[squid-dev] [PATCH] ICAP trailer support

[Alex Rousskov]

On 11/09/2016 08:16 AM, Amos Jeffries wrote:
> On 9/11/2016 3:05 a.m., Eduard Bagdasaryan wrote:
>> Also simplified and fixed headers isolating code while dealing with
>> empty (i.e. zero header fields) headers. Old httpMsgIsolateHeaders()
>> tried to re-implement header end detection/processing logic that is
>> actually covered by headersEnd(). Old httpMsgIsolateHeaders() could
>> return success for some garbage input (e.g., a buffer of several CRs)
>> even if no end of headers was found.


> Careful there. Since HttpMsg is actually HTTP parse logic a buffer
> containing several CR's can be a valid mime block (just empty). CR is
> part of BWS/OWS in HTTP.

Amos,

    Do you agree that a buffer consisting of several CRs and nothing
else must not result in httpMsgIsolateHeaders() returning 1 (i.e.
"success")?

The above preamble text is trying to say that the old
httpMsgIsolateHeaders() could return 1 in that invalid-input case. The
text should be rephrased for clarity if that is not how you interpreted
it. Suggestions welcomed.


In this context, the "HTTP header(s)" is defined as

  *( header-field CR?LF )
  CR?LF

where CR?LF is either CRLF or just LF.

Old httpMsgIsolateHeaders() and new HttpHeader::Isolate() must extract
the mime block (i.e., the *(header-field CR?LF) part) but only if
headersEnd() finds the end of the HTTP header first. The old
httpMsgIsolateHeaders was buggy. If you believe HttpHeader::Isolate() is
buggy, please speak up!


HTH,

Alex.