view ecdsa.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 99ca393afc56
children
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#ifndef DROPBEAR_ECDSA_H_
#define DROPBEAR_ECDSA_H_

#include "includes.h"
#include "buffer.h"
#include "signkey.h"

#if DROPBEAR_ECDSA

/* prefer 256 or 384 since those are SHOULD for
   draft-ietf-curdle-ssh-kex-sha2.txt */
#if DROPBEAR_ECC_256
#define ECDSA_DEFAULT_SIZE 256
#elif DROPBEAR_ECC_384
#define ECDSA_DEFAULT_SIZE 384
#elif DROPBEAR_ECC_521
#define ECDSA_DEFAULT_SIZE 521
#else
#error ECDSA cannot be enabled without enabling at least one size (256, 384, 521)
#endif

ecc_key *gen_ecdsa_priv_key(unsigned int bit_size);
ecc_key *buf_get_ecdsa_pub_key(buffer* buf);
ecc_key *buf_get_ecdsa_priv_key(buffer *buf);
void buf_put_ecdsa_pub_key(buffer *buf, ecc_key *key);
void buf_put_ecdsa_priv_key(buffer *buf, ecc_key *key);
enum signkey_type ecdsa_signkey_type(const ecc_key * key);

void buf_put_ecdsa_sign(buffer *buf, const ecc_key *key, const buffer *data_buf);
int buf_ecdsa_verify(buffer *buf, const ecc_key *key, const buffer *data_buf);
/* Returns 1 on success */
int signkey_is_ecdsa(enum signkey_type type);

#endif

#endif /* DROPBEAR_ECDSA_H_ */