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www/apache24: Fix HTTP/2 DoS vulnerability

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- Add patch from upstream security advisory
  - Bump PORTREVISION

PR:		215096
MFH:		2016Q4
Security:	cb0bf1ec-bb92-11e6-a9a5-b499baebfeaf
Security:	CVE-2016-8740
This commit is contained in:
Bernard Spil 2016-12-06 12:43:36 +00:00
parent 846c05edc0
commit 77cc7ac627
Notes: svn2git 2021-03-31 03:12:20 +00:00 
svn path=/head/; revision=427953
2 changed files with 117 additions and 1 deletions
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2
www/apache24/Makefile
View file

@ -2,7 +2,7 @@
PORTNAME= apache24
PORTVERSION= 2.4.23
PORTREVISION= 1
PORTREVISION= 2
CATEGORIES= www ipv6
MASTER_SITES= APACHE_HTTPD
DISTNAME= httpd-${PORTVERSION}

116
www/apache24/files/patch-CVE-2016-8740 Normal file
View file

@ -0,0 +1,116 @@
Security Advisory - Apache Software Foundation
Apache HTTPD WebServer / httpd.apache.org
Server memory can be exhausted and service denied when HTTP/2 is used
CVE-2016-8740
The Apache HTTPD web server (from 2.4.17-2.4.23) did not apply limitations
on request headers correctly when experimental module for the HTTP/2
protocol is used to access a resource.
The net result is that a the server allocates too much memory instead of denying
the request. This can lead to memory exhaustion of the server by a properly
crafted request.
Background:
- -----------
Apache has limits on the number and length of request header fields. which
limits the amount of memory a client can allocate on the server for a request.
Version 2.4.17 of the Apache HTTP Server introduced an experimental feature:
mod_http2 for the HTTP/2 protocol (RFC7540, previous versions were known as
Google SPDY).
This module is NOT compiled in by default -and- is not enabled by default,
although some distribution may have chosen to do so.
It is generally needs to be enabled in the 'Protocols' line in httpd by
adding 'h2' and/or 'h2c' to the 'http/1.1' only default.
The default distributions of the Apache Software Foundation do not include
this experimental feature.
Details:
- --------
- From version 2.4.17, upto and including version 2.4.23 the server failed
to take the limitations on request memory use into account when providing
access to a resource over HTTP/2. This issue has been fixed
in version 2.4.23 (r1772576).
As a result - with a request using the HTTP/2 protocol a specially crafted
request can allocate memory on the server until it reaches its limit. This can
lead to denial of service for all requests against the server.
Impact:
- -------
This can lead to denial of service for all server resources.
Versions affected:
- ------------------
All versions from 2.4.17 to 2.4.23.
Resolution:
- -----------
For a 2.4.23 version a patch is supplied. This will be included in the
next release.
Mitigations and work arounds:
- -----------------------------
As a temporary workaround - HTTP/2 can be disabled by changing
the configuration by removing h2 and h2c from the Protocols
line(s) in the configuration file.
The resulting line should read:
Protocols http/1.1
Credits and timeline
- --------------------
The flaw was found and reported by Naveen Tiwari <naveen.tiwari@asu.edu>
and CDF/SEFCOM at Arizona State University on 2016-11-22. The issue was
resolved by Stefan Eissing and incorporated in the Apache repository,
ready for inclusion in the next release.
Apache would like to thank all involved for their help with this.
Index: modules/http2/h2_stream.c
===================================================================
--- modules/http2/h2_stream.c (revision 1771866)
+++ modules/http2/h2_stream.c (working copy)
@@ -322,18 +322,18 @@
HTTP_REQUEST_HEADER_FIELDS_TOO_LARGE);
}
}
- }
-
- if (h2_stream_is_scheduled(stream)) {
- return h2_request_add_trailer(stream->request, stream->pool,
- name, nlen, value, vlen);
- }
- else {
- if (!input_open(stream)) {
- return APR_ECONNRESET;
+
+ if (h2_stream_is_scheduled(stream)) {
+ return h2_request_add_trailer(stream->request, stream->pool,
+ name, nlen, value, vlen);
}
- return h2_request_add_header(stream->request, stream->pool,
- name, nlen, value, vlen);
+ else {
+ if (!input_open(stream)) {
+ return APR_ECONNRESET;
+ }
+ return h2_request_add_header(stream->request, stream->pool,
+ name, nlen, value, vlen);
+ }
}
}