CSE2410 Fall 2014 Bounce

=pod

=head1 NAME

ca - sample minimal CA application

=head1 SYNOPSIS

B<openssl> B<ca>

[B<-verbose>]

[B<-config filename>]

[B<-name section>]

[B<-gencrl>]

[B<-revoke file>]

[B<-status serial>]

[B<-updatedb>]

[B<-crl_reason reason>]

[B<-crl_hold instruction>]

[B<-crl_compromise time>]

[B<-crl_CA_compromise time>]

[B<-crldays days>]

[B<-crlhours hours>]

[B<-crlexts section>]

[B<-startdate date>]

[B<-enddate date>]

[B<-days arg>]

[B<-md arg>]

[B<-policy arg>]

[B<-keyfile arg>]

[B<-keyform PEM|DER>]

[B<-key arg>]

[B<-passin arg>]

[B<-cert file>]

[B<-selfsign>]

[B<-in file>]

[B<-out file>]

[B<-notext>]

[B<-outdir dir>]

[B<-infiles>]

[B<-spkac file>]

[B<-ss_cert file>]

[B<-preserveDN>]

[B<-noemailDN>]

[B<-batch>]

[B<-msie_hack>]

[B<-extensions section>]

[B<-extfile section>]

[B<-engine id>]

[B<-subj arg>]

[B<-utf8>]

[B<-multivalue-rdn>]

=head1 DESCRIPTION

The B<ca> command is a minimal CA application. It can be used

to sign certificate requests in a variety of forms and generate

CRLs it also maintains a text database of issued certificates

and their status.

The options descriptions will be divided into each purpose.

=head1 CA OPTIONS

=over 4

=item B<-config filename>

specifies the configuration file to use.

=item B<-name section>

specifies the configuration file section to use (overrides

B<default_ca> in the B<ca> section).

=item B<-in filename>

an input filename containing a single certificate request to be

signed by the CA.

=item B<-ss_cert filename>

a single self signed certificate to be signed by the CA.

=item B<-spkac filename>

a file containing a single Netscape signed public key and challenge

and additional field values to be signed by the CA. See the B<SPKAC FORMAT>

section for information on the required input and output format.

=item B<-infiles>

if present this should be the last option, all subsequent arguments

are assumed to the the names of files containing certificate requests. 

=item B<-out filename>

the output file to output certificates to. The default is standard

output. The certificate details will also be printed out to this

file in PEM format (except that B<-spkac> outputs DER format).

=item B<-outdir directory>

the directory to output certificates to. The certificate will be

written to a filename consisting of the serial number in hex with

".pem" appended.

=item B<-cert>

the CA certificate file.

=item B<-keyfile filename>

the private key to sign requests with.

=item B<-keyform PEM|DER>

the format of the data in the private key file.

The default is PEM.

=item B<-key password>

the password used to encrypt the private key. Since on some

systems the command line arguments are visible (e.g. Unix with

the 'ps' utility) this option should be used with caution.

=item B<-selfsign>

indicates the issued certificates are to be signed with the key

the certificate requests were signed with (given with B<-keyfile>).

Cerificate requests signed with a different key are ignored.  If

B<-spkac>, B<-ss_cert> or B<-gencrl> are given, B<-selfsign> is

ignored.

A consequence of using B<-selfsign> is that the self-signed

certificate appears among the entries in the certificate database

(see the configuration option B<database>), and uses the same

serial number counter as all other certificates sign with the

self-signed certificate.

=item B<-passin arg>

the key password source. For more information about the format of B<arg>

see the B<PASS PHRASE ARGUMENTS> section in L<openssl(1)|openssl(1)>.

=item B<-verbose>

this prints extra details about the operations being performed.

=item B<-notext>

don't output the text form of a certificate to the output file.

=item B<-startdate date>

this allows the start date to be explicitly set. The format of the

date is YYMMDDHHMMSSZ (the same as an ASN1 UTCTime structure).

=item B<-enddate date>

this allows the expiry date to be explicitly set. The format of the

date is YYMMDDHHMMSSZ (the same as an ASN1 UTCTime structure).

=item B<-days arg>

the number of days to certify the certificate for.

