From 2a598d0b2800aa23ba51adcf060cec524aaa63b2 Mon Sep 17 00:00:00 2001
From: Herbert Xu <herbert@gondor.apana.org.au>
Date: Fri, 4 Aug 2023 17:24:34 +0800
Subject: 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>
---
lib/crypto/mpi/mpiutil.c | 330 +++++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 330 insertions(+)
create mode 100644 lib/crypto/mpi/mpiutil.c
(limited to 'lib/crypto/mpi/mpiutil.c')
diff --git a/lib/crypto/mpi/mpiutil.c b/lib/crypto/mpi/mpiutil.c
new file mode 100644
index 000000000000..aa8c46544af8
--- /dev/null
+++ b/lib/crypto/mpi/mpiutil.c
@@ -0,0 +1,330 @@
+/* mpiutil.ac - Utility functions for MPI
+ * 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"
+
+/* Constants allocated right away at startup. */
+static MPI constants[MPI_NUMBER_OF_CONSTANTS];
+
+/* Initialize the MPI subsystem. This is called early and allows to
+ * do some initialization without taking care of threading issues.
+ */
+static int __init mpi_init(void)
+{
+ int idx;
+ unsigned long value;
+
+ for (idx = 0; idx < MPI_NUMBER_OF_CONSTANTS; idx++) {
+ switch (idx) {
+ case MPI_C_ZERO:
+ value = 0;
+ break;
+ case MPI_C_ONE:
+ value = 1;
+ break;
+ case MPI_C_TWO:
+ value = 2;
+ break;
+ case MPI_C_THREE:
+ value = 3;
+ break;
+ case MPI_C_FOUR:
+ value = 4;
+ break;
+ case MPI_C_EIGHT:
+ value = 8;
+ break;
+ default:
+ pr_err("MPI: invalid mpi_const selector %d\n", idx);
+ return -EFAULT;
+ }
+ constants[idx] = mpi_alloc_set_ui(value);
+ constants[idx]->flags = (16|32);
+ }
+
+ return 0;
+}
+postcore_initcall(mpi_init);
+
+/* Return a constant MPI descripbed by NO which is one of the
+ * MPI_C_xxx macros. There is no need to copy this returned value; it
+ * may be used directly.
+ */
+MPI mpi_const(enum gcry_mpi_constants no)
+{
+ if ((int)no < 0 || no > MPI_NUMBER_OF_CONSTANTS)
+ pr_err("MPI: invalid mpi_const selector %d\n", no);
+ if (!constants[no])
+ pr_err("MPI: MPI subsystem not initialized\n");
+ return constants[no];
+}
+EXPORT_SYMBOL_GPL(mpi_const);
+
+/****************
+ * Note: It was a bad idea to use the number of limbs to allocate
+ * because on a alpha the limbs are large but we normally need
+ * integers of n bits - So we should change this to bits (or bytes).
+ *
+ * But mpi_alloc is used in a lot of places :-)
+ */
+MPI mpi_alloc(unsigned nlimbs)
+{
+ MPI a;
+
+ a = kmalloc(sizeof *a, GFP_KERNEL);
+ if (!a)
+ return a;
+
+ if (nlimbs) {
+ a->d = mpi_alloc_limb_space(nlimbs);
+ if (!a->d) {
+ kfree(a);
+ return NULL;
+ }
+ } else {
+ a->d = NULL;
+ }
+
+ a->alloced = nlimbs;
+ a->nlimbs = 0;
+ a->sign = 0;
+ a->flags = 0;
+ a->nbits = 0;
+ return a;
+}
+EXPORT_SYMBOL_GPL(mpi_alloc);
+
+mpi_ptr_t mpi_alloc_limb_space(unsigned nlimbs)
+{
+ size_t len = nlimbs * sizeof(mpi_limb_t);
+
+ if (!len)
+ return NULL;
+
+ return kmalloc(len, GFP_KERNEL);
+}
+
+void mpi_free_limb_space(mpi_ptr_t a)
+{
+ if (!a)
+ return;
+
+ kfree_sensitive(a);
+}
+
+void mpi_assign_limb_space(MPI a, mpi_ptr_t ap, unsigned nlimbs)
+{
+ mpi_free_limb_space(a->d);
+ a->d = ap;
+ a->alloced = nlimbs;
+}
+
+/****************
+ * Resize the array of A to NLIMBS. the additional space is cleared
+ * (set to 0) [done by m_realloc()]
+ */
+int mpi_resize(MPI a, unsigned nlimbs)
+{
+ void *p;
+
+ if (nlimbs <= a->alloced)
+ return 0; /* no need to do it */
+
+ if (a->d) {
+ p = kcalloc(nlimbs, sizeof(mpi_limb_t), GFP_KERNEL);
+ if (!p)
+ return -ENOMEM;
+ memcpy(p, a->d, a->alloced * sizeof(mpi_limb_t));
+ kfree_sensitive(a->d);
+ a->d = p;
+ } else {
+ a->d = kcalloc(nlimbs, sizeof(mpi_limb_t), GFP_KERNEL);
+ if (!a->d)
+ return -ENOMEM;
+ }
+ a->alloced = nlimbs;
+ return 0;
+}
+
+void mpi_clear(MPI a)
+{
+ if (!a)
+ return;
+ a->nlimbs = 0;
+ a->flags = 0;
+}
+EXPORT_SYMBOL_GPL(mpi_clear);
+
+void mpi_free(MPI a)
+{
+ if (!a)
+ return;
+
+ if (a->flags & 4)
+ kfree_sensitive(a->d);
+ else
+ mpi_free_limb_space(a->d);
+
+ if (a->flags & ~7)
+ pr_info("invalid flag value in mpi\n");
+ kfree(a);
+}
+EXPORT_SYMBOL_GPL(mpi_free);
+
+/****************
+ * Note: This copy function should not interpret the MPI
+ * but copy it transparently.
