IPv6 addresses for host name are incorrectly trimmed by nginx

Server NGINX
1

I’m trying to test IPv6 on a couple of sites and I seem to have
encountered
a bug with nginx.

I have 2 backend servers behind a proxy, all servers run nginx 0.8.53.

If I enter the IPv6 address into the browser, the address is trimmed
when it
reaches the backend server.

Here is an example using PHP:

Direct request to backend server (works):

http://[2a02:40:40:7::3]/test.php
$_SERVER[‘HTTP_HOST’] = [2a02:40:40:7::3]

Via proxy:

http://[2a02:40:40:7::7]/test.php
$_SERVER[‘HTTP_HOST’] = [2a02:40:40:7:

It appears the last semi colon and number are trimmed off the IPv6
address,
for example if I enter the full IPv6 address I get this:

http://[2a02:40:40:7:0:0:0:7]/test.php
$_SERVER[‘HTTP_HOST’] = [2a02:40:40:7:0:0:0

I’ve spent a couple of hours trying different scenarios and added custom
logging to log the value of the $host variable and as far as I can tell
nginx seems to always incorrectly trim the value of $host for IPv6
addresses.

Here is an example log entry, with an incorrectly logged host name:

[28/Nov/2010:17:50:08 +0000] [2a02:40:40:7: “GET /test.php HTTP/1.1”

The funny thing is that the correct value is always passed to PHP (for
direct requests), but the value of $host is always trimmed incorrectly.
As the host name is passed to the backend server via a proxy_set_header
directive the incorrect value is always passed to the backend and
therefore
incorrectly passed to PHP in this instance.

2

Here is debug output showing the problem:

