{Disarmed} Re: [IPP] Descriptions of CUPS additions to the Cancel-Job and Purge-Jobs operations
Michael Sweet
msweet at apple.com
Sun Oct 4 03:34:30 UTC 2009
That would be great if we *did* have a Cancel-Jobs operation; when you
mentioned it I looked and wasn't able to find it - Cancel-Job and
Cancel-Current-Job are all that I see...
On Oct 3, 2009, at 6:09 PM, Tom Hastings wrote:
> Good discussion.
>
> If Michael is willing to update CUPS (to support the old and
> something new), another new alternative would be to add the
> following Operation attribute to Cancel-Jobs:
>
> “all-my-jobs” (boolean) with default ‘false’ to the Cancel-Jobs
> operation
>
> instead of adding “cancel-jobs” (boolean) with default ‘false’ to
> the Purge-Jobs operation. Then we wouldn’t have an operation
> attribute (“cancel-jobs”) which changes an one operation (Purge-
> Jobs) into another operation (Cancel-Jobs).
>
> A variant on my alternative above which would allow the Operator/
> Administrator to be able to cancel all jobs (as is possible with
> current CUPS, but uses Purge-Jobs) is to add the following Operation
> attribute to the Cancel-Jobs operation:
>
> “which-jobs” (type2 keyword) with values:
> ‘specified-job’ – (default) the job specified by the supplied “job-
> id” or “job-url”
> ‘all-my-jobs’ – cancel all my jobs
> ‘all-jobs’ – cancel all jobs; If the Printer’s security policy does
> not allow the authenticated user to cancel jobs for which the
> requesting user is not the owner, then the IPP object MUST reject
> the operation and return client-error-not-authorized
>
>
>
> Following the thrust of the above alternatives which avoid having an
> operation attribute change the semantics of the operation to that of
> another operation, how about also adding “job-id” (integer(1:MAX))
> and “job-url” (URL) to the Purge-Jobs operation. If either are
> supplied, then the specified job is purged, rather than all jobs.
> If the requesting user is NOT an Operator/Administrator AND the
> specified job is NOT owned by the requesting user, then the IPP
> object MUST reject the operation and return client-error-not-
> authorized.
>
> Think about these alternative for the discussion at the IPP WG
> telecon, this Monday, October 5, 1:00 PM PDT = 4:00 PM EDT.
>
> In the meantime, I’ll post the original CUPS approach rather than
> making some of these discussed changes.
>
> Thanks,
> Tom
>
>
> From: Michael Sweet [mailto:msweet at apple.com]
> Sent: Friday, October 02, 2009 10:51
> To: Ira McDonald
> Cc: tom.hastings at alum.mit.edu; ipp at pwg.org
> Subject: Re: {Disarmed} Re: [IPP] Descriptions of CUPS additions to
> the Cancel-Job and Purge-Jobs operations
>
> FWIW, we can rev this to use a "cancel-jobs" attribute instead of
> "purge-jobs" for the Purge-Jobs operation, and I'll update CUPS
> accordingly (to support both the old and new names...) so that the
> defaults are all false.
>
> On Oct 2, 2009, at 10:24 AM, Ira McDonald wrote:
>
>
> Hi,
>
> I generally agree with Mike's comments below.
>
> But I really dislike a boolean that defaults to 'true' - this
> needs work.
>
> Cheers,
> - Ira
>
> Ira McDonald (Musician / Software Architect)
> Chair - Linux Foundation Open Printing WG
> Blue Roof Music/High North Inc
> email: blueroofmusic at gmail.com
> winter:
> 579 Park Place Saline, MI 48176
> 734-944-0094
> summer:
> PO Box 221 Grand Marais, MI 49839
> 906-494-2434
>
>
> On Fri, Oct 2, 2009 at 11:53 AM, Michael Sweet <msweet at apple.com>
> wrote:
> Comments inline...
>
> On Sep 30, 2009, at 7:10 PM, Tom Hastings wrote:
>> I'm struggling mightily to write up the Cancel-Job and Purge-Job
>> operations as suggested by Michael and have come up with a bunch of
>> issues. Since HTML may not come through the email reflector with
>> the 5 MS-WORD ISSUE comments intact and the table shown, I’ve also
>> downloaded the .doc of just these attributes with my suggested
>> descriptions and the ISSUES as MS-WORD comments to: ftp://ftp.pwg.org/pub/pwg/ipp/wd/Attributes_to_add_to_Cancel-Job_and_Purge-Jobs_operations.doc
>> .
