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Use SHA-256 algorithm for Windows timestamping

    • Closed (moved) Issue created by Georg Koppen @gk

    We switched to using SHA-256 for the authenticode signature but we should use that hash algo for the timestamp as well (currently that's still SHA-1)

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    • Trac
      Trac @tracbot ·

      Trac:
      Parent Ticket: #33168 (moved)

    • Georg Koppen added GeorgKoppen202004 TorBrowserTeam202004R component::applications/tor browser owner::gk parent::33168 priority::medium resolution::fixed severity::normal status::closed tbb-9.5a12 tbb-security tbb-sign type::defect labels

      added GeorgKoppen202004 TorBrowserTeam202004R component::applications/tor browser owner::gk parent::33168 priority::medium resolution::fixed severity::normal status::closed tbb-9.5a12 tbb-security tbb-sign type::defect labels

    • Georg Koppen
      Georg Koppen @gk ·
      Author

      Should be not too hard to adapt our timestamping script, see: https://sourceforge.net/p/osslsigncode/support-requests/9/.

    • Georg Koppen
      Georg Koppen @gk ·
      Author

      Moving my tickets to March.

      Trac:
      Keywords: TorBrowserTeam201902 deleted, TorBrowserTeam201903 added

    • Georg Koppen
      Georg Koppen @gk ·
      Author

      Now for my keyword.

      Trac:
      Keywords: GeorgKoppen201902 deleted, GeorgKoppen201903 added

    • Georg Koppen
      Georg Koppen @gk ·
      Author

      Tickets on our radar for 8.5

      Trac:
      Keywords: N/A deleted, tbb-8.5 added

    • Georg Koppen
      Georg Koppen @gk ·
      Author

      Replying to gk:

      Should be not too hard to adapt our timestamping script, see: https://sourceforge.net/p/osslsigncode/support-requests/9/.

      Unfortunately, this did not work. I'll need to look again at the code and our patch do decouple the signing from the timestamping to figure out what goes wrong here.

    • Georg Koppen
      Georg Koppen @gk ·
      Author

      Not to self: we likely need to adapt my patch for osslsigncode so that the -h option is available for the add command as well.

    • Georg Koppen
      Georg Koppen @gk ·
      Author

      Moving tickets to April.

      Trac:
      Keywords: TorBrowserTeam201903 deleted, TorBrowserTeam201904 added

    • Georg Koppen
      Georg Koppen @gk ·
      Author

      Moving my tickets for April

      Trac:
      Keywords: GeorgKoppen201903 deleted, GeorgKoppen201904 added

    • Georg Koppen
      Georg Koppen @gk ·
      Author

      Moving tickets to May

      Trac:
      Keywords: TorBrowserTeam201904 deleted, TorBrowserTeam201905 added

    • Georg Koppen
      Georg Koppen @gk ·
      Author

      Move my tickets.

      Trac:
      Keywords: GeorgKoppen201904 deleted, GeorgKoppen201905 added

    • Georg Koppen
      Georg Koppen @gk ·
      Author

      Moving tickets to June

      Trac:
      Keywords: TorBrowserTeam201905 deleted, TorBrowserTeam201906 added

    • Georg Koppen
      Georg Koppen @gk ·
      Author

      Moving my tickets to June

      Trac:
      Keywords: GeorgKoppen201905 deleted, GeorgKoppen201906 added

    • Georg Koppen
      Georg Koppen @gk ·
      Author

      Moving my tickets to July.

      Trac:
      Keywords: GeorgKoppen201906 deleted, GeorgKoppen201907 added

    • Georg Koppen
      Georg Koppen @gk ·
      Author

      Moving tickets to July

      Trac:
      Keywords: TorBrowserTeam201906 deleted, TorBrowserTeam201907 added

    • C
      cypherpunks @cypherpunks ·

      https://sourceforge.net/p/osslsigncode/patches/10/#98d2/d522

    • Georg Koppen
      Georg Koppen @gk ·
      Author

      Gonna do this while dealing with the new authenticode cert.

      Trac:
      Keywords: GeorgKoppen201907 deleted, GeorgKoppen202004, tbb-sign added
      Cc: N/A to tbb-team
      Parent: N/A to #33168 (moved)
      Owner: tbb-team to gk
      Status: new to assigned

    • Georg Koppen
      Georg Koppen @gk ·
      Author

      Replying to gk:

      Not to self: we likely need to adapt my patch for osslsigncode so that the -h option is available for the add command as well.

      Yes, that is needed (among other things). It took me longer to figure this issue out because I got confused. While osslsigncode verify shows the certs in the SHA-1 Authenticode scenario it does not show them when switching to RFC 3161 mode with SHA-256 which sent me digging into wrong direction. Not sure if that's an osslsigncode bug or not.

