Backports: r1710095, r1727544
Submitted by: ylavic, rpluem

core: Limit to ten the number of tolerated empty lines between request,
and consume them before the pipelining check to avoid possible response
delay when reading the next request without flushing.

Before this commit, the maximum number of empty lines was the same as
configured LimitRequestFields, defaulting to 100, which was way too much.
We now use a fixed/hard limit of 10 (DEFAULT_LIMIT_BLANK_LINES).

check_pipeline() is changed to check for (up to the limit) and comsume the
trailing [CR]LFs so that they won't be interpreted as pipelined requests,
otherwise we would block on the next read without flushing data, and hence
possibly delay pending response(s) until the next/real request comes in or
the keepalive timeout expires.
 
Finally, when the maximum number of empty line is reached in
read_request_line(), or that request line does not contains at least a method
and an (valid) URI, we can fail early and avoid some failure detected in
further processing.

Ensure that proto_num and protocol is set in another "error out early" edge
case. This can happen with invalid CONNECT requests as described in the PR.
PR: 58929

Borrow Yann's effort at cross-porting this to 2.2.x


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to allow us to apply the 2.4.x already-reviewed HttpProtocolOptions and
parser changes.



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Submitted by: trawick
Another comment-only backport syncing to 2.4.x




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Submitted by: trawick
s/ensure/insure/


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Submitted by: trawick
zap an unhelpful, out of date comment from httpd 1.2



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Submitted by: niq
Reject requests containing (invalid) NULL characters in request line
or request headers.
PR 43039

Backports: r892808
Submitted by: rpluem
Fix up r892678


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trunk patch: http://svn.apache.org/r1483005
Submitted by: jailletc36


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No effective code change


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navigated 2.4.x-merge-http-strict backport



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Submitted By: Edward Lu <Chaosed0 gmail.com>
Support custom ErrorDocuments for HTTP 501 and 414 status codes.
PR 57167 [Edward Lu <Chaosed0 gmail.com>]


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Submitted by: jailletc36
Fix sscanf format spotted by cppcheck 
(changes version major/minor types from signed to unsigned)


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Submitted by: jailletc36
Improve error message
PR 54384



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Submitted by: sf
remove obsolete comment from 1.3 days


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Submitted by: sf
remove some more old unused code


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Submitted by: sf
Remove unused code. "Next week" hasn't happened in the last 10 years or so.



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Submitted by: trawick
core: ErrorDocument now works for requests without a Host header.
PR: 48357


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Submitted by: sf
Make sure that a triggering LimitRequestFieldSize is always logged, even if the
first read already exeeds the limit and ap_rgetline does not return a header
name.



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Submitted by: trawick
s/ensure/insure/


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Submitted by: trawick
zap an unhelpful, out of date comment from httpd 1.2



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Submitted by: rpluem
Correctly return a 400 (Bad request) in case of a HTTP/0.9 request like
GET @example.org/foo


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Submitted by: sf
Downgrade some more log messages indicating client errors from level error to
info. Add log messages for various reasons to return HTTP_BAD_REQUEST.


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Submitted by: sf
Enforce LimitRequestFieldSize after multiple headers with the same
name have been merged.


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Submitted by: sf
Use APR_STATUS_IS_... in some more cases.
While this is not strictly necessary everywhere, it makes it much easier
to find the problematic cases.



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Submitted by: covener
use APR_STATUS_IS_TIMEUP() instead of direct comparison with APR_TIMEUP.




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Submitted by: trawick
comment on where multiple headers with same name get merged

(some strict Cookie parsers can't handle what happens later,
but that is not our fault)



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Submitted by: rpluem
Fix up r892678



git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/branches/2.2.x-merge-http-strict@1775692 13f79535-47bb-0310-9956-ffa450edef68

Submitted by: niq
Reject requests containing (invalid) NULL characters in request line
or request headers.
PR 43039


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warning in 2.2 codebase?)
Backports: r1514215
Submitted by: trawick



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