gpgme: Auswählen eines privaten Schlüssels beim Signieren von Daten

Question

Mit gpgme (der Entwicklungsbibliothek für gpg/gnupg) versuche ich einige Daten zu signieren. Im Schlüsselring habe ich mehr als 1 privaten Schlüssel, also möchte ich das richtige auswählen. Dies schlägt fehl mit: "Unusable secret key (117440566)". Der Schlüssel wurde mit gnupg2 selbst generiert. Bei Verwendung von gnupg tritt auch das Problem auf.

sec 1024R/14B7E8E6 2015-05-27 
     Key fingerprint = 95C7 6C5E F839 43DA 2F32 2CF4 D2C2 5144 14B7 E8E6 
uid     testkey2 (testkey2) <test@vanheusden.com> 
ssb 1024R/ED8059EA 2015-05-27 

pub rsa1024/14B7E8E6 
    created: 2015-05-27 expires: never  usage: SC 
    trust: ultimate  validity: ultimate 
sub rsa1024/ED8059EA 
    created: 2015-05-27 expires: never  usage: E 
sub rsa1024/74D6F5C6 
    created: 2015-05-31 expires: never  usage: S 

Zuerst habe ich prüfen, ob ein privater Schlüssel für den Schlüssel ist ausgewählt:

gpgme_op_keylist_start(..., ..., 1); 
if (gpgme_op_keylist_nex() == GPG_ERR_NO_ERROR) { proceed } 

die Unterzeichnung tun:

gpgme_new() 
gpgme_set_pinentry_mode(GPGME_PINENTRY_MODE_LOOPBACK) // yes i installed v2.1 
gpgme_set_passphrase_cb() 
/* ...binary to gpgme_data_t... */ 
gpgme_data_set_encoding(GPGME_DATA_ENCODING_BINARY) 
gpgme_signers_clear() 
gpgme_signers_add() // <- that key that I checked for existance earlier 
if (gpgme_signers_count() != 1) { fail(); } // sanity check 
gpgme_op_encrypt_sign(ctx, recipient, GPGME_ENCRYPT_ALWAYS_TRUST /* FIXME */, data_in, sig); 

Nun, da gpgme_op_encrypt_sign immer mit dem „Unbrauchbare geheimen Schlüssel fehlschlägt (117440566) "Fehler. Irgendwelche Tipps/Hinweise?

Software-Versionen:

gnupg 1.4.18-7 
gnupg-agent  2.1.4-1 
gnupg2 2.1.4-1 
libgpgme++2  4:4.14.2-2+b1 
libgpgme11:amd64   1.5.1-6 
libgpgme11-dev 1.5.1-6 
python-gnupginterface 0.3.2-9.1 

I aktiviert Debug-Tracing aber es tut mir nicht viel helfen:

