openssl/crypto/asn1/f_string.c

/*
 * 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 <stdio.h>
#include "crypto/ctype.h"
#include "internal/cryptlib.h"
#include <openssl/buffer.h>
#include <openssl/asn1.h>

int i2a_ASN1_STRING(BIO *bp, const ASN1_STRING *a, int type)
{
    int i, n = 0;
    static const char *h = "0123456789ABCDEF";
    char buf[2];

    if (a == NULL)
        return 0;

    if (a->length == 0) {
        if (BIO_write(bp, "0", 1) != 1)
            goto err;
        n = 1;
    } else {
        for (i = 0; i < a->length; i++) {
            if ((i != 0) && (i % 35 == 0)) {
                if (BIO_write(bp, "\\\n", 2) != 2)
                    goto err;
                n += 2;
            }
            buf[0] = h[((unsigned char)a->data[i] >> 4) & 0x0f];
            buf[1] = h[((unsigned char)a->data[i]) & 0x0f];
            if (BIO_write(bp, buf, 2) != 2)
                goto err;
            n += 2;
        }
    }
    return n;
 err:
    return -1;
}

int a2i_ASN1_STRING(BIO *bp, ASN1_STRING *bs, char *buf, int size)
{
    int i, j, k, m, n, again, bufsize;
    unsigned char *s = NULL, *sp;
    unsigned char *bufp;
    int num = 0, slen = 0, first = 1;

    bufsize = BIO_gets(bp, buf, size);
    for (;;) {
        if (bufsize < 1) {
            if (first)
                break;
            else
                goto err;
        }
        first = 0;

        i = bufsize;
        if (buf[i - 1] == '\n')
            buf[--i] = '\0';
        if (i == 0)
            goto err;
        if (buf[i - 1] == '\r')
            buf[--i] = '\0';
        if (i == 0)
            goto err;
        again = (buf[i - 1] == '\\');

        for (j = i - 1; j > 0; j--) {
            if (!ossl_isxdigit(buf[j])) {
                i = j;
                break;
            }
        }
        buf[i] = '\0';
        /*
         * We have now cleared all the crap off the end of the line
         */
        if (i < 2)
            goto err;

        bufp = (unsigned char *)buf;

        k = 0;
        i -= again;
        if (i % 2 != 0) {
            ASN1err(ASN1_F_A2I_ASN1_STRING, ASN1_R_ODD_NUMBER_OF_CHARS);
            OPENSSL_free(s);
            return 0;
        }
        i /= 2;
        if (num + i > slen) {
            sp = OPENSSL_realloc(s, (unsigned int)num + i * 2);
            if (sp == NULL) {
                ASN1err(ASN1_F_A2I_ASN1_STRING, ERR_R_MALLOC_FAILURE);
                OPENSSL_free(s);
                return 0;
            }
            s = sp;
            slen = num + i * 2;
        }
        for (j = 0; j < i; j++, k += 2) {
            for (n = 0; n < 2; n++) {
                m = OPENSSL_hexchar2int(bufp[k + n]);
                if (m < 0) {
                    ASN1err(ASN1_F_A2I_ASN1_STRING,
                            ASN1_R_NON_HEX_CHARACTERS);
                    OPENSSL_free(s);
                    return 0;
                }
                s[num + j] <<= 4;
                s[num + j] |= m;
            }
        }
        num += i;
        if (again)
            bufsize = BIO_gets(bp, buf, size);
        else
            break;
    }
    bs->length = num;
    bs->data = s;
    return 1;

 err:
    ASN1err(ASN1_F_A2I_ASN1_STRING, ASN1_R_SHORT_LINE);
    OPENSSL_free(s);
    return 0;
}