Bugs item #2980877, was opened at 2010-04-02 03:25
Message generated for change (Comment added) made by bagder
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Category: http
Group: bad behaviour
Status: Open
Resolution: Invalid
Priority: 5
Private: No
Submitted By: Anil Kumar (anilsf)
Assigned to: Daniel Stenberg (bagder)
Summary: CR at the beginning of header marks it as end of HTTP header

Initial Comment:
CR at the beginning of header marks it as end of HTTP header.
For example

print "HTTP/1.1 200 OK\r\n";
print "HHH1: v1\r\n";
print "HHH2: v2\r\n";
print "\rXYZ: vxyz\r\n";
print "HHH3: v3\r\n";
print "\r\n";

curl will treat '\r' at the beginning of XYZ as end of HTTP header and will finish header processing.

This bug is because of the following code at
http://github.com/bagder/curl/blob/master/lib/http.c#L3196
     /* headers are in network encoding so
       use 0x0a and 0x0d instead of '\n' and '\r' */
    if((0x0a == *k->p) || (0x0d == *k->p)) {
      size_t headerlen;
      /* Zero-length header line means end of headers! */

It should have been
    if((0x0a == *k->p) || ((0x0d == *k->p) && (0x0a == *(k->p + 1)))) {

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>Comment By: Daniel Stenberg (bagder)
Date: 2010-04-03 20:58

Message:
libcurl will assume two consecutive linebreaks to be the end of the
headers, and it is liberal in what a linebreak is. It can be CRLF, just CR
or just LF if I recall things correctly.

Apart from you trying to find a problem in libcurl, can you point out a
single server instance that would send headers like this and it would work
with any amount of ordinary browsers or HTTP clients? Until you can point
any such out, I will continue to believe that this is not legitimate HTTP
and libcurl will not treat it as a header.

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Comment By: Anil Kumar (anilsf)
Date: 2010-04-02 22:19

Message:
        generic-message = start-line
                          *(message-header CRLF)
                          CRLF
                          [ message-body ]
        start-line = Request-Line | Status-Line

without two consecutive CRLF it should not be considered as end of HTTP
header

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Comment By: Daniel Stenberg (bagder)
Date: 2010-04-02 20:57

Message:
Sorry, but a header cannot legally start with a CR, thus if the line starts
with CR it is no header...

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Received on 2010-04-03