crypto: lib - Move mpi into lib/crypto

As lib/mpi is mostly used by crypto code, move it under lib/crypto
so that patches touching it get directed to the right mailing list.

Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Reviewed-by: Mimi Zohar <zohar@linux.ibm.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

1 files changed, 752 insertions, 0 deletions

diff --git a/lib/crypto/mpi/mpicoder.c b/lib/crypto/mpi/mpicoder.c
new file mode 100644
index 000000000000..3cb6bd148fa9
--- /dev/null
+++ b/lib/crypto/mpi/mpicoder.c
@@ -0,0 +1,752 @@
+/* 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 <linux/bitops.h>
+#include <linux/count_zeros.h>
+#include <linux/byteorder/generic.h>
+#include <linux/scatterlist.h>
+#include <linux/string.h>
+#include "mpi-internal.h"
+
+#define MAX_EXTERN_SCAN_BYTES (16*1024*1024)
+#define MAX_EXTERN_MPI_BITS 16384
+
+/**
+ * mpi_read_raw_data - Read a raw byte stream as a positive integer
+ * @xbuffer: The data to read
+ * @nbytes: The amount of data to read
+ */
+MPI mpi_read_raw_data(const void *xbuffer, size_t nbytes)
+{
+	const uint8_t *buffer = xbuffer;
+	int i, j;
+	unsigned nbits, nlimbs;
+	mpi_limb_t a;
+	MPI val = NULL;
+
+	while (nbytes > 0 && buffer[0] == 0) {
+		buffer++;
+		nbytes--;
+	}
+
+	nbits = nbytes * 8;
+	if (nbits > MAX_EXTERN_MPI_BITS) {
+		pr_info("MPI: mpi too large (%u bits)\n", nbits);
+		return NULL;
+	}
+	if (nbytes > 0)
+		nbits -= count_leading_zeros(buffer[0]) - (BITS_PER_LONG - 8);
+
+	nlimbs = DIV_ROUND_UP(nbytes, BYTES_PER_MPI_LIMB);
+	val = mpi_alloc(nlimbs);
+	if (!val)
+		return NULL;
+	val->nbits = nbits;
+	val->sign = 0;
+	val->nlimbs = nlimbs;
+
+	if (nbytes > 0) {
+		i = BYTES_PER_MPI_LIMB - nbytes % BYTES_PER_MPI_LIMB;
+		i %= BYTES_PER_MPI_LIMB;
+		for (j = nlimbs; j > 0; j--) {
+			a = 0;
+			for (; i < BYTES_PER_MPI_LIMB; i++) {
+				a <<= 8;
+				a |= *buffer++;
+			}
+			i = 0;
+			val->d[j - 1] = a;
+		}
+	}
+	return val;
+}
+EXPORT_SYMBOL_GPL(mpi_read_raw_data);
+
+MPI mpi_read_from_buffer(const void *xbuffer, unsigned *ret_nread)
+{
+	const uint8_t *buffer = xbuffer;
+	unsigned int nbits, nbytes;
+	MPI val;
+
+	if (*ret_nread < 2)
+		return ERR_PTR(-EINVAL);
+	nbits = buffer[0] << 8 | buffer[1];
+
+	if (nbits > MAX_EXTERN_MPI_BITS) {
+		pr_info("MPI: mpi too large (%u bits)\n", nbits);
+		return ERR_PTR(-EINVAL);
+	}
+
+	nbytes = DIV_ROUND_UP(nbits, 8);
+	if (nbytes + 2 > *ret_nread) {
+		pr_info("MPI: mpi larger than buffer nbytes=%u ret_nread=%u\n",
+				nbytes, *ret_nread);
+		return ERR_PTR(-EINVAL);
+	}
+
+	val = mpi_read_raw_data(buffer + 2, nbytes);
+	if (!val)
+		return ERR_PTR(-ENOMEM);
+
+	*ret_nread = nbytes + 2;
+	return val;
+}
+EXPORT_SYMBOL_GPL(mpi_read_from_buffer);
+
+/****************
+ * Fill the mpi VAL from the hex string in STR.
