157 lines
3.3 KiB
Diff
157 lines
3.3 KiB
Diff
From f490ffd739f713fcf0be35b7fbbb8502dea40a0c Mon Sep 17 00:00:00 2001
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From: Jussi Kivilinna <jussi.kivilinna@iki.fi>
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Date: Sat, 3 Jun 2023 13:20:07 +0300
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Subject: [PATCH] addm/subm/mulm: fix case when destination is same MPI as
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divider
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* mpi/mpi-add.c (_gcry_mpi_addm, _gcry_mpi_subm): Take copy of M when
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W and M are the same MPI.
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* mpi/mpi-mul.c (_gcry_mpi_mulm): Likewise.
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* tests/mpitests.c (test_addm_subm_mulm): New.
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(main): Run addm/subm/mulm test.
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--
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Reported-by: Guido Vranken <guidovranken@gmail.com>
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Signed-off-by: Jussi Kivilinna <jussi.kivilinna@iki.fi>
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---
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mpi/mpi-add.c | 22 ++++++++++++++++++++
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mpi/mpi-mul.c | 11 ++++++++++
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tests/mpitests.c | 53 ++++++++++++++++++++++++++++++++++++++++++++++++
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3 files changed, 86 insertions(+)
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diff --git a/mpi/mpi-add.c b/mpi/mpi-add.c
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index 41dc3900..51dc71b7 100644
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--- a/mpi/mpi-add.c
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+++ b/mpi/mpi-add.c
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@@ -227,13 +227,35 @@ _gcry_mpi_sub(gcry_mpi_t w, gcry_mpi_t u, gcry_mpi_t v)
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void
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_gcry_mpi_addm( gcry_mpi_t w, gcry_mpi_t u, gcry_mpi_t v, gcry_mpi_t m)
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{
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+ gcry_mpi_t temp_m = NULL;
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+
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+ if (w == m)
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+ {
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+ temp_m = mpi_copy (m);
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+ m = temp_m;
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+ }
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+
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mpi_add (w, u, v);
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mpi_mod (w, w, m);
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+
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+ if (temp_m)
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+ mpi_free(temp_m);
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}
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void
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_gcry_mpi_subm( gcry_mpi_t w, gcry_mpi_t u, gcry_mpi_t v, gcry_mpi_t m)
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{
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+ gcry_mpi_t temp_m = NULL;
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+
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+ if (w == m)
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+ {
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+ temp_m = mpi_copy (m);
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+ m = temp_m;
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+ }
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+
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mpi_sub (w, u, v);
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mpi_mod (w, w, m);
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+
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+ if (temp_m)
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+ mpi_free(temp_m);
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}
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diff --git a/mpi/mpi-mul.c b/mpi/mpi-mul.c
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index 60f1ca48..e8e57475 100644
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--- a/mpi/mpi-mul.c
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+++ b/mpi/mpi-mul.c
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@@ -207,6 +207,17 @@ _gcry_mpi_mul (gcry_mpi_t w, gcry_mpi_t u, gcry_mpi_t v)
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void
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_gcry_mpi_mulm (gcry_mpi_t w, gcry_mpi_t u, gcry_mpi_t v, gcry_mpi_t m)
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{
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+ gcry_mpi_t temp_m = NULL;
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+
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+ if (w == m)
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+ {
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+ temp_m = mpi_copy (m);
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+ m = temp_m;
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+ }
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+
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mpi_mul (w, u, v);
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_gcry_mpi_tdiv_r (w, w, m);
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+
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+ if (temp_m)
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+ mpi_free(temp_m);
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}
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diff --git a/tests/mpitests.c b/tests/mpitests.c
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index 48ea18b2..2ee08bd3 100644
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--- a/tests/mpitests.c
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+++ b/tests/mpitests.c
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@@ -687,6 +687,58 @@ test_powm (void)
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}
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+/* What we test here is that using the same mpi for divider and result
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+ works. */
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+static int
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+test_addm_subm_mulm (void)
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+{
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+ int i;
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+
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+ for (i = 0; i < 3; i++)
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+ {
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+ unsigned int expect;
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+ const char *func;
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+ gcry_mpi_t A;
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+ gcry_mpi_t B;
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+ gcry_mpi_t C;
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+
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+ A = gcry_mpi_set_ui (NULL, 2);
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+ B = gcry_mpi_set_ui (NULL, 4);
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+ C = gcry_mpi_set_ui (NULL, 7);
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+
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+ if (i == 0)
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+ {
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+ func = "mpi_addm";
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+ expect = 6;
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+ gcry_mpi_addm(C, A, B, C);
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+ }
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+ else if (i == 1)
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+ {
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+ func = "mpi_subm";
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+ expect = 5;
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+ gcry_mpi_subm(C, A, B, C);
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+ }
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+ else if (i == 2)
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+ {
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+ func = "mpi_mulm";
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+ expect = 1;
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+ gcry_mpi_mulm(C, A, B, C);
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+ }
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+
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+ if (gcry_mpi_is_neg (C) || gcry_mpi_cmp_ui (C, expect))
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+ {
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+ die ("test_addm_subm_mulm failed for %s at %d\n", func, __LINE__);
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+ }
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+
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+ gcry_mpi_release(A);
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+ gcry_mpi_release(B);
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+ gcry_mpi_release(C);
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+ }
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+
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+ return 1;
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+}
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+
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+
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int
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main (int argc, char* argv[])
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{
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@@ -710,6 +762,7 @@ main (int argc, char* argv[])
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test_sub ();
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test_mul ();
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test_powm ();
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+ test_addm_subm_mulm ();
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return !!error_count;
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}
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--
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2.44.0
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