[patch] ftp: disallow redirect and reading from file://

[Hiltjo Posthuma]

Hi,

I noticed with the ftp program when downloading via HTTP or HTTPS it can 
be redirected to read from a local file directly.

While testing using a CGI program that responds with the HTTP headers:

        Status: 301 Moved Permanently
        Location: file:///dev/urandom

The patch below disallows redirections to a file scheme.


Patch:


diff --git usr.bin/ftp/fetch.c usr.bin/ftp/fetch.c
index eff558eba6f..1c749b21048 100644
--- usr.bin/ftp/fetch.c
+++ usr.bin/ftp/fetch.c
@@ -258,6 +258,9 @@ url_get(const char *origline, const char *proxyenv, const 
char *outfile, int las
        } else
                errx(1, "url_get: Invalid URL '%s'", newline);
 
+       if (isfileurl && redirect_loop > 0)
+               errx(1, "url_get: redirect to file '%s' not allowed", newline);
+
        if (isfileurl) {
                path = host;
        } else {

-- 
Kind regards,
Hiltjo