nginx serving wrong website under proxy_cache

[Igor Sysoev]

On Sun, May 03, 2009 at 01:18:30AM -0400, Jim Ohlstein wrote:

> 
> 
> Igor Sysoev wrote:
> >On Sat, May 02, 2009 at 11:16:47PM -0400, Jim Ohlstein wrote:
> >
> >  
> >>Correction:
> >>
> >>The question should read:
> >>
> >>Do I need to use two fastcgi_cache_key settings if a site serves both 
> >>http and https?
> >>    
> >
> >If you use the same backend - no:
> >
> >      server {
> >          listen 80;
> >          location / {
> >              fastcgi_pass       backend:9000;
> >              fastcgi_cache_key  backend:9000$request_uri;
> >          }
> >      }
> >
> >      server {
> >          listen 443;
> >          location / {
> >              fastcgi_pass       backend:9000;
> >              fastcgi_cache_key  backend:9000$request_uri;
> >          }
> >      }
> >
> >  
> 
> I am using the same backend and configured like this:
> 
> server {
>    listen  80;
> 
>    location / {
>        fastcgi_pass backend;
>        fastcgi_cache one;
>        fastcgi_cache_key backend$request_uri;
>    }
> }
> 
> server {
>    listen     443;
>    location / {
>        fastcgi_pass backend;
>        fastcgi_cache one;
>        fastcgi_cache_key backend$request_uri;
>    }
> }

Yes, this is OK.

> For what it may be worth, I have seen some md5 collisions in the error log:
> 
> 2009/05/03 00:39:18 [crit] 21997#0: *61 cache file 
> "/usr/local/nginx/cache/0/da/90e8de013d4126fbab247d12350fdda0" has md5 
> collision, client: my.ip.addr.ess, server: mydomain.com, request: "GET 
> /rtwhtrsyrn/010110A/687474702s7777772r777732746s7073697465732r636s6q2s627574746s6r2r7068703s753q776s726p6477617274776s7n6s6r655s636s6q 
> HTTP/1.1", host: "mydomain.com", referrer: 
> "https://mydomain.com/rtwhtrsyrn/010110A/687474702s776s726p6477617274776s7n6s6r652r636s6q2s666s72756q732s616r6r6s756r63656q656r74732s31333535392q6r6s2q796s752q6172656r742q6372617n792r68746q6p"
> 2009/05/03 00:39:24 [crit] 21997#0: *44 cache file 
> "/usr/local/nginx/cache/0/da/90e8de013d4126fbab247d12350fdda0" has md5 
> collision, client: my.ip.addr.ess, server: mydomain.com, request: "GET 
> /rtwhtrsyrn/010110A/687474702s7777772r777732746s7073697465732r636s6q2s627574746s6r2r7068703s753q776s726p6477617274776s7n6s6r655s636s6q 
> HTTP/1.1", host: "mydomain.com", referrer: 
> "https://mydomain.com/rtwhtrsyrn/010110A/687474702s776s726p6477617274776s7n6s6r652r636s6q2s666s72756q732s2r2r2s"

nginx uses md5 create a cache key and use the key as path to a cache file,
90e8de013d4126fbab247d12350fdda0 in you case. Besides, in the file there
is crc32 of the original key to test possible md5 collisions.

Could you run

head -1 /usr/local/nginx/cache/0/da/90e8de013d4126fbab247d12350fdda0 | hexdump
head -2 /usr/local/nginx/cache/0/da/90e8de013d4126fbab247d12350fdda0 | tail -1

?


-- 
Igor Sysoev
http://sysoev.ru/en/