[secnet] / transform.c

/* Transform module - bulk data transformation */

/* For now it's hard-coded to do sequence
   number/pkcs5/serpent-cbcmac/serpent with a 256 bit key for each
   instance of serpent. We also require key material for the IVs for
   cbcmac and cbc. Hack: we're not using full 128-bit IVs, we're just
   using 32 bits and encrypting to get the full IV to save space in
   the packets sent over the wire. */

#include <stdio.h>
#include <string.h>
#include "secnet.h"
#include "util.h"
#include "serpent.h"
#include "unaligned.h"

/* Required key length in bytes */
#define REQUIRED_KEYLEN ((512+64+32)/8)

struct transform {
    closure_t cl;
    uint32_t line;
    struct transform_if ops;
    uint32_t max_seq_skew;
};

struct transform_inst {
    struct transform_inst_if ops;
    struct keyInstance cryptkey;
    struct keyInstance mackey;
    uint32_t cryptiv;
    uint32_t maciv;
    uint32_t sendseq;
    uint32_t lastrecvseq;
    uint32_t max_skew;
    bool_t keyed;
};

#define PKCS5_MASK 15

static bool_t transform_setkey(void *sst, uint8_t *key, uint32_t keylen)
{
    struct transform_inst *ti=sst;

    if (keylen<REQUIRED_KEYLEN) {
	Message(M_ERR,"transform_create: insufficient key material supplied "
		"(need %d bytes, got %d)\n",REQUIRED_KEYLEN,keylen);
	return False;
    }

#if 0
    {
	int i;
	printf("Setting key to: ");
	for (i=0; i<keylen; i++)
	    printf("%02x",key[i]);
	printf("\n");
    }
#endif /* 0 */

    serpent_makekey(&ti->cryptkey,256,key);
    serpent_makekey(&ti->mackey,256,key+32);
    ti->cryptiv=GET_32BIT_MSB_FIRST(key+64);
    ti->maciv=GET_32BIT_MSB_FIRST(key+68);
    ti->sendseq=GET_32BIT_MSB_FIRST(key+72);
    ti->lastrecvseq=ti->sendseq;
    ti->keyed=True;

    return True;
}

static void transform_delkey(void *sst)
{
    struct transform_inst *ti=sst;

    memset(&ti->cryptkey,0,sizeof(ti->cryptkey));
    memset(&ti->mackey,0,sizeof(ti->mackey));
    ti->keyed=False;
}

static uint32_t transform_forward(void *sst, struct buffer_if *buf,
				  const char **errmsg)
{
    struct transform_inst *ti=sst;
    uint8_t *padp;
    int padlen;
    uint8_t iv[16];
    uint8_t macplain[16];
    uint8_t macacc[16];
    uint8_t *p, *n;
    int i;

    if (!ti->keyed) {
	*errmsg="transform unkeyed";
	return 1;
    }

    /* Sequence number */
    buf_prepend_uint32(buf,ti->sendseq);
    ti->sendseq++;

    /* PKCS5, stolen from IWJ */
                                    /* eg with blocksize=4 mask=3 mask+2=5   */
                                    /* msgsize    20    21    22    23   24  */
    padlen= PKCS5_MASK-buf->size;   /*           -17   -18   -19   -16  -17  */
    padlen &= PKCS5_MASK;           /*             3     2     1     0    3  */
    padlen++;                       /*             4     3     2     1    4  */

    padp=buf_append(buf,padlen);
    memset(padp,padlen,padlen);

    /* Serpent-CBCMAC. We expand the IV from 32-bit to 128-bit using
       one encryption. Then we do the MAC and append the result. We don't
       bother sending the IV - it's the same each time. (If we wanted to send
       it we've have to add 16 bytes to each message, not 4, so that the
       message stays a multiple of 16 bytes long.) */
    memset(iv,0,16);
    PUT_32BIT_MSB_FIRST(iv, ti->maciv);
    serpent_encrypt(&ti->mackey,iv,macacc);

    /* CBCMAC: encrypt in CBC mode. The MAC is the last encrypted
       block encrypted once again. */
    for (n=buf->start; n<buf->start+buf->size; n+=16)
    {
	for (i = 0; i < 16; i++)
	    macplain[i] = macacc[i] ^ n[i];
	serpent_encrypt(&ti->mackey,macplain,macacc);
    }
    serpent_encrypt(&ti->mackey,macacc,macacc);
    memcpy(buf_append(buf,16),macacc,16);

