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-rw-r--r--crypto/prng.c410
1 files changed, 0 insertions, 410 deletions
diff --git a/crypto/prng.c b/crypto/prng.c
deleted file mode 100644
index 24e4f3282c56..000000000000
--- a/crypto/prng.c
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@@ -1,410 +0,0 @@
1/*
2 * PRNG: Pseudo Random Number Generator
3 * Based on NIST Recommended PRNG From ANSI X9.31 Appendix A.2.4 using
4 * AES 128 cipher in RFC3686 ctr mode
5 *
6 * (C) Neil Horman <nhorman@tuxdriver.com>
7 *
8 * This program is free software; you can redistribute it and/or modify it
9 * under the terms of the GNU General Public License as published by the
10 * Free Software Foundation; either version 2 of the License, or (at your
11 * any later version.
12 *
13 *
14 */
15
16#include <linux/err.h>
17#include <linux/init.h>
18#include <linux/module.h>
19#include <linux/mm.h>
20#include <linux/slab.h>
21#include <linux/fs.h>
22#include <linux/scatterlist.h>
23#include <linux/string.h>
24#include <linux/crypto.h>
25#include <linux/highmem.h>
26#include <linux/moduleparam.h>
27#include <linux/jiffies.h>
28#include <linux/timex.h>
29#include <linux/interrupt.h>
30#include <linux/miscdevice.h>
31#include "prng.h"
32
33#define TEST_PRNG_ON_START 0
34
35#define DEFAULT_PRNG_KEY "0123456789abcdef1011"
36#define DEFAULT_PRNG_KSZ 20
37#define DEFAULT_PRNG_IV "defaultv"
38#define DEFAULT_PRNG_IVSZ 8
39#define DEFAULT_BLK_SZ 16
40#define DEFAULT_V_SEED "zaybxcwdveuftgsh"
41
42/*
43 * Flags for the prng_context flags field
44 */
45
46#define PRNG_FIXED_SIZE 0x1
47#define PRNG_NEED_RESET 0x2
48
49/*
50 * Note: DT is our counter value
51 * I is our intermediate value
52 * V is our seed vector
53 * See http://csrc.nist.gov/groups/STM/cavp/documents/rng/931rngext.pdf
54 * for implementation details
55 */
56
57
58struct prng_context {
59 char *prng_key;
60 char *prng_iv;
61 spinlock_t prng_lock;
62 unsigned char rand_data[DEFAULT_BLK_SZ];
63 unsigned char last_rand_data[DEFAULT_BLK_SZ];
64 unsigned char DT[DEFAULT_BLK_SZ];
65 unsigned char I[DEFAULT_BLK_SZ];
66 unsigned char V[DEFAULT_BLK_SZ];
67 u32 rand_data_valid;
68 struct crypto_blkcipher *tfm;
69 u32 flags;
70};
71
72static int dbg;
73
74static void hexdump(char *note, unsigned char *buf, unsigned int len)
75{
76 if (dbg) {
77 printk(KERN_CRIT "%s", note);
78 print_hex_dump(KERN_CONT, "", DUMP_PREFIX_OFFSET,
79 16, 1,
80 buf, len, false);
81 }
82}
83
84#define dbgprint(format, args...) do {if(dbg) printk(format, ##args);} while(0)
85
86static void xor_vectors(unsigned char *in1, unsigned char *in2,
87 unsigned char *out, unsigned int size)
88{
89 int i;
90
91 for (i=0;i<size;i++)
92 out[i] = in1[i] ^ in2[i];
93
94}
95/*
96 * Returns DEFAULT_BLK_SZ bytes of random data per call
97 * returns 0 if generation succeded, <0 if something went wrong
98 */
99static int _get_more_prng_bytes(struct prng_context *ctx)
100{
101 int i;
102 struct blkcipher_desc desc;
103 struct scatterlist sg_in, sg_out;
104 int ret;
105 unsigned char tmp[DEFAULT_BLK_SZ];
106
107 desc.tfm = ctx->tfm;
108 desc.flags = 0;
109
110
111 dbgprint(KERN_CRIT "Calling _get_more_prng_bytes for context %p\n",ctx);
112
113 hexdump("Input DT: ", ctx->DT, DEFAULT_BLK_SZ);
114 hexdump("Input I: ", ctx->I, DEFAULT_BLK_SZ);
115 hexdump("Input V: ", ctx->V, DEFAULT_BLK_SZ);
116
117 /*
118 * This algorithm is a 3 stage state machine
119 */
120 for (i=0;i<3;i++) {
121
122 desc.tfm = ctx->tfm;
123 desc.flags = 0;
124 switch (i) {
125 case 0:
126 /*
