Subject: Canonicalisation of embedded MIME objects

From: [email-masked]
Date: Fri, 23 Jun 2000 13:05:25 +0100

I have noticed that a number of files as produced by different mail programs do 
not seem to be performing canonicalisation of inner objects correctly.

The inner objects use LF for line termination not CRLF pairs. It is my 
understanding that breaks MIME rules for canonicalising embedded objects.

To illustrate the problem I enclose a signed-then-encrypted message I have 
received:(I have removed the routing information)

The outer message appears as follows(All lines are terminated with <CRLF> 
pairs.).
-----------------------------------------------------------
Content-Type: application/pkcs7-mime; smime-type=encrypted-data;                
              name="xxx.p7m"                                                    
Content-Disposition: attachment; filename=xxx.p7m                               
Content-Transfer-Encoding: base64                                               
Message-ID: 19991015:080159:REF12345                                            
                                                                                
MIIbrgYJKoZIhvcNAQcDoIIbnzCCG5sCAQAxggHEMIHfAgEAMEgwQDELMAkGA1UEBhMCVVMx        
ETAPBgNVBAoTCENpdGljb3JwMR4wHAYDVQQLExVFbnRydXN0IERldmVsb3BtZW50IDICBDUa
:
:        
VgIT6ci+93vJE1yRs4la/s3WjmovuOg/PSWUwXiw11EbAmBoB6CitHYFM/Q5sC4RdXrwyH2l        
1y59mZTTTtLwr7AbuOlojs/KrIe51CYQMeu14XN/K1tKZXpmB0qgcyDmXq69WYEo+aKglqhJ        
--------------------------------------------------------------------------------
----

The embedded message looks as follows(All lines are terminated with <LF>).

----------------------------------------------------------------------------
Content-Type: application/pkcs7-mime; smime-type=signed-data;
              name="xxx.p7m"
Content-Disposition: attachment; filename=xxx.p7m
Content-Transfer-Encoding: base64
Message-ID: 19990225:131734:20499

MIIggQYJKoZIhvcNAQcCoIIgcjCCIG4CAQExCzAJBgUrDgMCGgUAMIISiwYJKoZIhvcNAQcB
:
:
mXw0F0zhCL+ZZdic+fmLh1BQ+rIkVu45zKfJVSI1/F9oyZdaVFMkt0NZaGdjSlvuG6deAhgZ
XJ0KskSW4qT5
-----------------------------------------------------------------------------

The inner application file looks as follows: With Content lines terminated with 
<LF> and the data segment with no line ends.

----------------------------------------------------------------------------
Content-Type: application/EDIFACT;
              name="xxx.edi"
Content-Transfer-Encoding: binary

UNA:+.? 'UNB+UNOA:1+

-----------------------------------------------------------------------------

It is my interpretation that the use of <LF> to terminate the Content headers 
in the latter two messages above is not valid.

Can someone provide me with a definitive answer.

Thanks,
Bartley.