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Re: [Cbor] Robert Wilton's No Objection on draft-ietf-cbor-file-magic-11: (with COMMENT)

Michael Richardson <mcr+ietf@sandelman.ca> Sat, 23 April 2022 16:02 UTC

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From: Michael Richardson <mcr+ietf@sandelman.ca>
To: Carsten Bormann <cabo@tzi.org>, Robert Wilton <rwilton@cisco.com>, =?utf-8?Q?Christian_Ams=C3=BCss?= <christian@amsuess.com>, cbor@ietf.org, draft-ietf-cbor-file-magic@ietf.org, The IESG <iesg@ietf.org>, cbor-chairs@ietf.org
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Comments: In-reply-to Carsten Bormann <cabo@tzi.org> message dated "Thu, 21 Apr 2022 19:07:36 +0200."
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Date: Sat, 23 Apr 2022 12:02:39 -0400
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Subject: Re: [Cbor] Robert Wilton's No Objection on draft-ietf-cbor-file-magic-11: (with COMMENT)
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Carsten Bormann <cabo@tzi.org> wrote:
    >> I was less convinced by this statement because: (1) It seems like C
    >> treating this as null terminated string is probably not the right
    >> thing to do,

    > It is not, but I have seen too much code doing that with magic numbers
    > (strncpy, that is).

    >> I'm not sure that we should be implicitly endorsing that.

    > Of course, we could decide that we make zero bytes prominent enough and
    > mention that strncpy is not the way to do this.

It's not the sensible CBOR-aware code that would be treating the magic number
as a string, it's the non-CBOR-aware code that just wants some pattern to
deal with where the null/zero bytes become annoying to encode.

And: it's just mild advice.
Of course, code should all be proof against such things.

--
Michael Richardson <mcr+IETF@sandelman.ca>, Sandelman Software Works
 -= IPv6 IoT consulting =-

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