support PKCS#11 devices with external PIN entry devices

bz#2240, based on patch from Dirk-Willem van Gulik;
feedback and ok dtucker@

diff --git a/usr.bin/ssh/ssh-pkcs11.c b/usr.bin/ssh/ssh-pkcs11.c
index 561969e..ab296b6 100644 (file)
--- a/usr.bin/ssh/ssh-pkcs11.c
+++ b/usr.bin/ssh/ssh-pkcs11.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: ssh-pkcs11.c,v 1.18 2015/04/24 01:36:01 deraadt Exp $ */
+/* $OpenBSD: ssh-pkcs11.c,v 1.19 2015/05/27 05:15:02 djm Exp $ */
 /*
  * Copyright (c) 2010 Markus Friedl.  All rights reserved.
  *
@@ -231,7 +231,7 @@ pkcs11_rsa_private_encrypt(int flen, const u_char *from, u_char *to, RSA *rsa,
                {CKA_ID, NULL, 0},
                {CKA_SIGN, &true_val, sizeof(true_val) }
        };
-       char                    *pin, prompt[1024];
+       char                    *pin = NULL, prompt[1024];
        int                     rval = -1;
 
        if ((k11 = RSA_get_app_data(rsa)) == NULL) {
@@ -246,22 +246,30 @@ pkcs11_rsa_private_encrypt(int flen, const u_char *from, u_char *to, RSA *rsa,
        si = &k11->provider->slotinfo[k11->slotidx];
        if ((si->token.flags & CKF_LOGIN_REQUIRED) && !si->logged_in) {
                if (!pkcs11_interactive) {
-                       error("need pin");
+                       error("need pin entry%s", (si->token.flags &
+                           CKF_PROTECTED_AUTHENTICATION_PATH) ?
+                           " on reader keypad" : "");
                        return (-1);
                }
-               snprintf(prompt, sizeof(prompt), "Enter PIN for '%s': ",
-                   si->token.label);
-               pin = read_passphrase(prompt, RP_ALLOW_EOF);
-               if (pin == NULL)
-                       return (-1);    /* bail out */
-               rv = f->C_Login(si->session, CKU_USER,
-                   (u_char *)pin, strlen(pin));
-               if (rv != CKR_OK && rv != CKR_USER_ALREADY_LOGGED_IN) {
+               if (si->token.flags & CKF_PROTECTED_AUTHENTICATION_PATH)
+                       verbose("Deferring PIN entry to reader keypad.");
+               else {
+                       snprintf(prompt, sizeof(prompt),
+                           "Enter PIN for '%s': ", si->token.label);
+                       pin = read_passphrase(prompt, RP_ALLOW_EOF);
+                       if (pin == NULL)
+                               return (-1);    /* bail out */
+               }
+               rv = f->C_Login(si->session, CKU_USER, (u_char *)pin,
+                   (pin != NULL) ? strlen(pin) : 0);
+               if (pin != NULL) {
+                       explicit_bzero(pin, strlen(pin));
                        free(pin);
+               }
+               if (rv != CKR_OK && rv != CKR_USER_ALREADY_LOGGED_IN) {
                        error("C_Login failed: %lu", rv);
                        return (-1);
                }
-               free(pin);
                si->logged_in = 1;
        }
        key_filter[1].pValue = k11->keyid;