    /* Serpent-CBC. We expand the ID as for CBCMAC, do the encryption,
       and prepend the IV before increasing it. */
    memset(iv,0,16);
    PUT_32BIT_MSB_FIRST(iv, ti->cryptiv);
    serpent_encrypt(&ti->cryptkey,iv,iv);

    /* CBC: each block is XORed with the previous encrypted block (or the IV)
       before being encrypted. */
    p=iv;

    for (n=buf->start; n<buf->start+buf->size; n+=16)
    {
	for (i = 0; i < 16; i++)
	    n[i] ^= p[i];
	serpent_encrypt(&ti->cryptkey,n,n);
	p=n;
    }

    buf_prepend_uint32(buf,ti->cryptiv);
    ti->cryptiv++;
    return 0;
}

static uint32_t transform_reverse(void *sst, struct buffer_if *buf,
				  const char **errmsg)
{
    struct transform_inst *ti=sst;
    uint8_t *padp;
    unsigned padlen;
    int i;
    uint32_t seqnum, skew;
    uint8_t iv[16];
    uint8_t pct[16];
    uint8_t macplain[16];
    uint8_t macacc[16];
    uint8_t *n;
    uint8_t *macexpected;

    if (!ti->keyed) {
	*errmsg="transform unkeyed";
	return 1;
    }


    /* CBC */
    memset(iv,0,16);
    {
	uint32_t ivword = buf_unprepend_uint32(buf);
	PUT_32BIT_MSB_FIRST(iv, ivword);
    }
    /* Assert bufsize is multiple of blocksize */
    if (buf->size&0xf) {
	*errmsg="msg not multiple of cipher blocksize";
    }
    serpent_encrypt(&ti->cryptkey,iv,iv);
    for (n=buf->start; n<buf->start+buf->size; n+=16)
    {
	for (i = 0; i < 16; i++)
	    pct[i] = n[i];
	serpent_decrypt(&ti->cryptkey,n,n);
	for (i = 0; i < 16; i++)
	    n[i] ^= iv[i];
	memcpy(iv, pct, 16);
    }

    /* CBCMAC */
    macexpected=buf_unappend(buf,16);
    memset(iv,0,16);
    PUT_32BIT_MSB_FIRST(iv, ti->maciv);
    serpent_encrypt(&ti->mackey,iv,macacc);

    /* CBCMAC: encrypt in CBC mode. The MAC is the last encrypted
       block encrypted once again. */
    for (n=buf->start; n<buf->start+buf->size; n+=16)
    {
	for (i = 0; i < 16; i++)
	    macplain[i] = macacc[i] ^ n[i];
	serpent_encrypt(&ti->mackey,macplain,macacc);
    }
    serpent_encrypt(&ti->mackey,macacc,macacc);
    if (memcmp(macexpected,macacc,16)!=0) {
	*errmsg="invalid MAC";
	return 1;
    }

    /* PKCS5, stolen from IWJ */

    padp=buf_unappend(buf,1);
    padlen=*padp;
    if (!padlen || (padlen > PKCS5_MASK+1)) {
	*errmsg="pkcs5: invalid length";
	return 1;
    }

    padp=buf_unappend(buf,padlen-1);
    for (i=0; i<padlen-1; i++) {
	if (*++padp != padlen) {
	    *errmsg="pkcs5: corrupted padding";
	    return 1;
	}
    }

    /* Sequence number must be within max_skew of lastrecvseq; lastrecvseq
       is only allowed to increase. */
    seqnum=buf_unprepend_uint32(buf);
    skew=seqnum-ti->lastrecvseq;
    if (skew<0x8fffffff) {
	/* Ok */
	ti->lastrecvseq=seqnum;
    } else if ((0-skew)<ti->max_skew) {
	/* Ok */
    } else {
	/* Too much skew */
	*errmsg="seqnum: too much skew";
	return 1;
    }
    
    return 0;
}

static void transform_destroy(void *sst)
{
    struct transform_inst *st=sst;

    memset(st,0,sizeof(*st)); /* Destroy key material */
    free(st);
}

static struct transform_inst_if *transform_create(void *sst)
{
    struct transform_inst *ti;
    struct transform *st=sst;

