Fix issuerUID and subjectUID parsing in the key usage checker.

We have a few too many X.509 parsers.

Bug: chromium:1199744
Change-Id: Ib6f6b7bf6059ed542c334a5ca5a2d3928aae3bef
Reviewed-on: https://boringssl-review.googlesource.com/c/boringssl/+/46904
Commit-Queue: David Benjamin <davidben@google.com>
Commit-Queue: Adam Langley <agl@google.com>
Reviewed-by: Adam Langley <agl@google.com>

ssl/ssl_cert.cc

diff --git a/ssl/ssl_cert.cc b/ssl/ssl_cert.cc
index c64303a..68e010a 100644
--- a/ssl/ssl_cert.cc
+++ b/ssl/ssl_cert.cc
@@ -548,13 +548,11 @@
       // subjectPublicKeyInfo
       !CBS_get_asn1(&tbs_cert, NULL, CBS_ASN1_SEQUENCE) ||
       // issuerUniqueID
-      !CBS_get_optional_asn1(
-          &tbs_cert, NULL, NULL,
-          CBS_ASN1_CONSTRUCTED | CBS_ASN1_CONTEXT_SPECIFIC | 1) ||
+      !CBS_get_optional_asn1(&tbs_cert, NULL, NULL,
+                             CBS_ASN1_CONTEXT_SPECIFIC | 1) ||
       // subjectUniqueID
-      !CBS_get_optional_asn1(
-          &tbs_cert, NULL, NULL,
-          CBS_ASN1_CONSTRUCTED | CBS_ASN1_CONTEXT_SPECIFIC | 2) ||
+      !CBS_get_optional_asn1(&tbs_cert, NULL, NULL,
+                             CBS_ASN1_CONTEXT_SPECIFIC | 2) ||
       !CBS_get_optional_asn1(
           &tbs_cert, &outer_extensions, &has_extensions,
           CBS_ASN1_CONSTRUCTED | CBS_ASN1_CONTEXT_SPECIFIC | 3)) {