- From: Alex Rousskov <rousskov@measurement-factory.com>
- Date: Fri, 04 Feb 2011 10:42:03 -0700
- To: Mark Nottingham <mnot@mnot.net>
- CC: HTTP Working Group <ietf-http-wg@w3.org>
On 02/03/2011 09:13 PM, Mark Nottingham wrote: > Ah -- sorry, I cut/pasted the wrong text (we've split the definitions of the request and response directives in p6). > > Revision: > > Current: > > """ > The no-store request directive indicates that a cache MUST NOT store any part of either this request or any response to it. This directive applies to both non-shared and shared caches. "MUST NOT store" in this context means that the cache MUST NOT intentionally store the information in non-volatile storage, and MUST make a best-effort attempt to remove the information from volatile storage as promptly as possible after forwarding it. > > This directive is NOT a reliable or sufficient mechanism for ensuring privacy. In particular, malicious or compromised caches might not recognize or obey this directive, and communications networks might be vulnerable to eavesdropping. > """ > > Proposal: > > """ > The no-store request directive indicates that a cache MUST NOT store any part of either this request or any response to it. This directive applies to both non-shared and shared caches. "MUST NOT store" in this context means that the cache MUST NOT intentionally store the information in non-volatile storage, and MUST make a best-effort attempt to remove the information from volatile storage as promptly as possible after forwarding it. > > This directive is NOT a reliable or sufficient mechanism for ensuring privacy. In particular, malicious or compromised caches might not recognize or obey this directive, and communications networks might be vulnerable to eavesdropping. > > Note that if a request containing this directive is satisfied from a cache, it does not apply to the already stored response. > """ I would still replace the last "it" as it is not 100% clear what it refers to: """ Note that if a request containing this directive is satisfied from a cache, the no-store request directive does not apply to the already stored response. """ Which actually reads a little backwards because if the request is satisfied from a cache, the proxy obviously thinks the no-store does not apply! Consider this simplification: """ The server MAY ignore the no-store request directive when satisfying a request from a cache. """ Thank you, Alex. > On 04/02/2011, at 3:22 AM, Alex Rousskov wrote: > >> On 02/02/2011 10:46 PM, Mark Nottingham wrote: >>> Current text: >> >>> """ >>> no-store >>> >>> The no-store response directive indicates that a cache MUST NOT store >>> any part of either the immediate request or response. This directive >>> applies to both non-shared and shared caches. "MUST NOT store" in >>> this context means that the cache MUST NOT intentionally store the >>> information in non-volatile storage, and MUST make a best-effort >>> attempt to remove the information from volatile storage as promptly >>> as possible after forwarding it. >>> >>> This directive is NOT a reliable or sufficient mechanism for ensuring >>> privacy. In particular, malicious or compromised caches might not >>> recognize or obey this directive, and communications networks might >>> be vulnerable to eavesdropping. >>> >>> """ >> >> >>> Proposal: >>> >>> """ >>> no-store >>> >>> The no-store response directive indicates that a cache MUST NOT store >>> any part of either the immediate request or response. This directive >>> applies to both non-shared and shared caches. "MUST NOT store" in >>> this context means that the cache MUST NOT intentionally store the >>> information in non-volatile storage, and MUST make a best-effort >>> attempt to remove the information from volatile storage as promptly >>> as possible after forwarding it. >>> >>> This directive is NOT a reliable or sufficient mechanism for ensuring >>> privacy. In particular, malicious or compromised caches might not >>> recognize or obey this directive, and communications networks might >>> be vulnerable to eavesdropping. >>> >>> Note that if a request containing this directive is satisfied from a >>> cache, it does not apply to the already stored response. >>> """ >> >> >> The "no-store response directive" opening of the first paragraph may >> mislead the reader that the last two paragraphs apply only to no-store >> in responses, especially since those paragraphs contain such vague >> references as "this directive" and "it". >> >> How about moving the first paragraph down, making it the last of the >> three paragraphs above? After all, the last two paragraphs apply to both >> requests and responses. Or perhaps replace "this" and "it" references >> with something more specific like "The no-store request or response >> directive" and "the no-store request directive". >> >> Thank you, >> >> Alex. >> >> >> >> >>> On 18/10/2010, at 3:07 PM, Mark Nottingham wrote: >>> >>>> Now #249: >>>> http://trac.tools.ietf.org/wg/httpbis/trac/ticket/249 >>>> >>>> >>>> On 18/10/2010, at 10:53 AM, Mark Nottingham wrote: >>>> >>>>> Thoughts re: the below? >>>>> >>>>> My inclination is to clarify "any response to it" so that a cache can use the same cached response to serve multiple requests with no-store in them (or not). >>>>> >>>>> Cheers, >>>>> >>>>> >>>>> Begin forwarded message: >>>>> >>>>>> From: Alex Rousskov <rousskov@measurement-factory.com> >>>>>> Date: 23 September 2010 9:47:57 AM AEST >>>>>> To: Mark Nottingham <mnot@yahoo-inc.com> >>>>>> Cc: Squid Developers <squid-dev@squid-cache.org> >>>>>> Subject: Re: Does no-store in request imply no-cache? >>>>>> >>>>>> On 09/22/2010 05:05 PM, Mark Nottingham wrote: >>>>>> >>>>>>> Strictly, as a request directive it means "you can't store the >>>>>>> response to this request" -- it says nothing about whether or not you >>>>>>> can satisfy the request from a cache. >>>>>> >>>>>> Hi Mark, >>>>>> >>>>>> Let's assume the above is correct and Squid satisfied the no-store >>>>>> request from the cache. Should Squid purge the cached response afterwards? >>>>>> >>>>>> If Squid does not purge, the next regular request will get the same >>>>>> cached response as the no-store request got, kind of violating the "MUST >>>>>> NOT store any response to it" no-store requirement. >>>>>> >>>>>> If Squid purges, it is kind of silly because earlier requests could have >>>>>> gotten the same "sensitive" information before the no-store request came >>>>>> and declared the already cached information "sensitive". >>>>>> >>>>>> Thank you, >>>>>> >>>>>> Alex. >>>>>> >>>>>> >>>>>>> See also: >>>>>>> http://tools.ietf.org/html/draft-ietf-httpbis-p6-cache-11#section-3.2.1 >>>>>>> >>>>>>> >>>>>>> On 23/09/2010, at 4:27 AM, Alex Rousskov wrote: >>>>>>> >>>>>>>> Hello, >>>>>>>> >>>>>>>> One interpretation of RFC 2616 allows the proxy to serve hits when >>>>>>>> the request contains "Cache-Control: no-store". Do you think such an >>>>>>>> interpretation is valid? >>>>>>>> >>>>>>>> no-store >>>>>>>> The purpose of the no-store directive is to prevent the >>>>>>>> inadvertent release or retention of sensitive information (for >>>>>>>> example, on backup tapes). The no-store directive applies to the >>>>>>>> entire message, and MAY be sent either in a response or in a >>>>>>>> request. If sent in a request, a cache MUST NOT store any part of >>>>>>>> either this request or any response to it. >>>>>>>> >>>>>>>> Thank you, >>>>>>>> >>>>>>>> Alex. >>>>> >>>>> -- >>>>> Mark Nottingham http://www.mnot.net/ >>>>> >>>>> >>>>> >>>>> >>>> >>>> -- >>>> Mark Nottingham http://www.mnot.net/ >>>> >>>> >>>> >>>> >>> >>> -- >>> Mark Nottingham http://www.mnot.net/ >>> >>> >> > > -- > Mark Nottingham http://www.mnot.net/ > > >
Received on Friday, 4 February 2011 17:42:40 UTC