upstream: ssh-add support for U2F/FIDO keys

OpenBSD-Commit-ID: 7f88a5181c982687afedf3130c6ab2bba60f7644

2 files changed, 38 insertions, 12 deletions

diff --git a/ssh-add.1 b/ssh-add.1
index d4e1c603b..9dc44fa74 100644
--- a/ssh-add.1
+++ b/ssh-add.1
@@ -1,4 +1,4 @@
-.\"     $OpenBSD: ssh-add.1,v 1.69 2019/01/21 12:53:35 djm Exp $
+.\"     $OpenBSD: ssh-add.1,v 1.70 2019/10/31 21:19:56 djm Exp $
 .\"
 .\" Author: Tatu Ylonen <ylo@cs.hut.fi>
 .\" Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
@@ -35,7 +35,7 @@
 .\" (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
 .\" THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 .\"
-.Dd $Mdocdate: January 21 2019 $
+.Dd $Mdocdate: October 31 2019 $
 .Dt SSH-ADD 1
 .Os
 .Sh NAME
@@ -46,6 +46,7 @@
 .Op Fl cDdkLlqvXx
 .Op Fl E Ar fingerprint_hash
 .Op Fl t Ar life
+.Op Fl S Ar provider
 .Op Ar
 .Nm ssh-add
 .Fl s Ar pkcs11
@@ -134,6 +135,11 @@ Be quiet after a successful operation.
 .It Fl s Ar pkcs11
 Add keys provided by the PKCS#11 shared library
 .Ar pkcs11 .
+.It Fl S Ar provider
+Specifies a path to a security key provider library that will be used when
+adding any security key-hosted keys, overriding the default of using the
+.Ev "SSH_SK_PROVIDER"
+environment variable to specify a provider.
 .It Fl T Ar pubkey ...
 Tests whether the private keys that correspond to the specified
 .Ar pubkey
@@ -189,6 +195,9 @@ to make this work.)
 Identifies the path of a
 .Ux Ns -domain
 socket used to communicate with the agent.
+.It Ev SSH_SK_PROVIDER
+Specifies the path to a security key provider library used to interact with
+hardware security keys.
 .El
 .Sh FILES
 .Bl -tag -width Ds
diff --git a/ssh-add.c b/ssh-add.c
index 2c65d0272..3c8849ac4 100644
--- a/ssh-add.c
+++ b/ssh-add.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: ssh-add.c,v 1.142 2019/10/31 21:19:15 djm Exp $ */
+/* $OpenBSD: ssh-add.c,v 1.143 2019/10/31 21:19:56 djm Exp $ */
 /*
  * Author: Tatu Ylonen <ylo@cs.hut.fi>
  * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
@@ -77,6 +77,7 @@ static char *default_files[] = {
         _PATH_SSH_CLIENT_ID_DSA,
 #ifdef OPENSSL_HAS_ECC
         _PATH_SSH_CLIENT_ID_ECDSA,
+        _PATH_SSH_CLIENT_ID_ECDSA_SK,
 #endif
 #endif /* WITH_OPENSSL */
         _PATH_SSH_CLIENT_ID_ED25519,
@@ -191,7 +192,8 @@ delete_all(int agent_fd, int qflag)
 }
 
 static int
-add_file(int agent_fd, const char *filename, int key_only, int qflag)
+add_file(int agent_fd, const char *filename, int key_only, int qflag,
+    const char *skprovider)
 {
         struct sshkey *private, *cert;
         char *comment = NULL;
@@ -310,8 +312,16 @@ add_file(int agent_fd, const char *filename, int key_only, int qflag)
                 ssh_free_identitylist(idlist);
         }
 
