116 lines
4.9 KiB
C
116 lines
4.9 KiB
C
//
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// mpw-algorithm.c
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// MasterPassword
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//
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// Created by Maarten Billemont on 2014-12-20.
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// Copyright (c) 2014 Lyndir. All rights reserved.
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//
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#include <string.h>
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#include <errno.h>
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#include <arpa/inet.h>
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#include "mpw-types.h"
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#include "mpw-util.h"
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#define MP_N 32768
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#define MP_r 8
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#define MP_p 2
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#define MP_hash PearlHashSHA256
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static const uint8_t *mpw_masterKeyForUser_v1(const char *fullName, const char *masterPassword) {
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const char *mpKeyScope = mpw_scopeForVariant( MPSiteVariantPassword );
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trc( "algorithm: v%d\n", 1 );
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trc( "fullName: %s (%zu)\n", fullName, mpw_utf8_strlen( fullName ) );
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trc( "masterPassword: %s\n", masterPassword );
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trc( "key scope: %s\n", mpKeyScope );
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// Calculate the master key salt.
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// masterKeySalt = mpKeyScope . #fullName . fullName
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size_t masterKeySaltSize = 0;
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uint8_t *masterKeySalt = NULL;
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mpw_push_string( &masterKeySalt, &masterKeySaltSize, mpKeyScope );
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mpw_push_int( &masterKeySalt, &masterKeySaltSize, htonl( mpw_utf8_strlen( fullName ) ) );
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mpw_push_string( &masterKeySalt, &masterKeySaltSize, fullName );
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if (!masterKeySalt) {
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ftl( "Could not allocate master key salt: %d\n", errno );
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return NULL;
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}
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trc( "masterKeySalt ID: %s\n", mpw_id_buf( masterKeySalt, masterKeySaltSize ) );
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// Calculate the master key.
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// masterKey = scrypt( masterPassword, masterKeySalt )
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const uint8_t *masterKey = mpw_scrypt( MP_dkLen, masterPassword, masterKeySalt, masterKeySaltSize, MP_N, MP_r, MP_p );
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mpw_free( masterKeySalt, masterKeySaltSize );
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if (!masterKey) {
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ftl( "Could not allocate master key: %d\n", errno );
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return NULL;
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}
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trc( "masterKey ID: %s\n", mpw_id_buf( masterKey, MP_dkLen ) );
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return masterKey;
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}
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static const char *mpw_passwordForSite_v1(const uint8_t *masterKey, const char *siteName, const MPSiteType siteType, const uint32_t siteCounter,
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const MPSiteVariant siteVariant, const char *siteContext) {
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const char *siteScope = mpw_scopeForVariant( siteVariant );
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trc( "algorithm: v%d\n", 1 );
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trc( "siteName: %s\n", siteName );
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trc( "siteCounter: %d\n", siteCounter );
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trc( "siteVariant: %d\n", siteVariant );
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trc( "siteType: %d\n", siteType );
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trc( "site scope: %s, context: %s\n", siteScope, siteContext? "<empty>": siteContext );
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trc( "seed from: hmac-sha256(masterKey, %s | %s | %s | %s | %s | %s)\n",
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siteScope, mpw_hex_l( htonl( strlen( siteName ) ) ), siteName,
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mpw_hex_l( htonl( siteCounter ) ),
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mpw_hex_l( htonl( siteContext? strlen( siteContext ): 0 ) ), siteContext? "(null)": siteContext );
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// Calculate the site seed.
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// sitePasswordSeed = hmac-sha256( masterKey, siteScope . #siteName . siteName . siteCounter . #siteContext . siteContext )
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size_t sitePasswordInfoSize = 0;
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uint8_t *sitePasswordInfo = NULL;
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mpw_push_string( &sitePasswordInfo, &sitePasswordInfoSize, siteScope );
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mpw_push_int( &sitePasswordInfo, &sitePasswordInfoSize, htonl( mpw_utf8_strlen( siteName ) ) );
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mpw_push_string( &sitePasswordInfo, &sitePasswordInfoSize, siteName );
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mpw_push_int( &sitePasswordInfo, &sitePasswordInfoSize, htonl( siteCounter ) );
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if (siteContext) {
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mpw_push_int( &sitePasswordInfo, &sitePasswordInfoSize, htonl( mpw_utf8_strlen( siteContext ) ) );
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mpw_push_string( &sitePasswordInfo, &sitePasswordInfoSize, siteContext );
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}
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if (!sitePasswordInfo) {
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ftl( "Could not allocate site seed info: %d\n", errno );
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return NULL;
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}
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trc( "sitePasswordInfo ID: %s\n", mpw_id_buf( sitePasswordInfo, sitePasswordInfoSize ) );
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const uint8_t *sitePasswordSeed = mpw_hmac_sha256( masterKey, MP_dkLen, sitePasswordInfo, sitePasswordInfoSize );
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mpw_free( sitePasswordInfo, sitePasswordInfoSize );
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if (!sitePasswordSeed) {
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ftl( "Could not allocate site seed: %d\n", errno );
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return NULL;
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}
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trc( "sitePasswordSeed ID: %s\n", mpw_id_buf( sitePasswordSeed, 32 ) );
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// Determine the template.
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const char *template = mpw_templateForType( siteType, sitePasswordSeed[0] );
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trc( "type %d, template: %s\n", siteType, template );
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if (strlen( template ) > 32) {
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ftl( "Template too long for password seed: %lu", strlen( template ) );
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mpw_free( sitePasswordSeed, sizeof( sitePasswordSeed ) );
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return NULL;
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}
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// Encode the password from the seed using the template.
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char *const sitePassword = calloc( strlen( template ) + 1, sizeof( char ) );
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for (size_t c = 0; c < strlen( template ); ++c) {
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sitePassword[c] = mpw_characterFromClass( template[c], sitePasswordSeed[c + 1] );
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trc( "class %c, index %u (0x%02X) -> character: %c\n", template[c], sitePasswordSeed[c + 1], sitePasswordSeed[c + 1],
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sitePassword[c] );
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}
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mpw_free( sitePasswordSeed, sizeof( sitePasswordSeed ) );
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return sitePassword;
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}
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