Intermediate changes

1 files changed, 201 insertions, 0 deletions

diff --git a/contrib/libs/openssl/crypto/bn/bn_exp2.c b/contrib/libs/openssl/crypto/bn/bn_exp2.c
new file mode 100644
index 0000000000..eac0896e68
--- /dev/null
+++ b/contrib/libs/openssl/crypto/bn/bn_exp2.c
@@ -0,0 +1,201 @@
+/*
+ * Copyright 1995-2022 The OpenSSL Project Authors. All Rights Reserved.
+ *
+ * Licensed under the OpenSSL license (the "License").  You may not use
+ * this file except in compliance with the License.  You can obtain a copy
+ * in the file LICENSE in the source distribution or at
+ * https://www.openssl.org/source/license.html
+ */
+
+#include <stdio.h>
+#include "internal/cryptlib.h"
+#include "bn_local.h"
+
+#define TABLE_SIZE      32
+
+int BN_mod_exp2_mont(BIGNUM *rr, const BIGNUM *a1, const BIGNUM *p1,
+                     const BIGNUM *a2, const BIGNUM *p2, const BIGNUM *m,
+                     BN_CTX *ctx, BN_MONT_CTX *in_mont)
+{
+    int i, j, bits, b, bits1, bits2, ret =
+        0, wpos1, wpos2, window1, window2, wvalue1, wvalue2;
+    int r_is_one = 1;
+    BIGNUM *d, *r;
+    const BIGNUM *a_mod_m;
+    /* Tables of variables obtained from 'ctx' */
+    BIGNUM *val1[TABLE_SIZE], *val2[TABLE_SIZE];
+    BN_MONT_CTX *mont = NULL;
+
+    bn_check_top(a1);
+    bn_check_top(p1);
+    bn_check_top(a2);
+    bn_check_top(p2);
+    bn_check_top(m);
+
+    if (!BN_is_odd(m)) {
+        BNerr(BN_F_BN_MOD_EXP2_MONT, BN_R_CALLED_WITH_EVEN_MODULUS);
+        return 0;
+    }
+    bits1 = BN_num_bits(p1);
+    bits2 = BN_num_bits(p2);
+    if ((bits1 == 0) && (bits2 == 0)) {
+        ret = BN_one(rr);
+        return ret;
+    }
+
+    bits = (bits1 > bits2) ? bits1 : bits2;
+
+    BN_CTX_start(ctx);
+    d = BN_CTX_get(ctx);
+    r = BN_CTX_get(ctx);
+    val1[0] = BN_CTX_get(ctx);
+    val2[0] = BN_CTX_get(ctx);
+    if (val2[0] == NULL)
+        goto err;
+
+    if (in_mont != NULL)
+        mont = in_mont;
+    else {
+        if ((mont = BN_MONT_CTX_new()) == NULL)
+            goto err;
+        if (!BN_MONT_CTX_set(mont, m, ctx))
+            goto err;
+    }
+
+    window1 = BN_window_bits_for_exponent_size(bits1);
+    window2 = BN_window_bits_for_exponent_size(bits2);
+
+    /*
+     * Build table for a1:   val1[i] := a1^(2*i + 1) mod m  for i = 0 .. 2^(window1-1)
+     */
+    if (a1->neg || BN_ucmp(a1, m) >= 0) {
+        if (!BN_mod(val1[0], a1, m, ctx))
+            goto err;
+        a_mod_m = val1[0];
+    } else
+        a_mod_m = a1;
+    if (BN_is_zero(a_mod_m)) {
+        BN_zero(rr);
+        ret = 1;
+        goto err;
+    }
+
+    if (!BN_to_montgomery(val1[0], a_mod_m, mont, ctx))
+        goto err;
+    if (window1 > 1) {
+        if (!BN_mod_mul_montgomery(d, val1[0], val1[0], mont, ctx))
+            goto err;
+
+        j = 1 << (window1 - 1);
+        for (i = 1; i < j; i++) {
+            if (((val1[i] = BN_CTX_get(ctx)) == NULL) ||
+                !BN_mod_mul_montgomery(val1[i], val1[i - 1], d, mont, ctx))
+                goto err;
+        }
+    }
+
+    /*
+     * Build table for a2:   val2[i] := a2^(2*i + 1) mod m  for i = 0 .. 2^(window2-1)
+     */
+    if (a2->neg || BN_ucmp(a2, m) >= 0) {
+        if (!BN_mod(val2[0], a2, m, ctx))