+        if (sshkey_type_plain(private->type) != KEY_ECDSA_SK)
+                skprovider = NULL; /* Don't send constraint for other keys */
+        else if (skprovider == NULL) {
+                fprintf(stderr, "Cannot load security key %s without "
+                    "provider\n", filename);
+                goto out;
+        }
+
         if ((r = ssh_add_identity_constrained(agent_fd, private, comment,
-            lifetime, confirm, maxsign, NULL)) == 0) {
+            lifetime, confirm, maxsign, skprovider)) == 0) {
                 ret = 0;
                 if (!qflag) {
                         fprintf(stderr, "Identity added: %s (%s)\n",
@@ -364,7 +374,7 @@ add_file(int agent_fd, const char *filename, int key_only, int qflag)
         sshkey_free(cert);
 
         if ((r = ssh_add_identity_constrained(agent_fd, private, comment,
-            lifetime, confirm, maxsign, NULL)) != 0) {
+            lifetime, confirm, maxsign, skprovider)) != 0) {
                 error("Certificate %s (%s) add failed: %s", certpath,
                     private->cert->key_id, ssh_err(r));
                 goto out;
@@ -529,13 +539,14 @@ lock_agent(int agent_fd, int lock)
 }
 
 static int
-do_file(int agent_fd, int deleting, int key_only, char *file, int qflag)
+do_file(int agent_fd, int deleting, int key_only, char *file, int qflag,
+    const char *skprovider)
 {
         if (deleting) {
                 if (delete_file(agent_fd, file, key_only, qflag) == -1)
                         return -1;
         } else {
-                if (add_file(agent_fd, file, key_only, qflag) == -1)
+                if (add_file(agent_fd, file, key_only, qflag, skprovider) == -1)
                         return -1;
         }
         return 0;
@@ -561,6 +572,7 @@ usage(void)
         fprintf(stderr, "  -s pkcs11   Add keys from PKCS#11 provider.\n");
         fprintf(stderr, "  -e pkcs11   Remove keys provided by PKCS#11 provider.\n");
         fprintf(stderr, "  -T pubkey   Test if ssh-agent can access matching private key.\n");
+        fprintf(stderr, "  -S provider Specify security key provider.\n");
         fprintf(stderr, "  -q          Be quiet after a successful operation.\n");
         fprintf(stderr, "  -v          Be more verbose.\n");
 }
@@ -571,7 +583,7 @@ main(int argc, char **argv)
         extern char *optarg;
         extern int optind;
         int agent_fd;
-        char *pkcs11provider = NULL;
+        char *pkcs11provider = NULL, *skprovider = NULL;
         int r, i, ch, deleting = 0, ret = 0, key_only = 0;
         int xflag = 0, lflag = 0, Dflag = 0, qflag = 0, Tflag = 0;
         SyslogFacility log_facility = SYSLOG_FACILITY_AUTH;
@@ -600,7 +612,9 @@ main(int argc, char **argv)
                 exit(2);
         }
 
-        while ((ch = getopt(argc, argv, "vklLcdDTxXE:e:M:m:qs:t:")) != -1) {
+        skprovider = getenv("SSH_SK_PROVIDER");
+
+        while ((ch = getopt(argc, argv, "vklLcdDTxXE:e:M:m:qs:S:t:")) != -1) {
                 switch (ch) {
                 case 'v':
                         if (log_level == SYSLOG_LEVEL_INFO)
@@ -656,6 +670,9 @@ main(int argc, char **argv)
                 case 's':
                         pkcs11provider = optarg;
                         break;
+                case 'S':
+                        skprovider = optarg;
+                        break;
                 case 'e':
                         deleting = 1;
                         pkcs11provider = optarg;
@@ -732,7 +749,7 @@ main(int argc, char **argv)
                         if (stat(buf, &st) == -1)
                                 continue;
                         if (do_file(agent_fd, deleting, key_only, buf,
-                            qflag) == -1)
+                            qflag, skprovider) == -1)
                                 ret = 1;
                         else
                                 count++;
@@ -742,7 +759,7 @@ main(int argc, char **argv)
         } else {
                 for (i = 0; i < argc; i++) {
                         if (do_file(agent_fd, deleting, key_only,
-                            argv[i], qflag) == -1)
+                            argv[i], qflag, skprovider) == -1)
                                 ret = 1;
                 }
         }