      Either way, one can extract the signature with osslsigncode extract-signature and then inspect the nitty-gritty details with openssl pkcs7 and the SHA-256 timestamp is visible. I uploaded a test file for further inspection if needed:

      https://people.torproject.org/~gk/testbuilds/29614_test_sha2.exe https://people.torproject.org/~gk/testbuilds/29614_test_sha2.exe.asc

      bug_29614 (https://gitweb.torproject.org/user/gk/tor-browser-spec.git/commit/?h=bug_29614&id=26d833f346d9d7bf795fe1cec819555595d739f1) in my public tor-browser-spec repo contains the updated documentation/patch.

      Trac:
      Keywords: TorBrowserTeam201907 deleted, TorBrowserTeam202004R added
      Status: assigned to needs_review

    • C
      cypherpunks @cypherpunks ·

      Works on Windows 7 and later. Note: besides changing SHA-1 to SHA-256, you also change Authenticode timestamping to RFC 3161 timestamping (see https://sectigo.com/resources/time-stamping-server).

    • Georg Koppen
      Georg Koppen @gk ·
      Author

      Trac:
      Summary: Use SHA-256 algorithm for Windows authenticode timestamping to Use SHA-256 algorithm for Windows timestamping

    • S
      Matthew Finkel @sysrqb ·

      Okay, we're making progress on this. After misreading comment:17, gk walked me through the details of this process.

      For comparison, when using Authenticode Timestamping (with SHA-1), osslsigncode verify output something like:

      $ osslsigncode verify torbrowser-install-win64-9.5a12_cs.exe

      Signature verification: ok

Number of signers: 1
	Signer #0:
		Subject: /businessCategory=Private Organization/jurisdictionC=US/jurisdictionST=Washington/serialNumber=39070/street=#203/street=80 S Washington St/postalCode=98104/C=US/ST=Washington/L=Seattle/O=The Tor Project, Inc./CN=The Tor Project, Inc.
		Issuer : /C=US/O=DigiCert Inc/OU=www.digicert.com/CN=DigiCert EV Code Signing CA (SHA2)
		Serial : 0F622EF31D0F1EF94E520DBD7A43E58C

Number of certificates: 4
	Cert #0:
		Subject: /C=US/O=DigiCert Inc/OU=www.digicert.com/CN=DigiCert EV Code Signing CA (SHA2)
		Issuer : /C=US/O=DigiCert Inc/OU=www.digicert.com/CN=DigiCert High Assurance EV Root CA
		Serial : 03F1B4E15F3A82F1149678B3D7D8475C
	------------------
	Cert #1:
		Subject: /businessCategory=Private Organization/jurisdictionC=US/jurisdictionST=Washington/serialNumber=39070/street=#203/street=80 S Washington St/postalCode=98104/C=US/ST=Washington/L=Seattle/O=The Tor Project, Inc./CN=The Tor Project, Inc.
		Issuer : /C=US/O=DigiCert Inc/OU=www.digicert.com/CN=DigiCert EV Code Signing CA (SHA2)
		Serial : 0F622EF31D0F1EF94E520DBD7A43E58C
	------------------
	Cert #2:
		Subject: /C=US/O=DigiCert Inc/OU=www.digicert.com/CN=DigiCert Assured ID CA-1
		Issuer : /C=US/O=DigiCert Inc/OU=www.digicert.com/CN=DigiCert Assured ID Root CA
		Serial : 06FDF9039603ADEA000AEB3F27BBBA1B
	------------------
	Cert #3:
		Subject: /C=US/O=DigiCert/CN=DigiCert Timestamp Responder
		Issuer : /C=US/O=DigiCert Inc/OU=www.digicert.com/CN=DigiCert Assured ID CA-1
		Serial : 03019A023AFF58B16BD6D5EAE617F066

      Now, with RFC 3161 Timestamping (using any hashing algorithm, but in this case using SHA-256), osslsigncode verify only prints the code signing certificates (as gk described). This makes sense, because the RFC 2161 timestamp is appended onto the pkcs7 structure embedded in the PE file, and timestamping does not result in a new and independent cert chain.