=item B<-md alg>

the message digest to use. Possible values include md5, sha1 and mdc2.

This option also applies to CRLs.

=item B<-policy arg>

this option defines the CA "policy" to use. This is a section in

the configuration file which decides which fields should be mandatory

or match the CA certificate. Check out the B<POLICY FORMAT> section

for more information.

=item B<-msie_hack>

this is a legacy option to make B<ca> work with very old versions of

the IE certificate enrollment control "certenr3". It used UniversalStrings

for almost everything. Since the old control has various security bugs

its use is strongly discouraged. The newer control "Xenroll" does not

need this option.

=item B<-preserveDN>

Normally the DN order of a certificate is the same as the order of the

fields in the relevant policy section. When this option is set the order 

is the same as the request. This is largely for compatibility with the

older IE enrollment control which would only accept certificates if their

DNs match the order of the request. This is not needed for Xenroll.

=item B<-noemailDN>

The DN of a certificate can contain the EMAIL field if present in the

request DN, however it is good policy just having the e-mail set into

the altName extension of the certificate. When this option is set the

EMAIL field is removed from the certificate' subject and set only in

the, eventually present, extensions. The B<email_in_dn> keyword can be

used in the configuration file to enable this behaviour.

=item B<-batch>

this sets the batch mode. In this mode no questions will be asked

and all certificates will be certified automatically.

=item B<-extensions section>

the section of the configuration file containing certificate extensions

to be added when a certificate is issued (defaults to B<x509_extensions>

unless the B<-extfile> option is used). If no extension section is

present then, a V1 certificate is created. If the extension section

is present (even if it is empty), then a V3 certificate is created. See the:w

L<x509v3_config(5)|x509v3_config(5)> manual page for details of the

extension section format.

=item B<-extfile file>

an additional configuration file to read certificate extensions from

(using the default section unless the B<-extensions> option is also

used).

=item B<-engine id>

specifying an engine (by its unique B<id> string) will cause B<ca>

to attempt to obtain a functional reference to the specified engine,

thus initialising it if needed. The engine will then be set as the default

for all available algorithms.

=item B<-subj arg>

supersedes subject name given in the request.

The arg must be formatted as I</type0=value0/type1=value1/type2=...>,

characters may be escaped by \ (backslash), no spaces are skipped.

=item B<-utf8>

this option causes field values to be interpreted as UTF8 strings, by 

default they are interpreted as ASCII. This means that the field

values, whether prompted from a terminal or obtained from a

configuration file, must be valid UTF8 strings.

=item B<-multivalue-rdn>

this option causes the -subj argument to be interpretedt with full

support for multivalued RDNs. Example:

I</DC=org/DC=OpenSSL/DC=users/UID=123456+CN=John Doe>

If -multi-rdn is not used then the UID value is I<123456+CN=John Doe>.

=back

=head1 CRL OPTIONS

=over 4

=item B<-gencrl>

this option generates a CRL based on information in the index file.

=item B<-crldays num>

the number of days before the next CRL is due. That is the days from

now to place in the CRL nextUpdate field.

=item B<-crlhours num>

the number of hours before the next CRL is due.

=item B<-revoke filename>

a filename containing a certificate to revoke.

=item B<-status serial>

displays the revocation status of the certificate with the specified

serial number and exits.

=item B<-updatedb>

Updates the database index to purge expired certificates.

=item B<-crl_reason reason>

revocation reason, where B<reason> is one of: B<unspecified>, B<keyCompromise>,

B<CACompromise>, B<affiliationChanged>, B<superseded>, B<cessationOfOperation>,

B<certificateHold> or B<removeFromCRL>. The matching of B<reason> is case

insensitive. Setting any revocation reason will make the CRL v2.

In practive B<removeFromCRL> is not particularly useful because it is only used

in delta CRLs which are not currently implemented.

=item B<-crl_hold instruction>

This sets the CRL revocation reason code to B<certificateHold> and the hold

instruction to B<instruction> which must be an OID. Although any OID can be

used only B<holdInstructionNone> (the use of which is discouraged by RFC2459)

B<holdInstructionCallIssuer> or B<holdInstructionReject> will normally be used.

