From 8ac58de1857637f372a00ea16ab5497193b784a6 Mon Sep 17 00:00:00 2001 From: Aaron Gable Date: Wed, 6 Jul 2022 16:59:03 -0700 Subject: [PATCH] crypto/x509: populate Number and AKI of parsed CRLs The x509.RevocationList type has two fields which correspond to extensions, rather than native fields, of the underlying ASN.1 CRL: the .Number field corresponds to the crlNumber extension, and the .AuthorityKeyId field corresponds to the authorityKeyIdentifier extension. The x509.CreateRevocationList() function uses these fields to populate their respective extensions in the resulting CRL. However, the x509.ParseRevocationList() function does not perform the reverse operation: the fields retain their zero-values even after parsing a CRL which contains the relevant extensions. Add code which populates these fields when parsing their extensions. Add assertions to the existing tests to confirm that the values are populated appropriately. Fixes #53726 Change-Id: Ie5b71081e53034e0b5b9ff3c122065c62f15cf23 Reviewed-on: https://go-review.googlesource.com/c/go/+/416354 Run-TryBot: Roland Shoemaker Auto-Submit: Roland Shoemaker Reviewed-by: Roland Shoemaker TryBot-Result: Gopher Robot Reviewed-by: Damien Neil --- src/crypto/x509/parser.go | 17 +++++++++++++---- src/crypto/x509/x509.go | 7 +++++-- src/crypto/x509/x509_test.go | 13 +++++++++++++ 3 files changed, 31 insertions(+), 6 deletions(-) diff --git a/src/crypto/x509/parser.go b/src/crypto/x509/parser.go index e0e8f6125f..cd87044d17 100644 --- a/src/crypto/x509/parser.go +++ b/src/crypto/x509/parser.go @@ -1008,22 +1008,22 @@ func ParseRevocationList(der []byte) (*RevocationList, error) { // we can populate RevocationList.Raw, before unwrapping the // SEQUENCE so it can be operated on if !input.ReadASN1Element(&input, cryptobyte_asn1.SEQUENCE) { - return nil, errors.New("x509: malformed certificate") + return nil, errors.New("x509: malformed crl") } rl.Raw = input if !input.ReadASN1(&input, cryptobyte_asn1.SEQUENCE) { - return nil, errors.New("x509: malformed certificate") + return nil, errors.New("x509: malformed crl") } var tbs cryptobyte.String // do the same trick again as above to extract the raw // bytes for Certificate.RawTBSCertificate if !input.ReadASN1Element(&tbs, cryptobyte_asn1.SEQUENCE) { - return nil, errors.New("x509: malformed tbs certificate") + return nil, errors.New("x509: malformed tbs crl") } rl.RawTBSRevocationList = tbs if !tbs.ReadASN1(&tbs, cryptobyte_asn1.SEQUENCE) { - return nil, errors.New("x509: malformed tbs certificate") + return nil, errors.New("x509: malformed tbs crl") } var version int @@ -1148,6 +1148,15 @@ func ParseRevocationList(der []byte) (*RevocationList, error) { if err != nil { return nil, err } + if ext.Id.Equal(oidExtensionAuthorityKeyId) { + rl.AuthorityKeyId = ext.Value + } else if ext.Id.Equal(oidExtensionCRLNumber) { + value := cryptobyte.String(ext.Value) + rl.Number = new(big.Int) + if !value.ReadASN1Integer(rl.Number) { + return nil, errors.New("x509: malformed crl number") + } + } rl.Extensions = append(rl.Extensions, ext) } } diff --git a/src/crypto/x509/x509.go b/src/crypto/x509/x509.go index 87eb1f7720..7dcebfa5f1 100644 --- a/src/crypto/x509/x509.go +++ b/src/crypto/x509/x509.go @@ -2109,7 +2109,9 @@ type RevocationList struct { // Issuer contains the DN of the issuing certificate. Issuer pkix.Name // AuthorityKeyId is used to identify the public key associated with the - // issuing certificate. + // issuing certificate. It is populated from the authorityKeyIdentifier + // extension when parsing a CRL. It is ignored when creating a CRL; the + // extension is populated from the issuing certificate itself. AuthorityKeyId []byte Signature []byte @@ -2125,7 +2127,8 @@ type RevocationList struct { // Number is used to populate the X.509 v2 cRLNumber extension in the CRL, // which should be a monotonically increasing sequence number for a given - // CRL scope and CRL issuer. + // CRL scope and CRL issuer. It is also populated from the cRLNumber + // extension when parsing a CRL. Number *big.Int // ThisUpdate is used to populate the thisUpdate field in the CRL, which diff --git a/src/crypto/x509/x509_test.go b/src/crypto/x509/x509_test.go index 8ef6115df4..594ee1dceb 100644 --- a/src/crypto/x509/x509_test.go +++ b/src/crypto/x509/x509_test.go @@ -2681,6 +2681,19 @@ func TestCreateRevocationList(t *testing.T) { t.Fatalf("Extensions mismatch: got %v; want %v.", parsedCRL.Extensions[2:], tc.template.ExtraExtensions) } + + if tc.template.Number != nil && parsedCRL.Number == nil { + t.Fatalf("Generated CRL missing Number: got nil, want %s", + tc.template.Number.String()) + } + if tc.template.Number != nil && tc.template.Number.Cmp(parsedCRL.Number) != 0 { + t.Fatalf("Generated CRL has wrong Number: got %s, want %s", + parsedCRL.Number.String(), tc.template.Number.String()) + } + if !bytes.Equal(parsedCRL.AuthorityKeyId, expectedAKI) { + t.Fatalf("Generated CRL has wrong Number: got %x, want %x", + parsedCRL.AuthorityKeyId, expectedAKI) + } }) } }