Mercurial > dropbear
view libtomcrypt/src/mac/f9/f9_file.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 | e9dba7abd939 |
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 f9_file.c f9 support, process a file, Tom St Denis */ #ifdef LTC_F9_MODE /** f9 a file @param cipher The index of the cipher desired @param key The secret key @param keylen The length of the secret key (octets) @param fname The name of the file you wish to f9 @param out [out] Where the authentication tag is to be stored @param outlen [in/out] The max size and resulting size of the authentication tag @return CRYPT_OK if successful, CRYPT_NOP if file support has been disabled */ int f9_file(int cipher, const unsigned char *key, unsigned long keylen, const char *fname, unsigned char *out, unsigned long *outlen) { #ifdef LTC_NO_FILE LTC_UNUSED_PARAM(cipher); LTC_UNUSED_PARAM(key); LTC_UNUSED_PARAM(keylen); LTC_UNUSED_PARAM(fname); LTC_UNUSED_PARAM(out); LTC_UNUSED_PARAM(outlen); return CRYPT_NOP; #else size_t x; int err; f9_state f9; FILE *in; unsigned char *buf; LTC_ARGCHK(key != NULL); LTC_ARGCHK(fname != NULL); LTC_ARGCHK(out != NULL); LTC_ARGCHK(outlen != NULL); if ((buf = XMALLOC(LTC_FILE_READ_BUFSIZE)) == NULL) { return CRYPT_MEM; } if ((err = f9_init(&f9, cipher, key, keylen)) != CRYPT_OK) { goto LBL_ERR; } in = fopen(fname, "rb"); if (in == NULL) { err = CRYPT_FILE_NOTFOUND; goto LBL_ERR; } do { x = fread(buf, 1, LTC_FILE_READ_BUFSIZE, in); if ((err = f9_process(&f9, buf, (unsigned long)x)) != CRYPT_OK) { fclose(in); goto LBL_CLEANBUF; } } while (x == LTC_FILE_READ_BUFSIZE); if (fclose(in) != 0) { err = CRYPT_ERROR; goto LBL_CLEANBUF; } err = f9_done(&f9, out, outlen); LBL_CLEANBUF: zeromem(buf, LTC_FILE_READ_BUFSIZE); LBL_ERR: #ifdef LTC_CLEAN_STACK zeromem(&f9, sizeof(f9_state)); #endif XFREE(buf); return err; #endif } #endif /* ref: $Format:%D$ */ /* git commit: $Format:%H$ */ /* commit time: $Format:%ai$ */