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" |
980d1ab2 | 16 | #include "hexdebug.h" |
2fe58dfd SE |
17 | |
18 | /* Required key length in bytes */ | |
19 | #define REQUIRED_KEYLEN ((512+64+32)/8) | |
20 | ||
35d30aa3 IJ |
21 | #include "transform-common.h" |
22 | ||
9d69120a | 23 | struct transform_params { |
35d30aa3 | 24 | SEQNUM_PARAMS_FIELDS; |
9d69120a IJ |
25 | }; |
26 | ||
2fe58dfd SE |
27 | struct transform { |
28 | closure_t cl; | |
2fe58dfd | 29 | struct transform_if ops; |
9d69120a | 30 | struct transform_params p; |
2fe58dfd SE |
31 | }; |
32 | ||
33 | struct transform_inst { | |
34 | struct transform_inst_if ops; | |
9d69120a | 35 | struct transform_params p; |
2fe58dfd SE |
36 | struct keyInstance cryptkey; |
37 | struct keyInstance mackey; | |
38 | uint32_t cryptiv; | |
39 | uint32_t maciv; | |
35d30aa3 | 40 | SEQNUM_KEYED_FIELDS; |
2fe58dfd SE |
41 | }; |
42 | ||
43 | #define PKCS5_MASK 15 | |
44 | ||
0118121a IJ |
45 | static bool_t transform_setkey(void *sst, uint8_t *key, int32_t keylen, |
46 | bool_t direction) | |
2fe58dfd SE |
47 | { |
48 | struct transform_inst *ti=sst; | |
49 | ||
50 | if (keylen<REQUIRED_KEYLEN) { | |
469fd1d9 | 51 | Message(M_ERR,"transform_create: insufficient key material supplied " |
2fe58dfd SE |
52 | "(need %d bytes, got %d)\n",REQUIRED_KEYLEN,keylen); |
53 | return False; | |
54 | } | |
55 | ||
56 | #if 0 | |
57 | { | |
2fe58dfd | 58 | printf("Setting key to: "); |
980d1ab2 | 59 | hexdebug(stdout,key,keylen); |
2fe58dfd SE |
60 | printf("\n"); |
61 | } | |
62 | #endif /* 0 */ | |
63 | ||
af43f0b7 IJ |
64 | serpentbe_makekey(&ti->cryptkey,256,key); |
65 | serpentbe_makekey(&ti->mackey,256,key+32); | |
4a1a5919 IJ |
66 | ti->cryptiv=get_uint32(key+64); |
67 | ti->maciv=get_uint32(key+68); | |
35d30aa3 IJ |
68 | uint32_t firstseq=get_uint32(key+72); |
69 | SEQNUM_KEYED_INIT(firstseq,firstseq); | |
2fe58dfd SE |
70 | |
71 | return True; | |
72 | } | |
73 | ||
92a7d254 | 74 | TRANSFORM_VALID; |
b67dab18 | 75 | |
2fe58dfd SE |
76 | static void transform_delkey(void *sst) |
77 | { | |
78 | struct transform_inst *ti=sst; | |
79 | ||
076bb54e IJ |
80 | FILLZERO(ti->cryptkey); |
81 | FILLZERO(ti->mackey); | |
2fe58dfd SE |
82 | ti->keyed=False; |
83 | } | |
84 | ||
85 | static uint32_t transform_forward(void *sst, struct buffer_if *buf, | |
fe5e9cc4 | 86 | const char **errmsg) |
2fe58dfd SE |
87 | { |
88 | struct transform_inst *ti=sst; | |
89 | uint8_t *padp; | |
90 | int padlen; | |
3b83c932 SE |
91 | uint8_t iv[16]; |
92 | uint8_t macplain[16]; | |
93 | uint8_t macacc[16]; | |
94 | uint8_t *p, *n; | |
95 | int i; | |
2fe58dfd | 96 | |
92a7d254 | 97 | KEYED_CHECK; |
2fe58dfd SE |
98 | |
99 | /* Sequence number */ | |
59635212 | 100 | buf_prepend_uint32(buf,ti->sendseq); |
2fe58dfd SE |
101 | ti->sendseq++; |
102 | ||
103 | /* PKCS5, stolen from IWJ */ | |
104 | /* eg with blocksize=4 mask=3 mask+2=5 */ | |
105 | /* msgsize 20 21 22 23 24 */ | |
106 | padlen= PKCS5_MASK-buf->size; /* -17 -18 -19 -16 -17 */ | |
107 | padlen &= PKCS5_MASK; /* 3 2 1 0 3 */ | |
108 | padlen++; /* 4 3 2 1 4 */ | |
109 | ||
110 | padp=buf_append(buf,padlen); | |
111 | memset(padp,padlen,padlen); | |