+ */
+MPI mpi_copy(MPI a)
+{
+ int i;
+ MPI b;
+
+ if (a) {
+ b = mpi_alloc(a->nlimbs);
+ b->nlimbs = a->nlimbs;
+ b->sign = a->sign;
+ b->flags = a->flags;
+ b->flags &= ~(16|32); /* Reset the immutable and constant flags. */
+ for (i = 0; i < b->nlimbs; i++)
+ b->d[i] = a->d[i];
+ } else
+ b = NULL;
+ return b;
+}
+
+/****************
+ * This function allocates an MPI which is optimized to hold
+ * a value as large as the one given in the argument and allocates it
+ * with the same flags as A.
+ */
+MPI mpi_alloc_like(MPI a)
+{
+ MPI b;
+
+ if (a) {
+ b = mpi_alloc(a->nlimbs);
+ b->nlimbs = 0;
+ b->sign = 0;
+ b->flags = a->flags;
+ } else
+ b = NULL;
+
+ return b;
+}
+
+
+/* Set U into W and release U. If W is NULL only U will be released. */
+void mpi_snatch(MPI w, MPI u)
+{
+ if (w) {
+ mpi_assign_limb_space(w, u->d, u->alloced);
+ w->nlimbs = u->nlimbs;
+ w->sign = u->sign;
+ w->flags = u->flags;
+ u->alloced = 0;
+ u->nlimbs = 0;
+ u->d = NULL;
+ }
+ mpi_free(u);
+}
+
+
+MPI mpi_set(MPI w, MPI u)
+{
+ mpi_ptr_t wp, up;
+ mpi_size_t usize = u->nlimbs;
+ int usign = u->sign;
+
+ if (!w)
+ w = mpi_alloc(mpi_get_nlimbs(u));
+ RESIZE_IF_NEEDED(w, usize);
+ wp = w->d;
+ up = u->d;
+ MPN_COPY(wp, up, usize);
+ w->nlimbs = usize;
+ w->flags = u->flags;
+ w->flags &= ~(16|32); /* Reset the immutable and constant flags. */
+ w->sign = usign;
+ return w;
+}
+EXPORT_SYMBOL_GPL(mpi_set);
+
+MPI mpi_set_ui(MPI w, unsigned long u)
+{
+ if (!w)
+ w = mpi_alloc(1);
+ /* FIXME: If U is 0 we have no need to resize and thus possible
+ * allocating the limbs.
+ */
+ RESIZE_IF_NEEDED(w, 1);
+ w->d[0] = u;
+ w->nlimbs = u ? 1 : 0;
+ w->sign = 0;
+ w->flags = 0;
+ return w;
+}
+EXPORT_SYMBOL_GPL(mpi_set_ui);
+
+MPI mpi_alloc_set_ui(unsigned long u)
+{
+ MPI w = mpi_alloc(1);
+ w->d[0] = u;
+ w->nlimbs = u ? 1 : 0;
+ w->sign = 0;
+ return w;
+}
+
+/****************
+ * Swap the value of A and B, when SWAP is 1.
+ * Leave the value when SWAP is 0.
+ * This implementation should be constant-time regardless of SWAP.
+ */
+void mpi_swap_cond(MPI a, MPI b, unsigned long swap)
+{
+ mpi_size_t i;
+ mpi_size_t nlimbs;
+ mpi_limb_t mask = ((mpi_limb_t)0) - swap;
+ mpi_limb_t x;
+
+ if (a->alloced > b->alloced)
+ nlimbs = b->alloced;
+ else
+ nlimbs = a->alloced;
+ if (a->nlimbs > nlimbs || b->nlimbs > nlimbs)
+ return;
+
+ for (i = 0; i < nlimbs; i++) {
+ x = mask & (a->d[i] ^ b->d[i]);
+ a->d[i] = a->d[i] ^ x;
+ b->d[i] = b->d[i] ^ x;
+ }
+
+ x = mask & (a->nlimbs ^ b->nlimbs);
+ a->nlimbs = a->nlimbs ^ x;
+ b->nlimbs = b->nlimbs ^ x;
+
+ x = mask & (a->sign ^ b->sign);
+ a->sign = a->sign ^ x;
+ b->sign = b->sign ^ x;
+}
+
+MODULE_DESCRIPTION("Multiprecision maths library");
+MODULE_LICENSE("GPL");
--
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