Check TBSCertificate.algorithm and Certificate.signatureAlgorithm for consistency when verifying ce…

net/cert/asn1_util.h

Index: net/cert/asn1_util.h
diff --git a/net/cert/asn1_util.h b/net/cert/asn1_util.h
index fb64bfbb58b38462872e5f7e911dc8b38d86bd07..725072a932898ef91fb7d618382f376890e80fb7 100644
--- a/net/cert/asn1_util.h
+++ b/net/cert/asn1_util.h
@@ -50,6 +50,23 @@ NET_EXPORT_PRIVATE bool ExtractCRLURLsFromDERCert(
 // present or if there was a parsing failure.
 NET_EXPORT_PRIVATE bool HasTLSFeatureExtension(base::StringPiece cert);
 
+// Extracts the two (SEQUENCE) tag-length-values for the signature
+// AlgorithmIdentifiers in a DER encoded certificate. Does not use strict
+// parsing or validate the resulting AlgorithmIdentifiers.
+//
+// On success returns true, and assigns |cert_signature_algorithm_sequence| and
+// |tbs_signature_algorithm_sequence| to point into |cert|:
+//
+// * |cert_signature_algorithm_sequence| points at the TLV for
+//   Certificate.signatureAlgorithm.
+//
+// * |tbs_signature_algorithm_sequence| points at the TLV for
+//   TBSCertificate.algorithm.
+NET_EXPORT_PRIVATE bool ExtractSignatureAlgorithmsFromDERCert(
+    base::StringPiece cert,
+    base::StringPiece* cert_signature_algorithm_sequence,
+    base::StringPiece* tbs_signature_algorithm_sequence);
+
 } // namespace asn1
 
 } // namespace net