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1 change: 1 addition & 0 deletions ext/openssl/ossl.c
Original file line number Diff line number Diff line change
Expand Up @@ -1040,6 +1040,7 @@ Init_openssl(void)
Init_ossl_engine();
Init_ossl_hmac();
Init_ossl_kdf();
Init_ossl_mac();
Init_ossl_ns_spki();
Init_ossl_ocsp();
Init_ossl_pkcs12();
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1 change: 1 addition & 0 deletions ext/openssl/ossl.h
Original file line number Diff line number Diff line change
Expand Up @@ -188,6 +188,7 @@ extern VALUE dOSSL;
#include "ossl_engine.h"
#include "ossl_hmac.h"
#include "ossl_kdf.h"
#include "ossl_mac.h"
#include "ossl_ns_spki.h"
#include "ossl_ocsp.h"
#include "ossl_pkcs12.h"
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182 changes: 182 additions & 0 deletions ext/openssl/ossl_mac.c
Original file line number Diff line number Diff line change
@@ -0,0 +1,182 @@
#include "ossl.h"

#if OSSL_OPENSSL_PREREQ(3, 0, 0)
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I believe LibreSSL and AWS-LC will eventually implement the EVP_MAC API too. Please use an extconf.rb check instead of relying on the version number.

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Does any of the following approaches align with what you're suggesting?

  • OpenSSL::MAC should be defined if all necessary OpenSSL functions are available.
  • OpenSSL::MAC should be defined if a preselected OpenSSL function is available.
  • Each OpenSSL::MAC method should raise an exception unless all OpenSSL functions it needs are available.

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I think we can assume the type EVP_MAC{,_CTX} and the related functions will be added in the same release, so checking any one of them should be sufficient.


#define NewMAC(klass) \
TypedData_Wrap_Struct((klass), &ossl_mac_type, 0)
#define SetMAC(obj, ctx) do { \
if (!(ctx)) \
ossl_raise(rb_eRuntimeError, "MAC wasn't initialized"); \
RTYPEDDATA_DATA(obj) = (ctx); \
} while (0)
#define GetMAC(obj, ctx) do { \
TypedData_Get_Struct((obj), EVP_MAC_CTX, &ossl_mac_type, (ctx)); \
if (!(ctx)) \
ossl_raise(rb_eRuntimeError, "MAC wasn't initialized"); \
} while (0)

/*
* Classes
*/
static VALUE cMAC;
static VALUE cCMAC;
static VALUE eMACError;

/*
* Public
*/

/*
* Private
*/
static void
ossl_mac_free(void *ctx)
{
EVP_MAC_CTX_free(ctx);
}

static const rb_data_type_t ossl_mac_type = {
"OpenSSL/MAC",
{
0, ossl_mac_free,
},
0, 0, RUBY_TYPED_FREE_IMMEDIATELY | RUBY_TYPED_WB_PROTECTED,
};

static VALUE
ossl_mac_alloc(VALUE klass)
{
return NewMAC(klass);
}

static VALUE
ossl_mac_initialize(VALUE self, VALUE algorithm)
{
EVP_MAC *mac;
EVP_MAC_CTX *ctx;

TypedData_Get_Struct(self, EVP_MAC_CTX, &ossl_mac_type, ctx);
if (ctx)
rb_raise(rb_eTypeError, "MAC already initialized");

mac = EVP_MAC_fetch(NULL, StringValueCStr(algorithm), NULL);
if (!mac)
ossl_raise(eMACError, "EVP_MAC_fetch");
ctx = EVP_MAC_CTX_new(mac);
if (!ctx) {
EVP_MAC_free(mac);
ossl_raise(eMACError, "EVP_MAC_CTX_new");
}
SetMAC(self, ctx);

return self;
}

static VALUE
ossl_cmac_initialize(VALUE self, VALUE cipher, VALUE key)
{
EVP_MAC_CTX *ctx;
VALUE algorithm;
OSSL_PARAM params[2];

algorithm = rb_str_new_literal("CMAC");
rb_call_super(1, &algorithm);

GetMAC(self, ctx);
StringValue(key);
params[0] = OSSL_PARAM_construct_utf8_string("cipher", StringValueCStr(cipher), 0);
params[1] = OSSL_PARAM_construct_end();
if (EVP_MAC_init(ctx, (unsigned char *)RSTRING_PTR(key), RSTRING_LEN(key), params) != 1)
ossl_raise(eMACError, "EVP_MAC_init");

return self;
}

static VALUE
ossl_mac_copy(VALUE self, VALUE other)
{
EVP_MAC_CTX *ctx1, *ctx2;

