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-rw-r--r--usr.bin/ssh/PROTOCOL.u2f98
-rw-r--r--usr.bin/ssh/sk-api.h6
-rw-r--r--usr.bin/ssh/sk-usbhid.c13
-rw-r--r--usr.bin/ssh/ssh-keygen.19
-rw-r--r--usr.bin/ssh/ssh-keygen.c44
-rw-r--r--usr.bin/ssh/ssh-sk.c44
6 files changed, 96 insertions, 118 deletions
diff --git a/usr.bin/ssh/PROTOCOL.u2f b/usr.bin/ssh/PROTOCOL.u2f
index 5b8a06277c5..f8ca56b11c8 100644
--- a/usr.bin/ssh/PROTOCOL.u2f
+++ b/usr.bin/ssh/PROTOCOL.u2f
@@ -154,6 +154,16 @@ by trusted hardware before it will issue a certificate. To support this
case, OpenSSH optionally allows retaining the attestation information
at the time of key generation. It will take the following format:
+ string "ssh-sk-attest-v01"
+ string attestation certificate
+ string enrollment signature
+ string authenticator data (CBOR encoded)
+ uint32 reserved flags
+ string reserved string
+
+A previous version of this format, emitted prior to OpenSSH 8.4 omitted
+the authenticator data.
+
string "ssh-sk-attest-v00"
string attestation certificate
string enrollment signature
@@ -267,87 +277,15 @@ regress testing. For this reason, OpenSSH shall support a dynamically-
loaded middleware libraries to communicate with security keys, but offer
support for the common case of USB HID security keys internally.
-The middleware library need only expose a handful of functions:
-
- #define SSH_SK_VERSION_MAJOR 0x00050000 /* API version */
- #define SSH_SK_VERSION_MAJOR_MASK 0xffff0000
-
- /* Flags */
- #define SSH_SK_USER_PRESENCE_REQD 0x01
- #define SSH_SK_USER_VERIFICATION_REQD 0x04
- #define SSH_SK_RESIDENT_KEY 0x20
-
- /* Algs */
- #define SSH_SK_ECDSA 0x00
- #define SSH_SK_ED25519 0x01
-
- /* Error codes */
- #define SSH_SK_ERR_GENERAL -1
- #define SSH_SK_ERR_UNSUPPORTED -2
- #define SSH_SK_ERR_PIN_REQUIRED -3
- #define SSH_SK_ERR_DEVICE_NOT_FOUND -4
-
- struct sk_enroll_response {
- uint8_t *public_key;
- size_t public_key_len;
- uint8_t *key_handle;
- size_t key_handle_len;
- uint8_t *signature;
- size_t signature_len;
- uint8_t *attestation_cert;
- size_t attestation_cert_len;
- };
-
- struct sk_sign_response {
- uint8_t flags;
- uint32_t counter;
- uint8_t *sig_r;
- size_t sig_r_len;
- uint8_t *sig_s;
- size_t sig_s_len;
- };
-
- struct sk_resident_key {
- uint32_t alg;
- size_t slot;
- char *application;
- struct sk_enroll_response key;
- };
-
- struct sk_option {
- char *name;
- char *value;
- uint8_t important;
- };
-
- /* Return the version of the middleware API */
- uint32_t sk_api_version(void);
-
- /* Enroll a U2F key (private key generation) */
- int sk_enroll(uint32_t alg,
- const uint8_t *challenge, size_t challenge_len,
- const char *application, uint8_t flags, const char *pin,
- struct sk_option **options,
- struct sk_enroll_response **enroll_response);
-
- /* Sign a challenge */
- int sk_sign(uint32_t alg, const uint8_t *message, size_t message_len,
- const char *application,
- const uint8_t *key_handle, size_t key_handle_len,
- uint8_t flags, const char *pin, struct sk_option **options,
- struct sk_sign_response **sign_response);
-
- /* Enumerate all resident keys */
- int sk_load_resident_keys(const char *pin, struct sk_option **options,
- struct sk_resident_key ***rks, size_t *nrks);
-
-The SSH_SK_VERSION_MAJOR should be incremented for each incompatible
+The middleware library need only expose a handful of functions and
+numbers listed in sk-api.h. Included in the defined numbers is a
+SSH_SK_VERSION_MAJOR that should be incremented for each incompatible
API change.