<0x1927> gpgme_debug: level=4 
<0x1927> gpgme_check_version: call: 0=(nil), req_version=(null), VERSION=1.5.1 
<0x1927> gpgme_check_version_internal: call: 0=(nil), req_version=(null), offset_sig_validity=60 
<0x1927> gpgme_set_locale: enter: ctx=(nil), category=0, value=C 
<0x1927> gpgme_set_locale: leave 
<0x1927> gpgme_set_locale: enter: ctx=(nil), category=5, value=C 
<0x1927> gpgme_set_locale: leave 
<0x1927> gpgme-dinfo: gpgconf='/usr/bin/gpgconf' 
<0x1927> gpgme-dinfo:  gpg='/usr/bin/gpg2' 
<0x1927> gpgme-dinfo: gpgsm='/usr/bin/gpgsm' 
<0x1927> gpgme-dinfo: homedir='/home/folkert/.gnupg' 
<0x1927> gpgme-dinfo: agent='/home/folkert/.gnupg/S.gpg-agent' 
<0x1927> gpgme-dinfo: uisrv='/home/folkert/.gnupg/S.uiserver' 
<0x1927> gpgme_new: enter: r_ctx=0x7fff5afd07a8 
<0x1927> gpgme_new: leave: ctx=0x20c0810 
<0x1927> gpgme_op_keylist_start: enter: ctx=0x20c0810, pattern=0BF38589, secret_only=1 
<0x1927> _gpgme_add_io_cb: call: ctx=0x20c0810, fd 4, dir=1 -> tag=0x20c26b0 
<0x1927> _gpgme_add_io_cb: call: ctx=0x20c0810, fd 6, dir=1 -> tag=0x20c2800 
<0x1927> gpgme:gpg_io_event: call: gpg=0x20c0c10, event 0x7fd8b1a20ad0, type 0, type_data (nil) 
<0x1927> gpgme_op_keylist_start: leave 
<0x1927> gpgme_op_keylist_next: enter: ctx=0x20c0810 
<0x1927> _gpgme_run_io_cb: call: item=0x20c2820, need to check 
<0x1927> _gpgme_run_io_cb: call: item=0x20c2820, handler (0x20c0c10, 6) 
<0x1927> gpgme:keylist_colon_handler: call: ctx=0x20c0810, key = (nil), line = sec:u:2048:1:CC73A8A60BF38589:1433443717:::u:::scESC:::::: 
<0x1927> gpgme:keylist_colon_handler: call: ctx=0x20c0810, key = 0x20c2850, line = fpr:::::::::20CD3FF80DA6C1E46CD9F135CC73A8A60BF38589: 
<0x1927> gpgme:keylist_colon_handler: call: ctx=0x20c0810, key = 0x20c2850, line = uid:u::::1433443717::9963CFDE0C8920AD077B06A281992C4008E67E4F::testkey3 (testkey3) <test@vanheusden.com>: 
<0x1927> gpgme:keylist_colon_handler: call: ctx=0x20c0810, key = 0x20c2850, line = ssb:u:2048:1:22317805D48C1491:1433443717::::::e:::::: 
<0x1927> gpgme:keylist_colon_handler: call: ctx=0x20c0810, key = 0x20c2850, line = fpr:::::::::FB6FFB7D8BEC710A745DE86C22317805D48C1491: 
<0x1927> _gpgme_run_io_cb: call: item=0x20c26d0, need to check 
<0x1927> _gpgme_run_io_cb: call: item=0x20c26d0, handler (0x20c0c10, 4) 
<0x1927>  _gpgme_remove_io_cb: call: data=0x20c26b0, setting fd 0x4 (item=0x20c26d0) done 
<0x1927> _gpgme_run_io_cb: call: item=0x20c2820, need to check 
<0x1927> _gpgme_run_io_cb: call: item=0x20c2820, handler (0x20c0c10, 6) 
<0x1927> gpgme:keylist_colon_handler: call: ctx=0x20c0810, key = 0x20c2850, line = (null) 
<0x1927> gpgme:gpg_io_event: call: gpg=0x20c0c10, event 0x7fd8b1a20ad0, type 2, type_data 0x20c2850 
