Refuse to accept certificate chains containing any RSA public key smaller

net/base/x509_certificate_win.cc

Index: net/base/x509_certificate_win.cc
===================================================================
--- net/base/x509_certificate_win.cc	(revision 113824)
+++ net/base/x509_certificate_win.cc	(working copy)
@@ -1177,4 +1177,39 @@
                            length);
 }
 
+// static
+void X509Certificate::GetPublicKeyInfo(OSCertHandle cert_handle,
+                                       size_t* size_bits,
+                                       PublicKeyType* type) {
+  PCCRYPT_OID_INFO oid_info = CryptFindOIDInfo(
+      CRYPT_OID_INFO_OID_KEY,
+      cert_handle->pCertInfo->SubjectPublicKeyInfo.Algorithm.pszObjId,
+      CRYPT_SIGN_ALG_OID_GROUP_ID);

[Ryan Sleevi, 2011/12/13 05:45:35]

CRYPT_PUBKEY_ALG_OID_GROUP_ID

+  CHECK(oid_info);
+  CHECK(oid_info->dwGroupId == CRYPT_SIGN_ALG_OID_GROUP_ID);

[Ryan Sleevi, 2011/12/13 05:45:35]

CHECK_EQ(oid_info->dwGroupId, CRYPT_PUBKEY_ALG_OID_GROUP_ID)

+  CHECK(oid_info->ExtraInfo.cbData >= sizeof(DWORD));

[Ryan Sleevi, 2011/12/13 05:45:35]

Delete this CHECK (ExtraInfo.cbData may be 0 if no flags)

+  DWORD id = *reinterpret_cast<DWORD*>(oid_info->ExtraInfo.pbData);

[Ryan Sleevi, 2011/12/13 05:45:35]

Delete this (updated below at line 1197)

+
+  *size_bits = CertGetPublicKeyLength(
+      X509_ASN_ENCODING | PKCS_7_ASN_ENCODING,
+      &cert_handle->pCertInfo->SubjectPublicKeyInfo);
+
+  switch (id) {

[Ryan Sleevi, 2011/12/13 05:45:35]

switch (id) -> switch (oid_info->AlgId) {

+    case CALG_RSA_SIGN:

[Ryan Sleevi, 2011/12/13 05:45:35]

add
case CALG_RSA_KEYX:

+      *type = kPublicKeyTypeRSA;
+      break;
+    case CALG_DSS_SIGN:
+      *type = kPublicKeyTypeDSA;
+      break;
+    case CALG_ECDSA:
+      *type = kPublicKeyTypeECDSA;
+      break;
+    case CALG_ECDH:
+      *type = kPublicKeyTypeECDH;
+      break;
+    default:
+      *type = kPublicKeyTypeUnknown;
+  }
+}
+
 }  // namespace net