+ */
+int mpi_fromstr(MPI val, const char *str)
+{
+	int sign = 0;
+	int prepend_zero = 0;
+	int i, j, c, c1, c2;
+	unsigned int nbits, nbytes, nlimbs;
+	mpi_limb_t a;
+
+	if (*str == '-') {
+		sign = 1;
+		str++;
+	}
+
+	/* Skip optional hex prefix.  */
+	if (*str == '0' && str[1] == 'x')
+		str += 2;
+
+	nbits = strlen(str);
+	if (nbits > MAX_EXTERN_SCAN_BYTES) {
+		mpi_clear(val);
+		return -EINVAL;
+	}
+	nbits *= 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)
+		mpi_resize(val, nlimbs);
+
+	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++;
+
+			if (!c1) {
+				mpi_clear(val);
+				return -EINVAL;
+			}
+			c2 = *str++;
+			if (!c2) {
+				mpi_clear(val);
+				return -EINVAL;
+			}
+			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 -EINVAL;
+			}
+			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 -EINVAL;
+			}
+			a <<= 8;
+			a |= c;
+		}
+		i = 0;
+		val->d[j-1] = a;
+	}
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(mpi_fromstr);
+
+MPI mpi_scanval(const char *string)
+{
+	MPI a;
+
+	a = mpi_alloc(0);
+	if (!a)
+		return NULL;
+
+	if (mpi_fromstr(a, string)) {
+		mpi_free(a);
+		return NULL;
+	}
+	mpi_normalize(a);
+	return a;
+}
+EXPORT_SYMBOL_GPL(mpi_scanval);
+
+static int count_lzeros(MPI a)
+{
+	mpi_limb_t alimb;
+	int i, lzeros = 0;
+
+	for (i = a->nlimbs - 1; i >= 0; i--) {
+		alimb = a->d[i];
+		if (alimb == 0) {
+			lzeros += sizeof(mpi_limb_t);
+		} else {
+			lzeros += count_leading_zeros(alimb) / 8;
+			break;
+		}
+	}
+	return lzeros;
+}
+
+/**
+ * mpi_read_buffer() - read MPI to a buffer provided by user (msb first)
+ *
+ * @a:		a multi precision integer
+ * @buf:	buffer to which the output will be written to. Needs to be at
+ *		least mpi_get_size(a) long.
+ * @buf_len:	size of the buf.
+ * @nbytes:	receives the actual length of the data written on success and
+ *		the data to-be-written on -EOVERFLOW in case buf_len was too
+ *		small.
+ * @sign:	if not NULL, it will be set to the sign of a.
+ *
+ * Return:	0 on success or error code in case of error
+ */
+int mpi_read_buffer(MPI a, uint8_t *buf, unsigned buf_len, unsigned *nbytes,
+		    int *sign)
+{
+	uint8_t *p;
+#if BYTES_PER_MPI_LIMB == 4
+	__be32 alimb;
+#elif BYTES_PER_MPI_LIMB == 8
+	__be64 alimb;
+#else
+#error please implement for this limb size.
+#endif
+	unsigned int n = mpi_get_size(a);
+	int i, lzeros;
+
+	if (!buf || !nbytes)
+		return -EINVAL;
+
+	if (sign)
+		*sign = a->sign;
+
+	lzeros = count_lzeros(a);
+
+	if (buf_len < n - lzeros) {
+		*nbytes = n - lzeros;
+		return -EOVERFLOW;
+	}
+
+	p = buf;
+	*nbytes = n - lzeros;
+
+	for (i = a->nlimbs - 1 - lzeros / BYTES_PER_MPI_LIMB,
+			lzeros %= BYTES_PER_MPI_LIMB;
+		i >= 0; i--) {
+#if BYTES_PER_MPI_LIMB == 4
+		alimb = cpu_to_be32(a->d[i]);
+#elif BYTES_PER_MPI_LIMB == 8
+		alimb = cpu_to_be64(a->d[i]);
+#else
+#error please implement for this limb size.
+#endif
+		memcpy(p, (u8 *)&alimb + lzeros, BYTES_PER_MPI_LIMB - lzeros);
+		p += BYTES_PER_MPI_LIMB - lzeros;
+		lzeros = 0;
+	}
+	return 0;
+}
+EXPORT_SYMBOL_GPL(mpi_read_buffer);
+
+/*
+ * mpi_get_buffer() - Returns an allocated buffer with the MPI (msb first).
+ * 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.
+ *
+ * @a:		a multi precision integer.
+ * @nbytes:	receives the length of this buffer.
+ * @sign:	if not NULL, it will be set to the sign of the a.
