/*

 * Copyright 1999-2019 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

 */

/*-

 * This is an implementation of the ASN1 Time structure which is:

 *    Time ::= CHOICE {

 *      utcTime        UTCTime,

 *      generalTime    GeneralizedTime }

 */

#include <stdio.h>

#include <time.h>

#include "crypto/ctype.h"

#include "internal/cryptlib.h"

#include <openssl/asn1t.h>

#include "asn1_local.h"

IMPLEMENT_ASN1_MSTRING(ASN1_TIME, B_ASN1_TIME)

IMPLEMENT_ASN1_FUNCTIONS(ASN1_TIME)

static int is_utc(const int year)

{

    if (50 <= year && year <= 149)

        return 1;

    return 0;

}

static int leap_year(const int year)

{

    if (year % 400 == 0 || (year % 100 != 0 && year % 4 == 0))

        return 1;

    return 0;

}

/*

 * Compute the day of the week and the day of the year from the year, month

 * and day.  The day of the year is straightforward, the day of the week uses

 * a form of Zeller's congruence.  For this months start with March and are

 * numbered 4 through 15.

 */

static void determine_days(struct tm *tm)

{

    static const int ydays[12] = {

        0, 31, 59, 90, 120, 151, 181, 212, 243, 273, 304, 334

    };

    int y = tm->tm_year + 1900;

    int m = tm->tm_mon;

    int d = tm->tm_mday;

    int c;

    tm->tm_yday = ydays[m] + d - 1;

    if (m >= 2) {

        /* March and onwards can be one day further into the year */

        tm->tm_yday += leap_year(y);

        m += 2;

    } else {

        /* Treat January and February as part of the previous year */

        m += 14;

        y--;

    }

    c = y / 100;

    y %= 100;

    /* Zeller's congruence */

    tm->tm_wday = (d + (13 * m) / 5 + y + y / 4 + c / 4 + 5 * c + 6) % 7;

}

int asn1_time_to_tm(struct tm *tm, const ASN1_TIME *d)

{

    static const int min[9] = { 0, 0, 1, 1, 0, 0, 0, 0, 0 };

    static const int max[9] = { 99, 99, 12, 31, 23, 59, 59, 12, 59 };

    static const int mdays[12] = { 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31 };

    char *a;

    int n, i, i2, l, o, min_l = 11, strict = 0, end = 6, btz = 5, md;

    struct tm tmp;

#if defined(CHARSET_EBCDIC)

    const char upper_z = 0x5A, num_zero = 0x30, period = 0x2E, minus = 0x2D, plus = 0x2B;

#else

    const char upper_z = 'Z', num_zero = '0', period = '.', minus = '-', plus = '+';

#endif

    /*

     * ASN1_STRING_FLAG_X509_TIME is used to enforce RFC 5280

     * time string format, in which:

     *

     * 1. "seconds" is a 'MUST'

     * 2. "Zulu" timezone is a 'MUST'

     * 3. "+|-" is not allowed to indicate a time zone

     */

    if (d->type == V_ASN1_UTCTIME) {

        if (d->flags & ASN1_STRING_FLAG_X509_TIME) {

            min_l = 13;

            strict = 1;

        }

    } else if (d->type == V_ASN1_GENERALIZEDTIME) {

        end = 7;

        btz = 6;

        if (d->flags & ASN1_STRING_FLAG_X509_TIME) {

            min_l = 15;

            strict = 1;

        } else {

            min_l = 13;

        }

    } else {

        return 0;

    }

    l = d->length;

    a = (char *)d->data;

    o = 0;

    memset(&tmp, 0, sizeof(tmp));

    /*

     * GENERALIZEDTIME is similar to UTCTIME except the year is represented

     * as YYYY. This stuff treats everything as a two digit field so make

     * first two fields 00 to 99

     */

    if (l < min_l)

        goto err;

    for (i = 0; i < end; i++) {

        if (!strict && (i == btz) && ((a[o] == upper_z) || (a[o] == plus) || (a[o] == minus))) {

            i++;

            break;

        }

        if (!ascii_isdigit(a[o]))

            goto err;

        n = a[o] - num_zero;

        /* incomplete 2-digital number */

        if (++o == l)

            goto err;

        if (!ascii_isdigit(a[o]))

            goto err;

        n = (n * 10) + a[o] - num_zero;

