upstream: Support keys that set the CKA_ALWAYS_AUTHENTICATE by

requring a fresh login after the C_SignInit operation.

based on patch from Jakub Jelen in bz#2638; ok markus

OpenBSD-Commit-ID: a76e66996ba7c0923b46b74d46d499b811786661

1 files changed, 95 insertions, 26 deletions

diff --git a/ssh-pkcs11.c b/ssh-pkcs11.c
index 036ee8115..384ac1edb 100644
--- a/ssh-pkcs11.c
+++ b/ssh-pkcs11.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: ssh-pkcs11.c,v 1.39 2019/01/21 02:05:38 djm Exp $ */
+/* $OpenBSD: ssh-pkcs11.c,v 1.40 2019/01/22 12:00:50 djm Exp $ */
 /*
  * Copyright (c) 2010 Markus Friedl.  All rights reserved.
  * Copyright (c) 2014 Pedro Martelletto. All rights reserved.
@@ -240,6 +240,85 @@ pkcs11_find(struct pkcs11_provider *p, CK_ULONG slotidx, CK_ATTRIBUTE *attr,
 }
 
 static int
+pkcs11_login(struct pkcs11_key *k11, CK_USER_TYPE type)
+{
+        struct pkcs11_slotinfo  *si;
+        CK_FUNCTION_LIST        *f;
+        char                    *pin = NULL, prompt[1024];
+        CK_RV                    rv;
+
+        if (!k11->provider || !k11->provider->valid) {
+                error("no pkcs11 (valid) provider found");
+                return (-1);
+        }
+
+        f = k11->provider->function_list;
+        si = &k11->provider->slotinfo[k11->slotidx];
+
+        if (!pkcs11_interactive) {
+                error("need pin entry%s",
+                    (si->token.flags & CKF_PROTECTED_AUTHENTICATION_PATH) ?
+                    " on reader keypad" : "");
+                return (-1);
+        }
+        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);
+                if ((pin = read_passphrase(prompt, RP_ALLOW_EOF)) == NULL) {
+                        debug("%s: no pin specified", __func__);
+                        return (-1);    /* bail out */
+                }
+        }
+        rv = f->C_Login(si->session, type, (u_char *)pin,
+            (pin != NULL) ? strlen(pin) : 0);
+        if (pin != NULL)
+                freezero(pin, strlen(pin));
+        if (rv != CKR_OK && rv != CKR_USER_ALREADY_LOGGED_IN) {
+                error("C_Login failed: %lu", rv);
+                return (-1);
+        }
+        si->logged_in = 1;
+        return (0);
+}
+
+static int
+pkcs11_check_obj_bool_attrib(struct pkcs11_key *k11, CK_OBJECT_HANDLE obj,
+    CK_ATTRIBUTE_TYPE type, int *val)
+{
+        struct pkcs11_slotinfo  *si;
+        CK_FUNCTION_LIST        *f;
+        CK_BBOOL                flag = 0;
+        CK_ATTRIBUTE            attr;
+        CK_RV                    rv;
+
+        *val = 0;
+
+        if (!k11->provider || !k11->provider->valid) {
+                error("no pkcs11 (valid) provider found");
+                return (-1);
+        }
+
+        f = k11->provider->function_list;
+        si = &k11->provider->slotinfo[k11->slotidx];
+
+        attr.type = type;
+        attr.pValue = &flag;
+        attr.ulValueLen = sizeof(flag);
+
+        rv = f->C_GetAttributeValue(si->session, obj, &attr, 1);
+        if (rv != CKR_OK) {
+                error("C_GetAttributeValue failed: %lu", rv);
+                return (-1);
+        }
+        *val = flag != 0;
+        debug("%s: provider %p slot %lu object %lu: attrib %lu = %d",
+            __func__, k11->provider, k11->slotidx, obj, type, *val);
+        return (0);
+}
+
+static int
 pkcs11_get_key(struct pkcs11_key *k11, CK_MECHANISM_TYPE mech_type)
 {
         struct pkcs11_slotinfo  *si;
@@ -250,7 +329,8 @@ pkcs11_get_key(struct pkcs11_key *k11, CK_MECHANISM_TYPE mech_type)
         CK_BBOOL                 true_val;
         CK_MECHANISM             mech;
         CK_ATTRIBUTE             key_filter[3];
-        char                    *pin = NULL, prompt[1024];
+        int                      always_auth = 0;
+        int                      did_login = 0;
 
         if (!k11->provider || !k11->provider->valid) {
                 error("no pkcs11 (valid) provider found");
@@ -261,32 +341,11 @@ pkcs11_get_key(struct pkcs11_key *k11, CK_MECHANISM_TYPE mech_type)
         si = &k11->provider->slotinfo[k11->slotidx];
 
         if ((si->token.flags & CKF_LOGIN_REQUIRED) && !si->logged_in) {
-                if (!pkcs11_interactive) {
-                        error("need pin entry%s", (si->token.flags &
-                            CKF_PROTECTED_AUTHENTICATION_PATH) ?
-                            " on reader keypad" : "");
-                        return (-1);
-                }
-                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);
+                if (pkcs11_login(k11, CKU_USER) < 0) {
+                        error("login failed");
                         return (-1);
                 }
-                si->logged_in = 1;
+                did_login = 1;
         }
 
         memset(&key_filter, 0, sizeof(key_filter));
@@ -321,6 +380,16 @@ pkcs11_get_key(struct pkcs11_key *k11, CK_MECHANISM_TYPE mech_type)
                 return (-1);
         }
 
+        pkcs11_check_obj_bool_attrib(k11, obj, CKA_ALWAYS_AUTHENTICATE,
+            &always_auth); /* ignore errors here */
+        if (always_auth && !did_login) {
+                debug("%s: always-auth key", __func__);
+                if (pkcs11_login(k11, CKU_CONTEXT_SPECIFIC) < 0) {
+                        error("login failed for always-auth key");
+                        return (-1);
+                }
+        }
+
         return (0);
 }