v4.19.13 snapshot.
diff --git a/lib/mpi/mpicoder.c b/lib/mpi/mpicoder.c
new file mode 100644
index 0000000..eead4b3
--- /dev/null
+++ b/lib/mpi/mpicoder.c
@@ -0,0 +1,415 @@
+/* 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_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);
+
+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 bufer provided by user (msb first)
+ *
+ * @a: a multi precision integer
+ * @buf: bufer to which the output will be written to. Needs to be at
+ * leaset 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 = miter.length;
+
+ 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);