1 files changed, 263 insertions, 0 deletions
diff --git a/crypto/openssh/ssh-rsa.c b/crypto/openssh/ssh-rsa.c
new file mode 100644
index 0000000..0e16ff8
--- /dev/null
+++ b/crypto/openssh/ssh-rsa.c
@@ -0,0 +1,263 @@
+/* $OpenBSD: ssh-rsa.c,v 1.39 2006/08/03 03:34:42 deraadt Exp $ */
+/*
+ * Copyright (c) 2000, 2003 Markus Friedl <markus@openbsd.org>
+ *
+ * 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.
+ */
+
+#include "includes.h"
+
+#include <sys/types.h>
+
+#include <openssl/evp.h>
+#include <openssl/err.h>
+
+#include <stdarg.h>
+#include <string.h>
+
+#include "xmalloc.h"
+#include "log.h"
+#include "buffer.h"
+#include "key.h"
+#include "compat.h"
+#include "ssh.h"
+
+static int openssh_RSA_verify(int, u_char *, u_int, u_char *, u_int, RSA *);
+
+/* RSASSA-PKCS1-v1_5 (PKCS #1 v2.0 signature) with SHA1 */
+int
+ssh_rsa_sign(const Key *key, u_char **sigp, u_int *lenp,
+    const u_char *data, u_int datalen)
+{
+	const EVP_MD *evp_md;
+	EVP_MD_CTX md;
+	u_char digest[EVP_MAX_MD_SIZE], *sig;
+	u_int slen, dlen, len;
+	int ok, nid;
+	Buffer b;
+
+	if (key == NULL || key->type != KEY_RSA || key->rsa == NULL) {
+		error("ssh_rsa_sign: no RSA key");
+		return -1;
+	}
+	nid = (datafellows & SSH_BUG_RSASIGMD5) ? NID_md5 : NID_sha1;
+	if ((evp_md = EVP_get_digestbynid(nid)) == NULL) {
+		error("ssh_rsa_sign: EVP_get_digestbynid %d failed", nid);
+		return -1;
+	}
+	EVP_DigestInit(&md, evp_md);
+	EVP_DigestUpdate(&md, data, datalen);
+	EVP_DigestFinal(&md, digest, &dlen);
+
+	slen = RSA_size(key->rsa);
+	sig = xmalloc(slen);
+
+	ok = RSA_sign(nid, digest, dlen, sig, &len, key->rsa);
+	memset(digest, 'd', sizeof(digest));
+
+	if (ok != 1) {
+		int ecode = ERR_get_error();
+
+		error("ssh_rsa_sign: RSA_sign failed: %s",
+		    ERR_error_string(ecode, NULL));
+		xfree(sig);
+		return -1;
+	}
+	if (len < slen) {
+		u_int diff = slen - len;
+		debug("slen %u > len %u", slen, len);
+		memmove(sig + diff, sig, len);
+		memset(sig, 0, diff);
+	} else if (len > slen) {
+		error("ssh_rsa_sign: slen %u slen2 %u", slen, len);
+		xfree(sig);
+		return -1;
+	}
+	/* encode signature */
+	buffer_init(&b);
+	buffer_put_cstring(&b, "ssh-rsa");
+	buffer_put_string(&b, sig, slen);
+	len = buffer_len(&b);
+	if (lenp != NULL)
+		*lenp = len;
+	if (sigp != NULL) {
+		*sigp = xmalloc(len);
+		memcpy(*sigp, buffer_ptr(&b), len);
+	}
+	buffer_free(&b);
+	memset(sig, 's', slen);
+	xfree(sig);
+
+	return 0;
+}
+
+int
+ssh_rsa_verify(const Key *key, const u_char *signature, u_int signaturelen,
+    const u_char *data, u_int datalen)
+{
+	Buffer b;
+	const EVP_MD *evp_md;
+	EVP_MD_CTX md;
+	char *ktype;
+	u_char digest[EVP_MAX_MD_SIZE], *sigblob;
+	u_int len, dlen, modlen;
+	int rlen, ret, nid;
+
+	if (key == NULL || key->type != KEY_RSA || key->rsa == NULL) {
+		error("ssh_rsa_verify: no RSA key");
+		return -1;
+	}
+	if (BN_num_bits(key->rsa->n) < SSH_RSA_MINIMUM_MODULUS_SIZE) {
+		error("ssh_rsa_verify: RSA modulus too small: %d < minimum %d bits",
+		    BN_num_bits(key->rsa->n), SSH_RSA_MINIMUM_MODULUS_SIZE);
+		return -1;
+	}
+	buffer_init(&b);
+	buffer_append(&b, signature, signaturelen);
+	ktype = buffer_get_string(&b, NULL);
+	if (strcmp("ssh-rsa", ktype) != 0) {
+		error("ssh_rsa_verify: cannot handle type %s", 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("ssh_rsa_verify: remaining bytes in signature %d", rlen);
+		xfree(sigblob);