-The options may be used to pass miscellaneous options to the middleware
-as a NULL-terminated array of pointers to struct sk_option. The middleware
-may ignore unsupported or unknown options unless the "important" flag is
-set, in which case it should return failure if an unsupported option is
+miscellaneous options may be passed to the middleware as a NULL-
+terminated array of pointers to struct sk_option. The middleware may
+ignore unsupported or unknown options unless the "required" flag is set,
+in which case it should return failure if an unsupported option is
requested.
At present the following options names are supported:
@@ -368,4 +306,4 @@ In OpenSSH, the middleware will be invoked by using a similar mechanism to
ssh-pkcs11-helper to provide address-space containment of the
middleware from ssh-agent.
-$OpenBSD: PROTOCOL.u2f,v 1.25 2020/08/31 00:17:41 djm Exp $
+$OpenBSD: PROTOCOL.u2f,v 1.26 2020/09/09 03:08:01 djm Exp $
diff --git a/usr.bin/ssh/sk-api.h b/usr.bin/ssh/sk-api.h
index 6bf7c092875..40cdc834a04 100644
--- a/usr.bin/ssh/sk-api.h
+++ b/usr.bin/ssh/sk-api.h
@@ -1,4 +1,4 @@
-/* $OpenBSD: sk-api.h,v 1.10 2020/08/27 01:08:19 djm Exp $ */
+/* $OpenBSD: sk-api.h,v 1.11 2020/09/09 03:08:01 djm Exp $ */
/*
* Copyright (c) 2019 Google LLC
*
@@ -45,6 +45,8 @@ struct sk_enroll_response {
size_t signature_len;
uint8_t *attestation_cert;
size_t attestation_cert_len;
+ uint8_t *authdata;
+ size_t authdata_len;
};
struct sk_sign_response {
@@ -70,7 +72,7 @@ struct sk_option {
uint8_t required;
};
-#define SSH_SK_VERSION_MAJOR 0x00060000 /* current API version */
+#define SSH_SK_VERSION_MAJOR 0x00070000 /* current API version */
#define SSH_SK_VERSION_MAJOR_MASK 0xffff0000
/* Return the version of the middleware API */
diff --git a/usr.bin/ssh/sk-usbhid.c b/usr.bin/ssh/sk-usbhid.c
index 9dde5c10a26..878ce965111 100644
--- a/usr.bin/ssh/sk-usbhid.c
+++ b/usr.bin/ssh/sk-usbhid.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: sk-usbhid.c,v 1.25 2020/08/31 00:17:41 djm Exp $ */
+/* $OpenBSD: sk-usbhid.c,v 1.26 2020/09/09 03:08:01 djm Exp $ */
/*
* Copyright (c) 2019 Markus Friedl
* Copyright (c) 2020 Pedro Martelletto
@@ -781,6 +781,16 @@ sk_enroll(uint32_t alg, const uint8_t *challenge, size_t challenge_len,
memcpy(response->attestation_cert, ptr, len);
response->attestation_cert_len = len;
}
+ if ((ptr = fido_cred_authdata_ptr(cred)) != NULL) {
+ len = fido_cred_authdata_len(cred);
+ debug3("%s: authdata len=%zu", __func__, len);
+ if ((response->authdata = calloc(1, len)) == NULL) {
+ skdebug(__func__, "calloc authdata failed");
+ goto out;
+ }
+ memcpy(response->authdata, ptr, len);
+ response->authdata_len = len;
+ }
*enroll_response = response;
response = NULL;
ret = 0;
@@ -791,6 +801,7 @@ sk_enroll(uint32_t alg, const uint8_t *challenge, size_t challenge_len,
free(response->key_handle);
free(response->signature);
free(response->attestation_cert);
+ free(response->authdata);
free(response);
}
sk_close(sk);
diff --git a/usr.bin/ssh/ssh-keygen.1 b/usr.bin/ssh/ssh-keygen.1
index c51a0d9c8b5..3ae596caac8 100644
--- a/usr.bin/ssh/ssh-keygen.1
+++ b/usr.bin/ssh/ssh-keygen.1
@@ -1,4 +1,4 @@
-.\" $OpenBSD: ssh-keygen.1,v 1.208 2020/08/27 06:15:22 jmc Exp $
+.\" $OpenBSD: ssh-keygen.1,v 1.209 2020/09/09 03:08:01 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: August 27 2020 $
+.Dd $Mdocdate: September 9 2020 $
.Dt SSH-KEYGEN 1
.Os
.Sh NAME
@@ -520,9 +520,10 @@ Not all FIDO tokens support this option.
