Mercurial > dropbear
view libtomcrypt/src/misc/compare_testvector.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.h" /** @file compare_testvector.c Function to compare two testvectors and print a (detailed) error-message if required, Steffen Jaeckel */ #if defined(LTC_TEST) && defined(LTC_TEST_DBG) static void _print_hex(const char* what, const void* v, const unsigned long l) { const unsigned char* p = v; unsigned long x, y = 0, z; fprintf(stderr, "%s contents: \n", what); for (x = 0; x < l; ) { fprintf(stderr, "%02X ", p[x]); if (!(++x % 16) || x == l) { if((x % 16) != 0) { z = 16 - (x % 16); if(z >= 8) fprintf(stderr, " "); for (; z != 0; --z) { fprintf(stderr, " "); } } fprintf(stderr, " | "); for(; y < x; y++) { if((y % 8) == 0) fprintf(stderr, " "); if(isgraph(p[y])) fprintf(stderr, "%c", p[y]); else fprintf(stderr, "."); } fprintf(stderr, "\n"); } else if((x % 8) == 0) { fprintf(stderr, " "); } } } #endif /** Compare two test-vectors @param is The data as it is @param is_len The length of is @param should The data as it should @param should_len The length of should @param what The type of the data @param which The iteration count @return 0 on equality, -1 or 1 on difference */ int compare_testvector(const void* is, const unsigned long is_len, const void* should, const unsigned long should_len, const char* what, int which) { int res = 0; if(is_len != should_len) res = is_len > should_len ? -1 : 1; else res = XMEMCMP(is, should, is_len); #if defined(LTC_TEST) && defined(LTC_TEST_DBG) if (res != 0) { fprintf(stderr, "Testvector #%i of %s failed:\n", which, what); _print_hex("SHOULD", should, should_len); _print_hex("IS ", is, is_len); } #else LTC_UNUSED_PARAM(which); LTC_UNUSED_PARAM(what); #endif return res; } /* ref: $Format:%D$ */ /* git commit: $Format:%H$ */ /* commit time: $Format:%ai$ */