TypedData_Get_Struct(self, EVP_MAC_CTX, &ossl_mac_type, ctx2);
if (ctx2)
rb_raise(rb_eTypeError, "MAC already initialized");

rb_check_frozen(self);
if (self == other)
return self;

GetMAC(other, ctx1);
ctx2 = EVP_MAC_CTX_dup(ctx1);
if (!ctx2)
ossl_raise(eMACError, "EVP_MAC_CTX_dup");
SetMAC(self, ctx2);

return self;
}

static VALUE
ossl_mac_update(VALUE self, VALUE chunk)
{
EVP_MAC_CTX *ctx;

GetMAC(self, ctx);
StringValue(chunk);
if (EVP_MAC_update(ctx, (unsigned char *)RSTRING_PTR(chunk), RSTRING_LEN(chunk)) != 1)
ossl_raise(eMACError, "EVP_MAC_update");

return self;
}

static VALUE
ossl_mac_mac(VALUE self)
{
VALUE ret;
EVP_MAC_CTX *ctx1, *ctx2;
size_t len;

GetMAC(self, ctx1);
if (EVP_MAC_final(ctx1, NULL, &len, 0) != 1)
ossl_raise(eMACError, "EVP_MAC_final");
ret = rb_str_new(NULL, len);
ctx2 = EVP_MAC_CTX_dup(ctx1);
if (!ctx2)
ossl_raise(eMACError, "EVP_MAC_CTX_dup");
if (EVP_MAC_final(ctx2, (unsigned char *)RSTRING_PTR(ret), &len, RSTRING_LEN(ret)) != 1) {
EVP_MAC_CTX_free(ctx2);
ossl_raise(eMACError, "EVP_MAC_final");
}
EVP_MAC_CTX_free(ctx2);

return ret;
}

/*
* INIT
*/
void
Init_ossl_mac(void)
{
#if 0
mOSSL = rb_define_module("OpenSSL");
eOSSLError = rb_define_class_under(mOSSL, "OpenSSLError", rb_eStandardError);
#endif

cMAC = rb_define_class_under(mOSSL, "MAC", rb_cObject);
rb_define_alloc_func(cMAC, ossl_mac_alloc);
rb_define_method(cMAC, "initialize", ossl_mac_initialize, 1);
rb_define_method(cMAC, "initialize_copy", ossl_mac_copy, 1);
rb_define_method(cMAC, "update", ossl_mac_update, 1);
rb_define_alias(cMAC, "<<", "update");
rb_define_method(cMAC, "mac", ossl_mac_mac, 0);

cCMAC = rb_define_class_under(cMAC, "CMAC", cMAC);
rb_define_method(cCMAC, "initialize", ossl_cmac_initialize, 2);

eMACError = rb_define_class_under(mOSSL, "MACError", eOSSLError);
}
#else
void
Init_ossl_mac(void)
{
}
#endif
6 changes: 6 additions & 0 deletions ext/openssl/ossl_mac.h
Original file line number Diff line number Diff line change
@@ -0,0 +1,6 @@
#if !defined(_OSSL_MAC_H_)
#define _OSSL_MAC_H_

void Init_ossl_mac(void);

#endif /* _OSSL_MAC_H_ */
1 change: 1 addition & 0 deletions lib/openssl.rb
Original file line number Diff line number Diff line change
Expand Up @@ -18,6 +18,7 @@
require_relative 'openssl/cipher'
require_relative 'openssl/digest'
require_relative 'openssl/hmac'
require_relative 'openssl/mac'
require_relative 'openssl/x509'
require_relative 'openssl/ssl'
require_relative 'openssl/pkcs5'
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36 changes: 36 additions & 0 deletions lib/openssl/mac.rb
Original file line number Diff line number Diff line change
@@ -0,0 +1,36 @@
# frozen_string_literal: true

module OpenSSL
if defined?(MAC)
class MAC
def ==(other)
return false unless self.class === other
return false unless self.mac.bytesize == other.mac.bytesize

OpenSSL.fixed_length_secure_compare(self.mac, other.mac)
end
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Comparing MACs generated by different algorithms or parameters would be pointless, but this doesn't prevent it and it's probably not possible unless we store parameters or sensitive keys ourselves, which would be a bad idea.

