+++ /dev/null
-/* -*-c-*-
- *
- * $Id: cbc-def.h,v 1.6 2004/04/17 09:58:36 mdw Exp $
- *
- * Definitions for cipher block chaining mode
- *
- * (c) 1999 Straylight/Edgeware
- */
-
-/*----- Licensing notice --------------------------------------------------*
- *
- * This file is part of Catacomb.
- *
- * Catacomb is free software; you can redistribute it and/or modify
- * it under the terms of the GNU Library General Public License as
- * published by the Free Software Foundation; either version 2 of the
- * License, or (at your option) any later version.
- *
- * Catacomb is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
- * GNU Library General Public License for more details.
- *
- * You should have received a copy of the GNU Library General Public
- * License along with Catacomb; if not, write to the Free
- * Software Foundation, Inc., 59 Temple Place - Suite 330, Boston,
- * MA 02111-1307, USA.
- */
-
-#ifndef CATACOMB_CBC_DEF_H
-#define CATACOMB_CBC_DEF_H
-
-#ifdef __cplusplus
- extern "C" {
-#endif
-
-/*----- Header files ------------------------------------------------------*/
-
-#include <string.h>
-
-#include <mLib/bits.h>
-#include <mLib/sub.h>
-
-#ifndef CATACOMB_ARENA_H
-# include "arena.h"
-#endif
-
-#ifndef CATACOMB_BLKC_H
-# include "blkc.h"
-#endif
-
-#ifndef CATACOMB_GCIPHER_H
-# include "gcipher.h"
-#endif
-
-#ifndef CATACOMB_PARANOIA_H
-# include "paranoia.h"
-#endif
-
-/*----- Macros ------------------------------------------------------------*/
-
-/* --- @CBC_DEF@ --- *
- *
- * Arguments: @PRE@, @pre@ = prefixes for the underlying block cipher
- *
- * Use: Creates an implementation for CBC stealing mode.
- */
-
-#define CBC_DEF(PRE, pre) \
- \
-/* --- @pre_cbcgetiv@ --- * \
- * \
- * Arguments: @const pre_cbcctx *ctx@ = pointer to CBC context block \
- * @void *iv@ = pointer to output data block \
- * \
- * Returns: --- \
- * \
- * Use: Reads the currently set IV. Reading and setting an IV \
- * is transparent to the CBC encryption or decryption \
- * process. \
- */ \
- \
-void pre##_cbcgetiv(const pre##_cbcctx *ctx, void *iv) \
-{ \
- BLKC_STORE(PRE, iv, ctx->iv); \
-} \
- \
-/* --- @pre_cbcsetiv@ --- * \
- * \
- * Arguments: @pre_cbcctx *ctx@ = pointer to CBC context block \
- * @cnost void *iv@ = pointer to IV to set \
- * \
- * Returns: --- \
- * \
- * Use: Sets the IV to use for subsequent encryption. \
- */ \
- \
-void pre##_cbcsetiv(pre##_cbcctx *ctx, const void *iv) \
-{ \
- BLKC_LOAD(PRE, ctx->iv, iv); \
-} \
- \
-/* --- @pre_cbcsetkey@ --- * \
- * \
- * Arguments: @pre_cbcctx *ctx@ = pointer to CBC context block \
- * @const pre_ctx *k@ = pointer to cipher context \
- * \
- * Returns: --- \
- * \
- * Use: Sets the CBC context to use a different cipher key. \
- */ \
- \
-void pre##_cbcsetkey(pre##_cbcctx *ctx, const pre##_ctx *k) \
-{ \
- ctx->ctx = *k; \
-} \
- \
-/* --- @pre_cbcinit@ --- * \
- * \
- * Arguments: @pre_cbcctx *ctx@ = pointer to cipher context \
- * @const void *key@ = pointer to the key buffer \
- * @size_t sz@ = size of the key \
- * @const void *iv@ = pointer to initialization vector \
- * \
- * Returns: --- \
- * \
- * Use: Initializes a CBC context ready for use. The @iv@ \
- * argument may be passed as a null pointer to set a zero \
- * IV. Apart from that, this call is equivalent to calls \
- * to @pre_init@, @pre_cbcsetkey@ and @pre_cbcsetiv@. \
- */ \
- \
-void pre##_cbcinit(pre##_cbcctx *ctx, \
- const void *key, size_t sz, \
- const void *iv) \
