Mercurial > dropbear
view libtomcrypt/tests/modes_test.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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/* 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. */ /* test CFB/OFB/CBC modes */ #include <tomcrypt_test.h> int modes_test(void) { int ret = CRYPT_NOP; #ifdef LTC_CBC_MODE symmetric_CBC cbc; #endif #ifdef LTC_CFB_MODE symmetric_CFB cfb; #endif #ifdef LTC_OFB_MODE symmetric_OFB ofb; #endif #if defined(LTC_CBC_MODE) || defined(LTC_CFB_MODE) || defined(LTC_OFB_MODE) unsigned char pt[64], ct[64], tmp[64], key[16], iv[16], iv2[16]; int cipher_idx; unsigned long l; /* make a random pt, key and iv */ yarrow_read(pt, 64, &yarrow_prng); yarrow_read(key, 16, &yarrow_prng); yarrow_read(iv, 16, &yarrow_prng); /* get idx of AES handy */ cipher_idx = find_cipher("aes"); if (cipher_idx == -1) { fprintf(stderr, "test requires AES"); return 1; } #endif #ifdef LTC_F8_MODE DO(ret = f8_test_mode()); #endif #ifdef LTC_LRW_MODE DO(ret = lrw_test()); #endif #ifdef LTC_CBC_MODE /* test CBC mode */ /* encode the block */ DO(ret = cbc_start(cipher_idx, iv, key, 16, 0, &cbc)); l = sizeof(iv2); DO(ret = cbc_getiv(iv2, &l, &cbc)); if (l != 16 || memcmp(iv2, iv, 16)) { fprintf(stderr, "cbc_getiv failed"); return 1; } DO(ret = cbc_encrypt(pt, ct, 64, &cbc)); /* decode the block */ DO(ret = cbc_setiv(iv2, l, &cbc)); zeromem(tmp, sizeof(tmp)); DO(ret = cbc_decrypt(ct, tmp, 64, &cbc)); if (memcmp(tmp, pt, 64) != 0) { fprintf(stderr, "CBC failed"); return 1; } #endif #ifdef LTC_CFB_MODE /* test CFB mode */ /* encode the block */ DO(ret = cfb_start(cipher_idx, iv, key, 16, 0, &cfb)); l = sizeof(iv2); DO(ret = cfb_getiv(iv2, &l, &cfb)); /* note we don't memcmp iv2/iv since cfb_start processes the IV for the first block */ if (l != 16) { fprintf(stderr, "cfb_getiv failed"); return 1; } DO(ret = cfb_encrypt(pt, ct, 64, &cfb)); /* decode the block */ DO(ret = cfb_setiv(iv, l, &cfb)); zeromem(tmp, sizeof(tmp)); DO(ret = cfb_decrypt(ct, tmp, 64, &cfb)); if (memcmp(tmp, pt, 64) != 0) { fprintf(stderr, "CFB failed"); return 1; } #endif #ifdef LTC_OFB_MODE /* test OFB mode */ /* encode the block */ DO(ret = ofb_start(cipher_idx, iv, key, 16, 0, &ofb)); l = sizeof(iv2); DO(ret = ofb_getiv(iv2, &l, &ofb)); if (l != 16 || memcmp(iv2, iv, 16)) { fprintf(stderr, "ofb_getiv failed"); return 1; } DO(ret = ofb_encrypt(pt, ct, 64, &ofb)); /* decode the block */ DO(ret = ofb_setiv(iv2, l, &ofb)); zeromem(tmp, sizeof(tmp)); DO(ret = ofb_decrypt(ct, tmp, 64, &ofb)); if (memcmp(tmp, pt, 64) != 0) { fprintf(stderr, "OFB failed"); return 1; } #endif #if defined(LTC_CTR_MODE) && defined(LTC_RIJNDAEL) DO(ret = ctr_test()); #endif #ifdef LTC_XTS_MODE DO(ret = xts_test()); #endif return 0; } /* ref: $Format:%D$ */ /* git commit: $Format:%H$ */ /* commit time: $Format:%ai$ */