Bug #1720
closedRewrite/redirect rules and URL encoding
Description
Dear lighty community,
I am using lighty to serve a wiki; to have nice urls, i use the following in my lighttpd.conf:
url.rewrite-once = ( "^/wiki/(.*)$" => "/wiki/awki.cgi/$1" )
and so i was hoping that everything going through /wiki/ would be interpreted by the script 'awki.cgi'. However, if I url-encode a part of the url, the above rewrite rule does not apply: if I ask my browser to access /wik%69/, lighty does not execute the script and gives me a
listing of files in that directory!
Is there a way to avoid that?
I asked in the forum last week but, as I had no answer, I decided to open a ticket; I apologize if this is unapropriate.
-- gaetan.bisson
Updated by Anonymous over 16 years ago
I've come up with the following workaround:
url.rewrite-once = ( "^/wiki/(.*)$" => "/wiki/awki.cgi/$1" )
$HTTP["url"] =~ "^/wiki" {
$HTTP["url"] !~ "^/wiki/awki.cgi/" {
url.access-deny = ("")
}
}
It works because the $HTTP["url"] condition is evaluated after the URL is parsed (so all url-encoded characters are hopefully replaced); well, unless I'm mistaken.
-- gaetan.bisson
Updated by hoffie over 16 years ago
- Status changed from New to Fixed
- Resolution set to fixed
Should be fixed in r2278. Just for reference, in your case you consider this a security issue since it allows for unwanted disclosure of information.
Not sure if we are going to handle it as one, but I guess it should be at least noted.
stbuehler committed the fix and didn't close this ticket as trac was broken, so I'm doing that now. All kudos to him in any case. :p
Updated by stbuehler about 16 years ago
mod_redirect had similar problems:
Summary for now:- 1.4.x: fixed in r2278 (rewrite) and r2309 (redirect)
- trunk: fixed in r2307 (rewrite) and r2310 (redirect)
Updated by stbuehler about 16 years ago
- Status changed from Fixed to Reopened
- Target version changed from 1.4.20 to 1.4.21
- Patch available set to No
Patch(es) reverted in 1.4.x (r2362) - too many regressions came up.
See commit message for more details.
We are not sure yet what to do, maybe we won't fix this at all.
Updated by stbuehler almost 16 years ago
- Target version changed from 1.4.22 to 1.4.23
Updated by stbuehler over 15 years ago
- Target version changed from 1.4.23 to 1.4.x
Updated by gstrauss over 8 years ago
- Related to Bug #911: Need for URL encoding in mod_redirect and possibly mod_rewrite added
Updated by gstrauss over 8 years ago
- Status changed from Reopened to Need Feedback
con->request.uri is url-encoded and includes URI path and query-string
con->uri.path has been url-decoded and path has been simplified/normalized
con->uri.query is url-encoded
mod_rewrite operates on con->request.uri, meaning that there might be ways to subvert rewrite rules by url-encoding parts of it, since most rewrite rules will be against a normalized path and query string.
Perhaps the solution is to normalize the url-encoding of con->request.uri for rewrite rules, but there might still be complexities involved in virtual paths containing '.' or '..', PATH_INFO, whether or not to decode %2F ('/') in path and/or query-string parts, ...
I propose normalizing the url-encoding, including decoding %2F to '/'. Decoding %2F to '/' potentially loses some info in PATH_INFO and query string, but is a more secure default giving most people what they would expect. Maybe we could additionally provide a config switch to skip decode of %2F for the regex input.
Note: I am suggesting decoding con->request.uri temporarily for the regex match. If we were to normalize url-encoding at the start of the request, I would suggest leaving %2F url-encoded at that point of normalization. We might still decode %2F for regex matching, unless a new config flag were set.
(While discussing url-decoding here, please see url-encoding discussion of regex back-reference matches in #911)
Updated by gstrauss over 6 years ago
- Status changed from Need Feedback to Fixed
- % Done changed from 0 to 100
Applied in changeset 3eb7902e10ba75b3f2eb159e244d0d8e5037ccd2.
Updated by gstrauss over 6 years ago
See server.http-parseopts documentation for how to enable URL normalization (recommended)
For backwards compatibility, URL normalization is not enabled by default, though that may change in a future release.
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