112 | ||
113 | /* Serpent-CBCMAC. We expand the IV from 32-bit to 128-bit using | |
114 | one encryption. Then we do the MAC and append the result. We don't | |
115 | bother sending the IV - it's the same each time. (If we wanted to send | |
116 | it we've have to add 16 bytes to each message, not 4, so that the | |
117 | message stays a multiple of 16 bytes long.) */ | |
4f28e77e | 118 | FILLZERO(iv); |
4a1a5919 | 119 | put_uint32(iv, ti->maciv); |
af43f0b7 | 120 | serpentbe_encrypt(&ti->mackey,iv,macacc); |
2fe58dfd SE |
121 | |
122 | /* CBCMAC: encrypt in CBC mode. The MAC is the last encrypted | |
123 | block encrypted once again. */ | |
3b83c932 | 124 | for (n=buf->start; n<buf->start+buf->size; n+=16) |
2fe58dfd | 125 | { |
3b83c932 SE |
126 | for (i = 0; i < 16; i++) |
127 | macplain[i] = macacc[i] ^ n[i]; | |
af43f0b7 | 128 | serpentbe_encrypt(&ti->mackey,macplain,macacc); |
2fe58dfd | 129 | } |
af43f0b7 | 130 | serpentbe_encrypt(&ti->mackey,macacc,macacc); |
4f28e77e | 131 | BUF_ADD_BYTES(append,buf,macacc,16); |
2fe58dfd SE |
132 | |
133 | /* Serpent-CBC. We expand the ID as for CBCMAC, do the encryption, | |
134 | and prepend the IV before increasing it. */ | |
4f28e77e | 135 | FILLZERO(iv); |
4a1a5919 | 136 | put_uint32(iv, ti->cryptiv); |
af43f0b7 | 137 | serpentbe_encrypt(&ti->cryptkey,iv,iv); |
2fe58dfd SE |
138 | |
139 | /* CBC: each block is XORed with the previous encrypted block (or the IV) | |
140 | before being encrypted. */ | |
141 | p=iv; | |
3b83c932 SE |
142 | |
143 | for (n=buf->start; n<buf->start+buf->size; n+=16) | |
2fe58dfd | 144 | { |
3b83c932 SE |
145 | for (i = 0; i < 16; i++) |
146 | n[i] ^= p[i]; | |
af43f0b7 | 147 | serpentbe_encrypt(&ti->cryptkey,n,n); |
2fe58dfd SE |
148 | p=n; |
149 | } | |
150 | ||
59635212 | 151 | buf_prepend_uint32(buf,ti->cryptiv); |
2fe58dfd | 152 | ti->cryptiv++; |
2fe58dfd SE |
153 | return 0; |
154 | } | |
155 | ||
156 | static uint32_t transform_reverse(void *sst, struct buffer_if *buf, | |
fe5e9cc4 | 157 | const char **errmsg) |
2fe58dfd SE |
158 | { |
159 | struct transform_inst *ti=sst; | |
160 | uint8_t *padp; | |
1caa23ff | 161 | int padlen; |
2fe58dfd | 162 | int i; |
92a7d254 | 163 | uint32_t seqnum; |
3b83c932 SE |
164 | uint8_t iv[16]; |
165 | uint8_t pct[16]; | |
166 | uint8_t macplain[16]; | |
167 | uint8_t macacc[16]; | |
168 | uint8_t *n; | |
169 | uint8_t *macexpected; | |
2fe58dfd | 170 | |
92a7d254 | 171 | KEYED_CHECK; |
2fe58dfd | 172 | |
20138876 IJ |
173 | if (buf->size < 4 + 16 + 16) { |
174 | *errmsg="msg too short"; | |
175 | return 1; | |
176 | } | |
8689b3a9 | 177 | |
2fe58dfd | 178 | /* CBC */ |
4f28e77e | 179 | FILLZERO(iv); |
3b83c932 SE |
180 | { |
181 | uint32_t ivword = buf_unprepend_uint32(buf); | |
4a1a5919 | 182 | put_uint32(iv, ivword); |
3b83c932 | 183 | } |
8689b3a9 SE |
184 | /* Assert bufsize is multiple of blocksize */ |
185 | if (buf->size&0xf) { | |
186 | *errmsg="msg not multiple of cipher blocksize"; | |
20138876 | 187 | return 1; |
8689b3a9 | 188 | } |
af43f0b7 | 189 | serpentbe_encrypt(&ti->cryptkey,iv,iv); |
3b83c932 | 190 | for (n=buf->start; n<buf->start+buf->size; n+=16) |
2fe58dfd | 191 | { |
3b83c932 SE |