<0x1927>  _gpgme_remove_io_cb: call: data=0x20c2800, setting fd 0x6 (item=0x20c2820) done 
<0x1927> gpgme:gpg_io_event: call: gpg=0x20c0c10, event 0x7fd8b1a20ad0, type 1, type_data 0x7fff5afd0700 
<0x1927> gpgme_op_keylist_next: leave: key=0x20c2850 (20CD3FF80DA6C1E46CD9F135CC73A8A60BF38589) 
<0x1927> gpgme_release: call: ctx=0x20c0810 
<0x1927> gpgme_new: enter: r_ctx=0x7fff5afd0818 
<0x1927> gpgme_new: leave: ctx=0x20c2210 
<0x1927> gpgme_op_keylist_start: enter: ctx=0x20c2210, pattern=4BE78BDCF3F5352CF624A6DF3AD6F8118300CC02, secret_only=0 
<0x1927> _gpgme_add_io_cb: call: ctx=0x20c2210, fd 4, dir=1 -> tag=0x20c1f50 
<0x1927> _gpgme_add_io_cb: call: ctx=0x20c2210, fd 6, dir=1 -> tag=0x20c1fa0 
<0x1927> gpgme:gpg_io_event: call: gpg=0x20c0c10, event 0x7fd8b1a20ad0, type 0, type_data (nil) 
<0x1927> gpgme_op_keylist_start: leave 
<0x1927> gpgme_op_keylist_next: enter: ctx=0x20c2210 
<0x1927> _gpgme_run_io_cb: call: item=0x20c1fc0, need to check 
<0x1927> _gpgme_run_io_cb: call: item=0x20c1fc0, handler (0x20c0c10, 6) 
<0x1927> gpgme:keylist_colon_handler: call: ctx=0x20c2210, key = (nil), line = tru::0:1433443869:2410285847:3:1:5 
<0x1927> gpgme:keylist_colon_handler: call: ctx=0x20c2210, key = (nil), line = pub:-:1024:17:3AD6F8118300CC02:1039074767:::-:::scESC:::::: 
<0x1927> gpgme:keylist_colon_handler: call: ctx=0x20c2210, key = 0x20c2b70, line = fpr:::::::::4BE78BDCF3F5352CF624A6DF3AD6F8118300CC02: 
<0x1927> gpgme:keylist_colon_handler: call: ctx=0x20c2210, key = 0x20c2b70, line = uid:-::::1203999932::275AAD3E991F1962AD510CC96760907BE70FE668::Bla <bla@com>: 
<0x1927> gpgme:keylist_colon_handler: call: ctx=0x20c2210, key = 0x20c2b70, line = uid:-::::1203999938::59689891229F1817EF66BFC63D9D0BB2F45F5209::Bla <bla@com>: 
<0x1927> gpgme:keylist_colon_handler: call: ctx=0x20c2210, key = 0x20c2b70, line = uid:r::::::8A709552E7AB85B53DDAE18A48C0978E5EBF5547::Bla <bla@com>: 
<0x1927> gpgme:keylist_colon_handler: call: ctx=0x20c2210, key = 0x20c2b70, line = sub:-:2048:16:942E547C12A6B1C2:1039075030::::::e:::::: 
<0x1927> gpgme:keylist_colon_handler: call: ctx=0x20c2210, key = 0x20c2b70, line = fpr:::::::::E69EF5226BBF7EC14F1D7D96942E547C12A6B1C2: 
<0x1927> _gpgme_run_io_cb: call: item=0x20c1f70, need to check 
<0x1927> _gpgme_run_io_cb: call: item=0x20c1f70, handler (0x20c0c10, 4) 
<0x1927>  _gpgme_remove_io_cb: call: data=0x20c1f50, setting fd 0x4 (item=0x20c1f70) done 
<0x1927> _gpgme_run_io_cb: call: item=0x20c1fc0, need to check 
<0x1927> _gpgme_run_io_cb: call: item=0x20c1fc0, handler (0x20c0c10, 6) 
<0x1927> gpgme:keylist_colon_handler: call: ctx=0x20c2210, key = 0x20c2b70, line = (null) 
<0x1927> gpgme:gpg_io_event: call: gpg=0x20c0c10, event 0x7fd8b1a20ad0, type 2, type_data 0x20c2b70 