-{ \
- static const octet zero[PRE##_BLKSZ] = { 0 }; \
- pre##_init(&ctx->ctx, key, sz); \
- BLKC_LOAD(PRE, ctx->iv, iv ? iv : zero); \
-} \
- \
-/* --- @pre_cbcencrypt@ --- * \
- * \
- * Arguments: @pre_cbcctx *ctx@ = pointer to CBC context block \
- * @const void *src@ = pointer to source data \
- * @void *dest@ = pointer to destination data \
- * @size_t sz@ = size of block to be encrypted \
- * \
- * Returns: --- \
- * \
- * Use: Encrypts a block with a block cipher in CBC mode, with \
- * ciphertext stealing and other clever tricks. \
- * Essentially, data can be encrypted in arbitrary sized \
- * chunks, although decryption must use the same chunks. \
- */ \
- \
-void pre##_cbcencrypt(pre##_cbcctx *ctx, \
- const void *src, void *dest, \
- size_t sz) \
-{ \
- const octet *s = src; \
- octet *d = dest; \
- \
- /* --- Empty blocks are trivial --- */ \
- \
- if (!sz) \
- return; \
- \
- /* --- Extra magical case for a short block --- * \
- * \
- * Encrypt the IV, then exclusive-or the plaintext with the octets \
- * of the encrypted IV, shifting ciphertext octets in instead. This \
- * basically switches over to CFB. \
- */ \
- \
- if (sz < PRE##_BLKSZ) { \
- octet b[PRE##_BLKSZ]; \
- unsigned i; \
- \
- pre##_eblk(&ctx->ctx, ctx->iv, ctx->iv); \
- BLKC_STORE(PRE, b, ctx->iv); \
- if (d) { \
- for (i = 0; i < sz; i++) \
- d[i] = b[i] ^ (s ? s[i] : 0); \
- } \
- memmove(b, b + sz, PRE##_BLKSZ - sz); \
- memcpy(b + PRE##_BLKSZ - sz, d, sz); \
- BLKC_LOAD(PRE, ctx->iv, b); \
- return; \
- } \
- \
- /* --- Do the main chunk of encryption --- * \
- * \
- * This will do the whole lot if it's a whole number of blocks. For \
- * each block, XOR it with the previous ciphertext in @iv@, encrypt, \
- * and keep a copy of the ciphertext for the next block. \
- */ \
- \
- while (sz >= 2 * PRE##_BLKSZ || sz == PRE##_BLKSZ) { \
- if (s) { \
- BLKC_XLOAD(PRE, ctx->iv, s); \
- s += PRE##_BLKSZ; \
- } \
- pre##_eblk(&ctx->ctx, ctx->iv, ctx->iv); \
- if (d) { \
- BLKC_STORE(PRE, d, ctx->iv); \
- d += PRE##_BLKSZ; \
- } \
- sz -= PRE##_BLKSZ; \
- } \
- \
- /* --- Do the tail-end block and bit-left-over --- * \
- * \
- * This isn't very efficient. That shouldn't matter much. \
- */ \
- \
- if (sz) { \
- octet b[PRE##_BLKSZ]; \
- unsigned i; \
- \
- /* --- Let @sz@ be the size of the partial block --- */ \
- \
- sz -= PRE##_BLKSZ; \
- \
- /* --- First stage --- * \
- * \
- * XOR the complete block with the current IV, and encrypt it. The \
- * first part of the result is the partial ciphertext block. Don't \
- * write that out yet, because I've not read the partial plaintext \
- * block. \
- */ \
- \
- if (s) BLKC_XLOAD(PRE, ctx->iv, s); \
- pre##_eblk(&ctx->ctx, ctx->iv, ctx->iv); \
- BLKC_STORE(PRE, b, ctx->iv); \
- \
- /* --- Second stage --- * \
- * \
- * Now XOR in the partial plaintext block, writing out the \
- * ciphertext as I go. Then encrypt, and write the complete \
- * ciphertext block. \
- */ \
- \
- if (s) s += PRE##_BLKSZ; \
- if (d) d += PRE##_BLKSZ; \
- for (i = 0; i < sz; i++) { \
- register octet x = b[i]; \
- if (s) b[i] ^= s[i]; \
- if (d) d[i] = x; \
- } \
- BLKC_LOAD(PRE, ctx->iv, b); \
- pre##_eblk(&ctx->ctx, ctx->iv, ctx->iv); \
- if (d) BLKC_STORE(PRE, d - PRE##_BLKSZ, ctx->iv); \
- } \
- \
- /* --- Done --- */ \
- \
- return; \
-} \
- \
-/* --- @pre_cbcdecrypt@ --- * \
- * \
- * Arguments: @pre_cbcctx *ctx@ = pointer to CBC context block \
- * @const void *src@ = pointer to source data \