    ti=safe_malloc(sizeof(*ti),"transform_create");
    /* mlock XXX */

    ti->ops.st=ti;
    ti->ops.setkey=transform_setkey;
    ti->ops.delkey=transform_delkey;
    ti->ops.forwards=transform_forward;
    ti->ops.reverse=transform_reverse;
    ti->ops.destroy=transform_destroy;
    ti->max_skew=st->max_seq_skew;
    ti->keyed=False;

    return &ti->ops;
}

static list_t *transform_apply(closure_t *self, struct cloc loc,
			       dict_t *context, list_t *args)
{
    struct transform *st;
    item_t *item;
    dict_t *dict;

    st=safe_malloc(sizeof(*st),"serpent");
    st->cl.description="serpent-cbc256";
    st->cl.type=CL_TRANSFORM;
    st->cl.apply=NULL;
    st->cl.interface=&st->ops;
    st->ops.st=st;
    st->ops.max_start_pad=28; /* 4byte seqnum, 16byte pad, 4byte MACIV,
				 4byte IV */
    st->ops.max_end_pad=16; /* 16byte CBCMAC */

    /* We need 256*2 bits for serpent keys, 32 bits for CBC-IV and 32 bits
       for CBCMAC-IV, and 32 bits for init sequence number */
    st->ops.keylen=REQUIRED_KEYLEN;
    st->ops.create=transform_create;

    /* First parameter must be a dict */
    item=list_elem(args,0);
    if (!item || item->type!=t_dict)
	cfgfatal(loc,"userv-ipif","parameter must be a dictionary\n");
    
    dict=item->data.dict;
    st->max_seq_skew=dict_read_number(dict, "max-sequence-skew",
				      False, "serpent-cbc256", loc, 10);

    return new_closure(&st->cl);
}

void transform_module(dict_t *dict)
{
    struct keyInstance k;
    uint8_t data[32];
    uint8_t plaintext[16];
    uint8_t ciphertext[16];

    /*
     * Serpent self-test.
     * 
     * This test pattern is taken directly from the Serpent test
     * vectors, to ensure we have all endianness issues correct. -sgt
     */

    /* Serpent self-test */
    memcpy(data,
           "\x00\x11\x22\x33\x44\x55\x66\x77\x88\x99\xaa\xbb\xcc\xdd\xee\xff"
           "\xff\xee\xdd\xcc\xbb\xaa\x99\x88\x77\x66\x55\x44\x33\x22\x11\x00",
           32);
    serpent_makekey(&k,256,data);

    memcpy(plaintext,
           "\x01\x23\x45\x67\x89\xab\xcd\xef\xfe\xdc\xba\x98\x76\x54\x32\x10",
           16);
    serpent_encrypt(&k,plaintext,ciphertext);

    if (memcmp(ciphertext, "\xca\x7f\xa1\x93\xe3\xeb\x9e\x99"
               "\xbd\x87\xe3\xaf\x3c\x9a\xdf\x93", 16)) {
	fatal("transform_module: serpent failed self-test (encrypt)");
    }
    serpent_decrypt(&k,ciphertext,plaintext);
    if (memcmp(plaintext, "\x01\x23\x45\x67\x89\xab\xcd\xef"
               "\xfe\xdc\xba\x98\x76\x54\x32\x10", 16)) {
	fatal("transform_module: serpent failed self-test (decrypt)");
    }

    add_closure(dict,"serpent256-cbc",transform_apply);

#ifdef TEST_WHOLE_TRANSFORM
    {
	struct transform *tr;
	void *ti;
	struct buffer_if buf;
	const char text[] = "This is a piece of test text.";
	char keymaterial[76] =
	    "Seventy-six bytes i"
	    "n four rows of 19; "
	    "this looks almost l"
	    "ike a poem but not.";
	const char *errmsg;
	int i;

	tr = malloc(sizeof(struct transform));
	tr->max_seq_skew = 20;
	ti = transform_create(tr);

	transform_setkey(ti, keymaterial, 76);

