3 files changed, 121 insertions, 3 deletions

diff --git a/ssh-sk-client.c b/ssh-sk-client.c
index 8a7ac97c4..b2f062455 100644
--- a/ssh-sk-client.c
+++ b/ssh-sk-client.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: ssh-sk-client.c,v 1.1 2019/12/13 20:16:56 djm Exp $ */
+/* $OpenBSD: ssh-sk-client.c,v 1.2 2019/12/30 09:21:59 djm Exp $ */
 /*
  * Copyright (c) 2019 Google LLC
  *
@@ -331,3 +331,73 @@ sshsk_enroll(int type, const char *provider_path, const char *application,
         errno = oerrno;
         return r;
 }
+
+int
+sshsk_load_resident(const char *provider_path, const char *pin,
+    struct sshkey ***keysp, size_t *nkeysp)
+{
+        int oerrno, r = SSH_ERR_INTERNAL_ERROR;
+        struct sshbuf *kbuf = NULL, *req = NULL, *resp = NULL;
+        struct sshkey *key = NULL, **keys = NULL, **tmp;
+        size_t i, nkeys = 0;
+
+        *keysp = NULL;
+        *nkeysp = 0;
+
+        if ((resp = sshbuf_new()) == NULL ||
+            (kbuf = sshbuf_new()) == NULL ||
+            (req = sshbuf_new()) == NULL) {
+                r = SSH_ERR_ALLOC_FAIL;
+                goto out;
+        }
+
+        if ((r = sshbuf_put_u32(req, SSH_SK_HELPER_LOAD_RESIDENT)) != 0 ||
+            (r = sshbuf_put_cstring(req, provider_path)) != 0 ||
+            (r = sshbuf_put_cstring(req, pin)) != 0) {
+                error("%s: compose: %s", __func__, ssh_err(r));
+                goto out;
+        }
+
+        if ((r = client_converse(req, &resp)) != 0)
+                goto out;
+
+        while (sshbuf_len(resp) != 0) {
+                /* key, comment */
+                if ((r = sshbuf_get_stringb(resp, kbuf)) != 0 ||
+                    (r = sshbuf_get_cstring(resp, NULL, NULL)) != 0) {
+                        error("%s: parse signature: %s", __func__, ssh_err(r));
+                        r = SSH_ERR_INVALID_FORMAT;
+                        goto out;
+                }
+                if ((r = sshkey_private_deserialize(kbuf, &key)) != 0) {
+                        error("Unable to parse private key: %s", ssh_err(r));
+                        goto out;
+                }
+                if ((tmp = recallocarray(keys, nkeys, nkeys + 1,
+                    sizeof(*keys))) == NULL) {
+                        error("%s: recallocarray keys failed", __func__);
+                        goto out;
+                }
+                keys = tmp;
+                keys[nkeys++] = key;
+                key = NULL;
+        }
+
+        /* success */
+        r = 0;
+        *keysp = keys;
+        *nkeysp = nkeys;
+        keys = NULL;
+        nkeys = 0;
+ out:
+        oerrno = errno;
+        for (i = 0; i < nkeys; i++)
+                sshkey_free(keys[i]);
+        free(keys);
+        sshkey_free(key);
+        sshbuf_free(kbuf);
+        sshbuf_free(req);
+        sshbuf_free(resp);
+        errno = oerrno;
+        return r;
+}
diff --git a/ssh-sk-helper.c b/ssh-sk-helper.c
index 3dc149b95..ac528cfcf 100644
--- a/ssh-sk-helper.c
+++ b/ssh-sk-helper.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: ssh-sk-helper.c,v 1.4 2019/12/13 19:11:14 djm Exp $ */
+/* $OpenBSD: ssh-sk-helper.c,v 1.5 2019/12/30 09:21:59 djm Exp $ */
 /*
  * Copyright (c) 2019 Google LLC
  *
@@ -148,6 +148,50 @@ process_enroll(struct sshbuf *req)
         return resp;
 }
 
+static struct sshbuf *
+process_load_resident(struct sshbuf *req)
+{
+        int r;
+        char *provider, *pin;
+        struct sshbuf *kbuf, *resp;
+        struct sshkey **keys = NULL;
+        size_t nkeys = 0, i;
+
+        if ((resp = sshbuf_new()) == NULL ||
+            (kbuf = sshbuf_new()) == NULL)
+                fatal("%s: sshbuf_new failed", __progname);
+
+        if ((r = sshbuf_get_cstring(req, &provider, NULL)) != 0 ||
+            (r = sshbuf_get_cstring(req, &pin, NULL)) != 0)
+                fatal("%s: buffer error: %s", __progname, ssh_err(r));
+        if (sshbuf_len(req) != 0)
+                fatal("%s: trailing data in request", __progname);
+
+        if ((r = sshsk_load_resident(provider, pin, &keys, &nkeys)) != 0)
+                fatal("%s: sshsk_load_resident failed: %s",
+                    __progname, ssh_err(r));
+
+        for (i = 0; i < nkeys; i++) {
+                debug("%s: key %zu %s %s", __func__, i,
+                    sshkey_type(keys[i]), keys[i]->sk_application);
+                sshbuf_reset(kbuf);
+                if ((r = sshkey_private_serialize(keys[i], kbuf)) != 0)
+                        fatal("%s: serialize private key: %s",
+                            __progname, ssh_err(r));
+                if ((r = sshbuf_put_stringb(resp, kbuf)) != 0 ||
+                    (r = sshbuf_put_cstring(resp, "")) != 0) /* comment */
+                        fatal("%s: buffer error: %s", __progname, ssh_err(r));
+        }
+
+        for (i = 0; i < nkeys; i++)
+                sshkey_free(keys[i]);
+        free(keys);
+        sshbuf_free(kbuf);
+        free(provider);
+        freezero(pin, strlen(pin));
+        return resp;
+}
+
 int
 main(int argc, char **argv)
 {
@@ -212,6 +256,9 @@ main(int argc, char **argv)
         case SSH_SK_HELPER_ENROLL:
                 resp = process_enroll(req);
                 break;
+        case SSH_SK_HELPER_LOAD_RESIDENT:
+                resp = process_load_resident(req);
+                break;
         default:
                 fatal("%s: unsupported request type %u", __progname, rtype);
         }
diff --git a/sshkey.h b/sshkey.h
index 21ac802dc..699c6b817 100644
--- a/sshkey.h
+++ b/sshkey.h
@@ -1,4 +1,4 @@
-/* $OpenBSD: sshkey.h,v 1.42 2019/12/13 19:11:14 djm Exp $ */
+/* $OpenBSD: sshkey.h,v 1.43 2019/12/30 09:21:59 djm Exp $ */
 
 /*
  * Copyright (c) 2000, 2001 Markus Friedl.  All rights reserved.
@@ -57,6 +57,7 @@
 /* ssh-sk-helper messages */
 #define SSH_SK_HELPER_SIGN              1
 #define SSH_SK_HELPER_ENROLL            2
+#define SSH_SK_HELPER_LOAD_RESIDENT     3
 
 struct sshbuf;