Mercurial > dropbear
view libtomcrypt/src/mac/xcbc/xcbc_memory.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. */ #include "tomcrypt.h" /** @file xcbc_process.c XCBC Support, XCBC-MAC a block of memory */ #ifdef LTC_XCBC /** XCBC-MAC a block of memory @param cipher Index of cipher to use @param key [in] Secret key @param keylen Length of key in octets @param in [in] Message to MAC @param inlen Length of input in octets @param out [out] Destination for the MAC tag @param outlen [in/out] Output size and final tag size Return CRYPT_OK on success. */ int xcbc_memory(int cipher, const unsigned char *key, unsigned long keylen, const unsigned char *in, unsigned long inlen, unsigned char *out, unsigned long *outlen) { xcbc_state *xcbc; int err; /* is the cipher valid? */ if ((err = cipher_is_valid(cipher)) != CRYPT_OK) { return err; } /* Use accelerator if found */ if (cipher_descriptor[cipher].xcbc_memory != NULL) { return cipher_descriptor[cipher].xcbc_memory(key, keylen, in, inlen, out, outlen); } xcbc = XCALLOC(1, sizeof(*xcbc)); if (xcbc == NULL) { return CRYPT_MEM; } if ((err = xcbc_init(xcbc, cipher, key, keylen)) != CRYPT_OK) { goto done; } if ((err = xcbc_process(xcbc, in, inlen)) != CRYPT_OK) { goto done; } err = xcbc_done(xcbc, out, outlen); done: XFREE(xcbc); return err; } #endif /* ref: $Format:%D$ */ /* git commit: $Format:%H$ */ /* commit time: $Format:%ai$ */