Mercurial > dropbear
view libtomcrypt/src/pk/rsa/rsa_set.c @ 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 | 6dba84798cd5 |
children |
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line source
/* LibTomCrypt, modular cryptographic library -- Tom St Denis * * LibTomCrypt is a library that provides various cryptographic * algorithms in a highly modular and flexible manner. * * The library is free for all purposes without any express * guarantee it works. */ #include "tomcrypt.h" #ifdef LTC_MRSA /** Import RSA key from raw numbers @param N RSA's N @param Nlen RSA's N's length @param e RSA's e @param elen RSA's e's length @param d RSA's d (only private key, NULL for public key) @param dlen RSA's d's length @param key [out] the destination for the imported key @return CRYPT_OK if successful */ int rsa_set_key(const unsigned char *N, unsigned long Nlen, const unsigned char *e, unsigned long elen, const unsigned char *d, unsigned long dlen, rsa_key *key) { int err; LTC_ARGCHK(key != NULL); LTC_ARGCHK(N != NULL); LTC_ARGCHK(e != NULL); LTC_ARGCHK(ltc_mp.name != NULL); err = mp_init_multi(&key->e, &key->d, &key->N, &key->dQ, &key->dP, &key->qP, &key->p, &key->q, NULL); if (err != CRYPT_OK) return err; if ((err = mp_read_unsigned_bin(key->N , (unsigned char *)N , Nlen)) != CRYPT_OK) { goto LBL_ERR; } if ((err = mp_read_unsigned_bin(key->e , (unsigned char *)e , elen)) != CRYPT_OK) { goto LBL_ERR; } if (d && dlen) { if ((err = mp_read_unsigned_bin(key->d , (unsigned char *)d , dlen)) != CRYPT_OK) { goto LBL_ERR; } key->type = PK_PRIVATE; } else { key->type = PK_PUBLIC; } return CRYPT_OK; LBL_ERR: rsa_free(key); return err; } /** Import factors of an RSA key from raw numbers Only for private keys. @param p RSA's p @param plen RSA's p's length @param q RSA's q @param qlen RSA's q's length @param key [out] the destination for the imported key @return CRYPT_OK if successful */ int rsa_set_factors(const unsigned char *p, unsigned long plen, const unsigned char *q, unsigned long qlen, rsa_key *key) { int err; LTC_ARGCHK(key != NULL); LTC_ARGCHK(p != NULL); LTC_ARGCHK(q != NULL); LTC_ARGCHK(ltc_mp.name != NULL); if (key->type != PK_PRIVATE) return CRYPT_PK_TYPE_MISMATCH; if ((err = mp_read_unsigned_bin(key->p , (unsigned char *)p , plen)) != CRYPT_OK) { goto LBL_ERR; } if ((err = mp_read_unsigned_bin(key->q , (unsigned char *)q , qlen)) != CRYPT_OK) { goto LBL_ERR; } return CRYPT_OK; LBL_ERR: rsa_free(key); return err; } /** Import CRT parameters of an RSA key from raw numbers Only for private keys. @param dP RSA's dP @param dPlen RSA's dP's length @param dQ RSA's dQ @param dQlen RSA's dQ's length @param qP RSA's qP @param qPlen RSA's qP's length @param key [out] the destination for the imported key @return CRYPT_OK if successful */ int rsa_set_crt_params(const unsigned char *dP, unsigned long dPlen, const unsigned char *dQ, unsigned long dQlen, const unsigned char *qP, unsigned long qPlen, rsa_key *key) { int err; LTC_ARGCHK(key != NULL); LTC_ARGCHK(dP != NULL); LTC_ARGCHK(dQ != NULL); LTC_ARGCHK(qP != NULL); LTC_ARGCHK(ltc_mp.name != NULL); if (key->type != PK_PRIVATE) return CRYPT_PK_TYPE_MISMATCH; if ((err = mp_read_unsigned_bin(key->dP, (unsigned char *)dP, dPlen)) != CRYPT_OK) { goto LBL_ERR; } if ((err = mp_read_unsigned_bin(key->dQ, (unsigned char *)dQ, dQlen)) != CRYPT_OK) { goto LBL_ERR; } if ((err = mp_read_unsigned_bin(key->qP, (unsigned char *)qP, qPlen)) != CRYPT_OK) { goto LBL_ERR; } return CRYPT_OK; LBL_ERR: rsa_free(key); return err; } #endif /* LTC_MRSA */ /* ref: $Format:%D$ */ /* git commit: $Format:%H$ */ /* commit time: $Format:%ai$ */