Add asn1_time_to_tm function and check days in month

Based on discussion in PR #3566. Reduce duplicated code in original
asn1_utctime_to_tm and asn1_generalizedtime_to_tm, and introduce a new
internal function asn1_time_to_tm. This function also checks if the days
in the input time string is valid or not for the corresponding month.

Test cases are also added.

Reviewed-by: Andy Polyakov <appro@openssl.org>
Reviewed-by: Paul Dale <paul.dale@oracle.com>
(Merged from https://github.com/openssl/openssl/pull/3905)

1 files changed, 2 insertions, 111 deletions

diff --git a/crypto/asn1/a_utctm.c b/crypto/asn1/a_utctm.c
index 5a4b1742f7..2a864180e3 100644
--- a/crypto/asn1/a_utctm.c
+++ b/crypto/asn1/a_utctm.c
@@ -15,119 +15,10 @@
 
 int asn1_utctime_to_tm(struct tm *tm, const ASN1_UTCTIME *d)
 {
-    static const int min[8] = { 0, 1, 1, 0, 0, 0, 0, 0 };
-    static const int max[8] = { 99, 12, 31, 23, 59, 59, 12, 59 };
-    char *a;
-    int n, i, l, o, min_l = 11, strict = 0;
-
+    /* wrapper around ans1_time_to_tm */
     if (d->type != V_ASN1_UTCTIME)
         return 0;
-    l = d->length;
-    a = (char *)d->data;
-    o = 0;
-
-    /*
-     * 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->flags & ASN1_STRING_FLAG_X509_TIME) {
-        min_l = 13;
-        strict = 1;
-    }
-
-    if (l < min_l)
-        goto err;
-    for (i = 0; i < 6; i++) {
-        if (!strict && (i == 5) && ((a[o] == 'Z') || (a[o] == '+') || (a[o] == '-'))) {
-            i++;
-            if (tm)
-                tm->tm_sec = 0;
-            break;
-        }
-        if ((a[o] < '0') || (a[o] > '9'))
-            goto err;
-        n = a[o] - '0';
-        /* incomplete 2-digital number */
-        if (++o == l)
-            goto err;
-
-        if ((a[o] < '0') || (a[o] > '9'))
-            goto err;
-        n = (n * 10) + a[o] - '0';
-        /* no more bytes to read, but we haven't seen time-zone yet */
-        if (++o == l)
-            goto err;
-
-        if ((n < min[i]) || (n > max[i]))
-            goto err;
-        if (tm) {
-            switch (i) {
-            case 0:
-                tm->tm_year = n < 50 ? n + 100 : n;
-                break;
-            case 1:
-                tm->tm_mon = n - 1;
-                break;
-            case 2:
-                tm->tm_mday = n;
-                break;
-            case 3:
-                tm->tm_hour = n;
-                break;
-            case 4:
-                tm->tm_min = n;
-                break;
-            case 5:
-                tm->tm_sec = n;
-                break;
-            }
-        }
-    }
-
-    /*
-     * 'o' will never point to '\0' at this point, the only chance
-     * 'o' can point th '\0' is either the subsequent if or the first
-     * else if is true.
-     */
-    if (a[o] == 'Z') {
-        o++;
-    } else if (!strict && ((a[o] == '+') || (a[o] == '-'))) {
-        int offsign = a[o] == '-' ? 1 : -1, offset = 0;
-        o++;
-        if (o + 4 != l)
-            goto err;
-        for (i = 6; i < 8; i++) {
-            if ((a[o] < '0') || (a[o] > '9'))
-                goto err;
-            n = a[o] - '0';
-            o++;
-            if ((a[o] < '0') || (a[o] > '9'))
-                goto err;
-            n = (n * 10) + a[o] - '0';
-            if ((n < min[i]) || (n > max[i]))
-                goto err;
-            if (tm) {
-                if (i == 6)
-                    offset = n * 3600;
-                else if (i == 7)
-                    offset += n * 60;
-            }
-            o++;
-        }
-        if (offset && !OPENSSL_gmtime_adj(tm, 0, offset * offsign))
-            return 0;
-    } else {
-        /* not Z, or not +/- in non-strict mode */
-        return 0;
-    }
-    return o == l;
- err:
-    return 0;
+    return asn1_time_to_tm(tm, d);
 }
 
 int ASN1_UTCTIME_check(const ASN1_UTCTIME *d)