[lwip-devel] [bug #58754] httpd.c fix of incorrect null-termination of request-headers and other improvements

[Alister Fisher]

URL:
  <https://savannah.nongnu.org/bugs/?58754>

                 Summary: httpd.c fix of incorrect null-termination of
request-headers and other improvements
                 Project: lwIP - A Lightweight TCP/IP stack
            Submitted by: afisher
            Submitted on: Sun 12 Jul 2020 05:23:15 AM UTC
                Category: apps
                Severity: 3 - Normal
              Item Group: Change Request
                  Status: None
                 Privacy: Public
             Assigned to: None
             Open/Closed: Open
         Discussion Lock: Any
         Planned Release: None
            lwIP version: git head

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Details:

http_post_request incorrectly null-terminates the headers at the last header's
CRLF. That CRLF belongs to the last header and is necessary for header-value
searches. http_post_request itself uses a search of CRLF to find the
content-length header's value.
It should null-terminate at the empty-line that immediately follows it.

The improvements include
- Removed second search for request's empty-line.
- Search for headers from start of headers.
- Removed two impossible LWIP_MIN cases.
- Moved struct http_state and struct http_ssi_state to httpd_priv.h to
facilitate adding future features separate to httpd.c, e.g. websockets, which
was suggested by Simon Goldschmidt at
https://savannah.nongnu.org/patch/?9525.
- Removed unnecessary "+ 1" from httpd_req_buf's array definition and added 1
to LWIP_HTTPD_MAX_REQ_LENGTH's default definition.
- Moved http_remove_connection into http_state_eof. Reduces code size.
- Return ERR_ABRT from http_close_or_abort_conn if it calls altcp_abort. No
effect on execution. But more technically correct.
- Misc commenting.

The patch is to c385f31076b27efb8ee37f00cb5568783a58f299, the git head at the
time this bug was submitted.



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File Attachments:


-------------------------------------------------------
Date: Sun 12 Jul 2020 05:23:15 AM UTC  Name:
0001-Fix-HTTP-server-null-termination-of-request-headers-.patch  Size: 28KiB  
By: afisher

<http://savannah.nongnu.org/bugs/download.php?file_id=49474>

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