        /* no more bytes to read, but we haven't seen time-zone yet */

        if (++o == l)

            goto err;

        i2 = (d->type == V_ASN1_UTCTIME) ? i + 1 : i;

        if ((n < min[i2]) || (n > max[i2]))

            goto err;

        switch (i2) {

        case 0:

            /* UTC will never be here */

            tmp.tm_year = n * 100 - 1900;

            break;

        case 1:

            if (d->type == V_ASN1_UTCTIME)

                tmp.tm_year = n < 50 ? n + 100 : n;

            else

                tmp.tm_year += n;

            break;

        case 2:

            tmp.tm_mon = n - 1;

            break;

        case 3:

            /* check if tm_mday is valid in tm_mon */

            if (tmp.tm_mon == 1) {

                /* it's February */

                md = mdays[1] + leap_year(tmp.tm_year + 1900);

            } else {

                md = mdays[tmp.tm_mon];

            }

            if (n > md)

                goto err;

            tmp.tm_mday = n;

            determine_days(&tmp);

            break;

        case 4:

            tmp.tm_hour = n;

            break;

        case 5:

            tmp.tm_min = n;

            break;

        case 6:

            tmp.tm_sec = n;

            break;

        }

    }

    /*

     * Optional fractional seconds: decimal point followed by one or more

     * digits.

     */

    if (d->type == V_ASN1_GENERALIZEDTIME && a[o] == period) {

        if (strict)

            /* RFC 5280 forbids fractional seconds */

            goto err;

        if (++o == l)

            goto err;

        i = o;

        while ((o < l) && ascii_isdigit(a[o]))

            o++;

        /* Must have at least one digit after decimal point */

        if (i == o)

            goto err;

        /* no more bytes to read, but we haven't seen time-zone yet */

        if (o == l)

            goto err;

    }

    /*

     * 'o' will never point to '\0' at this point, the only chance

     * 'o' can point to '\0' is either the subsequent if or the first

     * else if is true.

     */

    if (a[o] == upper_z) {

        o++;

    } else if (!strict && ((a[o] == plus) || (a[o] == minus))) {

        int offsign = a[o] == minus ? 1 : -1;

        int offset = 0;

        o++;

        /*

         * if not equal, no need to do subsequent checks

         * since the following for-loop will add 'o' by 4

         * and the final return statement will check if 'l'

         * and 'o' are equal.

         */

        if (o + 4 != l)

            goto err;

        for (i = end; i < end + 2; i++) {

            if (!ascii_isdigit(a[o]))

                goto err;

            n = a[o] - num_zero;

            o++;

            if (!ascii_isdigit(a[o]))

                goto err;

            n = (n * 10) + a[o] - num_zero;

            i2 = (d->type == V_ASN1_UTCTIME) ? i + 1 : i;

            if ((n < min[i2]) || (n > max[i2]))

                goto err;

            /* if tm is NULL, no need to adjust */

            if (tm != NULL) {

                if (i == end)

                    offset = n * 3600;

                else if (i == end + 1)

                    offset += n * 60;

            }

            o++;

        }

        if (offset && !OPENSSL_gmtime_adj(&tmp, 0, offset * offsign))

            goto err;

    } else {

        /* not Z, or not +/- in non-strict mode */

        goto err;

    }

    if (o == l) {

        /* success, check if tm should be filled */

        if (tm != NULL)

            *tm = tmp;

        return 1;

    }

 err:

    return 0;

}

ASN1_TIME *asn1_time_from_tm(ASN1_TIME *s, struct tm *ts, int type)

{

    char* p;

    ASN1_TIME *tmps = NULL;

    const size_t len = 20;

    if (type == V_ASN1_UNDEF) {

        if (is_utc(ts->tm_year))

            type = V_ASN1_UTCTIME;

        else

            type = V_ASN1_GENERALIZEDTIME;

    } else if (type == V_ASN1_UTCTIME) {

        if (!is_utc(ts->tm_year))

            goto err;

    } else if (type != V_ASN1_GENERALIZEDTIME) {

        goto err;

    }

    if (s == NULL)

        tmps = ASN1_STRING_new();

    else

        tmps = s;

    if (tmps == NULL)

        return NULL;

    if (!ASN1_STRING_set(tmps, NULL, len))

        goto err;

    tmps->type = type;

    p = (char*)tmps->data;

    if (type == V_ASN1_GENERALIZEDTIME)

        tmps->length = BIO_snprintf(p, len, "%04d%02d%02d%02d%02d%02dZ",

                                    ts->tm_year + 1900, ts->tm_mon + 1,

                                    ts->tm_mday, ts->tm_hour, ts->tm_min,

                                    ts->tm_sec);

    else

        tmps->length = BIO_snprintf(p, len, "%02d%02d%02d%02d%02d%02dZ",

                                    ts->tm_year % 100, ts->tm_mon + 1,

                                    ts->tm_mday, ts->tm_hour, ts->tm_min,

                                    ts->tm_sec);

