Mercurial > dropbear
view libtomcrypt/src/stream/chacha/chacha_keystream.c @ 1715:3974f087d9c0
Disallow leading lines before the ident for server (#102)
Per RFC4253 4.2 clients must be able to process other lines of data
before the version string, server behavior is not defined neither
with MUST/SHOULD nor with MAY.
If server process up to 50 lines too - it may cause too long hanging
session with invalid/evil client that consume host resources and
potentially may lead to DDoS on poor embedded boxes.
Let's require first line from client to be version string and fail
early if it's not - matches both RFC and real OpenSSH behavior.
author | Vladislav Grishenko <themiron@users.noreply.github.com> |
---|---|
date | Mon, 15 Jun 2020 18:22:18 +0500 |
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. */ /* The implementation is based on: * chacha-ref.c version 20080118 * Public domain from D. J. Bernstein */ #include "tomcrypt.h" #ifdef LTC_CHACHA /** Generate a stream of random bytes via ChaCha @param st The ChaCha20 state @param out [out] The output buffer @param outlen The output length @return CRYPT_OK on success */ int chacha_keystream(chacha_state *st, unsigned char *out, unsigned long outlen) { if (outlen == 0) return CRYPT_OK; /* nothing to do */ LTC_ARGCHK(out != NULL); XMEMSET(out, 0, outlen); return chacha_crypt(st, out, outlen, out); } #endif /* ref: $Format:%D$ */ /* git commit: $Format:%H$ */ /* commit time: $Format:%ai$ */