192 | for (i = 0; i < 16; i++) |
193 | pct[i] = n[i]; | |
af43f0b7 | 194 | serpentbe_decrypt(&ti->cryptkey,n,n); |
3b83c932 SE |
195 | for (i = 0; i < 16; i++) |
196 | n[i] ^= iv[i]; | |
4f28e77e | 197 | COPY_OBJ(iv, pct); |
2fe58dfd SE |
198 | } |
199 | ||
200 | /* CBCMAC */ | |
201 | macexpected=buf_unappend(buf,16); | |
4f28e77e | 202 | FILLZERO(iv); |
4a1a5919 | 203 | put_uint32(iv, ti->maciv); |
af43f0b7 | 204 | serpentbe_encrypt(&ti->mackey,iv,macacc); |
2fe58dfd SE |
205 | |
206 | /* CBCMAC: encrypt in CBC mode. The MAC is the last encrypted | |
207 | block encrypted once again. */ | |
3b83c932 | 208 | for (n=buf->start; n<buf->start+buf->size; n+=16) |
2fe58dfd | 209 | { |
3b83c932 SE |
210 | for (i = 0; i < 16; i++) |
211 | macplain[i] = macacc[i] ^ n[i]; | |
af43f0b7 | 212 | serpentbe_encrypt(&ti->mackey,macplain,macacc); |
2fe58dfd | 213 | } |
af43f0b7 | 214 | serpentbe_encrypt(&ti->mackey,macacc,macacc); |
5ad34db2 | 215 | if (!consttime_memeq(macexpected,macacc,16)!=0) { |
2fe58dfd SE |
216 | *errmsg="invalid MAC"; |
217 | return 1; | |
218 | } | |
219 | ||
220 | /* PKCS5, stolen from IWJ */ | |
221 | ||
222 | padp=buf_unappend(buf,1); | |
223 | padlen=*padp; | |
224 | if (!padlen || (padlen > PKCS5_MASK+1)) { | |
225 | *errmsg="pkcs5: invalid length"; | |
226 | return 1; | |
227 | } | |
228 | ||
46008a7c | 229 | buf_unappend(buf,padlen-1); |
2fe58dfd SE |
230 | |
231 | /* Sequence number must be within max_skew of lastrecvseq; lastrecvseq | |
232 | is only allowed to increase. */ | |
59635212 | 233 | seqnum=buf_unprepend_uint32(buf); |
35d30aa3 | 234 | SEQNUM_CHECK(seqnum, &ti->p); |
2fe58dfd SE |
235 | |
236 | return 0; | |
237 | } | |
238 | ||
92a7d254 | 239 | TRANSFORM_DESTROY; |
2fe58dfd SE |
240 | |
241 | static struct transform_inst_if *transform_create(void *sst) | |
242 | { | |
2fe58dfd SE |
243 | struct transform *st=sst; |
244 | ||
92a7d254 | 245 | TRANSFORM_CREATE_CORE; |
2fe58dfd | 246 | |
9d69120a | 247 | ti->p=st->p; |
2fe58dfd SE |
248 | |
249 | return &ti->ops; | |
250 | } | |
251 | ||
252 | static list_t *transform_apply(closure_t *self, struct cloc loc, | |
253 | dict_t *context, list_t *args) | |
254 | { | |
255 | struct transform *st; | |
256 | item_t *item; | |
257 | dict_t *dict; | |
258 | ||
b7886fd4 | 259 | NEW(st); |
2fe58dfd SE |
260 | st->cl.description="serpent-cbc256"; |
261 | st->cl.type=CL_TRANSFORM; | |
262 | st->cl.apply=NULL; | |
263 | st->cl.interface=&st->ops; | |
264 | st->ops.st=st; | |
3abd18e8 IJ |
265 | update_max_start_pad(&transform_max_start_pad, 28); |
266 | /* 4byte seqnum, 16byte pad, 4byte MACIV, 4byte IV */ | |
2fe58dfd SE |
267 | |
268 | /* We need 256*2 bits for serpent keys, 32 bits for CBC-IV and 32 bits | |
269 | for CBCMAC-IV, and 32 bits for init sequence number */ | |
270 | st->ops.keylen=REQUIRED_KEYLEN; | |
271 | st->ops.create=transform_create; | |
272 | ||
273 | /* First parameter must be a dict */ | |
274 | item=list_elem(args,0); | |
275 | if (!item || item->type!=t_dict) | |
276 | cfgfatal(loc,"userv-ipif","parameter must be a dictionary\n"); | |
277 | ||
278 | dict=item->data.dict; | |
35d30aa3 IJ |
279 | |
280 | SEQNUM_PARAMS_INIT(dict,&st->p,"serpent-cbc256",loc); | |
