crypto/x509: correctly parse CRL entry extensions

When checking to see if a CRL entry has any extensions, attempt to read
them from the individual revokedCertificate, rather than from the parent
TBSCertList.

Additionally, crlEntryExtensions is not an EXPLICIT field (c.f.
crlExtension and Certificate extensions), so do not perform an extra
layer of unwrapping when parsing the field.

The added test case fails without the accompanying changes.

Fixes #53592

Change-Id: Icc00e4c911f196aef77e3248117de64ddc5ea27f
Reviewed-on: https://go-review.googlesource.com/c/go/+/414877
Reviewed-by: Damien Neil <dneil@google.com>
Reviewed-by: Roland Shoemaker <roland@golang.org>
Run-TryBot: Roland Shoemaker <roland@golang.org>
Auto-Submit: Roland Shoemaker <roland@golang.org>
TryBot-Result: Gopher Robot <gobot@golang.org>

diff --git a/src/crypto/x509/parser.go b/src/crypto/x509/parser.go
index cd87044d17d4ff7af82730857d4a0bec69435341..a2d3d809642b221fbde361eabaa86166c5b72c8f 100644 (file)
--- a/src/crypto/x509/parser.go
+++ b/src/crypto/x509/parser.go
@@ -1106,13 +1106,10 @@ func ParseRevocationList(der []byte) (*RevocationList, error) {
                        }
                        var extensions cryptobyte.String
                        var present bool
-                       if !tbs.ReadOptionalASN1(&extensions, &present, cryptobyte_asn1.SEQUENCE) {
+                       if !certSeq.ReadOptionalASN1(&extensions, &present, cryptobyte_asn1.SEQUENCE) {
                                return nil, errors.New("x509: malformed extensions")
                        }
                        if present {
-                               if !extensions.ReadASN1(&extensions, cryptobyte_asn1.SEQUENCE) {
-                                       return nil, errors.New("x509: malformed extensions")
-                               }
                                for !extensions.Empty() {
                                        var extension cryptobyte.String
                                        if !extensions.ReadASN1(&extension, cryptobyte_asn1.SEQUENCE) {

diff --git a/src/crypto/x509/x509_test.go b/src/crypto/x509/x509_test.go
index 594ee1dceb0b7f1d6eba78c0d9efecb91b05056e..cddad1e246c299d182f7de052ab6a3629398b574 100644 (file)
--- a/src/crypto/x509/x509_test.go
+++ b/src/crypto/x509/x509_test.go
@@ -2524,6 +2524,34 @@ func TestCreateRevocationList(t *testing.T) {
                                NextUpdate: time.Time{}.Add(time.Hour * 48),
                        },
                },
+               {
+                       name: "valid, extra entry extension",
+                       key:  ec256Priv,
+                       issuer: &Certificate{
+                               KeyUsage: KeyUsageCRLSign,
+                               Subject: pkix.Name{
+                                       CommonName: "testing",
+                               },
+                               SubjectKeyId: []byte{1, 2, 3},
+                       },
+                       template: &RevocationList{
+                               RevokedCertificates: []pkix.RevokedCertificate{
+                                       {
+                                               SerialNumber:   big.NewInt(2),
+                                               RevocationTime: time.Time{}.Add(time.Hour),
+                                               Extensions: []pkix.Extension{
+                                                       {
+                                                               Id:    []int{2, 5, 29, 99},
+                                                               Value: []byte{5, 0},
+                                                       },
+                                               },
+                                       },
+                               },
+                               Number:     big.NewInt(5),
+                               ThisUpdate: time.Time{}.Add(time.Hour * 24),
+                               NextUpdate: time.Time{}.Add(time.Hour * 48),
+                       },
+               },
                {
                        name: "valid, Ed25519 key",
                        key:  ed25519Priv,