Currently PIN authentication is the only supported verification method,
but other methods may be supported in the future.
.It Cm write-attestation Ns = Ns Ar path
-May be used at key generation time to record the attestation certificate
+May be used at key generation time to record the attestation data
returned from FIDO tokens during key generation.
-By default this information is discarded.
+Please note that this information is potentially sensitive.
+By default, this information is discarded.
.El
.Pp
The
diff --git a/usr.bin/ssh/ssh-keygen.c b/usr.bin/ssh/ssh-keygen.c
index 0e169a2aaac..703a5fb2102 100644
--- a/usr.bin/ssh/ssh-keygen.c
+++ b/usr.bin/ssh/ssh-keygen.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: ssh-keygen.c,v 1.419 2020/08/27 09:46:04 djm Exp $ */
+/* $OpenBSD: ssh-keygen.c,v 1.420 2020/09/09 03:08:01 djm Exp $ */
/*
* Author: Tatu Ylonen <ylo@cs.hut.fi>
* Copyright (c) 1994 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
@@ -3050,6 +3050,27 @@ do_download_sk(const char *skprovider, const char *device)
}
static void
+save_attestation(struct sshbuf *attest, const char *path)
+{
+ mode_t omask;
+ int r;
+
+ if (path == NULL)
+ return; /* nothing to do */
+ if (attest == NULL || sshbuf_len(attest) == 0)
+ fatal("Enrollment did not return attestation data");
+ omask = umask(077);
+ r = sshbuf_write_file(path, attest);
+ umask(omask);
+ if (r != 0)
+ fatal("Unable to write attestation data \"%s\": %s", path,
+ ssh_err(r));
+ if (!quiet)
+ printf("Your FIDO attestation certificate has been saved in "
+ "%s\n", path);
+}
+
+static void
usage(void)
{
fprintf(stderr,
@@ -3115,7 +3136,7 @@ main(int argc, char **argv)
unsigned long long cert_serial = 0;
char *identity_comment = NULL, *ca_key_path = NULL, **opts = NULL;
char *sk_application = NULL, *sk_device = NULL, *sk_user = NULL;
- char *sk_attestaion_path = NULL;
+ char *sk_attestation_path = NULL;
struct sshbuf *challenge = NULL, *attest = NULL;
size_t i, nopts = 0;
u_int32_t bits = 0;
@@ -3568,7 +3589,7 @@ main(int argc, char **argv)
}
} else if (strncasecmp(opts[i],
"write-attestation=", 18) == 0) {
- sk_attestaion_path = opts[i] + 18;
+ sk_attestation_path = opts[i] + 18;
} else if (strncasecmp(opts[i],
"application=", 12) == 0) {
sk_application = xstrdup(opts[i] + 12);
@@ -3690,20 +3711,9 @@ main(int argc, char **argv)
free(fp);
}
- if (sk_attestaion_path != NULL) {
- if (attest == NULL || sshbuf_len(attest) == 0) {
- fatal("Enrollment did not return attestation "
- "certificate");
- }
- if ((r = sshbuf_write_file(sk_attestaion_path, attest)) != 0) {
- fatal("Unable to write attestation certificate "
- "\"%s\": %s", sk_attestaion_path, ssh_err(r));
