X509 Subject Formatting

Problem this snippet solves:

TMOS v12.1.4.1 and v13 have a change where the output of X509::subject is formatted to match OpenSSL output. See https://cdn.f5.com/product/bugtracker/ID607410.html


<= TMOS v12 is CN=USERNAME,OU=CONTRACTOR,OU=PKI,OU=DEPT,O=COMPANY,C=US

>= TMOS v13 is C=US,O=COMPANY,OU=DEPT,OU=PKI,OU=CONTRACTOR,CN=USERNAME

How to use this snippet:

This procedure will change the output format to either v12 or v13 ( or you can easily modify it to create your own output ). Default output is v12.


Use v13 output:

set serialNumber [ call formatSubject [ X509::subject [SSL::cert 0] ] 13 ]


Use v12 output:

set serialNumber [ call formatSubject [ X509::subject [SSL::cert 0] ] ]


Code :

proc formatSubject { subject { f 12 }} {
    # subject is the subject string eg CN=USERNAME,OU=CONTRACTOR,OU=PKI,OU=DEPT,O=COMPANY,C=US
    # f is format version and is either 12 or 13. Default 12
    # This procedure formats the subject field according to TMOS v12 or v13 format
    # v12 is CN=USERNAME,OU=CONTRACTOR,OU=PKI,OU=DEPT,O=COMPANY,C=US
    # v13 is C=US,O=COMPANY,OU=DEPT,OU=PKI,OU=CONTRACTOR,CN=USERNAME
    # See https://cdn.f5.com/product/bugtracker/ID607410.html
    # dn is an array with format [ CN O { OU } CN ]

    array set dn {
        OU {}
    } 
    set subject [regsub -all {(".*?),(.*?")} $subject "\\1--COMMA--\\2"]
    
    foreach i [ split $subject , ] {
        set j [ split [ string trim $i] = ]
        if { [lindex $j 0] == "OU" } {
            lappend dn(OU) [lindex $j 1]
        } else {
            array set dn [ list [lindex $j 0] [lindex $j 1] ]
        }
    }
    # Loop through OUs and create a string
    set ouString ""
    foreach ou $dn(OU) {
        append ouString "OU=$ou, "
    }
																		
    if { $f == 12 } {
        set order { CN OU O C }
    } else {
        set order { C O OU CN }
    }
							  
    set returnString ""
    foreach a $order {
        if { [info exists dn($a)] } {
            if { $a == "OU" } { 
                append returnString $ouString 
            } else {
                append returnString "$a=$dn($a), "
            }
        }
    }
    set returnString [string map {"--COMMA--" ","} $returnString]
    return [ string trimright $returnString ", " ]
}

Tested this on version:

13.0
Published Oct 18, 2019
Version 1.0
  •  to prevent this issue, you can replace lines 13 to 20 with:

    array set dn [list]
    foreach {key val} [ split [string map {"\\," "\\," "," "|" "\\=" "\\=" "=" "|"} $subject] "|"] {
        lappend dn([string trim $key]) [string trim $val]
    }
  • uniqng this splits the DN on the comma so if there is an unexpected comma then it will break. If you have complex, specific requirements then I suggest you decode the field using the ASN1 commands

  • How is this proc going to behave in case the ','character is part of the CN or any other sub-string?