fix ASN.1 date parsing w/ milliseconds (#923)

Signed-off-by: Brian DeHamer <[email protected]>

.changeset/friendly-toes-end.md

@@ -0,0 +1,5 @@
+---
+"@sigstore/core": patch
+---
+
+Bug fix for parsing ASN.1 date/time values which include milliseconds

packages/core/src/__tests__/asn1/parse.test.ts

@@ -56,7 +56,7 @@ describe('parseTime', () => {
 
     describe('when year is less than 50', () => {
       it('parses the date', () => {
-        expect(parseTime(Buffer.from('180212121110Z'), true)).toEqual(
+        expect(parseTime(Buffer.from('180212121110.099Z'), true)).toEqual(
           new Date('2018-02-12T12:11:10Z')
         );
       });
@@ -71,6 +71,14 @@ describe('parseTime', () => {
     });
   });
 
+  describe('with long year and milliseconds', () => {
+    it('parses the date', () => {
+      expect(parseTime(Buffer.from('19180212121110.099Z'), false)).toEqual(
+        new Date('1918-02-12T12:11:10Z')
+      );
+    });
+  });
+
   describe('when the time is invalid', () => {
     it('throws an error', () => {
       expect(() => parseTime(Buffer.from('FOOBAR'), true)).toThrow(

packages/core/src/asn1/parse.ts

@@ -13,8 +13,10 @@ WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 See the License for the specific language governing permissions and
 limitations under the License.
 */
-const RE_TIME_SHORT_YEAR = /^(\d{2})(\d{2})(\d{2})(\d{2})(\d{2})(\d{2})Z$/;
-const RE_TIME_LONG_YEAR = /^(\d{4})(\d{2})(\d{2})(\d{2})(\d{2})(\d{2})Z$/;
+const RE_TIME_SHORT_YEAR =
+  /^(\d{2})(\d{2})(\d{2})(\d{2})(\d{2})(\d{2})(\.\d{3})?Z$/;
+const RE_TIME_LONG_YEAR =
+  /^(\d{4})(\d{2})(\d{2})(\d{2})(\d{2})(\d{2})(\.\d{3})?Z$/;
 
 // Parse a BigInt from the DER-encoded buffer
 // https://learn.microsoft.com/en-us/windows/win32/seccertenroll/about-integer