<0x1927>  _gpgme_remove_io_cb: call: data=0x20c1fa0, setting fd 0x6 (item=0x20c1fc0) done 
<0x1927> gpgme:gpg_io_event: call: gpg=0x20c0c10, event 0x7fd8b1a20ad0, type 1, type_data 0x7fff5afd0760 
<0x1927> gpgme_op_keylist_next: leave: key=0x20c2b70 (4BE78BDCF3F5352CF624A6DF3AD6F8118300CC02) 
<0x1927> gpgme_release: call: ctx=0x20c2210 
<0x1927> gpgme_new: enter: r_ctx=0x7fff5afd07c8 
<0x1927> gpgme_new: leave: ctx=0x20c2550 
<0x1927> gpgme_set_passphrase_cb: call: ctx=0x20c2550, passphrase_cb=(nil)/(nil) 
<0x1927> gpgme_set_pinentry_mode: call: ctx=0x20c2550, pinentry_mode=4 
<0x1927> gpgme_set_passphrase_cb: call: ctx=0x20c2550, passphrase_cb=0x403420/0x20c0058 
<0x1927> gpgme_set_passphrase_cb: call: ctx=0x20c2550, passphrase_cb=0x403420/0x20c0058 
<0x1927> gpgme_new: enter: r_ctx=0x7fff5afd0768 
<0x1927> gpgme_new: leave: ctx=0x20c0810 
<0x1927> gpgme_op_keylist_start: enter: ctx=0x20c0810, pattern=0BF38589, secret_only=0 
<0x1927> _gpgme_add_io_cb: call: ctx=0x20c0810, fd 4, dir=1 -> tag=0x20c4fd0 
<0x1927> _gpgme_add_io_cb: call: ctx=0x20c0810, fd 6, dir=1 -> tag=0x20c5120 
<0x1927> gpgme:gpg_io_event: call: gpg=0x20c1d50, event 0x7fd8b1a20ad0, type 0, type_data (nil) 
<0x1927> gpgme_op_keylist_start: leave 
<0x1927> gpgme_op_keylist_next: enter: ctx=0x20c0810 
<0x1927> _gpgme_run_io_cb: call: item=0x20c5140, need to check 
<0x1927> _gpgme_run_io_cb: call: item=0x20c5140, handler (0x20c1d50, 6) 
<0x1927> gpgme:keylist_colon_handler: call: ctx=0x20c0810, key = (nil), line = tru::0:1433443869:2410285847:3:1:5 
<0x1927> gpgme:keylist_colon_handler: call: ctx=0x20c0810, key = (nil), line = pub:u:2048:1:CC73A8A60BF38589:1433443717:::u:::scESC:::::: 
<0x1927> gpgme:keylist_colon_handler: call: ctx=0x20c0810, key = 0x20c5170, line = fpr:::::::::20CD3FF80DA6C1E46CD9F135CC73A8A60BF38589: 
<0x1927> gpgme:keylist_colon_handler: call: ctx=0x20c0810, key = 0x20c5170, line = uid:u::::1433443717::9963CFDE0C8920AD077B06A281992C4008E67E4F::testkey3 (testkey3) <test@vanheusden.com>: 
<0x1927> gpgme:keylist_colon_handler: call: ctx=0x20c0810, key = 0x20c5170, line = sub:u:2048:1:22317805D48C1491:1433443717::::::e:::::: 
<0x1927> gpgme:keylist_colon_handler: call: ctx=0x20c0810, key = 0x20c5170, line = fpr:::::::::FB6FFB7D8BEC710A745DE86C22317805D48C1491: 
<0x1927> _gpgme_run_io_cb: call: item=0x20c4ff0, need to check 
<0x1927> _gpgme_run_io_cb: call: item=0x20c4ff0, handler (0x20c1d50, 4) 
<0x1927>  _gpgme_remove_io_cb: call: data=0x20c4fd0, setting fd 0x4 (item=0x20c4ff0) done 
<0x1927> _gpgme_run_io_cb: call: item=0x20c5140, need to check 
<0x1927> _gpgme_run_io_cb: call: item=0x20c5140, handler (0x20c1d50, 6) 
<0x1927> gpgme:keylist_colon_handler: call: ctx=0x20c0810, key = 0x20c5170, line = (null) 