        buf.base = malloc(4096);
	buffer_init(&buf, 2048);
	memcpy(buf_append(&buf, sizeof(text)), text, sizeof(text));
	if (transform_forward(ti, &buf, &errmsg)) {
	    fatal("transform_forward test: %s", errmsg);
	}
	printf("transformed text is:\n");
	for (i = 0; i < buf.size; i++)
	    printf("%02x%c", buf.start[i],
		   (i%16==15 || i==buf.size-1 ? '\n' : ' '));
	if (transform_reverse(ti, &buf, &errmsg)) {
	    fatal("transform_reverse test: %s", errmsg);
	}
	printf("transform reversal worked OK\n");
    }
#endif
}
Commit	Line	Data
2fe58dfd SE	1	/* Transform module - bulk data transformation */
	2
	3	/* For now it's hard-coded to do sequence
	4	number/pkcs5/serpent-cbcmac/serpent with a 256 bit key for each
	5	instance of serpent. We also require key material for the IVs for
	6	cbcmac and cbc. Hack: we're not using full 128-bit IVs, we're just
	7	using 32 bits and encrypting to get the full IV to save space in
	8	the packets sent over the wire. */
	9
	10	#include <stdio.h>
469fd1d9	11	#include <string.h>
2fe58dfd SE	12	#include "secnet.h"
	13	#include "util.h"
	14	#include "serpent.h"
59635212	15	#include "unaligned.h"
2fe58dfd SE	16
	17	/* Required key length in bytes */
	18	#define REQUIRED_KEYLEN ((512+64+32)/8)
	19
	20	struct transform {
	21	closure_t cl;
	22	uint32_t line;
	23	struct transform_if ops;
	24	uint32_t max_seq_skew;
	25	};
	26
	27	struct transform_inst {
	28	struct transform_inst_if ops;
	29	struct keyInstance cryptkey;
	30	struct keyInstance mackey;
	31	uint32_t cryptiv;
	32	uint32_t maciv;
	33	uint32_t sendseq;
	34	uint32_t lastrecvseq;
	35	uint32_t max_skew;
	36	bool_t keyed;
	37	};
	38
	39	#define PKCS5_MASK 15
	40
	41	static bool_t transform_setkey(void sst, uint8_t key, uint32_t keylen)
	42	{
	43	struct transform_inst *ti=sst;
	44
	45	if (keylen<REQUIRED_KEYLEN) {
469fd1d9	46	Message(M_ERR,"transform_create: insufficient key material supplied "
2fe58dfd SE	47	"(need %d bytes, got %d)\n",REQUIRED_KEYLEN,keylen);
	48	return False;
	49	}
	50
	51	#if 0
	52	{
	53	int i;
	54	printf("Setting key to: ");
	55	for (i=0; i<keylen; i++)
	56	printf("%02x",key[i]);
	57	printf("\n");
	58	}
	59	#endif /* 0 */
	60
	61	serpent_makekey(&ti->cryptkey,256,key);
	62	serpent_makekey(&ti->mackey,256,key+32);
3b83c932 SE	63	ti->cryptiv=GET_32BIT_MSB_FIRST(key+64);
	64	ti->maciv=GET_32BIT_MSB_FIRST(key+68);
	65	ti->sendseq=GET_32BIT_MSB_FIRST(key+72);
2fe58dfd SE	66	ti->lastrecvseq=ti->sendseq;
	67	ti->keyed=True;
	68
	69	return True;
	70	}
	71
	72	static void transform_delkey(void *sst)
	73	{
	74	struct transform_inst *ti=sst;
	75
	76	memset(&ti->cryptkey,0,sizeof(ti->cryptkey));
	77	memset(&ti->mackey,0,sizeof(ti->mackey));
	78	ti->keyed=False;
	79	}
	80
	81	static uint32_t transform_forward(void sst, struct buffer_if buf,
fe5e9cc4	82	const char **errmsg)
2fe58dfd SE	83	{
	84	struct transform_inst *ti=sst;
	85	uint8_t *padp;
	86	int padlen;
3b83c932 SE	87	uint8_t iv[16];
	88	uint8_t macplain[16];
	89	uint8_t macacc[16];
	90	uint8_t p, n;
	91	int i;
2fe58dfd SE	92
	93	if (!ti->keyed) {