+ *
+ * Return:	Pointer to MPI buffer or NULL on error
+ */
+void *mpi_get_buffer(MPI a, unsigned *nbytes, int *sign)
+{
+	uint8_t *buf;
+	unsigned int n;
+	int ret;
+
+	if (!nbytes)
+		return NULL;
+
+	n = mpi_get_size(a);
+
+	if (!n)
+		n++;
+
+	buf = kmalloc(n, GFP_KERNEL);
+
+	if (!buf)
+		return NULL;
+
+	ret = mpi_read_buffer(a, buf, n, nbytes, sign);
+
+	if (ret) {
+		kfree(buf);
+		return NULL;
+	}
+	return buf;
+}
+EXPORT_SYMBOL_GPL(mpi_get_buffer);
+
+/**
+ * mpi_write_to_sgl() - Funnction exports MPI to an sgl (msb first)
+ *
+ * This function works in the same way as the mpi_read_buffer, but it
+ * takes an sgl instead of u8 * buf.
+ *
+ * @a:		a multi precision integer
+ * @sgl:	scatterlist to write to. Needs to be at least
+ *		mpi_get_size(a) long.
+ * @nbytes:	the number of bytes to write.  Leading bytes will be
+ *		filled with zero.
+ * @sign:	if not NULL, it will be set to the sign of a.
+ *
+ * Return:	0 on success or error code in case of error
+ */
+int mpi_write_to_sgl(MPI a, struct scatterlist *sgl, unsigned nbytes,
+		     int *sign)
+{
+	u8 *p, *p2;
+#if BYTES_PER_MPI_LIMB == 4
+	__be32 alimb;
+#elif BYTES_PER_MPI_LIMB == 8
+	__be64 alimb;
+#else
+#error please implement for this limb size.
+#endif
+	unsigned int n = mpi_get_size(a);
+	struct sg_mapping_iter miter;
+	int i, x, buf_len;
+	int nents;
+
+	if (sign)
+		*sign = a->sign;
+
+	if (nbytes < n)
+		return -EOVERFLOW;
+
+	nents = sg_nents_for_len(sgl, nbytes);
+	if (nents < 0)
+		return -EINVAL;
+
+	sg_miter_start(&miter, sgl, nents, SG_MITER_ATOMIC | SG_MITER_TO_SG);
+	sg_miter_next(&miter);
+	buf_len = miter.length;
+	p2 = miter.addr;
+
+	while (nbytes > n) {
+		i = min_t(unsigned, nbytes - n, buf_len);
+		memset(p2, 0, i);
+		p2 += i;
+		nbytes -= i;
+
+		buf_len -= i;
+		if (!buf_len) {
+			sg_miter_next(&miter);
+			buf_len = miter.length;
+			p2 = miter.addr;
+		}
+	}
+
+	for (i = a->nlimbs - 1; i >= 0; i--) {
+#if BYTES_PER_MPI_LIMB == 4
+		alimb = a->d[i] ? cpu_to_be32(a->d[i]) : 0;
+#elif BYTES_PER_MPI_LIMB == 8
+		alimb = a->d[i] ? cpu_to_be64(a->d[i]) : 0;
+#else
+#error please implement for this limb size.
+#endif
+		p = (u8 *)&alimb;
+
+		for (x = 0; x < sizeof(alimb); x++) {
+			*p2++ = *p++;
+			if (!--buf_len) {
+				sg_miter_next(&miter);
+				buf_len = miter.length;
+				p2 = miter.addr;
+			}
+		}
+	}
+
+	sg_miter_stop(&miter);
+	return 0;
+}
+EXPORT_SYMBOL_GPL(mpi_write_to_sgl);
+
+/*
+ * mpi_read_raw_from_sgl() - Function allocates an MPI and populates it with
+ *			     data from the sgl
+ *
+ * This function works in the same way as the mpi_read_raw_data, but it
+ * takes an sgl instead of void * buffer. i.e. it allocates
+ * a new MPI and reads the content of the sgl to the MPI.
