+/*
+ * Copyright 1995-2017 The OpenSSL Project Authors. All Rights Reserved.
+ *
+ * Licensed under the Apache License 2.0 (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 <openssl/err.h>
+#include "internal/ctype.h"
+#include "bn_lcl.h"
+
+static const char Hex[] = "0123456789ABCDEF";
+
+/* Must 'OPENSSL_free' the returned data */
+char *BN_bn2hex(const BIGNUM *a)
+{
+ int i, j, v, z = 0;
+ char *buf;
+ char *p;
+
+ if (BN_is_zero(a))
+ return OPENSSL_strdup("0");
+ buf = OPENSSL_malloc(a->top * BN_BYTES * 2 + 2);
+ if (buf == NULL) {
+ BNerr(BN_F_BN_BN2HEX, ERR_R_MALLOC_FAILURE);
+ goto err;
+ }
+ p = buf;
+ if (a->neg)
+ *p++ = '-';
+ for (i = a->top - 1; i >= 0; i--) {
+ for (j = BN_BITS2 - 8; j >= 0; j -= 8) {
+ /* strip leading zeros */
+ v = (int)((a->d[i] >> j) & 0xff);
+ if (z || v != 0) {
+ *p++ = Hex[v >> 4];
+ *p++ = Hex[v & 0x0f];
+ z = 1;
+ }
+ }
+ }
+ *p = '\0';
+ err:
+ return buf;
+}
+
+#ifndef FIPS_MODE
+/* No BIO_snprintf in FIPS_MODE */
+/* Must 'OPENSSL_free' the returned data */
+char *BN_bn2dec(const BIGNUM *a)
+{
+ int i = 0, num, ok = 0, n, tbytes;
+ char *buf = NULL;
+ char *p;
+ BIGNUM *t = NULL;
+ BN_ULONG *bn_data = NULL, *lp;
+ int bn_data_num;
+
+ /*-
+ * get an upper bound for the length of the decimal integer
+ * num <= (BN_num_bits(a) + 1) * log(2)
+ * <= 3 * BN_num_bits(a) * 0.101 + log(2) + 1 (rounding error)
+ * <= 3 * BN_num_bits(a) / 10 + 3 * BN_num_bits / 1000 + 1 + 1
+ */
+ i = BN_num_bits(a) * 3;
+ num = (i / 10 + i / 1000 + 1) + 1;
+ tbytes = num + 3; /* negative and terminator and one spare? */
+ bn_data_num = num / BN_DEC_NUM + 1;
+ bn_data = OPENSSL_malloc(bn_data_num * sizeof(BN_ULONG));
+ buf = OPENSSL_malloc(tbytes);
+ if (buf == NULL || bn_data == NULL) {
+ BNerr(BN_F_BN_BN2DEC, ERR_R_MALLOC_FAILURE);
+ goto err;
+ }
+ if ((t = BN_dup(a)) == NULL)
+ goto err;
+
+ p = buf;
+ lp = bn_data;
+ if (BN_is_zero(t)) {
+ *p++ = '0';
+ *p++ = '\0';
+ } else {
+ if (BN_is_negative(t))
+ *p++ = '-';
+
+ while (!BN_is_zero(t)) {
+ if (lp - bn_data >= bn_data_num)
+ goto err;
+ *lp = BN_div_word(t, BN_DEC_CONV);
+ if (*lp == (BN_ULONG)-1)
+ goto err;
+ lp++;
+ }
+ lp--;
+ /*
+ * We now have a series of blocks, BN_DEC_NUM chars in length, where
+ * the last one needs truncation. The blocks need to be reversed in
+ * order.
