[gnutls-devel] A certificate is verified by Gnutls but rejected by OpenSSL/PolarSSL

[陈雨亭]

The certificates are not the original ones. I have modified and 
resigned them (using the 1024 bit RSA keys).  

From: Peter Williams 
Sent: Thursday, April 02, 2015 10:15 AM
To: Yuting Chen ; Nikos Mavrogiannopoulos 
Cc: GnuTLS development list 
Subject: RE: [gnutls-devel] A certificate is verified by Gnutls but rejected by OpenSSL/PolarSSL

Why you trusting a 10 year old cert, with a 1024bit RSA key?

Because google say so?

Sent from my Windows Phone

--------------------------------------------------------------------------------
From: Yuting Chen
Sent: ‎4/‎2/‎2015 10:01 AM
To: Nikos Mavrogiannopoulos
Cc: GnuTLS development list
Subject: Re: [gnutls-devel] A certificate is verified by Gnutls but rejected by OpenSSL/PolarSSL


Hi, Nikos, I'm not very sure whether the certificate should or should not pass validation. It is a challenging problem to design tests for testing SSL tools. I used openssl to create 4000 valid or invalid test certificates (but I failed to design test oracles). It is interesting that the certificate is the only that can be accepted by Gnutls, but rejected by openssl and polarssl. The validation results are: 
(1) Gnutls:
Subject: C=GB,ST=Greater Manchester,L=Salford,O=Comodo CA Limited,CN=Secure Certificate Services
Issuer: C=US,ST=CA,O=Internet Widgits Pty Ltd,CN=Frankencert CA
Checked against: C=US,ST=CA,O=Internet Widgits Pty Ltd,CN=Frankencert CA
Output: Verified. The certificate is trusted. 

Subject: C=US,O=VeriSign\, Inc.,OU=Class 4 Public Primary Certification Authority - G2,OU=(c) 1998 VeriSign\, Inc. - For authorized use only,OU=VeriSign Trust Network
Issuer: C=GB,ST=Greater Manchester,L=Salford,O=Comodo CA Limited,CN=Secure Certificate Services
Checked against: C=GB,ST=Greater Manchester,L=Salford,O=Comodo CA Limited,CN=Secure Certificate Services
Output: Verified. The certificate is trusted. 

Chain verification output: Verified. The certificate is trusted. 

(2) Openssl:
140637590406816:error:04091077:rsa routines:INT_RSA_VERIFY:wrong signature length:rsa_sign.c:175:
140637590406816:error:0D0C5006:asn1 encoding routines:ASN1_item_verify:EVP lib:a_verify.c:221:
ZZZZZZZZZZZZZComodo_Secure_Services_root.pem: C = US, O = "VeriSign, Inc.", OU = Class 4 Public Primary Certification Authority - G2, OU = "(c) 1998 VeriSign, Inc. - For authorized use only", OU = VeriSign Trust Network
error 7 at 0 depth lookup:certificate signature failure

(3) PolarSSL:
  . Loading the CA root certificate ... ok (0 skipped)

  . Loading the certificate(s) ... ok
  . Peer certificate information    ...
      cert. version     : 1
      serial number     : 32:88:8E:9A:D2:F5:EB:13:47:F8:7F:C4:20:37:25:F8
      issuer name       : C=GB, ST=Greater Manchester, L=Salford, O=Comodo CA Limited, CN=Secure Certificate Services
      subject name      : C=US, O=VeriSign, Inc., OU=Class 4 Public Primary Certification Authority - G2, OU=(c) 1998 VeriSign, Inc. - For authorized use only, OU=VeriSign Trust Network
      issued  on        : 1998-05-18 00:00:00
      expires on        : 2028-08-01 23:59:59
      signed using      : RSA with SHA1
      RSA key size      : 1024 bits

  . Peer certificate information    ...
      cert. version     : 3
      serial number     : 01
      issuer name       : C=US, ST=CA, O=Internet Widgits Pty Ltd, CN=Frankencert CA
      subject name      : C=GB, ST=Greater Manchester, L=Salford, O=Comodo CA Limited, CN=Secure Certificate Services
      issued  on        : 2004-01-01 00:00:00
      expires on        : 2016-07-06 23:59:59
      signed using      : RSA with SHA1
      RSA key size      : 1024 bits
      basic constraints : CA=true
      key usage         : Digital Signature, Key Encipherment

  . Verifying X.509 certificate...
Verify requested for (Depth 0):
cert. version     : 1
serial number     : 32:88:8E:9A:D2:F5:EB:13:47:F8:7F:C4:20:37:25:F8
issuer name       : C=GB, ST=Greater Manchester, L=Salford, O=Comodo CA Limited, CN=Secure Certificate Services
subject name      : C=US, O=VeriSign, Inc., OU=Class 4 Public Primary Certification Authority - G2, OU=(c) 1998 VeriSign, Inc. - For authorized use only, OU=VeriSign Trust Network
issued  on        : 1998-05-18 00:00:00
expires on        : 2028-08-01 23:59:59
signed using      : RSA with SHA1
RSA key size      : 1024 bits
  ! self-signed or not signed by a trusted CA
failed

On Thu, Apr 2, 2015 at 12:21 AM, Nikos Mavrogiannopoulos <nmav at gnutls.org> wrote:

  On Wed, Apr 1, 2015 at 11:15 PM, Yuting Chen <chenyt at cs.sjtu.edu.cn> wrote:
  > I made a certificate and verified it using gnutls, openssl, and polarssl. It
  > can be verified by gnutls, but be rejected the other two due to certificate
  > signature failures. It is a special case because in many other cases in my
  > experiment, gnutls tends to "reject" certificates if openssl "rejects" them.
  > Can anyone help me find the reason (to ensure that gnutls has checked the
  > signature correctly)?

  Hello,
  What is the issue in the certificate? Why it shouldn't be verified
  successfully?

  regards,
  Nikos

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