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https://github.com/transmission/transmission
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117ab3e8d2
On a way to factoring out OpenSSL support to a standalone file to ease
addition of other crypto libraries support in the future, move helpers
providing DH key exchange to crypto-utils.{c,h}. OpenSSL-related
functionality (DH context management) is moved to crypto-utils-openssl.c.
Since we know in advance that DH secret key management code will be the
same for most of backends, implement common functionality in separate
crypto-utils-fallback.c.
Add new tr_dh_ctx_t and tr_dh_secret_t types and functions to be
implemented by crypto backends:
* tr_dh_new - allocate DH context,
* tr_dh_free - free the context,
* tr_dh_make_key - generate private/public keypair,
* tr_dh_agree - perform DH key exchange and generate secret key,
* tr_dh_secret_derive - calculate secret key hash,
* tr_dh_secret_free - free the secret key,
* tr_dh_align_key - align some DH key in the buffer allocated for it.
Make DH secret key not accessible in plain form outside the crypto
backend. This allows for implementations where the key is managed by
the underlying library and is not even exposed to our backend.
77 lines
1.9 KiB
C
77 lines
1.9 KiB
C
/*
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* This file Copyright (C) Mnemosyne LLC
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*
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* It may be used under the GNU GPL versions 2 or 3
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* or any future license endorsed by Mnemosyne LLC.
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*
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* $Id$
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*/
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/* This file is designed specifically to be included by other source files to
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implement missing (or duplicate) functionality without exposing internal
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details in header files. */
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#include <assert.h>
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#include "transmission.h"
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#include "crypto-utils.h"
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#include "utils.h"
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/***
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****
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***/
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#ifdef TR_CRYPTO_DH_SECRET_FALLBACK
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/* Most Diffie-Hellman backends handle secret key in the very same way: by
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manually allocating memory for it and storing the value in plain form. */
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struct tr_dh_secret
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{
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size_t key_length;
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uint8_t key[];
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};
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static struct tr_dh_secret *
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tr_dh_secret_new (size_t key_length)
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{
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struct tr_dh_secret * handle = tr_malloc (sizeof (struct tr_dh_secret) + key_length);
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handle->key_length = key_length;
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return handle;
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}
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static void
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tr_dh_secret_align (struct tr_dh_secret * handle,
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size_t current_key_length)
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{
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tr_dh_align_key (handle->key, current_key_length, handle->key_length);
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}
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bool
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tr_dh_secret_derive (tr_dh_secret_t raw_handle,
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const void * prepend_data,
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size_t prepend_data_size,
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const void * append_data,
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size_t append_data_size,
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uint8_t * hash)
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{
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struct tr_dh_secret * handle = raw_handle;
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assert (handle != NULL);
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assert (hash != NULL);
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return tr_sha1 (hash,
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prepend_data == NULL ? "" : prepend_data,
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prepend_data == NULL ? 0 : (int) prepend_data_size,
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handle->key, (int) handle->key_length,
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append_data, append_data == NULL ? 0 : (int) append_data_size,
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NULL);
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}
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void
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tr_dh_secret_free (tr_dh_secret_t handle)
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{
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tr_free (handle);
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}
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#endif /* TR_CRYPTO_DH_SECRET_FALLBACK */
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