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|
===========
vmod_digest
===========
---------------------
Varnish Digest Module
---------------------
:Manual section: 3
:Author: Kristian Lyngstøl
:Date: 2016-03-16
:Version: 1.0.2
SYNOPSIS
========
::
import digest;
digest.hmac_md5(<key>,<message>);
digest.hmac_sha1(<key>, <message>);
digest.hmac_sha256(<key>, <message));
digest.base64(<string>);
digest.base64url(<string>);
digest.base64url_nopad(<string>);
digest.base64_hex(<string>);
digest.base64url_hex(<string>);
digest.base64url_nopad_hex(<string>);
digest.base64_decode(<string>);
digest.base64url_decode(<string>);
digest.base64url_nopad_decode(<string>);
digest.version()
digest.hash_sha1(<string>);
digest.hash_sha224(<string>);
digest.hash_sha256(<string>);
digest.hash_sha384(<string>);
digest.hash_sha512(<string>);
digest.hash_gost(<string>);
digest.hash_md2(<string>);
digest.hash_md4(<string>);
digest.hash_md5(<string>);
digest.hash_crc32(<string>);
digest.hash_crc32b(<string>);
digest.hash_adler32(<string>);
digest.hash_haval128(<string>);
digest.hash_haval160(<string>);
digest.hash_haval192(<string>);
digest.hash_haval224(<string>);
digest.hash_haval256(<string>);
digest.hash_ripemd128(<string>);
digest.hash_ripemd160(<string>);
digest.hash_ripemd256(<string>);
digest.hash_ripemd320(<string>);
digest.hash_tiger(<string>);
digest.hash_tiger128(<string>);
digest.hash_tiger160(<string>);
digest.hash_snefru128(<string>);
digest.hash_snefru256(<string>);
DESCRIPTION
===========
Varnish Module (vmod) for computing HMAC, message digests and working with
base64.
All HMAC- and hash-functionality is provided by libmhash, while base64 is
implemented locally.
FUNCTIONS
=========
Example VCL::
backend foo { ... };
import digest;
sub vcl_recv {
if (digest.hmac_sha256("key",req.http.x-data) != req.http.x-data-sig)
{
return (synth(401, "Naughty user!"));
}
}
hmac_(hash)
-----------
Prototype
::
digest.hmac_md5(<key>,<message>);
digest.hmac_sha1(<key>, <message>);
digest.hmac_sha256(<key>, <message));
Returns
String. Hex-encoded prepended with 0x.
Description
All the various hmac-functions work the same, but use a different
hash mechanism.
Example
::
set resp.http.x-data-sig =
digest.hmac_sha256("secretkey",resp.http.x-data);
base64, base64url, base64url_nopad
----------------------------------
Prototype
::
digest.base64(<string>);
digest.base64url(<string>);
digest.base64url_nopad(<string>);
Returns
String
Description
Returns the base64-encoded version of the input-string. The
base64url-variant uses base64 url-encoding (+/ replaced by -_) and
the base64url_nopad does the same, but avoids adding padding. The
latter is more commonly used, though an (allowed) exception to the
RFC4648.
Example
::
set resp.http.x-data-sig =
digest.base64({"content with
newline in it"});
base64_hex, base64url_hex, base64url_nopad_hex
-----------------------------------------------
Prototype
::
digest.base64_hex(<string>);
digest.base64url_hex(<string>);
digest.base64url_nopad_hex(<string>);
Returns
String
Description
Returns the base64-encoded version of the hex encoded input-string. The
input-string can start with an optional 0x. Input is hex-decoded into binary
and the encoding is identical to base64, base64url, and base64url_nopad.
Example
::
set resp.http.x-data-sig =
digest.base64_hex("0xdd26bfddf122c1055d4c");
hash_(algorithm)
----------------
Prototype
::
digest.hash_sha1(<string>);
digest.hash_sha224(<string>);
digest.hash_sha256(<string>);
digest.hash_sha384(<string>);
digest.hash_sha512(<string>);
digest.hash_gost(<string>);
digest.hash_md2(<string>);
digest.hash_md4(<string>);
digest.hash_md5(<string>);
digest.hash_crc32(<string>);
digest.hash_crc32b(<string>);
digest.hash_adler32(<string>);
digest.hash_haval128(<string>);
digest.hash_haval160(<string>);
digest.hash_haval192(<string>);
digest.hash_haval224(<string>);
digest.hash_haval256(<string>);
digest.hash_ripemd128(<string>);
digest.hash_ripemd160(<string>);
digest.hash_ripemd256(<string>);
digest.hash_ripemd320(<string>);
digest.hash_tiger(<string>);
digest.hash_tiger128(<string>);
digest.hash_tiger160(<string>);
digest.hash_snefru128(<string>);
digest.hash_snefru256(<string>);
Returns
String
Description
Computes the digest/hash of the supplied, using the specified hash
algorithm. If in doubt as to which to pick, use SHA256. For
detailed discussions, see The Internet.
Example
::
set resp.http.x-data-md5 =
digest.hash_md5(resp.http.x-data);
base64_decode, base64url_decode, base64url_nopad_decode
-------------------------------------------------------
Prototype
::
digest.base64_decode(<string>);
digest.base64url_decode(<string>);
digest.base64url_nopad_decode(<string>);
Returns
String
Description
Decodes the bas64 and base64url-encoded strings. All functions
treat padding the same, meaning base64url_decode and
base64url_nopad_decode are identical, but available for consistency
and practicality.
Example
::
synthetic(digest.base64_decode(req.http.x-parrot));
version
-------
Prototype
::
digest.version()
Returns
string
Description
Returns the string constant version-number of the digest vmod.
Example
::
set resp.http.X-digest-version = digest.version();
INSTALLATION
============
The source tree is based on autotools to configure the building, and
does also have the necessary bits in place to do functional unit tests
using the ``varnishtest`` tool.
Building requires the Varnish header files and uses pkg-config to find
the necessary paths.
Usage::
./autogen.sh
./configure
If you have installed Varnish to a non-standard directory, call
``autogen.sh`` and ``configure`` with ``PKG_CONFIG_PATH`` pointing to
the appropriate path. For example, when varnishd configure was called
with ``--prefix=$PREFIX``, use
PKG_CONFIG_PATH=${PREFIX}/lib/pkgconfig
export PKG_CONFIG_PATH
Make targets:
* make - builds the vmod.
* make install - installs your vmod.
* make check - runs the unit tests in ``src/tests/*.vtc``
* make distcheck - run check and prepare a tarball of the vmod.
AUTHOR
======
Original author: Kristian Lyngstøl <kristian@varnish-software.com>.
This Vmod was written for Media Norge, Schibsted and others.
The bulk of the functionality is acquired through libmhash.
BUGS
====
No bugs at all!
If the key is NULL for hmac-functions, the function will fail and return
NULL itself, and do no hmac-computation at all. This should be used as an
indication of some greater flaw in your software/VCL. (I.e.: Your key
should be under your control, not user-supplied without verification).
The `base64url_nopad_decode()` and `base64url_decode()` functions do not
differ much. The exception is that nopad_decode() does not know about
padding at all, and might get confused if the input actually is padded.
SEE ALSO
========
* libmhash
* varnishd(1)
* vcl(7)
* https://github.com/varnish/libvmod-digest
|