+ */
+ n = BIO_snprintf(p, tbytes - (size_t)(p - buf), BN_DEC_FMT1, *lp);
+ if (n < 0)
+ goto err;
+ p += n;
+ while (lp != bn_data) {
+ lp--;
+ n = BIO_snprintf(p, tbytes - (size_t)(p - buf), BN_DEC_FMT2, *lp);
+ if (n < 0)
+ goto err;
+ p += n;
+ }
+ }
+ ok = 1;
+ err:
+ OPENSSL_free(bn_data);
+ BN_free(t);
+ if (ok)
+ return buf;
+ OPENSSL_free(buf);
+ return NULL;
+}
+#endif
+
+int BN_hex2bn(BIGNUM **bn, const char *a)
+{
+ BIGNUM *ret = NULL;
+ BN_ULONG l = 0;
+ int neg = 0, h, m, i, j, k, c;
+ int num;
+
+ if (a == NULL || *a == '\0')
+ return 0;
+
+ if (*a == '-') {
+ neg = 1;
+ a++;
+ }
+
+ for (i = 0; i <= INT_MAX / 4 && ossl_isxdigit(a[i]); i++)
+ continue;
+
+ if (i == 0 || i > INT_MAX / 4)
+ goto err;
+
+ num = i + neg;
+ if (bn == NULL)
+ return num;
+
+ /* a is the start of the hex digits, and it is 'i' long */
+ if (*bn == NULL) {
+ if ((ret = BN_new()) == NULL)
+ return 0;
+ } else {
+ ret = *bn;
+ BN_zero(ret);
+ }
+
+ /* i is the number of hex digits */
+ if (bn_expand(ret, i * 4) == NULL)
+ goto err;
+
+ j = i; /* least significant 'hex' */
+ m = 0;
+ h = 0;
+ while (j > 0) {
+ m = (BN_BYTES * 2 <= j) ? BN_BYTES * 2 : j;
+ l = 0;
+ for (;;) {
+ c = a[j - m];
+ k = OPENSSL_hexchar2int(c);
+ if (k < 0)
+ k = 0; /* paranoia */
+ l = (l << 4) | k;
+
+ if (--m <= 0) {
+ ret->d[h++] = l;
+ break;
+ }
+ }
+ j -= BN_BYTES * 2;
+ }
+ ret->top = h;
+ bn_correct_top(ret);
+
+ *bn = ret;
+ bn_check_top(ret);
+ /* Don't set the negative flag if it's zero. */
+ if (ret->top != 0)
+ ret->neg = neg;
+ return num;
+ err:
+ if (*bn == NULL)
+ BN_free(ret);
+ return 0;
+}
+
+int BN_dec2bn(BIGNUM **bn, const char *a)
+{
+ BIGNUM *ret = NULL;
+ BN_ULONG l = 0;
+ int neg = 0, i, j;
+ int num;
+
+ if (a == NULL || *a == '\0')
+ return 0;
+ if (*a == '-') {
+ neg = 1;
+ a++;
+ }
+
+ for (i = 0; i <= INT_MAX / 4 && ossl_isdigit(a[i]); i++)
+ continue;
+
+ if (i == 0 || i > INT_MAX / 4)
+ goto err;
+
+ num = i + neg;
+ if (bn == NULL)
+ return num;
+
+ /*
+ * a is the start of the digits, and it is 'i' long. We chop it into
+ * BN_DEC_NUM digits at a time
+ */
+ if (*bn == NULL) {
+ if ((ret = BN_new()) == NULL)
+ return 0;
+ } else {
+ ret = *bn;
+ BN_zero(ret);
+ }
+
+ /* i is the number of digits, a bit of an over expand */
+ if (bn_expand(ret, i * 4) == NULL)
+ goto err;
+
+ j = BN_DEC_NUM - i % BN_DEC_NUM;
+ if (j == BN_DEC_NUM)
+ j = 0;
+ l = 0;
+ while (--i >= 0) {
+ l *= 10;
+ l += *a - '0';
+ a++;
+ if (++j == BN_DEC_NUM) {
+ if (!BN_mul_word(ret, BN_DEC_CONV)
+ || !BN_add_word(ret, l))
+ goto err;
+ l = 0;
+ j = 0;
+ }
+ }
+
+ bn_correct_top(ret);
+ *bn = ret;
+ bn_check_top(ret);
+ /* Don't set the negative flag if it's zero. */
+ if (ret->top != 0)
+ ret->neg = neg;
+ return num;
+ err:
+ if (*bn == NULL)
+ BN_free(ret);
+ return 0;
+}
+
+int BN_asc2bn(BIGNUM **bn, const char *a)
+{
+ const char *p = a;
+
+ if (*p == '-')
+ p++;
+
+ if (p[0] == '0' && (p[1] == 'X' || p[1] == 'x')) {
+ if (!BN_hex2bn(bn, p + 2))
+ return 0;
+ } else {
+ if (!BN_dec2bn(bn, p))
+ return 0;
+ }
+ /* Don't set the negative flag if it's zero. */
+ if (*a == '-' && (*bn)->top != 0)
+ (*bn)->neg = 1;
+ return 1;
+}
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