diff options
author | Emilia Kasper <emilia@openssl.org> | 2017-02-17 19:00:15 +0100 |
---|---|---|
committer | Dr. Matthias St. Pierre <Matthias.St.Pierre@ncp-e.com> | 2018-05-05 22:14:37 +0200 |
commit | 7b6cfcd6dd99a86ecc3a1c51eef539494e191754 (patch) | |
tree | 4ed47c321206c2c6e94748d5cb652ad0b79efd05 /crypto | |
parent | 8dd55d9ee107337460e6a35b4ece234b4475e12d (diff) |
X509 time: tighten validation per RFC 5280
- Reject fractional seconds
- Reject offsets
- Check that the date/time digits are in valid range.
- Add documentation for X509_cmp_time
GH issue 2620
Backported from 80770da39e
Reviewed-by: Rich Salz <rsalz@openssl.org>
Reviewed-by: Matthias St. Pierre <Matthias.St.Pierre@ncp-e.com>
(Merged from https://github.com/openssl/openssl/pull/6182)
Diffstat (limited to 'crypto')
-rw-r--r-- | crypto/x509/x509_vfy.c | 140 |
1 files changed, 44 insertions, 96 deletions
diff --git a/crypto/x509/x509_vfy.c b/crypto/x509/x509_vfy.c index ff238331e6..869460d7cd 100644 --- a/crypto/x509/x509_vfy.c +++ b/crypto/x509/x509_vfy.c @@ -56,6 +56,7 @@ * [including the GNU Public Licence.] */ +#include <ctype.h> #include <stdio.h> #include <time.h> #include <errno.h> @@ -1937,120 +1938,67 @@ int X509_cmp_current_time(const ASN1_TIME *ctm) int X509_cmp_time(const ASN1_TIME *ctm, time_t *cmp_time) { - char *str; - ASN1_TIME atm; - long offset; - char buff1[24], buff2[24], *p; - int i, j, remaining; + static const size_t utctime_length = sizeof("YYMMDDHHMMSSZ") - 1; + static const size_t generalizedtime_length = sizeof("YYYYMMDDHHMMSSZ") - 1; + ASN1_TIME *asn1_cmp_time = NULL; + int i, day, sec, ret = 0; - p = buff1; - remaining = ctm->length; - str = (char *)ctm->data; /* - * Note that the following (historical) code allows much more slack in the - * time format than RFC5280. In RFC5280, the representation is fixed: + * Note that ASN.1 allows much more slack in the time format than RFC5280. + * In RFC5280, the representation is fixed: * UTCTime: YYMMDDHHMMSSZ * GeneralizedTime: YYYYMMDDHHMMSSZ + * + * We do NOT currently enforce the following RFC 5280 requirement: + * "CAs conforming to this profile MUST always encode certificate + * validity dates through the year 2049 as UTCTime; certificate validity + * dates in 2050 or later MUST be encoded as GeneralizedTime." */ - if (ctm->type == V_ASN1_UTCTIME) { - /* YYMMDDHHMM[SS]Z or YYMMDDHHMM[SS](+-)hhmm */ - int min_length = sizeof("YYMMDDHHMMZ") - 1; - int max_length = sizeof("YYMMDDHHMMSS+hhmm") - 1; - if (remaining < min_length || remaining > max_length) + switch (ctm->type) { + case V_ASN1_UTCTIME: + if (ctm->length != (int)(utctime_length)) return 0; - memcpy(p, str, 10); - p += 10; - str += 10; - remaining -= 10; - } else { - /* YYYYMMDDHHMM[SS[.fff]]Z or YYYYMMDDHHMM[SS[.f[f[f]]]](+-)hhmm */ - int min_length = sizeof("YYYYMMDDHHMMZ") - 1; - int max_length = sizeof("YYYYMMDDHHMMSS.fff+hhmm") - 1; - if (remaining < min_length || remaining > max_length) + break; + case V_ASN1_GENERALIZEDTIME: + if (ctm->length != (int)(generalizedtime_length)) return 0; - memcpy(p, str, 12); - p += 12; - str += 12; - remaining -= 12; + break; + default: + return 0; } - if ((*str == 'Z') || (*str == '-') || (*str == '+')) { - *(p++) = '0'; - *(p++) = '0'; - } else { - /* SS (seconds) */ - if (remaining < 2) + /** + * Verify the format: the ASN.1 functions we use below allow a more + * flexible format than what's mandated by RFC 5280. + * Digit and date ranges will be verified in the conversion methods. + */ + for (i = 0; i < ctm->length - 1; i++) { + if (!isdigit(ctm->data[i])) return 0; - *(p++) = *(str++); - *(p++) = *(str++); - remaining -= 2; - /* - * Skip any (up to three) fractional seconds... - * TODO(emilia): in RFC5280, fractional seconds are forbidden. - * Can we just kill them altogether? - */ - if (remaining && *str == '.') { - str++; - remaining--; - for (i = 0; i < 3 && remaining; i++, str++, remaining--) { - if (*str < '0' || *str > '9') - break; - } - } - } - *(p++) = 'Z'; - *(p++) = '\0'; - - /* We now need either a terminating 'Z' or an offset. */ - if (!remaining) + if (ctm->data[ctm->length - 1] != 'Z') return 0; - if (*str == 'Z') { - if (remaining != 1) - return 0; - offset = 0; - } else { - /* (+-)HHMM */ - if ((*str != '+') && (*str != '-')) - return 0; - /* Historical behaviour: the (+-)hhmm offset is forbidden in RFC5280. */ - if (remaining != 5) - return 0; - if (str[1] < '0' || str[1] > '9' || str[2] < '0' || str[2] > '9' || - str[3] < '0' || str[3] > '9' || str[4] < '0' || str[4] > '9') - return 0; - offset = ((str[1] - '0') * 10 + (str[2] - '0')) * 60; - offset += (str[3] - '0') * 10 + (str[4] - '0'); - if (*str == '-') - offset = -offset; - } - atm.type = ctm->type; - atm.flags = 0; - atm.length = sizeof(buff2); - atm.data = (unsigned char *)buff2; - if (X509_time_adj(&atm, offset * 60, cmp_time) == NULL) - return 0; + /* + * There is ASN1_UTCTIME_cmp_time_t but no + * ASN1_GENERALIZEDTIME_cmp_time_t or ASN1_TIME_cmp_time_t, + * so we go through ASN.1 + */ + asn1_cmp_time = X509_time_adj(NULL, 0, cmp_time); + if (asn1_cmp_time == NULL) + goto err; + if (!ASN1_TIME_diff(&day, &sec, ctm, asn1_cmp_time)) + goto err; - if (ctm->type == V_ASN1_UTCTIME) { - i = (buff1[0] - '0') * 10 + (buff1[1] - '0'); - if (i < 50) - i += 100; /* cf. RFC 2459 */ - j = (buff2[0] - '0') * 10 + (buff2[1] - '0'); - if (j < 50) - j += 100; - - if (i < j) - return -1; - if (i > j) - return 1; - } - i = strcmp(buff1, buff2); /* * X509_cmp_time comparison is <=. * The return value 0 is reserved for errors. */ - return i > 0 ? 1 : -1; + ret = (day >= 0 && sec >= 0) ? -1 : 1; + + err: + ASN1_TIME_free(asn1_cmp_time); + return ret; } ASN1_TIME *X509_gmtime_adj(ASN1_TIME *s, long adj) |