- * @void *dest@ = pointer to destination data \
- * @size_t sz@ = size of block to be encrypted \
- * \
- * Returns: --- \
- * \
- * Use: Decrypts a block with a block cipher in CBC mode, with \
- * ciphertext stealing and other clever tricks. \
- * Essentially, data can be encrypted in arbitrary sized \
- * chunks, although decryption must use the same chunks. \
- */ \
- \
-void pre##_cbcdecrypt(pre##_cbcctx *ctx, \
- const void *src, void *dest, \
- size_t sz) \
-{ \
- const octet *s = src; \
- octet *d = dest; \
- \
- /* --- Empty blocks are trivial --- */ \
- \
- if (!sz) \
- return; \
- \
- /* --- Extra magical case for a short block --- * \
- * \
- * Encrypt the IV, then exclusive-or the ciphertext with the octets \
- * of the encrypted IV, shifting ciphertext octets in instead. This \
- * basically switches over to CFB. \
- */ \
- \
- if (sz < PRE##_BLKSZ) { \
- octet b[PRE##_BLKSZ], c[PRE##_BLKSZ]; \
- unsigned i; \
- \
- pre##_eblk(&ctx->ctx, ctx->iv, ctx->iv); \
- BLKC_STORE(PRE, b, ctx->iv); \
- for (i = 0; i < sz; i++) { \
- register octet x = s[i]; \
- d[i] = b[i] ^ x; \
- c[i] = x; \
- } \
- memmove(b, b + sz, PRE##_BLKSZ - sz); \
- memcpy(b + PRE##_BLKSZ - sz, c, sz); \
- BLKC_LOAD(PRE, ctx->iv, b); \
- return; \
- } \
- \
- /* --- Do the main chunk of decryption --- * \
- * \
- * This will do the whole lot if it's a whole number of blocks. For \
- * each block, decrypt, XOR it with the previous ciphertext in @iv@, \
- * and keep a copy of the ciphertext for the next block. \
- */ \
- \
- while (sz >= 2 * PRE##_BLKSZ || sz == PRE##_BLKSZ) { \
- uint32 b[PRE##_BLKSZ / 4], niv[PRE##_BLKSZ / 4]; \
- BLKC_LOAD(PRE, niv, s); \
- pre##_dblk(&ctx->ctx, niv, b); \
- BLKC_XSTORE(PRE, d, b, ctx->iv); \
- BLKC_MOVE(PRE, ctx->iv, niv); \
- s += PRE##_BLKSZ; \
- d += PRE##_BLKSZ; \
- sz -= PRE##_BLKSZ; \
- } \
- \
- /* --- Do the tail-end block and bit-left-over --- * \
- * \
- * This isn't very efficient. That shouldn't matter much. \
- */ \
- \
- if (sz) { \
- octet b[PRE##_BLKSZ]; \
- uint32 bk[PRE##_BLKSZ / 4], niv[PRE##_BLKSZ / 4]; \
- unsigned i; \
- \
- /* --- Let @sz@ be the size of the partial block --- */ \
- \
- sz -= PRE##_BLKSZ; \
- \
- /* --- First stage --- * \
- * \
- * Take the complete ciphertext block, and decrypt it. This block \
- * is carried over for the next encryption operation. \
- */ \
- \
- BLKC_LOAD(PRE, niv, s); \
- pre##_dblk(&ctx->ctx, niv, bk); \
- \
- /* --- Second stage --- * \
- * \
- * XORing the first few bytes of this with the partial ciphertext \
- * block recovers the partial plaintext block. At the same time, \
- * write the partial ciphertext block's contents in ready for stage \
- * three. \
- */ \
- \
- BLKC_STORE(PRE, b, bk); \
- s += PRE##_BLKSZ; \
- d += PRE##_BLKSZ; \
- for (i = 0; i < sz; i++) { \
- register octet x = s[i]; \
- d[i] = b[i] ^ x; \
- b[i] = x; \
- } \
- \
- /* --- Third stage --- * \
- * \
- * Decrypt the block we've got left, and XOR with the initial IV to \
- * recover the complete plaintext block. \
- */ \
- \
- BLKC_LOAD(PRE, bk, b); \
- pre##_dblk(&ctx->ctx, bk, bk); \
- BLKC_XSTORE(PRE, d - PRE##_BLKSZ, bk, ctx->iv); \
- BLKC_MOVE(PRE, ctx->iv, niv); \
- } \
- \
- /* --- Done --- */ \
- \
- return; \
-} \
- \
-/* --- Generic cipher interface --- */ \
- \
-static const gcipher_ops gops; \
- \
-typedef struct gctx { \
- gcipher c; \
- pre##_cbcctx k; \
-} gctx; \
- \
-static gcipher *ginit(const void *k, size_t sz) \
-{ \