	94	*errmsg="transform unkeyed";
	95	return 1;
	96	}
	97
	98	/* Sequence number */
59635212	99	buf_prepend_uint32(buf,ti->sendseq);
2fe58dfd SE	100	ti->sendseq++;
	101
	102	/* PKCS5, stolen from IWJ */
	103	/* eg with blocksize=4 mask=3 mask+2=5 */
	104	/* msgsize 20 21 22 23 24 */
	105	padlen= PKCS5_MASK-buf->size; /* -17 -18 -19 -16 -17 */
	106	padlen &= PKCS5_MASK; /* 3 2 1 0 3 */
	107	padlen++; /* 4 3 2 1 4 */
	108
	109	padp=buf_append(buf,padlen);
	110	memset(padp,padlen,padlen);
	111
	112	/* Serpent-CBCMAC. We expand the IV from 32-bit to 128-bit using
	113	one encryption. Then we do the MAC and append the result. We don't
	114	bother sending the IV - it's the same each time. (If we wanted to send
	115	it we've have to add 16 bytes to each message, not 4, so that the
	116	message stays a multiple of 16 bytes long.) */
	117	memset(iv,0,16);
3b83c932	118	PUT_32BIT_MSB_FIRST(iv, ti->maciv);
2fe58dfd SE	119	serpent_encrypt(&ti->mackey,iv,macacc);
	120
	121	/* CBCMAC: encrypt in CBC mode. The MAC is the last encrypted
	122	block encrypted once again. */
3b83c932	123	for (n=buf->start; n<buf->start+buf->size; n+=16)
2fe58dfd	124	{
3b83c932 SE	125	for (i = 0; i < 16; i++)
3b83c932 SE	126	macplain[i] = macacc[i] ^ n[i];
2fe58dfd SE	127	serpent_encrypt(&ti->mackey,macplain,macacc);
	128	}
	129	serpent_encrypt(&ti->mackey,macacc,macacc);
	130	memcpy(buf_append(buf,16),macacc,16);
	131
	132	/* Serpent-CBC. We expand the ID as for CBCMAC, do the encryption,
	133	and prepend the IV before increasing it. */
	134	memset(iv,0,16);
3b83c932	135	PUT_32BIT_MSB_FIRST(iv, ti->cryptiv);
2fe58dfd SE	136	serpent_encrypt(&ti->cryptkey,iv,iv);
	137
	138	/* CBC: each block is XORed with the previous encrypted block (or the IV)
	139	before being encrypted. */
	140	p=iv;
3b83c932 SE	141
3b83c932 SE	142	for (n=buf->start; n<buf->start+buf->size; n+=16)
2fe58dfd	143	{
3b83c932 SE	144	for (i = 0; i < 16; i++)
3b83c932 SE	145	n[i] ^= p[i];
2fe58dfd SE	146	serpent_encrypt(&ti->cryptkey,n,n);
	147	p=n;
	148	}
	149
59635212	150	buf_prepend_uint32(buf,ti->cryptiv);
2fe58dfd	151	ti->cryptiv++;
2fe58dfd SE	152	return 0;
	153	}
	154
	155	static uint32_t transform_reverse(void sst, struct buffer_if buf,
fe5e9cc4	156	const char **errmsg)
2fe58dfd SE	157	{
	158	struct transform_inst *ti=sst;
	159	uint8_t *padp;
	160	unsigned padlen;
	161	int i;
	162	uint32_t seqnum, skew;
3b83c932 SE	163	uint8_t iv[16];
	164	uint8_t pct[16];
	165	uint8_t macplain[16];
	166	uint8_t macacc[16];
	167	uint8_t *n;
	168	uint8_t *macexpected;
2fe58dfd SE	169
	170	if (!ti->keyed) {
	171	*errmsg="transform unkeyed";
	172	return 1;
	173	}
	174
8689b3a9	175
2fe58dfd SE	176	/* CBC */
2fe58dfd SE	177	memset(iv,0,16);
3b83c932 SE	178	{
	179	uint32_t ivword = buf_unprepend_uint32(buf);
	180	PUT_32BIT_MSB_FIRST(iv, ivword);
	181	}
8689b3a9 SE	182	/* Assert bufsize is multiple of blocksize */
	183	if (buf->size&0xf) {
	184	*errmsg="msg not multiple of cipher blocksize";
	185	}
2fe58dfd	186	serpent_encrypt(&ti->cryptkey,iv,iv);
3b83c932	187	for (n=buf->start; n<buf->start+buf->size; n+=16)