+ *
+ * @sgl:	scatterlist to read from
+ * @nbytes:	number of bytes to read
+ *
+ * Return:	Pointer to a new MPI or NULL on error
+ */
+MPI mpi_read_raw_from_sgl(struct scatterlist *sgl, unsigned int nbytes)
+{
+	struct sg_mapping_iter miter;
+	unsigned int nbits, nlimbs;
+	int x, j, z, lzeros, ents;
+	unsigned int len;
+	const u8 *buff;
+	mpi_limb_t a;
+	MPI val = NULL;
+
+	ents = sg_nents_for_len(sgl, nbytes);
+	if (ents < 0)
+		return NULL;
+
+	sg_miter_start(&miter, sgl, ents, SG_MITER_ATOMIC | SG_MITER_FROM_SG);
+
+	lzeros = 0;
+	len = 0;
+	while (nbytes > 0) {
+		while (len && !*buff) {
+			lzeros++;
+			len--;
+			buff++;
+		}
+
+		if (len && *buff)
+			break;
+
+		sg_miter_next(&miter);
+		buff = miter.addr;
+		len = miter.length;
+
+		nbytes -= lzeros;
+		lzeros = 0;
+	}
+
+	miter.consumed = lzeros;
+
+	nbytes -= lzeros;
+	nbits = nbytes * 8;
+	if (nbits > MAX_EXTERN_MPI_BITS) {
+		sg_miter_stop(&miter);
+		pr_info("MPI: mpi too large (%u bits)\n", nbits);
+		return NULL;
+	}
+
+	if (nbytes > 0)
+		nbits -= count_leading_zeros(*buff) - (BITS_PER_LONG - 8);
+
+	sg_miter_stop(&miter);
+
+	nlimbs = DIV_ROUND_UP(nbytes, BYTES_PER_MPI_LIMB);
+	val = mpi_alloc(nlimbs);
+	if (!val)
+		return NULL;
+
+	val->nbits = nbits;
+	val->sign = 0;
+	val->nlimbs = nlimbs;
+
+	if (nbytes == 0)
+		return val;
+
+	j = nlimbs - 1;
+	a = 0;
+	z = BYTES_PER_MPI_LIMB - nbytes % BYTES_PER_MPI_LIMB;
+	z %= BYTES_PER_MPI_LIMB;
+
+	while (sg_miter_next(&miter)) {
+		buff = miter.addr;
+		len = min_t(unsigned, miter.length, nbytes);
+		nbytes -= len;
+
+		for (x = 0; x < len; x++) {
+			a <<= 8;
+			a |= *buff++;
+			if (((z + x + 1) % BYTES_PER_MPI_LIMB) == 0) {
+				val->d[j--] = a;
+				a = 0;
+			}
+		}
+		z += x;
+	}
+
+	return val;
+}
+EXPORT_SYMBOL_GPL(mpi_read_raw_from_sgl);
+
+/* Perform a two's complement operation on buffer P of size N bytes.  */
+static void twocompl(unsigned char *p, unsigned int n)
+{
+	int i;
+
+	for (i = n-1; i >= 0 && !p[i]; i--)
+		;
+	if (i >= 0) {
+		if ((p[i] & 0x01))
+			p[i] = (((p[i] ^ 0xfe) | 0x01) & 0xff);
+		else if ((p[i] & 0x02))
+			p[i] = (((p[i] ^ 0xfc) | 0x02) & 0xfe);
+		else if ((p[i] & 0x04))
+			p[i] = (((p[i] ^ 0xf8) | 0x04) & 0xfc);
+		else if ((p[i] & 0x08))
+			p[i] = (((p[i] ^ 0xf0) | 0x08) & 0xf8);
+		else if ((p[i] & 0x10))
+			p[i] = (((p[i] ^ 0xe0) | 0x10) & 0xf0);
+		else if ((p[i] & 0x20))
+			p[i] = (((p[i] ^ 0xc0) | 0x20) & 0xe0);
+		else if ((p[i] & 0x40))
+			p[i] = (((p[i] ^ 0x80) | 0x40) & 0xc0);
+		else
+			p[i] = 0x80;
+
+		for (i--; i >= 0; i--)
+			p[i] ^= 0xff;
+	}
+}
+
+int mpi_print(enum gcry_mpi_format format, unsigned char *buffer,
+			size_t buflen, size_t *nwritten, MPI a)
+{
+	unsigned int nbits = mpi_get_nbits(a);
+	size_t len;
+	size_t dummy_nwritten;
+	int negative;
+
+	if (!nwritten)
+		nwritten = &dummy_nwritten;
+
+	/* Libgcrypt does no always care to set clear the sign if the value
+	 * is 0.  For printing this is a bit of a surprise, in particular
+	 * because if some of the formats don't support negative numbers but
+	 * should be able to print a zero.  Thus we need this extra test
+	 * for a negative number.
+	 */
+	if (a->sign && mpi_cmp_ui(a, 0))
+		negative = 1;
+	else
+		negative = 0;
+
+	len = buflen;
+	*nwritten = 0;
+	if (format == GCRYMPI_FMT_STD) {
+		unsigned char *tmp;
+		int extra = 0;
+		unsigned int n;
+
+		tmp = mpi_get_buffer(a, &n, NULL);
+		if (!tmp)
+			return -EINVAL;
+
+		if (negative) {
+			twocompl(tmp, n);
+			if (!(*tmp & 0x80)) {
+				/* Need to extend the sign.  */
+				n++;
+				extra = 2;
+			}
+		} else if (n && (*tmp & 0x80)) {
+			/* Positive but the high bit of the returned buffer is set.
