Mercurial > dropbear
view libtomcrypt/tests/pkcs_1_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. */ #include <tomcrypt_test.h> #ifdef LTC_PKCS_1 #ifdef LTC_TEST_REAL_RAND #define LTC_TEST_RAND_SEED time(NULL) #else #define LTC_TEST_RAND_SEED 23 #endif int pkcs_1_test(void) { unsigned char buf[3][128]; int res1, res2, res3, prng_idx, hash_idx; unsigned long x, y, l1, l2, l3, i1, i2, lparamlen, saltlen, modlen; static const unsigned char lparam[] = { 1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16 }; /* get hash/prng */ hash_idx = find_hash("sha1"); prng_idx = find_prng("yarrow"); if (hash_idx == -1 || prng_idx == -1) { fprintf(stderr, "pkcs_1 tests require sha1/yarrow"); return 1; } srand(LTC_TEST_RAND_SEED); /* do many tests */ for (x = 0; x < 100; x++) { zeromem(buf, sizeof(buf)); /* make a dummy message (of random length) */ l3 = (rand() & 31) + 8; for (y = 0; y < l3; y++) buf[0][y] = rand() & 255; /* pick a random lparam len [0..16] */ lparamlen = abs(rand()) % 17; /* pick a random saltlen 0..16 */ saltlen = abs(rand()) % 17; /* PKCS #1 v2.0 supports modlens not multiple of 8 */ modlen = 800 + (abs(rand()) % 224); /* encode it */ l1 = sizeof(buf[1]); DO(pkcs_1_oaep_encode(buf[0], l3, lparam, lparamlen, modlen, &yarrow_prng, prng_idx, hash_idx, buf[1], &l1)); /* decode it */ l2 = sizeof(buf[2]); DO(pkcs_1_oaep_decode(buf[1], l1, lparam, lparamlen, modlen, hash_idx, buf[2], &l2, &res1)); if (res1 != 1 || l2 != l3 || memcmp(buf[2], buf[0], l3) != 0) { fprintf(stderr, "Outsize == %lu, should have been %lu, res1 = %d, lparamlen = %lu, msg contents follow.\n", l2, l3, res1, lparamlen); fprintf(stderr, "ORIGINAL:\n"); for (x = 0; x < l3; x++) { fprintf(stderr, "%02x ", buf[0][x]); } fprintf(stderr, "\nRESULT:\n"); for (x = 0; x < l2; x++) { fprintf(stderr, "%02x ", buf[2][x]); } fprintf(stderr, "\n\n"); return 1; } /* test PSS */ l1 = sizeof(buf[1]); DO(pkcs_1_pss_encode(buf[0], l3, saltlen, &yarrow_prng, prng_idx, hash_idx, modlen, buf[1], &l1)); DO(pkcs_1_pss_decode(buf[0], l3, buf[1], l1, saltlen, hash_idx, modlen, &res1)); buf[0][i1 = abs(rand()) % l3] ^= 1; DO(pkcs_1_pss_decode(buf[0], l3, buf[1], l1, saltlen, hash_idx, modlen, &res2)); buf[0][i1] ^= 1; buf[1][i2 = abs(rand()) % (l1 - 1)] ^= 1; pkcs_1_pss_decode(buf[0], l3, buf[1], l1, saltlen, hash_idx, modlen, &res3); if (!(res1 == 1 && res2 == 0 && res3 == 0)) { fprintf(stderr, "PSS failed: %d, %d, %d, %lu, %lu\n", res1, res2, res3, l3, saltlen); return 1; } } return 0; } #else int pkcs_1_test(void) { return CRYPT_NOP; } #endif /* ref: $Format:%D$ */ /* git commit: $Format:%H$ */ /* commit time: $Format:%ai$ */