2fe58dfd	188	{
3b83c932 SE	189	for (i = 0; i < 16; i++)
3b83c932 SE	190	pct[i] = n[i];
2fe58dfd	191	serpent_decrypt(&ti->cryptkey,n,n);
3b83c932 SE	192	for (i = 0; i < 16; i++)
	193	n[i] ^= iv[i];
	194	memcpy(iv, pct, 16);
2fe58dfd SE	195	}
	196
	197	/* CBCMAC */
	198	macexpected=buf_unappend(buf,16);
	199	memset(iv,0,16);
3b83c932	200	PUT_32BIT_MSB_FIRST(iv, ti->maciv);
2fe58dfd SE	201	serpent_encrypt(&ti->mackey,iv,macacc);
	202
	203	/* CBCMAC: encrypt in CBC mode. The MAC is the last encrypted
	204	block encrypted once again. */
3b83c932	205	for (n=buf->start; n<buf->start+buf->size; n+=16)
2fe58dfd	206	{
3b83c932 SE	207	for (i = 0; i < 16; i++)
3b83c932 SE	208	macplain[i] = macacc[i] ^ n[i];
2fe58dfd SE	209	serpent_encrypt(&ti->mackey,macplain,macacc);
	210	}
	211	serpent_encrypt(&ti->mackey,macacc,macacc);
	212	if (memcmp(macexpected,macacc,16)!=0) {
	213	*errmsg="invalid MAC";
	214	return 1;
	215	}
	216
	217	/* PKCS5, stolen from IWJ */
	218
	219	padp=buf_unappend(buf,1);
	220	padlen=*padp;
	221	if (!padlen \|\| (padlen > PKCS5_MASK+1)) {
	222	*errmsg="pkcs5: invalid length";
	223	return 1;
	224	}
	225
	226	padp=buf_unappend(buf,padlen-1);
	227	for (i=0; i<padlen-1; i++) {
	228	if (*++padp != padlen) {
	229	*errmsg="pkcs5: corrupted padding";
	230	return 1;
	231	}
	232	}
	233
	234	/* Sequence number must be within max_skew of lastrecvseq; lastrecvseq
	235	is only allowed to increase. */
59635212	236	seqnum=buf_unprepend_uint32(buf);
2fe58dfd	237	skew=seqnum-ti->lastrecvseq;
c6f79b17	238	if (skew<0x8fffffff) {
2fe58dfd SE	239	/* Ok */
2fe58dfd SE	240	ti->lastrecvseq=seqnum;
c6f79b17	241	} else if ((0-skew)<ti->max_skew) {
2fe58dfd SE	242	/* Ok */
	243	} else {
	244	/* Too much skew */
	245	*errmsg="seqnum: too much skew";
	246	return 1;
	247	}
	248
	249	return 0;
	250	}
	251
	252	static void transform_destroy(void *sst)
	253	{
	254	struct transform_inst *st=sst;
	255
	256	memset(st,0,sizeof(st)); / Destroy key material */
	257	free(st);
	258	}
	259
	260	static struct transform_inst_if transform_create(void sst)
	261	{
	262	struct transform_inst *ti;
	263	struct transform *st=sst;
	264
	265	ti=safe_malloc(sizeof(*ti),"transform_create");
	266	/* mlock XXX */
	267
	268	ti->ops.st=ti;
	269	ti->ops.setkey=transform_setkey;
	270	ti->ops.delkey=transform_delkey;
	271	ti->ops.forwards=transform_forward;
	272	ti->ops.reverse=transform_reverse;
	273	ti->ops.destroy=transform_destroy;
	274	ti->max_skew=st->max_seq_skew;
	275	ti->keyed=False;
	276
	277	return &ti->ops;
	278	}
	279
	280	static list_t transform_apply(closure_t self, struct cloc loc,
	281	dict_t context, list_t args)
	282	{
	283	struct transform *st;
	284	item_t *item;
	285	dict_t *dict;
	286
	287	st=safe_malloc(sizeof(*st),"serpent");
	288	st->cl.description="serpent-cbc256";
	289	st->cl.type=CL_TRANSFORM;
	290	st->cl.apply=NULL;
	291	st->cl.interface=&st->ops;
	292	st->ops.st=st;
	293	st->ops.max_start_pad=28; /* 4byte seqnum, 16byte pad, 4byte MACIV,
	294	4byte IV */
	295	st->ops.max_end_pad=16; /* 16byte CBCMAC */
	296