+			 * Thus we need to print an extra leading 0x00 so that the
+			 * output is interpreted as a positive number.
+			 */
+			n++;
+			extra = 1;
+		}
+
+		if (buffer && n > len) {
+			/* The provided buffer is too short. */
+			kfree(tmp);
+			return -E2BIG;
+		}
+		if (buffer) {
+			unsigned char *s = buffer;
+
+			if (extra == 1)
+				*s++ = 0;
+			else if (extra)
+				*s++ = 0xff;
+			memcpy(s, tmp, n-!!extra);
+		}
+		kfree(tmp);
+		*nwritten = n;
+		return 0;
+	} else if (format == GCRYMPI_FMT_USG) {
+		unsigned int n = (nbits + 7)/8;
+
+		/* Note:  We ignore the sign for this format.  */
+		/* FIXME: for performance reasons we should put this into
+		 * mpi_aprint because we can then use the buffer directly.
+		 */
+
+		if (buffer && n > len)
+			return -E2BIG;
+		if (buffer) {
+			unsigned char *tmp;
+
+			tmp = mpi_get_buffer(a, &n, NULL);
+			if (!tmp)
+				return -EINVAL;
+			memcpy(buffer, tmp, n);
+			kfree(tmp);
+		}
+		*nwritten = n;
+		return 0;
+	} else if (format == GCRYMPI_FMT_PGP) {
+		unsigned int n = (nbits + 7)/8;
+
+		/* The PGP format can only handle unsigned integers.  */
+		if (negative)
+			return -EINVAL;
+
+		if (buffer && n+2 > len)
+			return -E2BIG;
+
+		if (buffer) {
+			unsigned char *tmp;
+			unsigned char *s = buffer;
+
+			s[0] = nbits >> 8;
+			s[1] = nbits;
+
+			tmp = mpi_get_buffer(a, &n, NULL);
+			if (!tmp)
+				return -EINVAL;
+			memcpy(s+2, tmp, n);
+			kfree(tmp);
+		}
+		*nwritten = n+2;
+		return 0;
+	} else if (format == GCRYMPI_FMT_SSH) {
+		unsigned char *tmp;
+		int extra = 0;
+		unsigned int n;
+
+		tmp = mpi_get_buffer(a, &n, NULL);
+		if (!tmp)
+			return -EINVAL;
+
+		if (negative) {
+			twocompl(tmp, n);
+			if (!(*tmp & 0x80)) {
+				/* Need to extend the sign.  */
+				n++;
+				extra = 2;
+			}
+		} else if (n && (*tmp & 0x80)) {
+			n++;
+			extra = 1;
+		}
+
+		if (buffer && n+4 > len) {
+			kfree(tmp);
+			return -E2BIG;
+		}
+
+		if (buffer) {
+			unsigned char *s = buffer;
+
+			*s++ = n >> 24;
+			*s++ = n >> 16;
+			*s++ = n >> 8;
+			*s++ = n;
+			if (extra == 1)
+				*s++ = 0;
+			else if (extra)
+				*s++ = 0xff;
+			memcpy(s, tmp, n-!!extra);
+		}
+		kfree(tmp);
+		*nwritten = 4+n;
+		return 0;
+	} else if (format == GCRYMPI_FMT_HEX) {
+		unsigned char *tmp;
+		int i;
+		int extra = 0;
+		unsigned int n = 0;
+
+		tmp = mpi_get_buffer(a, &n, NULL);
+		if (!tmp)
+			return -EINVAL;
+		if (!n || (*tmp & 0x80))
+			extra = 2;
+
+		if (buffer && 2*n + extra + negative + 1 > len) {
+			kfree(tmp);
+			return -E2BIG;
+		}
+		if (buffer) {
+			unsigned char *s = buffer;
+
+			if (negative)
+				*s++ = '-';
+			if (extra) {
+				*s++ = '0';
+				*s++ = '0';
+			}
+
+			for (i = 0; i < n; i++) {
+				unsigned int c = tmp[i];
+
+				*s++ = (c >> 4) < 10 ? '0'+(c>>4) : 'A'+(c>>4)-10;
+				c &= 15;
+				*s++ = c < 10 ? '0'+c : 'A'+c-10;
+			}
+			*s++ = 0;
+			*nwritten = s - buffer;
+		} else {
+			*nwritten = 2*n + extra + negative + 1;
+		}
+		kfree(tmp);
+		return 0;
+	} else
+		return -EINVAL;
+}
+EXPORT_SYMBOL_GPL(mpi_print);