#ifdef CHARSET_EBCDIC

    ebcdic2ascii(tmps->data, tmps->data, tmps->length);

#endif

    return tmps;

 err:

    if (tmps != s)

        ASN1_STRING_free(tmps);

    return NULL;

}

ASN1_TIME *ASN1_TIME_set(ASN1_TIME *s, time_t t)

{

    return ASN1_TIME_adj(s, t, 0, 0);

}

ASN1_TIME *ASN1_TIME_adj(ASN1_TIME *s, time_t t,

                         int offset_day, long offset_sec)

{

    struct tm *ts;

    struct tm data;

    ts = OPENSSL_gmtime(&t, &data);

    if (ts == NULL) {

        ASN1err(ASN1_F_ASN1_TIME_ADJ, ASN1_R_ERROR_GETTING_TIME);

        return NULL;

    }

    if (offset_day || offset_sec) {

        if (!OPENSSL_gmtime_adj(ts, offset_day, offset_sec))

            return NULL;

    }

    return asn1_time_from_tm(s, ts, V_ASN1_UNDEF);

}

int ASN1_TIME_check(const ASN1_TIME *t)

{

    if (t->type == V_ASN1_GENERALIZEDTIME)

        return ASN1_GENERALIZEDTIME_check(t);

    else if (t->type == V_ASN1_UTCTIME)

        return ASN1_UTCTIME_check(t);

    return 0;

}

/* Convert an ASN1_TIME structure to GeneralizedTime */

ASN1_GENERALIZEDTIME *ASN1_TIME_to_generalizedtime(const ASN1_TIME *t,

                                                   ASN1_GENERALIZEDTIME **out)

{

    ASN1_GENERALIZEDTIME *ret = NULL;

    struct tm tm;

    if (!ASN1_TIME_to_tm(t, &tm))

        return NULL;

    if (out != NULL)

        ret = *out;

    ret = asn1_time_from_tm(ret, &tm, V_ASN1_GENERALIZEDTIME);

    if (out != NULL && ret != NULL)

        *out = ret;

    return ret;

}

int ASN1_TIME_set_string(ASN1_TIME *s, const char *str)

{

    /* Try UTC, if that fails, try GENERALIZED */

    if (ASN1_UTCTIME_set_string(s, str))

        return 1;

    return ASN1_GENERALIZEDTIME_set_string(s, str);

}

int ASN1_TIME_set_string_X509(ASN1_TIME *s, const char *str)

{

    ASN1_TIME t;

    struct tm tm;

    int rv = 0;

    t.length = strlen(str);

    t.data = (unsigned char *)str;

    t.flags = ASN1_STRING_FLAG_X509_TIME;

    t.type = V_ASN1_UTCTIME;

    if (!ASN1_TIME_check(&t)) {

        t.type = V_ASN1_GENERALIZEDTIME;

        if (!ASN1_TIME_check(&t))

            goto out;

    }

    /*

     * Per RFC 5280 (section 4.1.2.5.), the valid input time

     * strings should be encoded with the following rules:

     *

     * 1. UTC: YYMMDDHHMMSSZ, if YY < 50 (20YY) --> UTC: YYMMDDHHMMSSZ

     * 2. UTC: YYMMDDHHMMSSZ, if YY >= 50 (19YY) --> UTC: YYMMDDHHMMSSZ

     * 3. G'd: YYYYMMDDHHMMSSZ, if YYYY >= 2050 --> G'd: YYYYMMDDHHMMSSZ

     * 4. G'd: YYYYMMDDHHMMSSZ, if YYYY < 2050 --> UTC: YYMMDDHHMMSSZ

     *

     * Only strings of the 4th rule should be reformatted, but since a

     * UTC can only present [1950, 2050), so if the given time string

     * is less than 1950 (e.g. 19230419000000Z), we do nothing...

     */

    if (s != NULL && t.type == V_ASN1_GENERALIZEDTIME) {

        if (!asn1_time_to_tm(&tm, &t))

            goto out;

        if (is_utc(tm.tm_year)) {

            t.length -= 2;

            /*

             * it's OK to let original t.data go since that's assigned

             * to a piece of memory allocated outside of this function.