2010/11/28 21:22:37 [debug] 10417#0: accept on [2a02:40:40:7::7]:80,
ready:
0
2010/11/28 21:22:37 [debug] 10417#0: posix_memalign:
0000000001031DA0:256
@16
2010/11/28 21:22:37 [debug] 10417#0: *8 accept:
2001:0:5ef5:79fd:3472:2f12:921f:6666 fd:3
2010/11/28 21:22:37 [debug] 10417#0: *8 event timer add: 3:
60000:1290979417739
2010/11/28 21:22:37 [debug] 10417#0: *8 epoll add event: fd:3 op:1
ev:80000001
2010/11/28 21:22:37 [debug] 10417#0: *8 posix_memalign:
0000000001063DD0:256
@16
2010/11/28 21:22:37 [debug] 10417#0: *8 malloc: 000000000103FB90:1288
2010/11/28 21:22:37 [debug] 10417#0: *8 malloc: 00000000010400A0:1024
2010/11/28 21:22:37 [debug] 10417#0: *8 posix_memalign:
00000000010404B0:4096 @16
2010/11/28 21:22:37 [debug] 10417#0: *8 http process request line
2010/11/28 21:22:37 [debug] 10417#0: *8 recv: fd:3 644 of 1024
2010/11/28 21:22:37 [debug] 10417#0: *8 http request line: “GET /
HTTP/1.1”
2010/11/28 21:22:37 [debug] 10417#0: *8 http uri: “/”
2010/11/28 21:22:37 [debug] 10417#0: *8 http args: “”
2010/11/28 21:22:37 [debug] 10417#0: *8 http exten: “”
2010/11/28 21:22:37 [debug] 10417#0: *8 http process request header line
2010/11/28 21:22:37 [debug] 10417#0: *8 http header: “Accept:
application/x-ms-application, image/jpeg, application/xaml+xml,
image/gif,
image/pjpeg, application/x-ms-xbap, application/x-shockwave-flash,
application/vnd.ms-excel, application/vnd.ms-powerpoint,
application/msword,
/”
2010/11/28 21:22:37 [debug] 10417#0: *8 http header: “Accept-Language:
en-GB”
2010/11/28 21:22:37 [debug] 10417#0: *8 http header: “User-Agent:
Mozilla/4.0 (compatible; MSIE 8.0; Windows NT 6.1; WOW64; Trident/4.0;
SLCC2; .NET CLR 2.0.50727; .NET CLR 3.5.30729; .NET CLR 3.0.30729; Media
Center PC 6.0; InfoPath.2; .NET CLR 1.1.4322; OfficeLiveConnector.1.5;
OfficeLivePatch.1.3; .NET4.0C; Creative AutoUpdate v1.40.02)”
2010/11/28 21:22:37 [debug] 10417#0: *8 http header: “Accept-Encoding:
gzip,
deflate”
*2010/11/28 21:22:37 [debug] 10417#0: 8 http header: “Host:
[2a02:40:40:7::7]”
2010/11/28 21:22:37 [debug] 10417#0: *8 http header: “Connection:
Keep-Alive”
2010/11/28 21:22:37 [debug] 10417#0: *8 http header done
2010/11/28 21:22:37 [debug] 10417#0: *8 event timer del: 3:
1290979417739
2010/11/28 21:22:37 [debug] 10417#0: *8 generic phase: 0
2010/11/28 21:22:37 [debug] 10417#0: *8 rewrite phase: 1
2010/11/28 21:22:37 [debug] 10417#0: *8 test location: “/”
2010/11/28 21:22:37 [debug] 10417#0: *8 using configuration “/”
2010/11/28 21:22:37 [debug] 10417#0: *8 http cl:-1 max:1048576
2010/11/28 21:22:37 [debug] 10417#0: *8 rewrite phase: 3
2010/11/28 21:22:37 [debug] 10417#0: *8 post rewrite phase: 4
2010/11/28 21:22:37 [debug] 10417#0: *8 generic phase: 5
2010/11/28 21:22:37 [debug] 10417#0: *8 generic phase: 6
2010/11/28 21:22:37 [debug] 10417#0: *8 generic phase: 7
2010/11/28 21:22:37 [debug] 10417#0: *8 access phase: 8
2010/11/28 21:22:37 [debug] 10417#0: *8 access phase: 9
2010/11/28 21:22:37 [debug] 10417#0: *8 post access phase: 10
2010/11/28 21:22:37 [debug] 10417#0: *8 http init upstream, client
timer: 0
2010/11/28 21:22:37 [debug] 10417#0: *8 epoll add event: fd:3 op:3
ev:80000005
2010/11/28 21:22:37 [debug] 10417#0: *8 posix_memalign:
0000000001036860:4096 @16
2010/11/28 21:22:37 [debug] 10417#0: *8 http script copy: "Host: "
*2010/11/28 21:22:37 [debug] 10417#0: 8 http script var:
“[2a02:40:40:7:”
2010/11/28 21:22:37 [debug] 10417#0: *8 http script copy: "
2010/11/28 21:22:37 [debug] 10417#0: *8 http script copy: "X-Real-IP: "
2010/11/28 21:22:37 [debug] 10417#0: *8 http script var:
“2001:0:5ef5:79fd:3472:2f12:921f:6666”
2010/11/28 21:22:37 [debug] 10417#0: *8 http script copy: "
2010/11/28 21:22:37 [debug] 10417#0: *8 http script copy:
"X-Forwarded-For:
"
2010/11/28 21:22:37 [debug] 10417#0: *8 http script var:
“2001:0:5ef5:79fd:3472:2f12:921f:6666”
2010/11/28 21:22:37 [debug] 10417#0: *8 http script copy: "
2010/11/28 21:22:37 [debug] 10417#0: *8 http script copy: "Connection:
close

3

Hello!

On Sun, Nov 28, 2010 at 07:19:17PM +0000, Phil B. wrote:

Direct request to backend server (works):

http://[2a02:40:40:7::3]/test.php
$_SERVER[‘HTTP_HOST’] = [2a02:40:40:7::3]

Via proxy:

http://[2a02:40:40:7::7]/test.php
$_SERVER[‘HTTP_HOST’] = [2a02:40:40:7:

Known issue, ipv6 address literals not supported.

http://nginx.org/pipermail/nginx/2010-November/023652.html

Maxim D.

4

On 29 November 2010 01:15, Maxim D. [email protected] wrote:

If I enter the IPv6 address into the browser, the address is trimmed when
Via proxy:

http://[2a02:40:40:7::7]/test.php
$_SERVER[‘HTTP_HOST’] = [2a02:40:40:7:

Known issue, ipv6 address literals not supported.

IPv6 bug

Thanks for the info, will have to hope that someone has time to fix it
at
some point!
Unfortunately the only way to test via a 6to4 tunnel on an IPv4
connection
is to use the full IPv6 address.