upstream: Extends the SK API to accept a set of key/value options

for all operations. These are intended to future-proof the API a little by
making it easier to specify additional fields for without having to change
the API version for each.

At present, only two options are defined: one to explicitly specify
the device for an operation (rather than accepting the middleware's
autoselection) and another to specify the FIDO2 username that may
be used when generating a resident key. These new options may be
invoked at key generation time via ssh-keygen -O

This also implements a suggestion from Markus to avoid "int" in favour
of uint32_t for the algorithm argument in the API, to make implementation
of ssh-sk-client/helper a little easier.

feedback, fixes and ok markus@

OpenBSD-Commit-ID: 973ce11704609022ab36abbdeb6bc23c8001eabc

1 files changed, 8 insertions, 6 deletions

diff --git a/ssh-sk.h b/ssh-sk.h
index 348759a9..ea9ff6e1 100644
--- a/ssh-sk.h
+++ b/ssh-sk.h
@@ -1,4 +1,4 @@
-/* $OpenBSD: ssh-sk.h,v 1.8 2019/12/30 09:23:28 djm Exp $ */
+/* $OpenBSD: ssh-sk.h,v 1.9 2020/01/06 02:00:47 djm Exp $ */
 /*
  * Copyright (c) 2019 Google LLC
  *
@@ -20,9 +20,10 @@
 
 struct sshbuf;
 struct sshkey;
+struct sk_option;
 
 /* Version of protocol expected from ssh-sk-helper */
-#define SSH_SK_HELPER_VERSION		3
+#define SSH_SK_HELPER_VERSION		4
 
 /* ssh-sk-helper messages */
 #define SSH_SK_HELPER_ERROR		0	/* Only valid H->C */
@@ -40,8 +41,9 @@ struct sshkey;
  * If successful and the attest_data buffer is not NULL then attestation
  * information is placed there.
  */
-int sshsk_enroll(int type, const char *provider_path, const char *application,
-    uint8_t flags, const char *pin, struct sshbuf *challenge_buf,
+int sshsk_enroll(int type, const char *provider_path, const char *device,
+    const char *application, const char *userid, uint8_t flags,
+    const char *pin, struct sshbuf *challenge_buf,
     struct sshkey **keyp, struct sshbuf *attest);
 
 /*
@@ -60,8 +62,8 @@ int sshsk_sign(const char *provider_path, struct sshkey *key,
  *
  * Returns 0 on success or a ssherr.h error code on failure.
  */
-int sshsk_load_resident(const char *provider_path, const char *pin,
-    struct sshkey ***keysp, size_t *nkeysp);
+int sshsk_load_resident(const char *provider_path, const char *device,
+    const char *pin, struct sshkey ***keysp, size_t *nkeysp);
 
 #endif /* _SSH_SK_H */