             * new t.data would be freed after ASN1_STRING_copy is done.

             */

            t.data = OPENSSL_zalloc(t.length + 1);

            if (t.data == NULL)

                goto out;

            memcpy(t.data, str + 2, t.length);

            t.type = V_ASN1_UTCTIME;

        }

    }

    if (s == NULL || ASN1_STRING_copy((ASN1_STRING *)s, (ASN1_STRING *)&t))

        rv = 1;

    if (t.data != (unsigned char *)str)

        OPENSSL_free(t.data);

out:

    return rv;

}

int ASN1_TIME_to_tm(const ASN1_TIME *s, struct tm *tm)

{

    if (s == NULL) {

        time_t now_t;

        time(&now_t);

        memset(tm, 0, sizeof(*tm));

        if (OPENSSL_gmtime(&now_t, tm) != NULL)

            return 1;

        return 0;

    }

    return asn1_time_to_tm(tm, s);

}

int ASN1_TIME_diff(int *pday, int *psec,

                   const ASN1_TIME *from, const ASN1_TIME *to)

{

    struct tm tm_from, tm_to;

    if (!ASN1_TIME_to_tm(from, &tm_from))

        return 0;

    if (!ASN1_TIME_to_tm(to, &tm_to))

        return 0;

    return OPENSSL_gmtime_diff(pday, psec, &tm_from, &tm_to);

}

static const char _asn1_mon[12][4] = {

    "Jan", "Feb", "Mar", "Apr", "May", "Jun",

    "Jul", "Aug", "Sep", "Oct", "Nov", "Dec"

};

int ASN1_TIME_print(BIO *bp, const ASN1_TIME *tm)

{

    char *v;

    int gmt = 0, l;

    struct tm stm;

    const char upper_z = 0x5A, period = 0x2E;

    if (!asn1_time_to_tm(&stm, tm)) {

        /* asn1_time_to_tm will check the time type */

        goto err;

    }

    l = tm->length;

    v = (char *)tm->data;

    if (v[l - 1] == upper_z)

        gmt = 1;

    if (tm->type == V_ASN1_GENERALIZEDTIME) {

        char *f = NULL;

        int f_len = 0;

        /*

         * Try to parse fractional seconds. '14' is the place of

         * 'fraction point' in a GeneralizedTime string.

         */

        if (tm->length > 15 && v[14] == period) {

            f = &v[14];

            f_len = 1;

            while (14 + f_len < l && ascii_isdigit(f[f_len]))

                ++f_len;

        }

        return BIO_printf(bp, "%s %2d %02d:%02d:%02d%.*s %d%s",

                          _asn1_mon[stm.tm_mon], stm.tm_mday, stm.tm_hour,

                          stm.tm_min, stm.tm_sec, f_len, f, stm.tm_year + 1900,

                          (gmt ? " GMT" : "")) > 0;

    } else {

        return BIO_printf(bp, "%s %2d %02d:%02d:%02d %d%s",

                          _asn1_mon[stm.tm_mon], stm.tm_mday, stm.tm_hour,

                          stm.tm_min, stm.tm_sec, stm.tm_year + 1900,

                          (gmt ? " GMT" : "")) > 0;

    }

 err:

    BIO_write(bp, "Bad time value", 14);

    return 0;

}

int ASN1_TIME_cmp_time_t(const ASN1_TIME *s, time_t t)

{

    struct tm stm, ttm;

    int day, sec;

    if (!ASN1_TIME_to_tm(s, &stm))

        return -2;

    if (!OPENSSL_gmtime(&t, &ttm))

        return -2;

    if (!OPENSSL_gmtime_diff(&day, &sec, &ttm, &stm))

        return -2;

    if (day > 0 || sec > 0)

        return 1;

    if (day < 0 || sec < 0)

        return -1;

    return 0;

}

int ASN1_TIME_normalize(ASN1_TIME *t)

{

    struct tm tm;

    if (!ASN1_TIME_to_tm(t, &tm))

        return 0;

    return asn1_time_from_tm(t, &tm, V_ASN1_UNDEF) != NULL;

}

int ASN1_TIME_compare(const ASN1_TIME *a, const ASN1_TIME *b)

{

    int day, sec;

    if (!ASN1_TIME_diff(&day, &sec, b, a))

        return -2;

    if (day > 0 || sec > 0)

        return 1;

    if (day < 0 || sec < 0)

        return -1;

    return 0;

}