=item B<-crl_compromise time>

This sets the revocation reason to B<keyCompromise> and the compromise time to

B<time>. B<time> should be in GeneralizedTime format that is B<YYYYMMDDHHMMSSZ>.

=item B<-crl_CA_compromise time>

This is the same as B<crl_compromise> except the revocation reason is set to

B<CACompromise>.

=item B<-crlexts section>

the section of the configuration file containing CRL extensions to

include. If no CRL extension section is present then a V1 CRL is

created, if the CRL extension section is present (even if it is

empty) then a V2 CRL is created. The CRL extensions specified are

CRL extensions and B<not> CRL entry extensions.  It should be noted

that some software (for example Netscape) can't handle V2 CRLs. See

L<x509v3_config(5)|x509v3_config(5)> manual page for details of the

extension section format.

=back

=head1 CONFIGURATION FILE OPTIONS

The section of the configuration file containing options for B<ca>

is found as follows: If the B<-name> command line option is used,

then it names the section to be used. Otherwise the section to

be used must be named in the B<default_ca> option of the B<ca> section

of the configuration file (or in the default section of the

configuration file). Besides B<default_ca>, the following options are

read directly from the B<ca> section:

 RANDFILE

 preserve

 msie_hack

With the exception of B<RANDFILE>, this is probably a bug and may

change in future releases.

Many of the configuration file options are identical to command line

options. Where the option is present in the configuration file

and the command line the command line value is used. Where an

option is described as mandatory then it must be present in

the configuration file or the command line equivalent (if

any) used.

=over 4

=item B<oid_file>

This specifies a file containing additional B<OBJECT IDENTIFIERS>.

Each line of the file should consist of the numerical form of the

object identifier followed by white space then the short name followed

by white space and finally the long name. 

=item B<oid_section>

This specifies a section in the configuration file containing extra

object identifiers. Each line should consist of the short name of the

object identifier followed by B<=> and the numerical form. The short

and long names are the same when this option is used.

=item B<new_certs_dir>

the same as the B<-outdir> command line option. It specifies

the directory where new certificates will be placed. Mandatory.

=item B<certificate>

the same as B<-cert>. It gives the file containing the CA

certificate. Mandatory.

=item B<private_key>

same as the B<-keyfile> option. The file containing the

CA private key. Mandatory.

=item B<RANDFILE>

a file used to read and write random number seed information, or

an EGD socket (see L<RAND_egd(3)|RAND_egd(3)>).

=item B<default_days>

the same as the B<-days> option. The number of days to certify

a certificate for. 

=item B<default_startdate>

the same as the B<-startdate> option. The start date to certify

a certificate for. If not set the current time is used.

=item B<default_enddate>

the same as the B<-enddate> option. Either this option or

B<default_days> (or the command line equivalents) must be

present.

=item B<default_crl_hours default_crl_days>

the same as the B<-crlhours> and the B<-crldays> options. These

will only be used if neither command line option is present. At

least one of these must be present to generate a CRL.

=item B<default_md>

the same as the B<-md> option. The message digest to use. Mandatory.

=item B<database>

the text database file to use. Mandatory. This file must be present

though initially it will be empty.

=item B<unique_subject>

if the value B<yes> is given, the valid certificate entries in the

database must have unique subjects.  if the value B<no> is given,

several valid certificate entries may have the exact same subject.

The default value is B<yes>, to be compatible with older (pre 0.9.8)

versions of OpenSSL.  However, to make CA certificate roll-over easier,

it's recommended to use the value B<no>, especially if combined with

the B<-selfsign> command line option.

=item B<serial>

a text file containing the next serial number to use in hex. Mandatory.

This file must be present and contain a valid serial number.

=item B<crlnumber>

a text file containing the next CRL number to use in hex. The crl number

will be inserted in the CRLs only if this file exists. If this file is

present, it must contain a valid CRL number.

=item B<x509_extensions>

the same as B<-extensions>.

=item B<crl_extensions>

the same as B<-crlexts>.

=item B<preserve>

the same as B<-preserveDN>

=item B<email_in_dn>

the same as B<-noemailDN>. If you want the EMAIL field to be removed

from the DN of the certificate simply set this to 'no'. If not present

the default is to allow for the EMAIL filed in the certificate's DN.