>>
>>
>> The 5 ISSUES are as follows:
>>
>>
>> ISSUE 1: Allowing an unprivileged user to purge his job using
>> Cancel-Job, could circumvent accounting in those systems that use
>> Retained Jobs and Job History for accounting.
>>
>>
>> ISSUE 2: Allowing an unprivileged user to purge his jobs using
>> Purge-Jobs, could circumvent accounting in those systems that use
>> Retained Jobs and Job History for accounting.
>>
>> One solution would be to only allow Purge-Jobs for operator or
>> administrator as in [RFC 2911].
>>
>> ISSUE 3: Instead of adding “my-jobs” and “purge-job” to Purge-Jobs,
>> a simpler way to allow an unprivileged user to cancel all his jobs,
>> instead of just a specified job, would be to add “all-my-
>> jobs” (boolean) Operation attribute to the Cancel-Job operation.
>> When the client supplies this attribute with a ‘true’ value, the
>> client MUST NOT supply a “job-id” or “job-url” Operation attribute.
>>
>>
>> ISSUE 4: Or should the spec say the Printer MUST reject the Purge-
>> Jobs operation if the unprivileged client supplies the “my-jobs” =
>> ‘false’ and return: client-error-forbidden, client-error-not-
>> authenticated, and client-error-not-authorized as appropriate, as
>> for Purge-Jobs in RFC 2911 section 3.2.9
>>
>>
>> ISSUE 5: The “purge-job” (boolean) Operation attribute has the
>> ‘true’ value here as its default. Usually, it’s the ‘false’ value
>> that is the default. More confusingly, the “purge-job” (boolean)
>> Operation attribute (correctly) has the ‘false’ value in the Cancel-
>> Job operation above.
>>
>>
>> I’ve included the text in the draft which I will post tomorrow for
>> this Monday’s IPP WG telecon, October 5, at 1:00 PM PDT = 4:00 PM
>> EDT, but I wanted to start people thinking about these issues.
>> Hopefully, we can resolve these issues at the meeting so that I can
>> update the draft for the face to face meeting in Cupertino, the
>> following week, October 12-14.
>>
>>
>>
>> Here is what I've come up with. Comments and suggestions are
>> welcome:
>>
>>
>> 4.3 Cancel-Job operation
>>
>> This section specified an additional operation attribute for use
>> with the Cancel-Jobs operation (see [RFC2911] Section 3.3.3).
>>
>> 4.3.1 purge-job[th1] (boolean)
>>
>> The “purge-job” Operation attribute controls whether the specified
>> job is canceled or purged as follows:
>>
>> ‘false’: Default value. The Printer cancels the specified job as
>> specified in [RFC2911] Section 3.3.3 which MAY leave a Retained Job
>> with document data on the Printer for possible re-processing (e.g.,
>> using the Reprocess-Job or Resubmit-Job operations) and/or Job
>> History. Note: If the client omits this attribute or supplies the
>> ‘false’ value, the behavior of the Cancel-Job operation is as
>> specified in [RFC2911].
>>
>> ‘true’: If the authenticated user is the job owner of the job
>> specified by the “job-id” or “job-uri” operation attribute or is a
>> privileged operator or administrator of the Printer, the Printer
>> MUST purge the specified job according to the semantics of the
>> Purge-Jobs operation independent of the job’s state, but only for
>> the specified job, i.e., remove all record of the specified job,
>> including attributes, history and document data.
>>
>> The client MAY supply this Operation attribute and the Printer MAY
>> support this Operation attribute in the Cancel-Job operation.
>>
>
> I'd just make the authenticated user case more generic, and also
> document that Cancel-Jobs with purge-jobs=true will fail if the user
> is not authorized, e.g.:
>
> ‘true’: If the authenticated user is allowed to purge a job by the
> Printer's security policy (typically if the owner of the job
> specified by the “job-id” or “job-uri” operation attribute matches)
> or is a privileged operator or administrator of the Printer, the
> Printer MUST purge the specified job according to the semantics of
> the Purge-Jobs operation independent of the job’s state, but only
> for the specified job, i.e., remove all record of the specified job,
> including attributes, history and document data. Otherwise, the IPP
> object MUST reject the operation and return: client-error-forbidden,
> client-error-not-authenticated, and client-error-not-authorized as
> appropriate.
>
> The wording of the last sentence matches RFC 2911's Purge-Jobs
> description.
>>
>> 4.4 Purge-Jobs operation
>>
>> This section specified additional operation attributes for use with
>> the Cancel-Jobs operation (see [RFC2911] Section 3.3.7).