	297	/* We need 256*2 bits for serpent keys, 32 bits for CBC-IV and 32 bits
	298	for CBCMAC-IV, and 32 bits for init sequence number */
	299	st->ops.keylen=REQUIRED_KEYLEN;
	300	st->ops.create=transform_create;
	301
	302	/* First parameter must be a dict */
	303	item=list_elem(args,0);
	304	if (!item \|\| item->type!=t_dict)
	305	cfgfatal(loc,"userv-ipif","parameter must be a dictionary\n");
306
307	dict=item->data.dict;
308	st->max_seq_skew=dict_read_number(dict, "max-sequence-skew",
309	False, "serpent-cbc256", loc, 10);
310
311	return new_closure(&st->cl);
312	}
313
2fe58dfd SE	314	void transform_module(dict_t *dict)
	315	{
	316	struct keyInstance k;
	317	uint8_t data[32];
3b83c932 SE	318	uint8_t plaintext[16];
	319	uint8_t ciphertext[16];
	320
	321	/*
	322	* Serpent self-test.
	323	*
	324	* This test pattern is taken directly from the Serpent test
	325	* vectors, to ensure we have all endianness issues correct. -sgt
	326	*/
2fe58dfd SE	327
2fe58dfd SE	328	/* Serpent self-test */
3b83c932 SE	329	memcpy(data,
	330	"\x00\x11\x22\x33\x44\x55\x66\x77\x88\x99\xaa\xbb\xcc\xdd\xee\xff"
	331	"\xff\xee\xdd\xcc\xbb\xaa\x99\x88\x77\x66\x55\x44\x33\x22\x11\x00",
	332	32);
2fe58dfd	333	serpent_makekey(&k,256,data);
3b83c932 SE	334
	335	memcpy(plaintext,
	336	"\x01\x23\x45\x67\x89\xab\xcd\xef\xfe\xdc\xba\x98\x76\x54\x32\x10",
	337	16);
2fe58dfd	338	serpent_encrypt(&k,plaintext,ciphertext);
3b83c932 SE	339
	340	if (memcmp(ciphertext, "\xca\x7f\xa1\x93\xe3\xeb\x9e\x99"
	341	"\xbd\x87\xe3\xaf\x3c\x9a\xdf\x93", 16)) {
4f5e39ec	342	fatal("transform_module: serpent failed self-test (encrypt)");
2fe58dfd SE	343	}
2fe58dfd SE	344	serpent_decrypt(&k,ciphertext,plaintext);
3b83c932 SE	345	if (memcmp(plaintext, "\x01\x23\x45\x67\x89\xab\xcd\xef"
3b83c932 SE	346	"\xfe\xdc\xba\x98\x76\x54\x32\x10", 16)) {
4f5e39ec	347	fatal("transform_module: serpent failed self-test (decrypt)");
2fe58dfd SE	348	}
	349
	350	add_closure(dict,"serpent256-cbc",transform_apply);
3b83c932 SE	351
	352	#ifdef TEST_WHOLE_TRANSFORM
	353	{
	354	struct transform *tr;
	355	void *ti;
	356	struct buffer_if buf;
	357	const char text[] = "This is a piece of test text.";
	358	char keymaterial[76] =
	359	"Seventy-six bytes i"
	360	"n four rows of 19; "
	361	"this looks almost l"
	362	"ike a poem but not.";
	363	const char *errmsg;
	364	int i;
	365
	366	tr = malloc(sizeof(struct transform));
	367	tr->max_seq_skew = 20;
	368	ti = transform_create(tr);
	369
	370	transform_setkey(ti, keymaterial, 76);
	371
	372	buf.base = malloc(4096);
	373	buffer_init(&buf, 2048);
	374	memcpy(buf_append(&buf, sizeof(text)), text, sizeof(text));
	375	if (transform_forward(ti, &buf, &errmsg)) {
	376	fatal("transform_forward test: %s", errmsg);
	377	}
	378	printf("transformed text is:\n");
	379	for (i = 0; i < buf.size; i++)
	380	printf("%02x%c", buf.start[i],
	381	(i%16==15 \|\| i==buf.size-1 ? '\n' : ' '));
	382	if (transform_reverse(ti, &buf, &errmsg)) {
	383	fatal("transform_reverse test: %s", errmsg);
	384	}
	385	printf("transform reversal worked OK\n");
	386	}
	387	#endif
2fe58dfd	388	}