- gctx *g = S_CREATE(gctx); \
- g->c.ops = &gops; \
- pre##_cbcinit(&g->k, k, sz, 0); \
- return (&g->c); \
-} \
- \
-static void gencrypt(gcipher *c, const void *s, void *t, size_t sz) \
-{ \
- gctx *g = (gctx *)c; \
- pre##_cbcencrypt(&g->k, s, t, sz); \
-} \
- \
-static void gdecrypt(gcipher *c, const void *s, void *t, size_t sz) \
-{ \
- gctx *g = (gctx *)c; \
- pre##_cbcdecrypt(&g->k, s, t, sz); \
-} \
- \
-static void gdestroy(gcipher *c) \
-{ \
- gctx *g = (gctx *)c; \
- BURN(*g); \
- S_DESTROY(g); \
-} \
- \
-static void gsetiv(gcipher *c, const void *iv) \
-{ \
- gctx *g = (gctx *)c; \
- pre##_cbcsetiv(&g->k, iv); \
-} \
- \
-static const gcipher_ops gops = { \
- &pre##_cbc, \
- gencrypt, gdecrypt, gdestroy, gsetiv, 0 \
-}; \
- \
-const gccipher pre##_cbc = { \
- #pre "-cbc", pre##_keysz, PRE##_BLKSZ, \
- ginit \
-}; \
- \
-CBC_TEST(PRE, pre)
-
-/*----- Test rig ----------------------------------------------------------*/
-
-#ifdef TEST_RIG
-
-#include <stdio.h>
-
-#include "daftstory.h"
-
-/* --- @CBC_TEST@ --- *
- *
- * Arguments: @PRE@, @pre@ = prefixes for block cipher definitions
- *
- * Use: Standard test rig for CBC functions.
- */
-
-#define CBC_TEST(PRE, pre) \
- \
-/* --- Initial plaintext for the test --- */ \
- \
-static const octet text[] = TEXT; \
- \
-/* --- Key and IV to use --- */ \
- \
-static const octet key[] = KEY; \
-static const octet iv[] = IV; \
- \
-/* --- Buffers for encryption and decryption output --- */ \
- \
-static octet ct[sizeof(text)]; \
-static octet pt[sizeof(text)]; \
- \
-static void hexdump(const octet *p, size_t sz) \
-{ \
- const octet *q = p + sz; \
- for (sz = 0; p < q; p++, sz++) { \
- printf("%02x", *p); \
- if ((sz + 1) % PRE##_BLKSZ == 0) \
- putchar(':'); \
- } \
-} \
- \
-int main(void) \
-{ \
- size_t sz = 0, rest; \
- pre##_cbcctx ctx; \
- pre##_ctx k; \
- int status = 0; \
- int done = 0; \
- \
- size_t keysz = PRE##_KEYSZ ? \
- PRE##_KEYSZ : strlen((const char *)key); \
- \
- fputs(#pre "-cbc: ", stdout); \
- \
- pre##_init(&k, key, keysz); \
- pre##_cbcsetkey(&ctx, &k); \
- \
- while (sz <= sizeof(text)) { \
- rest = sizeof(text) - sz; \
- memcpy(ct, text, sizeof(text)); \
- pre##_cbcsetiv(&ctx, iv); \
- pre##_cbcencrypt(&ctx, ct, ct, sz); \
- pre##_cbcencrypt(&ctx, ct + sz, ct + sz, rest); \
- memcpy(pt, ct, sizeof(text)); \
- pre##_cbcsetiv(&ctx, iv); \
- pre##_cbcdecrypt(&ctx, pt, pt, sz); \
- pre##_cbcdecrypt(&ctx, pt + sz, pt + sz, rest); \
- if (memcmp(pt, text, sizeof(text)) == 0) { \
- done++; \
- if (sizeof(text) < 40 || done % 8 == 0) \
- fputc('.', stdout); \
- if (done % 480 == 0) \
- fputs("\n\t", stdout); \
- fflush(stdout); \
- } else { \
- printf("\nError (sz = %lu)\n", (unsigned long)sz); \
- status = 1; \
- printf("\tplaintext = "); hexdump(text, sz); \
- printf(", "); hexdump(text + sz, rest); \
- fputc('\n', stdout); \
- printf("\tciphertext = "); hexdump(ct, sz); \
- printf(", "); hexdump(ct + sz, rest); \
- fputc('\n', stdout); \
- printf("\trecovered text = "); hexdump(pt, sz); \
- printf(", "); hexdump(pt + sz, rest); \
- fputc('\n', stdout); \
- fputc('\n', stdout); \
- } \
- if (sz < 63) \
- sz++; \
- else \
- sz += 9; \
- } \
- \
- fputs(status ? " failed\n" : " ok\n", stdout); \
- return (status); \
-}
-
-#else
-# define CBC_TEST(PRE, pre)
-#endif
-
-/*----- That's all, folks -------------------------------------------------*/
-
-#ifdef __cplusplus
- }
-#endif
-
-#endif
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