127 * Start by encrypting the counter value
128 * This gives us an intermediate value I
129 */
130 memcpy(tmp, ctx->DT, DEFAULT_BLK_SZ);
131 sg_init_one(&sg_out, &ctx->I[0], DEFAULT_BLK_SZ);
132 hexdump("tmp stage 0: ", tmp, DEFAULT_BLK_SZ);
133 break;
134 case 1:
135
136 /*
137 * Next xor I with our secret vector V
138 * encrypt that result to obtain our
139 * pseudo random data which we output
140 */
141 xor_vectors(ctx->I, ctx->V, tmp, DEFAULT_BLK_SZ);
142 sg_init_one(&sg_out, &ctx->rand_data[0], DEFAULT_BLK_SZ);
143 hexdump("tmp stage 1: ", tmp, DEFAULT_BLK_SZ);
144 break;
145 case 2:
146 /*
147 * First check that we didn't produce the same random data
148 * that we did last time around through this
149 */
150 if (!memcmp(ctx->rand_data, ctx->last_rand_data, DEFAULT_BLK_SZ)) {
151 printk(KERN_ERR "ctx %p Failed repetition check!\n",
152 ctx);
153 ctx->flags |= PRNG_NEED_RESET;
154 return -1;
155 }
156 memcpy(ctx->last_rand_data, ctx->rand_data, DEFAULT_BLK_SZ);
157
158 /*
159 * Lastly xor the random data with I
160 * and encrypt that to obtain a new secret vector V
161 */
162 xor_vectors(ctx->rand_data, ctx->I, tmp, DEFAULT_BLK_SZ);
163 sg_init_one(&sg_out, &ctx->V[0], DEFAULT_BLK_SZ);
164 hexdump("tmp stage 2: ", tmp, DEFAULT_BLK_SZ);
165 break;
166 }
167
168 /* Initialize our input buffer */
169 sg_init_one(&sg_in, &tmp[0], DEFAULT_BLK_SZ);
170
171 /* do the encryption */
172 ret = crypto_blkcipher_encrypt(&desc, &sg_out, &sg_in, DEFAULT_BLK_SZ);
173
174 /* And check the result */
175 if (ret) {
176 dbgprint(KERN_CRIT "Encryption of new block failed for context %p\n",ctx);
177 ctx->rand_data_valid = DEFAULT_BLK_SZ;
178 return -1;
179 }
180
181 }
182
183 /*
184 * Now update our DT value
185 */
186 for (i=DEFAULT_BLK_SZ-1;i>0;i--) {
187 ctx->DT[i] = ctx->DT[i-1];
188 }
189 ctx->DT[0] += 1;
190
191 dbgprint("Returning new block for context %p\n",ctx);
192 ctx->rand_data_valid = 0;
193
194 hexdump("Output DT: ", ctx->DT, DEFAULT_BLK_SZ);
195 hexdump("Output I: ", ctx->I, DEFAULT_BLK_SZ);
196 hexdump("Output V: ", ctx->V, DEFAULT_BLK_SZ);
197 hexdump("New Random Data: ", ctx->rand_data, DEFAULT_BLK_SZ);
198
199 return 0;
200}
201
202/* Our exported functions */
203int get_prng_bytes(char *buf, int nbytes, struct prng_context *ctx)
204{
205 unsigned long flags;
206 unsigned char *ptr = buf;
207 unsigned int byte_count = (unsigned int)nbytes;
208 int err;
209
210
211 if (nbytes < 0)
212 return -EINVAL;
213
214 spin_lock_irqsave(&ctx->prng_lock, flags);
215
216 err = -EFAULT;
217 if (ctx->flags & PRNG_NEED_RESET)
218 goto done;
219
220 /*
221 * If the FIXED_SIZE flag is on, only return whole blocks of
222 * pseudo random data
223 */
224 err = -EINVAL;
225 if (ctx->flags & PRNG_FIXED_SIZE) {
226 if (nbytes < DEFAULT_BLK_SZ)
227 goto done;
228 byte_count = DEFAULT_BLK_SZ;
229 }
230
231 err = byte_count;
232
233 dbgprint(KERN_CRIT "getting %d random bytes for context %p\n",byte_count, ctx);
234
235
236remainder:
237 if (ctx->rand_data_valid == DEFAULT_BLK_SZ) {
238 if (_get_more_prng_bytes(ctx) < 0) {
239 memset(buf, 0, nbytes);
240 err = -EFAULT;
241 goto done;
242 }
243 }
244
245 /*
246 * Copy up to the next whole block size
247 */
248 if (byte_count < DEFAULT_BLK_SZ) {
249 for (;ctx->rand_data_valid < DEFAULT_BLK_SZ; ctx->rand_data_valid++) {
250 *ptr = ctx->rand_data[ctx->rand_data_valid];
251 ptr++;
252 byte_count--;
253 if (byte_count == 0)
254 goto done;
255 }
256 }
257
258 /*
259 * Now copy whole blocks
260 */