      Signature verification: ok

Number of signers: 1
	Signer #0:
		Subject: /businessCategory=Private Organization/jurisdictionC=US/jurisdictionST=Washington/serialNumber=39070/street=#203/street=80 S Washington St/postalCode=98104/C=US/ST=Washington/L=Seattle/O=The Tor Project, Inc./CN=The Tor Project, Inc.
		Issuer : /C=US/O=DigiCert Inc/OU=www.digicert.com/CN=DigiCert EV Code Signing CA (SHA2)
		Serial : 0F622EF31D0F1EF94E520DBD7A43E58C

Number of certificates: 2
	Cert #0:
		Subject: /C=US/O=DigiCert Inc/OU=www.digicert.com/CN=DigiCert EV Code Signing CA (SHA2)
		Issuer : /C=US/O=DigiCert Inc/OU=www.digicert.com/CN=DigiCert High Assurance EV Root CA
		Serial : 03F1B4E15F3A82F1149678B3D7D8475C
	------------------
	Cert #1:
		Subject: /businessCategory=Private Organization/jurisdictionC=US/jurisdictionST=Washington/serialNumber=39070/street=#203/street=80 S Washington St/postalCode=98104/C=US/ST=Washington/L=Seattle/O=The Tor Project, Inc./CN=The Tor Project, Inc.
		Issuer : /C=US/O=DigiCert Inc/OU=www.digicert.com/CN=DigiCert EV Code Signing CA (SHA2)
		Serial : 0F622EF31D0F1EF94E520DBD7A43E58C

Succeeded

      Using openssl pkcs7, as gk described, we can see the asn.1 object appended within the unauthenticated portion. First, we must extract the signatures from the file, then we can parse the resulting pkcs7 object:

      $ osslsigncode extract-signature -pem -in torbrowser-install-win64-9.5a12_cs.exe -out torbrowser-install-win64-9.5a12_cs.exe.sigs
$ openssl pkcs7 -print -in torbrowser-install-win64-9.5a12_cs.exe.sigs
              unauth_attr:
            object: undefined (1.3.6.1.4.1.311.3.3.1)
            set:
              SEQUENCE:
    0:d=0  hl=4 l=3761 cons: SEQUENCE          
    4:d=1  hl=2 l=   9 prim:  OBJECT            :pkcs7-signedData
   15:d=1  hl=4 l=3746 cons:  cont [ 0 ]        
   19:d=2  hl=4 l=3742 cons:   SEQUENCE          
   23:d=3  hl=2 l=   1 prim:    INTEGER           :03
   26:d=3  hl=2 l=  15 cons:    SET               
   28:d=4  hl=2 l=  13 cons:     SEQUENCE          
   30:d=5  hl=2 l=   9 prim:      OBJECT            :sha256
   41:d=5  hl=2 l=   0 prim:      NULL              
   43:d=3  hl=2 l= 120 cons:    SEQUENCE          
   45:d=4  hl=2 l=  11 prim:     OBJECT            :id-smime-ct-TSTInfo
[snip]
  282:d=8  hl=2 l=  47 cons:         SEQUENCE          
  284:d=9  hl=2 l=   3 prim:          OBJECT            :commonName
  289:d=9  hl=2 l=  40 prim:          PRINTABLESTRING   :DigiCert SHA2 Assured ID Timestamping CA
  331:d=6  hl=2 l=  30 cons:       SEQUENCE          
  333:d=7  hl=2 l=  13 prim:        UTCTIME           :191001000000Z
  348:d=7  hl=2 l=  13 prim:        UTCTIME           :301017000000Z
  363:d=6  hl=2 l=  76 cons:       SEQUENCE          
  365:d=7  hl=2 l=  11 cons:        SET               
  367:d=8  hl=2 l=   9 cons:         SEQUENCE          
  369:d=9  hl=2 l=   3 prim:          OBJECT            :countryName
  374:d=9  hl=2 l=   2 prim:          PRINTABLESTRING   :US
  378:d=7  hl=2 l=  23 cons:        SET               
  380:d=8  hl=2 l=  21 cons:         SEQUENCE          
  382:d=9  hl=2 l=   3 prim:          OBJECT            :organizationName
  387:d=9  hl=2 l=  14 prim:          PRINTABLESTRING   :DigiCert, Inc.
  403:d=7  hl=2 l=  36 cons:        SET               
  405:d=8  hl=2 l=  34 cons:         SEQUENCE          
  407:d=9  hl=2 l=   3 prim:          OBJECT            :commonName
  412:d=9  hl=2 l=  27 prim:          PRINTABLESTRING   :TIMESTAMP-SHA256-2019-10-15
[snip]
    • S
      Matthew Finkel @sysrqb ·

      Okay, all of the installers for Windows were timestamped using SHA-256 in 9.5a12.

      I merged the spec patch with commit f07e8109ef72e895fd87b83413743828cfa180cc.

      I think we're done here. Thanks for figuring this out, gk!

      Trac:
      Resolution: N/A to fixed
      Status: needs_review to closed
      Keywords: tbb-8.5 deleted, tbb-9.5a12 added

    • Trac closed

      closed

    • Trac mentioned in issue #33168 (moved)

      mentioned in issue #33168 (moved)

    • Trac moved to tpo/applications/tor-browser#29614 (closed)

      moved to tpo/applications/tor-browser#29614 (closed)

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