186	*p++ = alimb >> 24;
	187	*p++ = alimb >> 16;
	188	*p++ = alimb >> 8;
	189	*p++ = alimb;
	190	#else
	191	#error please implement for this limb size.
	192	#endif
	193	}
	194
	195	/* this is sub-optimal but we need to do the shift operation
	196	* because the caller has to free the returned buffer */
	197	for (p = buffer; !p && nbytes; p++, --*nbytes)
	198	;
	199	if (p != buffer)
	200	memmove(buffer, p, *nbytes);
	201
	202	return buffer;
	203	}
	204	EXPORT_SYMBOL_GPL(mpi_get_buffer);
	205
	206	/****************
	207	* Use BUFFER to update MPI.
	208	*/
	209	int mpi_set_buffer(MPI a, const void *xbuffer, unsigned nbytes, int sign)
	210	{
	211	const uint8_t buffer = xbuffer, p;
	212	mpi_limb_t alimb;
	213	int nlimbs;
	214	int i;
	215
	216	nlimbs = (nbytes + BYTES_PER_MPI_LIMB - 1) / BYTES_PER_MPI_LIMB;
	217	if (RESIZE_IF_NEEDED(a, nlimbs) < 0)
	218	return -ENOMEM;
	219	a->sign = sign;
	220
	221	for (i = 0, p = buffer + nbytes - 1; p >= buffer + BYTES_PER_MPI_LIMB;) {
	222	#if BYTES_PER_MPI_LIMB == 4
	223	alimb = (mpi_limb_t) *p--;
	224	alimb \|= (mpi_limb_t) *p-- << 8;
	225	alimb \|= (mpi_limb_t) *p-- << 16;
	226	alimb \|= (mpi_limb_t) *p-- << 24;
	227	#elif BYTES_PER_MPI_LIMB == 8
	228	alimb = (mpi_limb_t) *p--;
	229	alimb \|= (mpi_limb_t) *p-- << 8;
	230	alimb \|= (mpi_limb_t) *p-- << 16;
	231	alimb \|= (mpi_limb_t) *p-- << 24;
	232	alimb \|= (mpi_limb_t) *p-- << 32;
	233	alimb \|= (mpi_limb_t) *p-- << 40;
	234	alimb \|= (mpi_limb_t) *p-- << 48;
	235	alimb \|= (mpi_limb_t) *p-- << 56;
	236	#else
237	#error please implement for this limb size.
238	#endif
239	a->d[i++] = alimb;
240	}
241	if (p >= buffer) {
242	#if BYTES_PER_MPI_LIMB == 4
243	alimb = *p--;
244	if (p >= buffer)
245	alimb \|= (mpi_limb_t) *p-- << 8;
246	if (p >= buffer)
247	alimb \|= (mpi_limb_t) *p-- << 16;
248	if (p >= buffer)
249	alimb \|= (mpi_limb_t) *p-- << 24;
250	#elif BYTES_PER_MPI_LIMB == 8
251	alimb = (mpi_limb_t) *p--;
252	if (p >= buffer)
253	alimb \|= (mpi_limb_t) *p-- << 8;
254	if (p >= buffer)
255	alimb \|= (mpi_limb_t) *p-- << 16;
256	if (p >= buffer)
257	alimb \|= (mpi_limb_t) *p-- << 24;
258	if (p >= buffer)
259	alimb \|= (mpi_limb_t) *p-- << 32;
260	if (p >= buffer)
261	alimb \|= (mpi_limb_t) *p-- << 40;
262	if (p >= buffer)
263	alimb \|= (mpi_limb_t) *p-- << 48;
264	if (p >= buffer)
265	alimb \|= (mpi_limb_t) *p-- << 56;
266	#else
267	#error please implement for this limb size.
268	#endif
269	a->d[i++] = alimb;
270	}
271	a->nlimbs = i;
272
273	if (i != nlimbs) {
274	pr_emerg("MPI: mpi_set_buffer: Assertion failed (%d != %d)", i,
275	nlimbs);
276	BUG();
277	}
278	return 0;
279	}
280	EXPORT_SYMBOL_GPL(mpi_set_buffer);