1 files changed, 168 insertions, 0 deletions

diff --git a/ssh-ecdsa.c b/ssh-ecdsa.c
new file mode 100644
index 000000000..c8276b460
--- /dev/null
+++ b/ssh-ecdsa.c
@@ -0,0 +1,168 @@
+/* $OpenBSD: ssh-ecdsa.c,v 1.4 2010/09/10 01:04:10 djm Exp $ */
+/*
+ * Copyright (c) 2000 Markus Friedl.  All rights reserved.
+ * Copyright (c) 2010 Damien Miller.  All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
+ * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
+ * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
+ * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
+ * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
+ * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include "includes.h"
+
+#ifdef OPENSSL_HAS_ECC
+
+#include <sys/types.h>
+
+#include <openssl/bn.h>
+#include <openssl/ec.h>
+#include <openssl/ecdsa.h>
+#include <openssl/evp.h>
+
+#include <string.h>
+
+#include "xmalloc.h"
+#include "buffer.h"
+#include "compat.h"
+#include "log.h"
+#include "key.h"
+
+int
+ssh_ecdsa_sign(const Key *key, u_char **sigp, u_int *lenp,
+    const u_char *data, u_int datalen)
+{
+        ECDSA_SIG *sig;
+        const EVP_MD *evp_md;
+        EVP_MD_CTX md;
+        u_char digest[EVP_MAX_MD_SIZE];
+        u_int len, dlen;
+        Buffer b, bb;
+
+        if (key == NULL || key->ecdsa == NULL ||
+            (key->type != KEY_ECDSA && key->type != KEY_ECDSA_CERT)) {
+                error("%s: no ECDSA key", __func__);
+                return -1;
+        }
+        evp_md = key_ec_nid_to_evpmd(key->ecdsa_nid);
+        EVP_DigestInit(&md, evp_md);
+        EVP_DigestUpdate(&md, data, datalen);
+        EVP_DigestFinal(&md, digest, &dlen);
+
+        sig = ECDSA_do_sign(digest, dlen, key->ecdsa);
+        memset(digest, 'd', sizeof(digest));
+
+        if (sig == NULL) {
+                error("%s: sign failed", __func__);
+                return -1;
+        }
+
+        buffer_init(&bb);
+        buffer_put_bignum2(&bb, sig->r);
+        buffer_put_bignum2(&bb, sig->s);
+        ECDSA_SIG_free(sig);
+
+        buffer_init(&b);
+        buffer_put_cstring(&b, key_ssh_name_plain(key));
+        buffer_put_string(&b, buffer_ptr(&bb), buffer_len(&bb));
+        buffer_free(&bb);
+        len = buffer_len(&b);
+        if (lenp != NULL)
+                *lenp = len;
+        if (sigp != NULL) {
+                *sigp = xmalloc(len);
+                memcpy(*sigp, buffer_ptr(&b), len);
+        }
+        buffer_free(&b);
+
+        return 0;
+}
+int
+ssh_ecdsa_verify(const Key *key, const u_char *signature, u_int signaturelen,
+    const u_char *data, u_int datalen)
+{
+        ECDSA_SIG *sig;
+        const EVP_MD *evp_md;
+        EVP_MD_CTX md;
+        u_char digest[EVP_MAX_MD_SIZE], *sigblob;
+        u_int len, dlen;
+        int rlen, ret;
+        Buffer b, bb;
+        char *ktype;
+
+        if (key == NULL || key->ecdsa == NULL ||
+            (key->type != KEY_ECDSA && key->type != KEY_ECDSA_CERT)) {
+                error("%s: no ECDSA key", __func__);
+                return -1;
+        }
+        evp_md = key_ec_nid_to_evpmd(key->ecdsa_nid);
+
+        /* fetch signature */
+        buffer_init(&b);
+        buffer_append(&b, signature, signaturelen);
+        ktype = buffer_get_string(&b, NULL);
+        if (strcmp(key_ssh_name_plain(key), ktype) != 0) {
+                error("%s: cannot handle type %s", __func__, ktype);
+                buffer_free(&b);
+                xfree(ktype);
+                return -1;
+        }
+        xfree(ktype);
+        sigblob = buffer_get_string(&b, &len);
+        rlen = buffer_len(&b);
+        buffer_free(&b);
+        if (rlen != 0) {
+                error("%s: remaining bytes in signature %d", __func__, rlen);
+                xfree(sigblob);
+                return -1;
+        }
+
+        /* parse signature */
+        if ((sig = ECDSA_SIG_new()) == NULL)
+                fatal("%s: ECDSA_SIG_new failed", __func__);
+        if ((sig->r = BN_new()) == NULL ||
+            (sig->s = BN_new()) == NULL)
+                fatal("%s: BN_new failed", __func__);
+
+        buffer_init(&bb);
+        buffer_append(&bb, sigblob, len);
+        buffer_get_bignum2(&bb, sig->r);
+        buffer_get_bignum2(&bb, sig->s);
+        if (buffer_len(&bb) != 0)
+                fatal("%s: remaining bytes in inner sigblob", __func__);
+
+        /* clean up */
+        memset(sigblob, 0, len);
+        xfree(sigblob);
+
+        /* hash the data */
+        EVP_DigestInit(&md, evp_md);
+        EVP_DigestUpdate(&md, data, datalen);
+        EVP_DigestFinal(&md, digest, &dlen);
+
+        ret = ECDSA_do_verify(digest, dlen, sig, key->ecdsa);
+        memset(digest, 'd', sizeof(digest));
+
+        ECDSA_SIG_free(sig);
+
+        debug("%s: signature %s", __func__,
+            ret == 1 ? "correct" : ret == 0 ? "incorrect" : "error");
+        return ret;
+}
+
+#endif /* OPENSSL_HAS_ECC */