2fe58dfd | 281 | |
5b5f297f IJ |
282 | SET_CAPAB_TRANSFORMNUM(CAPAB_TRANSFORMNUM_SERPENT256CBC); |
283 | ||
2fe58dfd SE |
284 | return new_closure(&st->cl); |
285 | } | |
286 | ||
92a7d254 | 287 | void transform_cbcmac_module(dict_t *dict) |
2fe58dfd SE |
288 | { |
289 | struct keyInstance k; | |
290 | uint8_t data[32]; | |
3b83c932 SE |
291 | uint8_t plaintext[16]; |
292 | uint8_t ciphertext[16]; | |
293 | ||
294 | /* | |
295 | * Serpent self-test. | |
296 | * | |
af43f0b7 IJ |
297 | * This test pattern was taken directly from the Serpent test |
298 | * vectors, which results in a big-endian Serpent which is not | |
299 | * compatible with other implementations. | |
3b83c932 | 300 | */ |
2fe58dfd SE |
301 | |
302 | /* Serpent self-test */ | |
3b83c932 SE |
303 | memcpy(data, |
304 | "\x00\x11\x22\x33\x44\x55\x66\x77\x88\x99\xaa\xbb\xcc\xdd\xee\xff" | |
305 | "\xff\xee\xdd\xcc\xbb\xaa\x99\x88\x77\x66\x55\x44\x33\x22\x11\x00", | |
306 | 32); | |
af43f0b7 | 307 | serpentbe_makekey(&k,256,data); |
3b83c932 SE |
308 | |
309 | memcpy(plaintext, | |
310 | "\x01\x23\x45\x67\x89\xab\xcd\xef\xfe\xdc\xba\x98\x76\x54\x32\x10", | |
311 | 16); | |
af43f0b7 | 312 | serpentbe_encrypt(&k,plaintext,ciphertext); |
3b83c932 SE |
313 | |
314 | if (memcmp(ciphertext, "\xca\x7f\xa1\x93\xe3\xeb\x9e\x99" | |
315 | "\xbd\x87\xe3\xaf\x3c\x9a\xdf\x93", 16)) { | |
4f5e39ec | 316 | fatal("transform_module: serpent failed self-test (encrypt)"); |
2fe58dfd | 317 | } |
af43f0b7 | 318 | serpentbe_decrypt(&k,ciphertext,plaintext); |
3b83c932 SE |
319 | if (memcmp(plaintext, "\x01\x23\x45\x67\x89\xab\xcd\xef" |
320 | "\xfe\xdc\xba\x98\x76\x54\x32\x10", 16)) { | |
4f5e39ec | 321 | fatal("transform_module: serpent failed self-test (decrypt)"); |
2fe58dfd SE |
322 | } |
323 | ||
324 | add_closure(dict,"serpent256-cbc",transform_apply); | |
3b83c932 SE |
325 | |
326 | #ifdef TEST_WHOLE_TRANSFORM | |
327 | { | |
328 | struct transform *tr; | |
329 | void *ti; | |
330 | struct buffer_if buf; | |
331 | const char text[] = "This is a piece of test text."; | |
332 | char keymaterial[76] = | |
333 | "Seventy-six bytes i" | |
334 | "n four rows of 19; " | |
335 | "this looks almost l" | |
336 | "ike a poem but not."; | |
337 | const char *errmsg; | |
338 | int i; | |
339 | ||
c921f0c5 | 340 | tr = safe_malloc(sizeof(struct transform),"test transform"); |
3b83c932 SE |
341 | tr->max_seq_skew = 20; |
342 | ti = transform_create(tr); | |
343 | ||
344 | transform_setkey(ti, keymaterial, 76); | |
345 | ||
346 | buf.base = malloc(4096); | |
347 | buffer_init(&buf, 2048); | |
4f28e77e | 348 | BUF_ADD_OBJ(append, buf, text, sizeof(text)); |
3b83c932 SE |
349 | if (transform_forward(ti, &buf, &errmsg)) { |
350 | fatal("transform_forward test: %s", errmsg); | |
351 | } | |
352 | printf("transformed text is:\n"); | |
353 | for (i = 0; i < buf.size; i++) | |
354 | printf("%02x%c", buf.start[i], | |
355 | (i%16==15 || i==buf.size-1 ? '\n' : ' ')); | |
356 | if (transform_reverse(ti, &buf, &errmsg)) { | |
357 | fatal("transform_reverse test: %s", errmsg); | |
358 | } | |
359 | printf("transform reversal worked OK\n"); | |
360 | } | |
361 | #endif | |
2fe58dfd | 362 | } |