>>
>> 4.4.1 my-jobs[th2] [th3] (boolean)
>>
>> The “my-jobs” Operation attribute allows the client to request the
>> target jobs to be (1) all jobs or (2) only jobs owned by the
>> requesting user. However, the Printer MUST further restrict the
>> target jobs as follows:
>>
>> ‘false’: Default value. The target jobs are all jobs, unless the
>> Authenticated user supplying the request is NOT an operator or
>> administrator of the Printer, in which case the Printer MUST
>> restrict the target jobs to those belonging to the requesting user.
>> [th4]
>>
>> ‘true’: The target jobs are limited to those owned by the
>> Authenticated user submitting the request.
>>
>> The client MAY supply this Operation attribute and the Printer MAY
>> support this Operation attribute in the Purge-Jobs operation.
>>
>
> I'd add the following to the 4.4 introduction to address th2-th5:
>
> Access Rights: The following attributes may allow the authenticated
> user (see RFC 2911 section 8.3) performing this operation to be an
> ordinary user depending on the Printer's security policy. When
> ordinary users are not allowed to use the Purge-Jobs operation, the
> IPP object MUST continue to reject the operation and return: client-
> error-forbidden, client-error-not-authenticated, and client-error-
> not-authorized as appropriate.
>
> Then move the table into 4.4, before the description of the
> attributes.
>
>
> 4.4.2 purge-job (boolean)
>
> The “purge-job” Operation attribute controls whether the target jobs
> are canceled or purged as follows:
>
> ‘false’: The Printer cancels the target jobs as specified in
> [RFC2911] Section 3.3.3 Cancel-Job which MAY leave a Retained Job
> with document data on the Printer for possible re-processing (e.g.,
> using the Reprocess-Job or Resubmit-Job operations) and/or Job
> History.
>
> ‘true’: Default value[th5] . The Printer purges the target jobs
> as specified in [RFC2911] Section 3.2.9 Purge-Jobs. Note: If the
> client omits this attribute or supplies the ‘true’ value, the
> behavior of the Purge-Jobs operation is as specified in [RFC2911]
> for the target jobs.
>
> The client MAY supply this Operation attribute and the Printer MAY
> support this Operation attribute in the Purge-Jobs operation.
>
> The behavior for the Purge-Jobs operation for these two Operation
> attributes for unprivileged users vs. operators and administrator of
> the Printer is shown in Table 2.
>
> Table 2: Interaction of "my-jobs" and "purge-jobs" attributes in the
> Purge-Jobs operation
>
> Operation attributes
>
> Unprivileged user
>
> Operator or Administrator of the Printer
>
> “my-jobs” = ‘false’ or omitted
> “purge-jobs” = ‘false’
>
> Cancel only my jobs (Printer overrides “my-jobs” = ‘false’)
>
> Cancel all jobs
>
> “my-jobs” = ‘true’
> “purge-jobs” = ‘false’
>
> Cancel only my jobs
>
> Cancel only my jobs
>
> “my-jobs” = ‘false’ or omitted
> “purge-jobs” = ‘true’ or omitted
>
> Purge only my jobs (Printer overrides “my-jobs” = ‘false’)
>
> Purge all jobs
>
> “my-jobs” = ‘true’
> “purge-jobs” = ‘true’ or omitted
>
> Purge only my jobs
>
> Purge only my jobs
>
>
>
> -----Original Message-----
> From: ipp-bounces at pwg.org [mailto:ipp-bounces at pwg.org] On Behalf Of
> Michael Sweet
> Sent: Monday, September 14, 2009 14:41
> To: ipp at pwg.org
> Subject: [IPP] Descriptions of CUPS additions to the Cancel-Job and
> Purge-Jobs operations
>
> All,
>
> Here are the descriptions for the CUPS additions to the Cancel-Job and
> Purge-Jobs operations. These came up in today's conference call...
>
> ------------------------------------------------------
>
> Cancel Job Operation
>
> The Cancel-Job operation (0x0008) cancels the specified job. CUPS 1.4
> adds a new purge-job (boolean) attribute that allows you to purge both
> active and completed jobs, removing all history and document files for
> the job as well.
>
> Cancel-Job Request
>
> The following groups of attributes are supplied as part of the Cancel-
> Job request:
>
> Group 1: Operation Attributes
>
> Natural Language and Character Set:
> The "attributes-charset" and "attributes-natural-language"
> attributes as described in section 3.1.4.1 of the IPP Model and
> Semantics document.
>
> "printer-uri" (uri) and "job-id" (integer)
> OR
> "job-uri":
> The client MUST supply a URI for the specified printer and a job
> ID number, or the job URI.
