From 6cdf7ef033bf9c0108842f01506a7d565c18e4e0 Mon Sep 17 00:00:00 2001
From: Brian DeHamer <bdehamer@github.com>
Date: Thu, 4 Jan 2024 09:51:00 -0800
Subject: [PATCH] fix ASN.1 date parsing w/ milliseconds (#923)

Signed-off-by: Brian DeHamer <bdehamer@github.com>
---
 .changeset/friendly-toes-end.md                |  5 +++++
 packages/core/src/__tests__/asn1/parse.test.ts | 10 +++++++++-
 packages/core/src/asn1/parse.ts                |  6 ++++--
 3 files changed, 18 insertions(+), 3 deletions(-)
 create mode 100644 .changeset/friendly-toes-end.md

diff --git a/.changeset/friendly-toes-end.md b/.changeset/friendly-toes-end.md
new file mode 100644
index 00000000..1ef4a0ff
--- /dev/null
+++ b/.changeset/friendly-toes-end.md
@@ -0,0 +1,5 @@
+---
+"@sigstore/core": patch
+---
+
+Bug fix for parsing ASN.1 date/time values which include milliseconds
diff --git a/packages/core/src/__tests__/asn1/parse.test.ts b/packages/core/src/__tests__/asn1/parse.test.ts
index 65f70a34..f4ccc8db 100644
--- a/packages/core/src/__tests__/asn1/parse.test.ts
+++ b/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(
diff --git a/packages/core/src/asn1/parse.ts b/packages/core/src/asn1/parse.ts
index 54d41e52..1a51c7c5 100644
--- a/packages/core/src/asn1/parse.ts
+++ b/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