view signkey.h @ 1790:42745af83b7d

Introduce extra delay before closing unauthenticated sessions To make it harder for attackers, introduce a delay to keep an unauthenticated session open a bit longer, thus blocking a connection slot until after the delay. Without this, while there is a limit on the amount of attempts an attacker can make at the same time (MAX_UNAUTH_PER_IP), the time taken by dropbear to handle one attempt is still short and thus for each of the allowed parallel attempts many attempts can be chained one after the other. The attempt rate is then: "MAX_UNAUTH_PER_IP / <process time of one attempt>". With the delay, this rate becomes: "MAX_UNAUTH_PER_IP / UNAUTH_CLOSE_DELAY".
author Thomas De Schampheleire <thomas.de_schampheleire@nokia.com>
date Wed, 15 Feb 2017 13:53:04 +0100
parents d5cdc60db08e
children 35d504d59c05
line wrap: on
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/*
 * Dropbear - a SSH2 server
 * 
 * Copyright (c) 2002,2003 Matt Johnston
 * All rights reserved.
 * 
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 * 
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 * 
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 * SOFTWARE. */

#ifndef DROPBEAR_SIGNKEY_H_
#define DROPBEAR_SIGNKEY_H_

#include "buffer.h"

/* Forward declarations */
struct dropbear_DSS_Key;
struct dropbear_RSA_Key;
struct dropbear_ED25519_Key;

/* Must match with signature_type below */
enum signkey_type {
#if DROPBEAR_RSA
	DROPBEAR_SIGNKEY_RSA,
#endif
#if DROPBEAR_DSS
	DROPBEAR_SIGNKEY_DSS,
#endif
#if DROPBEAR_ECDSA
	DROPBEAR_SIGNKEY_ECDSA_NISTP256,
	DROPBEAR_SIGNKEY_ECDSA_NISTP384,
	DROPBEAR_SIGNKEY_ECDSA_NISTP521,
#endif /* DROPBEAR_ECDSA */
#if DROPBEAR_ED25519
	DROPBEAR_SIGNKEY_ED25519,
#endif
	DROPBEAR_SIGNKEY_NUM_NAMED,
	DROPBEAR_SIGNKEY_ECDSA_KEYGEN = 70, /* just "ecdsa" for keygen */
	DROPBEAR_SIGNKEY_ANY = 80,
	DROPBEAR_SIGNKEY_NONE = 90,
};

/* Must match with signkey_type above, apart from rsa */
enum signature_type {
#if DROPBEAR_DSS
	DROPBEAR_SIGNATURE_DSS = DROPBEAR_SIGNKEY_DSS,
#endif
#if DROPBEAR_ECDSA
	DROPBEAR_SIGNATURE_ECDSA_NISTP256 = DROPBEAR_SIGNKEY_ECDSA_NISTP256,
	DROPBEAR_SIGNATURE_ECDSA_NISTP384 = DROPBEAR_SIGNKEY_ECDSA_NISTP384,
	DROPBEAR_SIGNATURE_ECDSA_NISTP521 = DROPBEAR_SIGNKEY_ECDSA_NISTP521,
#endif /* DROPBEAR_ECDSA */
#if DROPBEAR_ED25519
	DROPBEAR_SIGNATURE_ED25519 = DROPBEAR_SIGNKEY_ED25519,
#endif
#if DROPBEAR_RSA_SHA1
	DROPBEAR_SIGNATURE_RSA_SHA1 = 100, /* ssh-rsa signature (sha1) */
#endif
#if DROPBEAR_RSA_SHA256
	DROPBEAR_SIGNATURE_RSA_SHA256 = 101, /* rsa-sha2-256 signature. has a ssh-rsa key */
#endif
	DROPBEAR_SIGNATURE_NONE = DROPBEAR_SIGNKEY_NONE,
};


/* Sources for signing keys */
typedef enum {
	SIGNKEY_SOURCE_RAW_FILE,
	SIGNKEY_SOURCE_AGENT,
	SIGNKEY_SOURCE_INVALID,	
} signkey_source;

struct SIGN_key {

	enum signkey_type type;
	signkey_source source;
	char *filename;

#if DROPBEAR_DSS
	struct dropbear_DSS_Key * dsskey;
#endif
#if DROPBEAR_RSA
	struct dropbear_RSA_Key * rsakey;
#endif
#if DROPBEAR_ECDSA
#if DROPBEAR_ECC_256
	ecc_key * ecckey256;
#endif
#if DROPBEAR_ECC_384
	ecc_key * ecckey384;
#endif
#if DROPBEAR_ECC_521
	ecc_key * ecckey521;
#endif
#endif
#if DROPBEAR_ED25519
	struct dropbear_ED25519_Key * ed25519key;
#endif
};

typedef struct SIGN_key sign_key;

sign_key * new_sign_key(void);
const char* signkey_name_from_type(enum signkey_type type, unsigned int *namelen);
enum signkey_type signkey_type_from_name(const char* name, unsigned int namelen);
const char* signature_name_from_type(enum signature_type type, unsigned int *namelen);
enum signature_type signature_type_from_name(const char* name, unsigned int namelen);
enum signkey_type signkey_type_from_signature(enum signature_type sigtype);
enum signature_type signature_type_from_signkey(enum signkey_type keytype);

int buf_get_pub_key(buffer *buf, sign_key *key, enum signkey_type *type);
int buf_get_priv_key(buffer* buf, sign_key *key, enum signkey_type *type);
void buf_put_pub_key(buffer* buf, sign_key *key, enum signkey_type type);
void buf_put_priv_key(buffer* buf, sign_key *key, enum signkey_type type);
void sign_key_free(sign_key *key);
void buf_put_sign(buffer* buf, sign_key *key, enum signature_type sigtype, const buffer *data_buf);
#if DROPBEAR_SIGNKEY_VERIFY
int buf_verify(buffer * buf, sign_key *key, enum signature_type expect_sigtype, const buffer *data_buf);
char * sign_key_fingerprint(const unsigned char* keyblob, unsigned int keybloblen);
#endif
int cmp_base64_key(const unsigned char* keyblob, unsigned int keybloblen, 
					const unsigned char* algoname, unsigned int algolen, 
					const buffer * line, char ** fingerprint);

void** signkey_key_ptr(sign_key *key, enum signkey_type type);

#endif /* DROPBEAR_SIGNKEY_H_ */