+		return -1;
+	}
+	/* RSA_verify expects a signature of RSA_size */
+	modlen = RSA_size(key->rsa);
+	if (len > modlen) {
+		error("ssh_rsa_verify: len %u > modlen %u", len, modlen);
+		xfree(sigblob);
+		return -1;
+	} else if (len < modlen) {
+		u_int diff = modlen - len;
+		debug("ssh_rsa_verify: add padding: modlen %u > len %u",
+		    modlen, len);
+		sigblob = xrealloc(sigblob, 1, modlen);
+		memmove(sigblob + diff, sigblob, len);
+		memset(sigblob, 0, diff);
+		len = modlen;
+	}
+	nid = (datafellows & SSH_BUG_RSASIGMD5) ? NID_md5 : NID_sha1;
+	if ((evp_md = EVP_get_digestbynid(nid)) == NULL) {
+		error("ssh_rsa_verify: EVP_get_digestbynid %d failed", nid);
+		xfree(sigblob);
+		return -1;
+	}
+	EVP_DigestInit(&md, evp_md);
+	EVP_DigestUpdate(&md, data, datalen);
+	EVP_DigestFinal(&md, digest, &dlen);
+
+	ret = openssh_RSA_verify(nid, digest, dlen, sigblob, len, key->rsa);
+	memset(digest, 'd', sizeof(digest));
+	memset(sigblob, 's', len);
+	xfree(sigblob);
+	debug("ssh_rsa_verify: signature %scorrect", (ret==0) ? "in" : "");
+	return ret;
+}
+
+/*
+ * See:
+ * http://www.rsasecurity.com/rsalabs/pkcs/pkcs-1/
+ * ftp://ftp.rsasecurity.com/pub/pkcs/pkcs-1/pkcs-1v2-1.asn
+ */
+/*
+ * id-sha1 OBJECT IDENTIFIER ::= { iso(1) identified-organization(3)
+ *	oiw(14) secsig(3) algorithms(2) 26 }
+ */
+static const u_char id_sha1[] = {
+	0x30, 0x21, /* type Sequence, length 0x21 (33) */
+	0x30, 0x09, /* type Sequence, length 0x09 */
+	0x06, 0x05, /* type OID, length 0x05 */
+	0x2b, 0x0e, 0x03, 0x02, 0x1a, /* id-sha1 OID */
+	0x05, 0x00, /* NULL */
+	0x04, 0x14  /* Octet string, length 0x14 (20), followed by sha1 hash */
+};
+/*
+ * id-md5 OBJECT IDENTIFIER ::= { iso(1) member-body(2) us(840)
+ *	rsadsi(113549) digestAlgorithm(2) 5 }
+ */
+static const u_char id_md5[] = {
+	0x30, 0x20, /* type Sequence, length 0x20 (32) */
+	0x30, 0x0c, /* type Sequence, length 0x09 */
+	0x06, 0x08, /* type OID, length 0x05 */
+	0x2a, 0x86, 0x48, 0x86, 0xF7, 0x0D, 0x02, 0x05, /* id-md5 */
+	0x05, 0x00, /* NULL */
+	0x04, 0x10  /* Octet string, length 0x10 (16), followed by md5 hash */
+};
+
+static int
+openssh_RSA_verify(int type, u_char *hash, u_int hashlen,
+    u_char *sigbuf, u_int siglen, RSA *rsa)
+{
+	u_int ret, rsasize, oidlen = 0, hlen = 0;
+	int len;
+	const u_char *oid = NULL;
+	u_char *decrypted = NULL;
+
+	ret = 0;
+	switch (type) {
+	case NID_sha1:
+		oid = id_sha1;
+		oidlen = sizeof(id_sha1);
+		hlen = 20;
+		break;
+	case NID_md5:
+		oid = id_md5;
+		oidlen = sizeof(id_md5);
+		hlen = 16;
+		break;
+	default:
+		goto done;
+	}
+	if (hashlen != hlen) {
+		error("bad hashlen");
+		goto done;
+	}
+	rsasize = RSA_size(rsa);
+	if (siglen == 0 || siglen > rsasize) {
+		error("bad siglen");
+		goto done;
+	}
+	decrypted = xmalloc(rsasize);
+	if ((len = RSA_public_decrypt(siglen, sigbuf, decrypted, rsa,
+	    RSA_PKCS1_PADDING)) < 0) {
+		error("RSA_public_decrypt failed: %s",
+		    ERR_error_string(ERR_get_error(), NULL));
+		goto done;
+	}
+	if (len < 0 || (u_int)len != hlen + oidlen) {
+		error("bad decrypted len: %d != %d + %d", len, hlen, oidlen);
+		goto done;
+	}
+	if (memcmp(decrypted, oid, oidlen) != 0) {
+		error("oid mismatch");
+		goto done;
+	}
+	if (memcmp(decrypted + oidlen, hash, hlen) != 0) {
+		error("hash mismatch");
+		goto done;
+	}
+	ret = 1;
+done:
+	if (decrypted)
+		xfree(decrypted);
+	return ret;
+}