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| -rw-r--r-- | docs/libcurl/opts/CURLOPT_URL.3 | 25 |
1 files changed, 24 insertions, 1 deletions
diff --git a/docs/libcurl/opts/CURLOPT_URL.3 b/docs/libcurl/opts/CURLOPT_URL.3 index bf192282c..030ed7395 100644 --- a/docs/libcurl/opts/CURLOPT_URL.3 +++ b/docs/libcurl/opts/CURLOPT_URL.3 @@ -5,7 +5,7 @@ .\" * | (__| |_| | _ <| |___ .\" * \___|\___/|_| \_\_____| .\" * -.\" * Copyright (C) 1998 - 2014, Daniel Stenberg, <daniel@haxx.se>, et al. +.\" * Copyright (C) 1998 - 2015, Daniel Stenberg, <daniel@haxx.se>, et al. .\" * .\" * This software is licensed as described in the file COPYING, which .\" * you should have received as part of this distribution. The terms @@ -284,6 +284,29 @@ escape it by providing it as backslash and its ASCII value in hexadecimal: .SH DEFAULT There is no default URL. If this option isn't set, no transfer can be performed. +.SH SECURITY CONCERNS +Applications may at times find it convenient to allow users to specify URLs +for various purposes and that string would then end up feeded to this option. + +Getting a URL from an external untrusted party will bring reasons for several +security concerns: + +If you have an application that runs as or in a server application, getting an +unfiltered URL can easily trick your application to access a local resource +instead of a remote. Protecting yourself against localhost accesses is very +hard when accepting user provided URLs. + +Such custom URLs can also access other ports than you planned as port numbers +are part of the regular URL format. The combination of a local host and a +custom port number can allow external users to play tricks with your local +services. + +Accepting external URLs may also use other protocols than http:// or other +common ones. Restrict what accept with \fICURLOPT_PROTOCOLS(3)\fP. + +User provided URLs can also be made to point to sites that redirect further on +(possibly to other protocols too). Consider your +\fICURLOPT_FOLLOWLOCATION(3)\fP and \fICURLOPT_REDIR_PROTOCOLS(3)\fP settings. .SH PROTOCOLS All .SH EXAMPLE |