+            goto err;
+        a_mod_m = val2[0];
+    } else
+        a_mod_m = a2;
+    if (BN_is_zero(a_mod_m)) {
+        BN_zero(rr);
+        ret = 1;
+        goto err;
+    }
+    if (!BN_to_montgomery(val2[0], a_mod_m, mont, ctx))
+        goto err;
+    if (window2 > 1) {
+        if (!BN_mod_mul_montgomery(d, val2[0], val2[0], mont, ctx))
+            goto err;
+
+        j = 1 << (window2 - 1);
+        for (i = 1; i < j; i++) {
+            if (((val2[i] = BN_CTX_get(ctx)) == NULL) ||
+                !BN_mod_mul_montgomery(val2[i], val2[i - 1], d, mont, ctx))
+                goto err;
+        }
+    }
+
+    /* Now compute the power product, using independent windows. */
+    r_is_one = 1;
+    wvalue1 = 0;                /* The 'value' of the first window */
+    wvalue2 = 0;                /* The 'value' of the second window */
+    wpos1 = 0;                  /* If wvalue1 > 0, the bottom bit of the
+                                 * first window */
+    wpos2 = 0;                  /* If wvalue2 > 0, the bottom bit of the
+                                 * second window */
+
+    if (!BN_to_montgomery(r, BN_value_one(), mont, ctx))
+        goto err;
+    for (b = bits - 1; b >= 0; b--) {
+        if (!r_is_one) {
+            if (!BN_mod_mul_montgomery(r, r, r, mont, ctx))
+                goto err;
+        }
+
+        if (!wvalue1)
+            if (BN_is_bit_set(p1, b)) {
+                /*
+                 * consider bits b-window1+1 .. b for this window
+                 */
+                i = b - window1 + 1;
+                while (!BN_is_bit_set(p1, i)) /* works for i<0 */
+                    i++;
+                wpos1 = i;
+                wvalue1 = 1;
+                for (i = b - 1; i >= wpos1; i--) {
+                    wvalue1 <<= 1;
+                    if (BN_is_bit_set(p1, i))
+                        wvalue1++;
+                }
+            }
+
+        if (!wvalue2)
+            if (BN_is_bit_set(p2, b)) {
+                /*
+                 * consider bits b-window2+1 .. b for this window
+                 */
+                i = b - window2 + 1;
+                while (!BN_is_bit_set(p2, i))
+                    i++;
+                wpos2 = i;
+                wvalue2 = 1;
+                for (i = b - 1; i >= wpos2; i--) {
+                    wvalue2 <<= 1;
+                    if (BN_is_bit_set(p2, i))
+                        wvalue2++;
+                }
+            }
+
+        if (wvalue1 && b == wpos1) {
+            /* wvalue1 is odd and < 2^window1 */
+            if (!BN_mod_mul_montgomery(r, r, val1[wvalue1 >> 1], mont, ctx))
+                goto err;
+            wvalue1 = 0;
+            r_is_one = 0;
+        }
+
+        if (wvalue2 && b == wpos2) {
+            /* wvalue2 is odd and < 2^window2 */
+            if (!BN_mod_mul_montgomery(r, r, val2[wvalue2 >> 1], mont, ctx))
+                goto err;
+            wvalue2 = 0;
+            r_is_one = 0;
+        }
+    }
+    if (!BN_from_montgomery(rr, r, mont, ctx))
+        goto err;
+    ret = 1;
+ err:
+    if (in_mont == NULL)
+        BN_MONT_CTX_free(mont);
+    BN_CTX_end(ctx);
+    bn_check_top(rr);
+    return ret;
+}