>
> "purge-job" (boolean):
> The client OPTIONALLY supplies this attribute. When true, all job
> files (history and document) are purged. The default is false, leading
> to the standard IPP behavior.
>
>
> Cancel-Job Response
>
> The following groups of attributes are send as part of the Cancel-Job
> Response:
>
> Group 1: Operation Attributes
>
> Status Message:
> The standard response status message.
>
> Natural Language and Character Set:
> The "attributes-charset" and "attributes-natural-language"
> attributes as described in section 3.1.4.2 of the IPP Model and
> Semantics document.
>
>
> Purge-Jobs Operation
>
> The Purge-Jobs operation (0x0012) cancels all of the jobs on a given
> destination and optionally removes all history and document files for
> the jobs as well.
>
> Purge-Jobs Request
>
> The following groups of attributes are supplied as part of the Purge-
> Jobs request:
>
> Group 1: Operation Attributes
>
> Natural Language and Character Set:
> The "attributes-charset" and "attributes-natural-language"
> attributes as described in section 3.1.4.1 of the IPP Model and
> Semantics document.
>
> "printer-uri" (uri):
> The client MUST supply a URI for the specified printer or "ipp://.../printers
> " for all printers and classes.
>
> "requesting-user-name" (name(MAX)):
> The client OPTIONALLY supplies this attribute to specify whose
> jobs jobs are purged or canceled.
>
> "my-jobs" (boolean):
> The client OPTIONALLY supplies this attribute to specify that
> only the jobs owned by the requesting user are purged or canceled. The
> default is false.
>
> "purge-jobs" (boolean):
> The client OPTIONALLY supplies this attribute to specify whether
> the jobs are purged (true) or just canceled (false). The default is
> true.
>
>
> Purge-Jobs Response
>
> The following groups of attributes are send as part of the Purge-Jobs
> Response:
>
> Group 1: Operation Attributes
>
> Status Message:
> The standard response status message.
>
> Natural Language and Character Set:
> The "attributes-charset" and "attributes-natural-language"
> attributes as described in section 3.1.4.2 of the IPP Model and
> Semantics document.
> __________________________________________________
> Michael Sweet, Senior Printing System Engineer
>
> --
> This message has been scanned for viruses and
> dangerous content by MailScanner, and is
> believed to be clean.
> _______________________________________________
> ipp mailing list
> ipp at pwg.org
> https://www.pwg.org/mailman/listinfo/ipp
> ISSUE: Allowing an unprivileged user to purge his job using Cancel-
> Job, could circumvent accounting in those systems that use Retained
> Jobs and Job History for accounting.
>
> ISSUE: Allowing an unprivileged user to purge his jobs using Purge-
> Jobs, could circumvent accounting in those systems that use Retained
> Jobs and Job History for accounting.
>
>
> One solution would be to only allow Purge-Jobs for operator or
> administrator as in [RFC 2911].
>
> ISSUE: Instead of adding “my-jobs” and “purge-job” to Purge-Jobs, a
> simpler way to allow an unprivileged user to cancel all his jobs,
> instead of just a specified job, would be to add “all-my-
> jobs” (boolean) Operation attribute to the Cancel-Job operation.
> When the client supplies this attribute with a ‘true’ value, the
> client MUST NOT supply a “job-id” or “job-url” Operation attribute.
>
> ISSUE: Or should the spec say the Printer MUST reject the operation
> and return: client-error-forbidden, client-error-not-authenticated,
> and client-error-not-authorized as appropriate, as for Purge-Jobs in
> RFC 2911 section 3.2.9
>
> ISSUE: The “purge-job” (boolean) Operation attribute has the ‘true’
> value here as its default. Usually, it’s the ‘false’ value that is
> the default. More confusingly, the “purge-job” (boolean) Operation
> attribute (correctly) has the ‘false’ value in the Cancel-Job
> operation above.
>
> __________________________________________________
>
> Michael Sweet, Senior Printing System Engineer
>
> --
> This message has been scanned for viruses and
> dangerous content by MailScanner, and is
> believed to be clean.
> _______________________________________________
> ipp mailing list
> ipp at pwg.org
> https://www.pwg.org/mailman/listinfo/ipp
> ___________________________________________________
> Michael Sweet, Senior Printing System Engineer
>
>
>
___________________________________________________
Michael Sweet, Senior Printing System Engineer
--
This message has been scanned for viruses and
dangerous content by MailScanner, and is
believed to be clean.
More information about the ipp
mailing list