=item B<msie_hack>

the same as B<-msie_hack>

=item B<policy>

the same as B<-policy>. Mandatory. See the B<POLICY FORMAT> section

for more information.

=item B<name_opt>, B<cert_opt>

these options allow the format used to display the certificate details

when asking the user to confirm signing. All the options supported by

the B<x509> utilities B<-nameopt> and B<-certopt> switches can be used

here, except the B<no_signame> and B<no_sigdump> are permanently set

and cannot be disabled (this is because the certificate signature cannot

be displayed because the certificate has not been signed at this point).

For convenience the values B<ca_default> are accepted by both to produce

a reasonable output.

If neither option is present the format used in earlier versions of

OpenSSL is used. Use of the old format is B<strongly> discouraged because

it only displays fields mentioned in the B<policy> section, mishandles

multicharacter string types and does not display extensions.

=item B<copy_extensions>

determines how extensions in certificate requests should be handled.

If set to B<none> or this option is not present then extensions are

ignored and not copied to the certificate. If set to B<copy> then any

extensions present in the request that are not already present are copied

to the certificate. If set to B<copyall> then all extensions in the

request are copied to the certificate: if the extension is already present

in the certificate it is deleted first. See the B<WARNINGS> section before

using this option.

The main use of this option is to allow a certificate request to supply

values for certain extensions such as subjectAltName.

=back

=head1 POLICY FORMAT

The policy section consists of a set of variables corresponding to

certificate DN fields. If the value is "match" then the field value

must match the same field in the CA certificate. If the value is

"supplied" then it must be present. If the value is "optional" then

it may be present. Any fields not mentioned in the policy section

are silently deleted, unless the B<-preserveDN> option is set but

this can be regarded more of a quirk than intended behaviour.

=head1 SPKAC FORMAT

The input to the B<-spkac> command line option is a Netscape

signed public key and challenge. This will usually come from

the B<KEYGEN> tag in an HTML form to create a new private key. 

It is however possible to create SPKACs using the B<spkac> utility.

The file should contain the variable SPKAC set to the value of

the SPKAC and also the required DN components as name value pairs.

If you need to include the same component twice then it can be

preceded by a number and a '.'.

When processing SPKAC format, the output is DER if the B<-out>

flag is used, but PEM format if sending to stdout or the B<-outdir>

flag is used.

=head1 EXAMPLES

Note: these examples assume that the B<ca> directory structure is

already set up and the relevant files already exist. This usually

involves creating a CA certificate and private key with B<req>, a

serial number file and an empty index file and placing them in

the relevant directories.

To use the sample configuration file below the directories demoCA,

demoCA/private and demoCA/newcerts would be created. The CA

certificate would be copied to demoCA/cacert.pem and its private

key to demoCA/private/cakey.pem. A file demoCA/serial would be

created containing for example "01" and the empty index file

demoCA/index.txt.

Sign a certificate request:

 openssl ca -in req.pem -out newcert.pem

Sign a certificate request, using CA extensions:

 openssl ca -in req.pem -extensions v3_ca -out newcert.pem

Generate a CRL

 openssl ca -gencrl -out crl.pem

Sign several requests:

 openssl ca -infiles req1.pem req2.pem req3.pem

Certify a Netscape SPKAC:

 openssl ca -spkac spkac.txt

A sample SPKAC file (the SPKAC line has been truncated for clarity):

 SPKAC=MIG0MGAwXDANBgkqhkiG9w0BAQEFAANLADBIAkEAn7PDhCeV/xIxUg8V70YRxK2A5

 CN=Steve Test

 emailAddress=steve@openssl.org

 0.OU=OpenSSL Group

 1.OU=Another Group

A sample configuration file with the relevant sections for B<ca>:

 [ ca ]

 default_ca      = CA_default            # The default ca section

 [ CA_default ]

 dir            = ./demoCA              # top dir

 database       = $dir/index.txt        # index file.