<0x1927> gpgme:gpg_io_event: call: gpg=0x20c1d50, event 0x7fd8b1a20ad0, type 2, type_data 0x20c5170 
<0x1927>  _gpgme_remove_io_cb: call: data=0x20c5120, setting fd 0x6 (item=0x20c5140) done 
<0x1927> gpgme:gpg_io_event: call: gpg=0x20c1d50, event 0x7fd8b1a20ad0, type 1, type_data 0x7fff5afd06c0 
<0x1927> gpgme_op_keylist_next: leave: key=0x20c5170 (20CD3FF80DA6C1E46CD9F135CC73A8A60BF38589) 
<0x1927> gpgme_release: call: ctx=0x20c0810 
<0x1927> gpgme_signers_clear: call: ctx=0x20c2550 
<0x1927> gpgme_signers_add: enter: ctx=0x20c2550, key=0x20c2850 (20CD3FF80DA6C1E46CD9F135CC73A8A60BF38589) 
<0x1927> gpgme_signers_add: leave 
<0x1927> gpgme_op_encrypt_sign: enter: ctx=0x20c2550, flags=0x1, plain=0x20c2ed0, cipher=0x20c3f20 
<0x1927> gpgme_op_encrypt_sign: check: ctx=0x20c2550, recipient[0] = 0x20c5170 (20CD3FF80DA6C1E46CD9F135CC73A8A60BF38589) 
<0x1927> gpgme_sig_notation_get: call: ctx=0x20c2550, ctx->sig_notations=(nil) 
<0x1927> _gpgme_add_io_cb: call: ctx=0x20c2550, fd 4, dir=1 -> tag=0x20c2070 
<0x1927> _gpgme_add_io_cb: call: ctx=0x20c2550, fd 8, dir=1 -> tag=0x20c21c0 
<0x1927> _gpgme_add_io_cb: call: ctx=0x20c2550, fd 11, dir=0 -> tag=0x20c2210 
<0x1927> gpgme:gpg_io_event: call: gpg=0x20c1d50, event 0x7fd8b1a20ad0, type 0, type_data (nil) 
<0x1927> _gpgme_run_io_cb: call: item=0x20c2230, need to check 
<0x1927> _gpgme_run_io_cb: call: item=0x20c2230, handler (0x20c2ed0, 11) 
<0x1927> _gpgme_data_outbound_handler: enter: dh=0x20c2ed0, fd=0xb 
<0x1927> _gpgme_data_outbound_handler: leave 
<0x1927> _gpgme_run_io_cb: call: item=0x20c2230, need to check 
<0x1927> _gpgme_run_io_cb: call: item=0x20c2230, handler (0x20c2ed0, 11) 
<0x1927> _gpgme_data_outbound_handler: enter: dh=0x20c2ed0, fd=0xb 
<0x1927>  _gpgme_remove_io_cb: call: data=0x20c2210, setting fd 0xb (item=0x20c2230) done 
<0x1927> _gpgme_data_outbound_handler: leave 
<0x1927> _gpgme_run_io_cb: call: item=0x20c2090, need to check 
<0x1927> _gpgme_run_io_cb: call: item=0x20c2090, handler (0x20c1d50, 4) 
<0x1927> _gpgme_run_io_cb: call: item=0x20c2090, need to check 
<0x1927> _gpgme_run_io_cb: call: item=0x20c2090, handler (0x20c1d50, 4) 
<0x1927> _gpgme_cancel_with_err: enter: ctx=0x20c2550, ctx_err=117440566, op_err=0 
<0x1927>  _gpgme_remove_io_cb: call: data=0x20c2070, setting fd 0x4 (item=0x20c2090) done 
<0x1927>  _gpgme_remove_io_cb: call: data=0x20c21c0, setting fd 0x8 (item=0x20c21e0) done 
<0x1927>  gpgme:gpg_io_event: call: gpg=0x20c1d50, event 0x7fd8b1a20ad0, type 1, type_data 0x7fff5afd06c0 
<0x1927> _gpgme_cancel_with_err: leave 
<0x1927> gpgme_op_encrypt_sign: error: Unusable secret key <GPGME> 
<0x1927> gpgme_release: call: ctx=0x20c2550 

