4 files changed, 142 insertions, 3 deletions

diff --git a/Makefile.in b/Makefile.in
index fddc82576..3acfab5c5 100644
--- a/Makefile.in
+++ b/Makefile.in
@@ -94,7 +94,7 @@ LIBSSH_OBJS=${LIBOPENSSH_OBJS} \
         readpass.o ttymodes.o xmalloc.o addrmatch.o \
         atomicio.o dispatch.o mac.o misc.o utf8.o \
         monitor_fdpass.o rijndael.o ssh-dss.o ssh-ecdsa.o ssh-ecdsa-sk.o \
-        ssh-rsa.o dh.o \
+        ssh-ed25519-sk.o ssh-rsa.o dh.o \
         msg.o progressmeter.o dns.o entropy.o gss-genr.o umac.o umac128.o \
         ssh-pkcs11.o smult_curve25519_ref.o \
         poly1305.o chacha.o cipher-chachapoly.o \
diff --git a/ssh-ed25519-sk.c b/ssh-ed25519-sk.c
new file mode 100644
index 000000000..f42c88303
--- /dev/null
+++ b/ssh-ed25519-sk.c
@@ -0,0 +1,130 @@
+/* $OpenBSD: ssh-ed25519-sk.c,v 1.1 2019/11/12 19:29:24 markus Exp $ */
+/*
+ * Copyright (c) 2019 Markus Friedl.  All rights reserved.
+ *
+ * Permission to use, copy, modify, and distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+ * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ */
+#define SSHKEY_INTERNAL
+#include <sys/types.h>
+#include <limits.h>
+
+#include "crypto_api.h"
+
+#include <string.h>
+#include <stdarg.h>
+
+#include "log.h"
+#include "sshbuf.h"
+#include "sshkey.h"
+#include "ssherr.h"
+#include "ssh.h"
+#include "digest.h"
+
+int
+ssh_ed25519_sk_verify(const struct sshkey *key,
+    const u_char *signature, size_t signaturelen,
+    const u_char *data, size_t datalen, u_int compat)
+{
+        struct sshbuf *b = NULL;
+        struct sshbuf *sigbuf = NULL;
+        struct sshbuf *encoded = NULL;
+        char *ktype = NULL;
+        const u_char *sigblob;
+        const u_char *sm;
+        u_char *m = NULL;
+        u_char apphash[32];
+        u_char msghash[32];
+        u_char sig_flags;
+        u_int sig_counter;
+        size_t len;
+        unsigned long long smlen = 0, mlen = 0;
+        int r = SSH_ERR_INTERNAL_ERROR;
+        int ret;
+
+        if (key == NULL ||
+            sshkey_type_plain(key->type) != KEY_ED25519_SK ||
+            key->ed25519_pk == NULL ||
+            signature == NULL || signaturelen == 0)
+                return SSH_ERR_INVALID_ARGUMENT;
+
+        if ((b = sshbuf_from(signature, signaturelen)) == NULL)
+                return SSH_ERR_ALLOC_FAIL;
+        if (sshbuf_get_cstring(b, &ktype, NULL) != 0 ||
+            sshbuf_froms(b, &sigbuf) != 0 ||
+            sshbuf_get_string_direct(sigbuf, &sigblob, &len) != 0 ||
+            sshbuf_get_u8(sigbuf, &sig_flags) != 0 ||
+            sshbuf_get_u32(sigbuf, &sig_counter) != 0) {
+                r = SSH_ERR_INVALID_FORMAT;
+                goto out;
+        }
+        if (strcmp(sshkey_ssh_name_plain(key), ktype) != 0) {
+                r = SSH_ERR_KEY_TYPE_MISMATCH;
+                goto out;
+        }
+        if (sshbuf_len(b) != 0) {
+                r = SSH_ERR_UNEXPECTED_TRAILING_DATA;
+                goto out;
+        }
+        if (len > crypto_sign_ed25519_BYTES) {
+                r = SSH_ERR_INVALID_FORMAT;
+                goto out;
+        }
+        if (ssh_digest_memory(SSH_DIGEST_SHA256, key->sk_application,
+            strlen(key->sk_application), apphash, sizeof(apphash)) != 0 ||
+            ssh_digest_memory(SSH_DIGEST_SHA256, data, datalen,
+            msghash, sizeof(msghash)) != 0) {
+                r = SSH_ERR_INVALID_ARGUMENT;
