diff options
Diffstat (limited to 'tools/plink/sshcrcda.c')
| -rw-r--r-- | tools/plink/sshcrcda.c | 172 |
1 files changed, 0 insertions, 172 deletions
diff --git a/tools/plink/sshcrcda.c b/tools/plink/sshcrcda.c deleted file mode 100644 index c2cf705b2..000000000 --- a/tools/plink/sshcrcda.c +++ /dev/null @@ -1,172 +0,0 @@ -/* $OpenBSD: deattack.c,v 1.14 2001/06/23 15:12:18 itojun Exp $ */
-
-/*
- * Cryptographic attack detector for ssh - source code
- *
- * Copyright (c) 1998 CORE SDI S.A., Buenos Aires, Argentina.
- *
- * All rights reserved. Redistribution and use in source and binary
- * forms, with or without modification, are permitted provided that
- * this copyright notice is retained.
- *
- * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED
- * WARRANTIES ARE DISCLAIMED. IN NO EVENT SHALL CORE SDI S.A. BE
- * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY OR
- * CONSEQUENTIAL DAMAGES RESULTING FROM THE USE OR MISUSE OF THIS
- * SOFTWARE.
- *
- * Ariel Futoransky <futo@core-sdi.com>
- * <http://www.core-sdi.com>
- *
- * Modified for use in PuTTY by Simon Tatham
- */
-
-#include <assert.h>
-#include "misc.h"
-#include "ssh.h"
-
-typedef unsigned char uchar;
-typedef unsigned short uint16;
-
-/* SSH Constants */
-#define SSH_MAXBLOCKS (32 * 1024)
-#define SSH_BLOCKSIZE (8)
-
-/* Hashing constants */
-#define HASH_MINSIZE (8 * 1024)
-#define HASH_ENTRYSIZE (sizeof(uint16))
-#define HASH_FACTOR(x) ((x)*3/2)
-#define HASH_UNUSEDCHAR (0xff)
-#define HASH_UNUSED (0xffff)
-#define HASH_IV (0xfffe)
-
-#define HASH_MINBLOCKS (7*SSH_BLOCKSIZE)
-
-/* Hash function (Input keys are cipher results) */
-#define HASH(x) GET_32BIT_MSB_FIRST(x)
-
-#define CMP(a, b) (memcmp(a, b, SSH_BLOCKSIZE))
-
-uchar ONE[4] = { 1, 0, 0, 0 };
-uchar ZERO[4] = { 0, 0, 0, 0 };
-
-struct crcda_ctx {
- uint16 *h;
- uint32 n;
-};
-
-void *crcda_make_context(void)
-{
- struct crcda_ctx *ret = snew(struct crcda_ctx);
- ret->h = NULL;
- ret->n = HASH_MINSIZE / HASH_ENTRYSIZE;
- return ret;
-}
-
-void crcda_free_context(void *handle)
-{
- struct crcda_ctx *ctx = (struct crcda_ctx *)handle;
- if (ctx) {
- sfree(ctx->h);
- ctx->h = NULL;
- sfree(ctx);
- }
-}
-
-static void crc_update(uint32 *a, void *b)
-{
- *a = crc32_update(*a, b, 4);
-}
-
-/* detect if a block is used in a particular pattern */
-static int check_crc(uchar *S, uchar *buf, uint32 len, uchar *IV)
-{
- uint32 crc;
- uchar *c;
-
- crc = 0;
- if (IV && !CMP(S, IV)) {
- crc_update(&crc, ONE);
- crc_update(&crc, ZERO);
- }
- for (c = buf; c < buf + len; c += SSH_BLOCKSIZE) {
- if (!CMP(S, c)) {
- crc_update(&crc, ONE);
- crc_update(&crc, ZERO);
- } else {
- crc_update(&crc, ZERO);
- crc_update(&crc, ZERO);
- }
- }
- return (crc == 0);
-}
-
-/* Detect a crc32 compensation attack on a packet */
-int detect_attack(void *handle, uchar *buf, uint32 len, uchar *IV)
-{
- struct crcda_ctx *ctx = (struct crcda_ctx *)handle;
- register uint32 i, j;
- uint32 l;
- register uchar *c;
- uchar *d;
-
- assert(!(len > (SSH_MAXBLOCKS * SSH_BLOCKSIZE) ||
- len % SSH_BLOCKSIZE != 0));
- for (l = ctx->n; l < HASH_FACTOR(len / SSH_BLOCKSIZE); l = l << 2)
- ;
-
- if (ctx->h == NULL) {
- ctx->n = l;
- ctx->h = snewn(ctx->n, uint16);
- } else {
- if (l > ctx->n) {
- ctx->n = l;
- ctx->h = sresize(ctx->h, ctx->n, uint16);
- }
- }
-
- if (len <= HASH_MINBLOCKS) {
- for (c = buf; c < buf + len; c += SSH_BLOCKSIZE) {
- if (IV && (!CMP(c, IV))) {
- if ((check_crc(c, buf, len, IV)))
- return 1; /* attack detected */
- else
- break;
- }
- for (d = buf; d < c; d += SSH_BLOCKSIZE) {
- if (!CMP(c, d)) {
- if ((check_crc(c, buf, len, IV)))
- return 1; /* attack detected */
- else
- break;
- }
- }
- }
- return 0; /* ok */
- }
- memset(ctx->h, HASH_UNUSEDCHAR, ctx->n * HASH_ENTRYSIZE);
-
- if (IV)
- ctx->h[HASH(IV) & (ctx->n - 1)] = HASH_IV;
-
- for (c = buf, j = 0; c < (buf + len); c += SSH_BLOCKSIZE, j++) {
- for (i = HASH(c) & (ctx->n - 1); ctx->h[i] != HASH_UNUSED;
- i = (i + 1) & (ctx->n - 1)) {
- if (ctx->h[i] == HASH_IV) {
- if (!CMP(c, IV)) {
- if (check_crc(c, buf, len, IV))
- return 1; /* attack detected */
- else
- break;
- }
- } else if (!CMP(c, buf + ctx->h[i] * SSH_BLOCKSIZE)) {
- if (check_crc(c, buf, len, IV))
- return 1; /* attack detected */
- else
- break;
- }
- }
- ctx->h[i] = j;
- }
- return 0; /* ok */
-}
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