EDIT

Wie @kylehuff angefordert, Hier ist der Code für die Schlüsselauswahl:

dann im Konstruktor ich tun:

std::string error; 
    if (find_key(my_key_id, true, &my_key, &error) != SK_FOUND) 
      error_exit(false, "Cannot find key %s: %s", my_key_id.c_str(), error.c_str()); 

und wenn es an der Zeit zu unterzeichnen ist:

  if (find_key(target_uid, false, &recipient[0], error) != SK_FOUND) 
        break; 

      gpgme_signers_clear(ctx); 
      err = gpgme_signers_add(ctx, my_key); 
      if (err != GPG_ERR_NO_ERROR) 
      { 
        error -> append(format("gpgme_signers_add(%s) failed: %s (%d)", my_key_id.c_str(), gpg_strerror(err), err)); 
        break; 
      } 

      int n_signers = gpgme_signers_count(ctx); 
      if (n_signers != 1) 
      { 
        error -> append(format("Number of signers (%d) not expected number (1)", n_signers)); 
        break; 
      } 

      err = gpgme_op_encrypt_sign(ctx, recipient, GPGME_ENCRYPT_ALWAYS_TRUST /* FIXME */, data_in, sig); 
      if (err != GPG_ERR_NO_ERROR) 
      { 
        error -> append(format("gpgme_op_encrypt failed: %s (%d)", gpg_strerror(err), err)); 
        break; 
      } 

@kylehuff, ist es das, was Sie beantragt? Dank

EDIT

Hier ist das Angebot für 20CD3FF80DA6C1E46CD9F135CC73A8A60BF38589:

tru::0:1433443869:2410285847:3:1:5 
pub:u:2048:1:CC73A8A60BF38589:2015-06-04:::u:testkey3 (testkey3) <test@vanheusden.com>::scESC: 
sub:u:2048:1:22317805D48C1491:2015-06-04::::::e: 

EDIT

Folkert @ travel: ~ $ gpg2 --local-Benutzer 14B7E8E6 --sign bla .txt

folkert @travelmate: ~ $ gpg --verify bla.txt.gpg gpg: Unterschrift gemacht Do 18. Juni 2015 19.18.17 UTC mit RSA-Schlüssel-ID 74D6F5C6 gpg: Korrekte Unterschrift von "testkey2 (testkey2)"

und mit Editier-Taste kann ich sehen, dass 74d6f5c6 ist in der Tat das Zeichen Unterschlüssel:

Unter 1024R/74D6F5C6 erstellt: 2015.05.31 gültig bis: nie Nutzung: S

Also ich bin ein wenig überrascht, das funktioniert nicht für gpgme. Nicht die Suche, sondern direkt die gpgme_get_key() gibt den gleichen Fehler.

Answer 1

Es ist schwer zu sagen, was los ist, auch mit der Probe, aber hier sind einige mögliche Szenarien -

Etwas in der Methode getan my_gpgme_new(&ctx, false, error) unberechenbaren sein könnte. Was macht diese Funktion genau? Warum nicht die Standardmethode gpgme_new verwenden?

In der mitgelieferten Beispiel verwenden Sie die Funktion search_key_result_t gpgme::find_key(); Gibt es einen Bedarf für mehrere Unterzeichner? wenn ja, zumindest für die Prüfung, warum nicht vereinfachen und einfach verwenden gpgme_get_key()? d. h.

gpgme_error_t err; 
    gpgme_key_t key; 

    err = gpgme_get_key (ctx, key_string, &key, 1); 
    if (err) { 
    // .. error handling 
    } 
    gpgme_signers_clear(); 
    err = gpgme_signers_add (ctx, key); 
    gpgme_key_unref (key); 

    int n_signers = gpgme_signers_count(ctx); 
    if (n_signers != 1) { 
    // .. error handling 
    } 

    err = gpgme_op_encrypt_sign(ctx, recipient, ....); 

Bei dieser Methode scheint es, als ob Sie diese Methode zu gpgme namesapce hinzufügen. Ist es möglich, die eingebaute Methode auch im gpgme-Namespace zu trampeln?

Wie für das Empfängerobjekt, wie ist das aufgebaut? Es sollte eine Null gpgme_key_tgpgme_key_t Struktur sein, selbst wenn es nur ein einzelner Empfänger ist. das heißt

gpgme_key_t recipients[2] = { NULL, NULL }; 
    err = gpgme_get_key (ctx, recipient_fpr.c_str(), &recipients[0], 0); 
    if (err) { // .. error handling } 

Alternativ kann, wenn der Empfänger als Array zur Verfügung gestellt:

gpgme_key_t recipients = new gpgme_key_t[recip_array.size()]; 
    err = gpgme_get_key (ctx, recipient_fpr.c_str(), &recipients[0], 0); 
    if (err) { // .. error handling } 
    recipients[recip_array.size()] = NULL; // null terminate the array