Honestly, I'm not sure if this should be provided by this library.

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This, too, aims to align OpenSSL::MAC subclasses with OpenSSL::HMAC to facilitate future migrations to OpenSSL::MAC::HMAC .
OpenSSL::HMAC has an == method similar to this one, thereby comparing its objects as calculated values.
That said, objects of these classes are essentially calculators.
There seems little need to compare them as such, and as you indicate, no appropriate way to implement such a comparison.
If OpenSSL::HMAC didn't exist, I'd prefer to treat OpenSSL::MAC::CMAC objects only as calculators and avoid adding this == method.
Considering this, should we remove OpenSSL::MAC#== ?

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I've forgotten it was in OpenSSL::HMAC. It seems to have the same issue.

IMO we should not add it to OpenSSL::MAC, though we can't remove the existing method from OpenSSL::HMAC.


def hexmac
mac.unpack1('H*')
end
alias inspect hexmac
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I think people would expect #inspect to show the class name or the algorithm rather than the calculated MAC.

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This aims to align OpenSSL::MAC subclasses with OpenSSL::HMAC to facilitate future migrations to OpenSSL::MAC::HMAC .
OpenSSL::HMAC has inspect as an alias for hexdigest , though it's unlikely that anyone would depend on that alias in production code.
If OpenSSL::HMAC didn't exist, I'd prefer OpenSSL::MAC::CMAC#inspect to behave exactly like Object#inspect .
Considering this, should we remove OpenSSL::MAC#inspect ?

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Good point it's in OpenSSL::HMAC. IMHO OpenSSL::MAC doesn't have to follow it.

The digest library (and thus OpenSSL::Digest)'s #inspect seems to return an Object#inspect-style string.

alias to_s hexmac

def base64mac
[mac].pack('m0')
end

class CMAC < MAC
class << self
def mac(cipher, key, message)
cmac = new(cipher, key)
cmac << message
cmac.send(__callee__)
end
alias hexmac mac
alias base64mac mac
end
end
end
end
end
34 changes: 34 additions & 0 deletions test/openssl/test_cmac.rb
Original file line number Diff line number Diff line change
@@ -0,0 +1,34 @@
# frozen_string_literal: true
require_relative "utils"

if defined?(OpenSSL::MAC::CMAC)

class OpenSSL::TestCMAC < OpenSSL::TestCase
def test_cmac
cmac = OpenSSL::MAC::CMAC.new("AES-128-CBC", ["2b7e151628aed2a6abf7158809cf4f3c"].pack("H*"))
cmac.update(["6bc1bee22e409f96e93d7e117393172a"].pack("H*"))
assert_equal ["070a16b46b4d4144f79bdd9dd04a287c"].pack("H*"), cmac.mac
assert_equal "070a16b46b4d4144f79bdd9dd04a287c", cmac.hexmac
assert_equal "BwoWtGtNQUT3m92d0EoofA==", cmac.base64mac
end

def test_dup
cmac1 = OpenSSL::MAC::CMAC.new("AES-192-CBC", ["8e73b0f7da0e6452c810f32b809079e562f8ead2522c6b7b"].pack("H*"))
cmac2 = cmac1.dup
assert_equal cmac2, cmac1

cmac1.update("message")
assert_not_equal cmac2, cmac1

cmac2.update("message")
assert_equal cmac2, cmac1
end

def test_class_methods
assert_equal ["28a7023f452e8f82bd4bf28d8c37c35c"].pack("H*"), OpenSSL::MAC::CMAC.mac("AES-256-CBC", ["603deb1015ca71be2b73aef0857d77811f352c073b6108d72d9810a30914dff4"].pack("H*"), ["6bc1bee22e409f96e93d7e117393172a"].pack("H*"))
assert_equal "28a7023f452e8f82bd4bf28d8c37c35c", OpenSSL::MAC::CMAC.hexmac("AES-256-CBC", ["603deb1015ca71be2b73aef0857d77811f352c073b6108d72d9810a30914dff4"].pack("H*"), ["6bc1bee22e409f96e93d7e117393172a"].pack("H*"))
assert_equal "KKcCP0Uuj4K9S/KNjDfDXA==", OpenSSL::MAC::CMAC.base64mac("AES-256-CBC", ["603deb1015ca71be2b73aef0857d77811f352c073b6108d72d9810a30914dff4"].pack("H*"), ["6bc1bee22e409f96e93d7e117393172a"].pack("H*"))
end
end

end