+                goto out;
+        }
+        if ((encoded = sshbuf_new()) == NULL) {
+                r = SSH_ERR_ALLOC_FAIL;
+                goto out;
+        }
+        if (sshbuf_put(encoded, sigblob, len) != 0 ||
+            sshbuf_put(encoded, apphash, sizeof(apphash)) != 0 ||
+            sshbuf_put_u8(encoded, sig_flags) != 0 ||
+            sshbuf_put_u32(encoded, sig_counter) != 0 ||
+            sshbuf_put(encoded, msghash, sizeof(msghash)) != 0) {
+                r = SSH_ERR_ALLOC_FAIL;
+                goto out;
+        }
+        sm = sshbuf_ptr(encoded);
+        smlen = sshbuf_len(encoded);
+        mlen = smlen;
+        if ((m = malloc(smlen)) == NULL) {
+                r = SSH_ERR_ALLOC_FAIL;
+                goto out;
+        }
+        if ((ret = crypto_sign_ed25519_open(m, &mlen, sm, smlen,
+            key->ed25519_pk)) != 0) {
+                debug2("%s: crypto_sign_ed25519_open failed: %d",
+                    __func__, ret);
+        }
+        if (ret != 0 || mlen != smlen - len) {
+                r = SSH_ERR_SIGNATURE_INVALID;
+                goto out;
+        }
+        /* XXX compare 'm' and 'sm + len' ? */
+        /* success */
+        r = 0;
+ out:
+        if (m != NULL) {
+                explicit_bzero(m, smlen); /* NB mlen may be invalid if r != 0 */
+                free(m);
+        }
+        sshbuf_free(b);
+        sshbuf_free(sigbuf);
+        sshbuf_free(encoded);
+        free(ktype);
+        return r;
+}
diff --git a/sshkey.c b/sshkey.c
index 861d77689..b72f38a2f 100644
--- a/sshkey.c
+++ b/sshkey.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: sshkey.c,v 1.86 2019/10/31 21:23:19 djm Exp $ */
+/* $OpenBSD: sshkey.c,v 1.87 2019/11/12 19:29:24 markus Exp $ */
 /*
  * Copyright (c) 2000, 2001 Markus Friedl.  All rights reserved.
  * Copyright (c) 2008 Alexander von Gernler.  All rights reserved.
@@ -2750,6 +2750,10 @@ sshkey_verify(const struct sshkey *key,
         case KEY_ED25519:
         case KEY_ED25519_CERT:
                 return ssh_ed25519_verify(key, sig, siglen, data, dlen, compat);
+        case KEY_ED25519_SK:
+        case KEY_ED25519_SK_CERT:
+                return ssh_ed25519_sk_verify(key, sig, siglen, data, dlen,
+                    compat);
 #ifdef WITH_XMSS
         case KEY_XMSS:
         case KEY_XMSS_CERT:
diff --git a/sshkey.h b/sshkey.h
index 1d36a24a9..8cd12bd95 100644
--- a/sshkey.h
+++ b/sshkey.h
@@ -1,4 +1,4 @@
-/* $OpenBSD: sshkey.h,v 1.36 2019/10/31 21:23:19 djm Exp $ */
+/* $OpenBSD: sshkey.h,v 1.37 2019/11/12 19:29:25 markus Exp $ */
 
 /*
  * Copyright (c) 2000, 2001 Markus Friedl.  All rights reserved.
@@ -67,6 +67,8 @@ enum sshkey_types {
         KEY_XMSS_CERT,
         KEY_ECDSA_SK,
         KEY_ECDSA_SK_CERT,
+        KEY_ED25519_SK,
+        KEY_ED25519_SK_CERT,
         KEY_UNSPEC
 };
 
@@ -291,6 +293,9 @@ int ssh_ed25519_sign(const struct sshkey *key, u_char **sigp, size_t *lenp,
 int ssh_ed25519_verify(const struct sshkey *key,
     const u_char *signature, size_t signaturelen,
     const u_char *data, size_t datalen, u_int compat);
+int ssh_ed25519_sk_verify(const struct sshkey *key,
+    const u_char *signature, size_t signaturelen,
+    const u_char *data, size_t datalen, u_int compat);
 int ssh_xmss_sign(const struct sshkey *key, u_char **sigp, size_t *lenp,
     const u_char *data, size_t datalen, u_int compat);
 int ssh_xmss_verify(const struct sshkey *key,