/src/openssl/crypto/bn/bn_conv.c

Source (jump to first uncovered line)
/*
 * Copyright 1995-2024 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 "crypto/ctype.h"
#include "bn_local.h"

/* 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)
        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 += ossl_to_hex(p, v);
                z = 1;
            }
        }
    }
    *p = '\0';
 err:
    return buf;
}

#ifndef FIPS_MODULE
/* No BIO_snprintf in FIPS_MODULE */
/* 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)
        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)
        return 0;

    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;
        if (BN_get_flags(ret, BN_FLG_STATIC_DATA)) {
            ERR_raise(ERR_LIB_BN, ERR_R_PASSED_INVALID_ARGUMENT);
            return 0;
        }
        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;
}

Coverage Report

Created: 2025-06-13 06:56

Line	Count	Source (jump to first uncovered line)
1		/*
2		* Copyright 1995-2024 The OpenSSL Project Authors. All Rights Reserved.
3		*
4		* Licensed under the Apache License 2.0 (the "License"). You may not use
5		* this file except in compliance with the License. You can obtain a copy
6		* in the file LICENSE in the source distribution or at
7		* https://www.openssl.org/source/license.html
8		*/
9
10		#include <openssl/err.h>
11		#include "crypto/ctype.h"
12		#include "bn_local.h"
13
14		/* Must 'OPENSSL_free' the returned data */
15		char BN_bn2hex(const BIGNUM a)
16	0	{
17	0	int i, j, v, z = 0;
18	0	char *buf;
19	0	char *p;
20
21	0	if (BN_is_zero(a))
22	0	return OPENSSL_strdup("0");
23	0	buf = OPENSSL_malloc(a->top * BN_BYTES * 2 + 2);
24	0	if (buf == NULL)
25	0	goto err;
26	0	p = buf;
27	0	if (a->neg)
28	0	*p++ = '-';
29	0	for (i = a->top - 1; i >= 0; i--) {
30	0	for (j = BN_BITS2 - 8; j >= 0; j -= 8) {
31		/* strip leading zeros */
32	0	v = (int)((a->d[i] >> j) & 0xff);
33	0	if (z \|\| v != 0) {
34	0	p += ossl_to_hex(p, v);
35	0	z = 1;
36	0	}
37	0	}
38	0	}
39	0	*p = '\0';
40	0	err:
41	0	return buf;
42	0	}
43
44		#ifndef FIPS_MODULE
45		/* No BIO_snprintf in FIPS_MODULE */
46		/* Must 'OPENSSL_free' the returned data */
47		char BN_bn2dec(const BIGNUM a)
48	0	{
49	0	int i = 0, num, ok = 0, n, tbytes;
50	0	char *buf = NULL;
51	0	char *p;
52	0	BIGNUM *t = NULL;
53	0	BN_ULONG bn_data = NULL, lp;
54	0	int bn_data_num;
55
56		/*-
57		* get an upper bound for the length of the decimal integer
58		* num <= (BN_num_bits(a) + 1) * log(2)
59		* <= 3 * BN_num_bits(a) * 0.101 + log(2) + 1 (rounding error)
60		* <= 3 * BN_num_bits(a) / 10 + 3 * BN_num_bits / 1000 + 1 + 1
61		*/
62	0	i = BN_num_bits(a) * 3;
63	0	num = (i / 10 + i / 1000 + 1) + 1;
64	0	tbytes = num + 3; /* negative and terminator and one spare? */
65	0	bn_data_num = num / BN_DEC_NUM + 1;
66	0	bn_data = OPENSSL_malloc(bn_data_num * sizeof(BN_ULONG));
67	0	buf = OPENSSL_malloc(tbytes);
68	0	if (buf == NULL \|\| bn_data == NULL)
69	0	goto err;
70	0	if ((t = BN_dup(a)) == NULL)
71	0	goto err;
72
73	0	p = buf;
74	0	lp = bn_data;
75	0	if (BN_is_zero(t)) {
76	0	*p++ = '0';
77	0	*p++ = '\0';
78	0	} else {
79	0	if (BN_is_negative(t))
80	0	*p++ = '-';
81
82	0	while (!BN_is_zero(t)) {
83	0	if (lp - bn_data >= bn_data_num)
84	0	goto err;
85	0	*lp = BN_div_word(t, BN_DEC_CONV);
86	0	if (*lp == (BN_ULONG)-1)
87	0	goto err;
88	0	lp++;
89	0	}
90	0	lp--;
91		/*
92		* We now have a series of blocks, BN_DEC_NUM chars in length, where
93		* the last one needs truncation. The blocks need to be reversed in
94		* order.
95		*/
96	0	n = BIO_snprintf(p, tbytes - (size_t)(p - buf), BN_DEC_FMT1, *lp);
97	0	if (n < 0)
98	0	goto err;
99	0	p += n;
100	0	while (lp != bn_data) {
101	0	lp--;
102	0	n = BIO_snprintf(p, tbytes - (size_t)(p - buf), BN_DEC_FMT2, *lp);