- }
- if (!quiet) {
- printf("Your FIDO attestation certificate has been "
- "saved in %s\n", sk_attestaion_path);
- }
- }
+ if (sk_attestation_path != NULL)
+ save_attestation(attest, sk_attestation_path);
+
sshbuf_free(attest);
sshkey_free(public);
diff --git a/usr.bin/ssh/ssh-sk.c b/usr.bin/ssh/ssh-sk.c
index 6a2422f2bba..1262bce4b97 100644
--- a/usr.bin/ssh/ssh-sk.c
+++ b/usr.bin/ssh/ssh-sk.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: ssh-sk.c,v 1.31 2020/08/27 01:08:19 djm Exp $ */
+/* $OpenBSD: ssh-sk.c,v 1.32 2020/09/09 03:08:02 djm Exp $ */
/*
* Copyright (c) 2019 Google LLC
*
@@ -164,6 +164,7 @@ sshsk_free_enroll_response(struct sk_enroll_response *r)
freezero(r->public_key, r->public_key_len);
freezero(r->signature, r->signature_len);
freezero(r->attestation_cert, r->attestation_cert_len);
+ freezero(r->authdata, r->authdata_len);
freezero(r, sizeof(*r));
}
@@ -409,6 +410,31 @@ make_options(const char *device, const char *user_id,
return ret;
}
+
+static int
+fill_attestation_blob(const struct sk_enroll_response *resp,
+ struct sshbuf *attest)
+{
+ int r;
+
+ if (attest == NULL)
+ return 0; /* nothing to do */
+ if ((r = sshbuf_put_cstring(attest, "ssh-sk-attest-v01")) != 0 ||
+ (r = sshbuf_put_string(attest,
+ resp->attestation_cert, resp->attestation_cert_len)) != 0 ||
+ (r = sshbuf_put_string(attest,
+ resp->signature, resp->signature_len)) != 0 ||
+ (r = sshbuf_put_string(attest,
+ resp->authdata, resp->authdata_len)) != 0 ||
+ (r = sshbuf_put_u32(attest, 0)) != 0 || /* resvd flags */
+ (r = sshbuf_put_string(attest, NULL, 0)) != 0 /* resvd */) {
+ error("%s: buffer error: %s", __func__, ssh_err(r));
+ return r;
+ }
+ /* success */
+ return 0;
+}
+
int
sshsk_enroll(int type, const char *provider_path, const char *device,
const char *application, const char *userid, uint8_t flags,
@@ -496,19 +522,9 @@ sshsk_enroll(int type, const char *provider_path, const char *device,
goto out;
/* Optionally fill in the attestation information */
- if (attest != NULL) {
- if ((r = sshbuf_put_cstring(attest,
- "ssh-sk-attest-v00")) != 0 ||
- (r = sshbuf_put_string(attest,
- resp->attestation_cert, resp->attestation_cert_len)) != 0 ||
- (r = sshbuf_put_string(attest,
- resp->signature, resp->signature_len)) != 0 ||
- (r = sshbuf_put_u32(attest, 0)) != 0 || /* resvd flags */
- (r = sshbuf_put_string(attest, NULL, 0)) != 0 /* resvd */) {
- error("%s: buffer error: %s", __func__, ssh_err(r));
- goto out;
- }
- }
+ if ((r = fill_attestation_blob(resp, attest)) != 0)
+ goto out;
+
/* success */
*keyp = key;
key = NULL; /* transferred */
generated by cgit v1.2.3 (git 2.25.1) at 2024-12-11 21:24:08 +0000