BUG/MINOR: h2: reject more chars from the :path pseudo header

BUG/MINOR: h2: reject more chars from the :path pseudo header

Origin: https://git.haproxy.org/?p=haproxy-2.6.git;a=commit;h=c8e07f2fd8b5462527f102f7145d6027c0d041da

This is the h2 version of this previous fix:

    BUG/MINOR: h1: do not accept '#' as part of the URI component

In addition to the current NUL/CR/LF, this will also reject all other
control chars, the space and '#' from the :path pseudo-header, to avoid
taking the '#' for a part of the path. It's still possible to fall back
to the previous behavior using "option accept-invalid-http-request".

This patch modifies the request parser to change the ":path" pseudo header
validation function with a new one that rejects 0x00-0x1F (control chars),
space and '#'. This way such chars will be dropped early in the chain, and
the search for '#' doesn't incur a second pass over the header's value.

This should be progressively backported to stable versions, along with the
following commits it relies on:

     REGTESTS: http-rules: add accept-invalid-http-request for normalize-uri tests
     REORG: http: move has_forbidden_char() from h2.c to http.h
     MINOR: ist: add new function ist_find_range() to find a character range
     MINOR: http: add new function http_path_has_forbidden_char()
     MINOR: h2: pass accept-invalid-http-request down the request parser

(cherry picked from commit b3119d4fb4588087e2483a80b01d322683719e29)
Signed-off-by: Amaury Denoyelle <adenoyelle@haproxy.com>
(cherry picked from commit 462a8600ce9e478573a957e046b446a7dcffd286)
Signed-off-by: Amaury Denoyelle <adenoyelle@haproxy.com>
(cherry picked from commit 648e59e30723b8fd4e71aab02cb679f6ea7446e7)
Signed-off-by: Amaury Denoyelle <adenoyelle@haproxy.com>
Gbp-Pq: Name BUG-MINOR-h2-reject-more-chars-from-the-path-pseudo-.patch