103	0	if (n < 0)
104	0	goto err;
105	0	p += n;
106	0	}
107	0	}
108	0	ok = 1;
109	0	err:
110	0	OPENSSL_free(bn_data);
111	0	BN_free(t);
112	0	if (ok)
113	0	return buf;
114	0	OPENSSL_free(buf);
115	0	return NULL;
116	0	}
117		#endif
118
119		int BN_hex2bn(BIGNUM *bn, const char a)
120	0	{
121	0	BIGNUM *ret = NULL;
122	0	BN_ULONG l = 0;
123	0	int neg = 0, h, m, i, j, k, c;
124	0	int num;
125
126	0	if (a == NULL \|\| *a == '\0')
127	0	return 0;
128
129	0	if (*a == '-') {
130	0	neg = 1;
131	0	a++;
132	0	}
133
134	0	for (i = 0; i <= INT_MAX / 4 && ossl_isxdigit(a[i]); i++)
135	0	continue;
136
137	0	if (i == 0 \|\| i > INT_MAX / 4)
138	0	return 0;
139
140	0	num = i + neg;
141	0	if (bn == NULL)
142	0	return num;
143
144		/* a is the start of the hex digits, and it is 'i' long */
145	0	if (*bn == NULL) {
146	0	if ((ret = BN_new()) == NULL)
147	0	return 0;
148	0	} else {
149	0	ret = *bn;
150	0	if (BN_get_flags(ret, BN_FLG_STATIC_DATA)) {
151	0	ERR_raise(ERR_LIB_BN, ERR_R_PASSED_INVALID_ARGUMENT);
152	0	return 0;
153	0	}
154	0	BN_zero(ret);
155	0	}
156
157		/* i is the number of hex digits */
158	0	if (bn_expand(ret, i * 4) == NULL)
159	0	goto err;
160
161	0	j = i; /* least significant 'hex' */
162	0	m = 0;
163	0	h = 0;
164	0	while (j > 0) {
165	0	m = (BN_BYTES * 2 <= j) ? BN_BYTES * 2 : j;
166	0	l = 0;
167	0	for (;;) {
168	0	c = a[j - m];
169	0	k = OPENSSL_hexchar2int(c);
170	0	if (k < 0)
171	0	k = 0; /* paranoia */
172	0	l = (l << 4) \| k;
173
174	0	if (--m <= 0) {
175	0	ret->d[h++] = l;
176	0	break;
177	0	}
178	0	}
179	0	j -= BN_BYTES * 2;
180	0	}
181	0	ret->top = h;
182	0	bn_correct_top(ret);
183
184	0	*bn = ret;
185	0	bn_check_top(ret);
186		/* Don't set the negative flag if it's zero. */
187	0	if (ret->top != 0)
188	0	ret->neg = neg;
189	0	return num;
190	0	err:
191	0	if (*bn == NULL)
192	0	BN_free(ret);
193	0	return 0;
194	0	}
195
196		int BN_dec2bn(BIGNUM *bn, const char a)
197	0	{
198	0	BIGNUM *ret = NULL;
199	0	BN_ULONG l = 0;
200	0	int neg = 0, i, j;
201	0	int num;
202
203	0	if (a == NULL \|\| *a == '\0')
204	0	return 0;
205	0	if (*a == '-') {
206	0	neg = 1;
207	0	a++;
208	0	}
209
210	0	for (i = 0; i <= INT_MAX / 4 && ossl_isdigit(a[i]); i++)
211	0	continue;
212
213	0	if (i == 0 \|\| i > INT_MAX / 4)
214	0	goto err;
215
216	0	num = i + neg;
217	0	if (bn == NULL)
218	0	return num;
219
220		/*
221		* a is the start of the digits, and it is 'i' long. We chop it into
222		* BN_DEC_NUM digits at a time
223		*/
224	0	if (*bn == NULL) {
225	0	if ((ret = BN_new()) == NULL)
226	0	return 0;
227	0	} else {
228	0	ret = *bn;
229	0	BN_zero(ret);
230	0	}
231
232		/* i is the number of digits, a bit of an over expand */
233	0	if (bn_expand(ret, i * 4) == NULL)
234	0	goto err;
235
236	0	j = BN_DEC_NUM - i % BN_DEC_NUM;
237	0	if (j == BN_DEC_NUM)
238	0	j = 0;
239	0	l = 0;
240	0	while (--i >= 0) {
241	0	l *= 10;
242	0	l += *a - '0';
243	0	a++;
244	0	if (++j == BN_DEC_NUM) {
245	0	if (!BN_mul_word(ret, BN_DEC_CONV)
246	0	\|\| !BN_add_word(ret, l))
247	0	goto err;
248	0	l = 0;
249	0	j = 0;
250	0	}
251	0	}
252
253	0	bn_correct_top(ret);
254	0	*bn = ret;
255	0	bn_check_top(ret);
256		/* Don't set the negative flag if it's zero. */
257	0	if (ret->top != 0)
258	0	ret->neg = neg;
259	0	return num;
260	0	err:
261	0	if (*bn == NULL)
262	0	BN_free(ret);
263	0	return 0;
264	0	}
265
266		int BN_asc2bn(BIGNUM *bn, const char a)
267	0	{
268	0	const char *p = a;
269
270	0	if (*p == '-')
271	0	p++;
272
273	0	if (p[0] == '0' && (p[1] == 'X' \|\| p[1] == 'x')) {
274	0	if (!BN_hex2bn(bn, p + 2))
275	0	return 0;
276	0	} else {
277	0	if (!BN_dec2bn(bn, p))
278	0	return 0;
279	0	}
280		/* Don't set the negative flag if it's zero. */
281	0	if (a == '-' && (bn)->top != 0)
282	0	(*bn)->neg = 1;
283	0	return 1;
284	0	}