From 102a0743326a03cd1a1202ceda21e175b7d3575c Mon Sep 17 00:00:00 2001
From: hc <hc@nodka.com>
Date: Tue, 20 Feb 2024 01:20:52 +0000
Subject: [PATCH] add new system file
---
kernel/lib/mpi/mpiutil.c | 210 +++++++++++++++++++++++++++++++++++++++++++++++++++
1 files changed, 207 insertions(+), 3 deletions(-)
diff --git a/kernel/lib/mpi/mpiutil.c b/kernel/lib/mpi/mpiutil.c
index 0082502..e6c4b31 100644
--- a/kernel/lib/mpi/mpiutil.c
+++ b/kernel/lib/mpi/mpiutil.c
@@ -20,6 +20,63 @@
#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
@@ -69,7 +126,7 @@
if (!a)
return;
- kzfree(a);
+ kfree_sensitive(a);
}
void mpi_assign_limb_space(MPI a, mpi_ptr_t ap, unsigned nlimbs)
@@ -95,7 +152,7 @@
if (!p)
return -ENOMEM;
memcpy(p, a->d, a->alloced * sizeof(mpi_limb_t));
- kzfree(a->d);
+ kfree_sensitive(a->d);
a->d = p;
} else {
a->d = kcalloc(nlimbs, sizeof(mpi_limb_t), GFP_KERNEL);
@@ -106,13 +163,22 @@
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)
- kzfree(a->d);
+ kfree_sensitive(a->d);
else
mpi_free_limb_space(a->d);
@@ -122,5 +188,143 @@
}
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 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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