[cifs-protocol] [EXTERNAL] Re: [MS-DTYP] Conditional ACE attr-name2 whitespace escaping - TrackingID#2303010040009037

[Douglas Bagnall]

hi Kristian,

Well I only ever write to you in a state of confusion.

Ultimately the question I care about is this one:

>> So my question I guess broadens into which characters actually
>> MUST be escaped and which MUST be literal.

Which, yes, I think boils down to the range 0x0001-0x07f, or parts of 
it. Actually really just the comma.

My current understanding is there are four classes of character:

1. Forbidden in any form: 0x0000.

2. Allowed in unescaped form only:
    the ASCII numbers and letters [A-Za-z0-9] and
    "#", "$", "'", "*", "+", "-", ".", "/", ":", ";", "?", "@",
    "[", "\", "]", "^", "_", "`", "{", "}", "~".

3. Allowed in escaped form only:
     "!", "&", "(", ")", ">", "<", "=", "|", "%", space and DQUOTE

4. Allowed in either form:
    Anything 0x007f and over, anything 0x001f and below, and ",".

Are these correct? Is it true that the comma is special?

Douglas


On 30/03/23 06:36, Kristian Smith wrote:
> Hi Douglas,
> 
> My apologies on the delay on your ABNF asks. Looking at this question, 
> the way lit_char is described is indeed confusing.
> 
> Specifically:
> %x0080-FFFF / ( "%" 4HEXDIG); 4HEXDIG can have any value except 0000 (NULL)
> 
> I believe your primary question here is "what about 0x0001-0x080"? If I 
> find that those are all accepted for lit_char, would that answer your 
> question?
> 
> Thanks again for your patience.
> -Kristian
> 
> Kristian Smith
> 
> Support Escalation Engineer
> 
> Microsoft Azure DevOps &
> 
> Windows Open Spec Protocols
> 
> Office: (425) 421-4442
> 
> kristian.smith at microsoft.com<mailto:kristian.smith at microsoft.com>
> 
> 
> ------------------------------------------------------------------------
> *From:* Douglas Bagnall <douglas.bagnall at catalyst.net.nz>
> *Sent:* Tuesday, February 28, 2023 7:31 PM
> *To:* cifs-protocol at lists.samba.org <cifs-protocol at lists.samba.org>; 
> Interoperability Documentation Help <dochelp at microsoft.com>
> *Subject:* [EXTERNAL] Re: [cifs-protocol] [MS-DTYP] Conditional ACE 
> attr-name2 whitespace escaping
> On 1/03/23 16:18, Douglas Bagnall via cifs-protocol wrote:
>> In MS-DTYP 2.5.1.1, attr-name2 is defined as containing attr-char2, 
>> which is described thus in the text:
>> 
>>> attr-char2: A character valid for use in an attribute name in 
>>> @Prefixed form. Valid characters include
>>> all ASCII and UNICODE characters of the range 0x0-0xFFFF. Characters 
>>> MAY be encoded either as
>>> literals or be encoded with a five-character sequence %XXXX, where 
>>> XXXX are hexadecimal digits
>>> that represent the corresponding 16-bit Unicode value of the character 
>>> with the following
>>> exceptions:
>>> 1. The following characters: "!", "&", "(", ")", ">", "<", "=", "|", 
>>> "%", SP (space) and DQUOTE (as
>>> specified in [RFC5234]) MUST be encoded in the preceding 
>>> five-character sequence.
>>> 2. The following characters MUST be encoded as literals: "#", "$", 
>>> "'", "*", "+", "-", ".", "/", ":",
>>> ";", "?", "@", "[", "\", "]", "^", "_", "`", "{", "}", "~" and any 
>>> characters in the ASCII ranges
>>> 0x41-0x5A (A-Z), 0x61-0x7A (a-z) and 0x30-0x39 (0-9.)
> 
> Okay, I see the definition in the ABNF is quite a bit different:
> 
>> attr-char2 = attr-char1 / lit-char
>> attr-char1 = 1*(ALPHA / DIGIT / ":" / "." / "/" / "_")
>> lit-char = "#" / "$" / "'" / "*" / "+" / "-" / "." / "/" / ":" / ";" / "?" / "@" / "[" / "\"
>>  / "]" / "^" / "_" / "`" / "{" / "}" / "~" / %x0080-FFFF / ( "%" 4HEXDIG) 
>> ; 4HEXDIG can have any value except 0000 (NULL)
> 
> where the valid literal characters are more constrained, and seem to
> allow no ASCII control characters at all. Also no \u0000, which the text
> explicitly allows.
> 
> So my question I guess broadens into which characters actually
> MUST be escaped and which MUST be literal.
> 
> Douglas
>