 new_certs_dir	= $dir/newcerts         # new certs dir

 certificate    = $dir/cacert.pem       # The CA cert

 serial         = $dir/serial           # serial no file

 private_key    = $dir/private/cakey.pem# CA private key

 RANDFILE       = $dir/private/.rand    # random number file

 default_days   = 365                   # how long to certify for

 default_crl_days= 30                   # how long before next CRL

 default_md     = md5                   # md to use

 policy         = policy_any            # default policy

 email_in_dn    = no                    # Don't add the email into cert DN

 name_opt	= ca_default		# Subject name display option

 cert_opt	= ca_default		# Certificate display option

 copy_extensions = none			# Don't copy extensions from request

 [ policy_any ]

 countryName            = supplied

 stateOrProvinceName    = optional

 organizationName       = optional

 organizationalUnitName = optional

 commonName             = supplied

 emailAddress           = optional

=head1 FILES

Note: the location of all files can change either by compile time options,

configuration file entries, environment variables or command line options.

The values below reflect the default values.

 /usr/local/ssl/lib/openssl.cnf - master configuration file

 ./demoCA                       - main CA directory

 ./demoCA/cacert.pem            - CA certificate

 ./demoCA/private/cakey.pem     - CA private key

 ./demoCA/serial                - CA serial number file

 ./demoCA/serial.old            - CA serial number backup file

 ./demoCA/index.txt             - CA text database file

 ./demoCA/index.txt.old         - CA text database backup file

 ./demoCA/certs                 - certificate output file

 ./demoCA/.rnd                  - CA random seed information

=head1 ENVIRONMENT VARIABLES

B<OPENSSL_CONF> reflects the location of master configuration file it can

be overridden by the B<-config> command line option.

=head1 RESTRICTIONS

The text database index file is a critical part of the process and 

if corrupted it can be difficult to fix. It is theoretically possible

to rebuild the index file from all the issued certificates and a current

CRL: however there is no option to do this.

V2 CRL features like delta CRLs are not currently supported.

Although several requests can be input and handled at once it is only

possible to include one SPKAC or self signed certificate.

=head1 BUGS

The use of an in memory text database can cause problems when large

numbers of certificates are present because, as the name implies

the database has to be kept in memory.

The B<ca> command really needs rewriting or the required functionality

exposed at either a command or interface level so a more friendly utility

(perl script or GUI) can handle things properly. The scripts B<CA.sh> and

B<CA.pl> help a little but not very much.

Any fields in a request that are not present in a policy are silently

deleted. This does not happen if the B<-preserveDN> option is used. To

enforce the absence of the EMAIL field within the DN, as suggested by

RFCs, regardless the contents of the request' subject the B<-noemailDN>

option can be used. The behaviour should be more friendly and

configurable.

Cancelling some commands by refusing to certify a certificate can

create an empty file.

=head1 WARNINGS

The B<ca> command is quirky and at times downright unfriendly.

The B<ca> utility was originally meant as an example of how to do things

in a CA. It was not supposed to be used as a full blown CA itself:

nevertheless some people are using it for this purpose.

The B<ca> command is effectively a single user command: no locking is

done on the various files and attempts to run more than one B<ca> command

on the same database can have unpredictable results.

The B<copy_extensions> option should be used with caution. If care is

not taken then it can be a security risk. For example if a certificate

request contains a basicConstraints extension with CA:TRUE and the

B<copy_extensions> value is set to B<copyall> and the user does not spot

this when the certificate is displayed then this will hand the requestor

a valid CA certificate.

This situation can be avoided by setting B<copy_extensions> to B<copy>

and including basicConstraints with CA:FALSE in the configuration file.

Then if the request contains a basicConstraints extension it will be

ignored.

It is advisable to also include values for other extensions such

as B<keyUsage> to prevent a request supplying its own values.

Additional restrictions can be placed on the CA certificate itself.

For example if the CA certificate has:

 basicConstraints = CA:TRUE, pathlen:0

then even if a certificate is issued with CA:TRUE it will not be valid.

=head1 SEE ALSO

L<req(1)|req(1)>, L<spkac(1)|spkac(1)>, L<x509(1)|x509(1)>, L<CA.pl(1)|CA.pl(1)>,

L<config(5)|config(5)>, L<x509v3_config(5)|x509v3_config(5)> 

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