261 for(;byte_count >= DEFAULT_BLK_SZ; byte_count -= DEFAULT_BLK_SZ) {
262 if (_get_more_prng_bytes(ctx) < 0) {
263 memset(buf, 0, nbytes);
264 err = -1;
265 goto done;
266 }
267 memcpy(ptr, ctx->rand_data, DEFAULT_BLK_SZ);
268 ctx->rand_data_valid += DEFAULT_BLK_SZ;
269 ptr += DEFAULT_BLK_SZ;
270 }
271
272 /*
273 * Now copy any extra partial data
274 */
275 if (byte_count)
276 goto remainder;
277
278done:
279 spin_unlock_irqrestore(&ctx->prng_lock, flags);
280 dbgprint(KERN_CRIT "returning %d from get_prng_bytes in context %p\n",err, ctx);
281 return err;
282}
283EXPORT_SYMBOL_GPL(get_prng_bytes);
284
285struct prng_context *alloc_prng_context(void)
286{
287 struct prng_context *ctx=kzalloc(sizeof(struct prng_context), GFP_KERNEL);
288
289 spin_lock_init(&ctx->prng_lock);
290
291 if (reset_prng_context(ctx, NULL, NULL, NULL, NULL)) {
292 kfree(ctx);
293 ctx = NULL;
294 }
295
296 dbgprint(KERN_CRIT "returning context %p\n",ctx);
297 return ctx;
298}
299
300EXPORT_SYMBOL_GPL(alloc_prng_context);
301
302void free_prng_context(struct prng_context *ctx)
303{
304 crypto_free_blkcipher(ctx->tfm);
305 kfree(ctx);
306}
307EXPORT_SYMBOL_GPL(free_prng_context);
308
309int reset_prng_context(struct prng_context *ctx,
310 unsigned char *key, unsigned char *iv,
311 unsigned char *V, unsigned char *DT)
312{
313 int ret;
314 int iv_len;
315 int rc = -EFAULT;
316
317 spin_lock(&ctx->prng_lock);
318 ctx->flags |= PRNG_NEED_RESET;
319
320 if (key)
321 memcpy(ctx->prng_key,key,strlen(ctx->prng_key));
322 else
323 ctx->prng_key = DEFAULT_PRNG_KEY;
324
325 if (iv)
326 memcpy(ctx->prng_iv,iv, strlen(ctx->prng_iv));
327 else
328 ctx->prng_iv = DEFAULT_PRNG_IV;
329
330 if (V)
331 memcpy(ctx->V,V,DEFAULT_BLK_SZ);
332 else
333 memcpy(ctx->V,DEFAULT_V_SEED,DEFAULT_BLK_SZ);
334
335 if (DT)
336 memcpy(ctx->DT, DT, DEFAULT_BLK_SZ);
337 else
338 memset(ctx->DT, 0, DEFAULT_BLK_SZ);
339
340 memset(ctx->rand_data,0,DEFAULT_BLK_SZ);
341 memset(ctx->last_rand_data,0,DEFAULT_BLK_SZ);
342
343 if (ctx->tfm)
344 crypto_free_blkcipher(ctx->tfm);
345
346 ctx->tfm = crypto_alloc_blkcipher("rfc3686(ctr(aes))",0,0);
347 if (!ctx->tfm) {
348 dbgprint(KERN_CRIT "Failed to alloc crypto tfm for context %p\n",ctx->tfm);
349 goto out;
350 }
351
352 ctx->rand_data_valid = DEFAULT_BLK_SZ;
353
354 ret = crypto_blkcipher_setkey(ctx->tfm, ctx->prng_key, strlen(ctx->prng_key));
355 if (ret) {
356 dbgprint(KERN_CRIT "PRNG: setkey() failed flags=%x\n",
357 crypto_blkcipher_get_flags(ctx->tfm));
358 crypto_free_blkcipher(ctx->tfm);
359 goto out;
360 }
361
362 iv_len = crypto_blkcipher_ivsize(ctx->tfm);
363 if (iv_len) {
364 crypto_blkcipher_set_iv(ctx->tfm, ctx->prng_iv, iv_len);
365 }
366 rc = 0;
367 ctx->flags &= ~PRNG_NEED_RESET;
368out:
369 spin_unlock(&ctx->prng_lock);
370
371 return rc;
372
373}
374EXPORT_SYMBOL_GPL(reset_prng_context);
375
376/* Module initalization */
377static int __init prng_mod_init(void)
378{
379
380#ifdef TEST_PRNG_ON_START
381 int i;
382 unsigned char tmpbuf[DEFAULT_BLK_SZ];
383
384 struct prng_context *ctx = alloc_prng_context();
385 if (ctx == NULL)
386 return -EFAULT;
387 for (i=0;i<16;i++) {
388 if (get_prng_bytes(tmpbuf, DEFAULT_BLK_SZ, ctx) < 0) {
389 free_prng_context(ctx);
390 return -EFAULT;
391 }
392 }
393 free_prng_context(ctx);
394#endif
395
396 return 0;
397}
398
399static void __exit prng_mod_fini(void)
400{
401 return;
402}
403
404MODULE_LICENSE("GPL");
405MODULE_DESCRIPTION("Software Pseudo Random Number Generator");
406MODULE_AUTHOR("Neil Horman <nhorman@tuxdriver.com>");
407module_param(dbg, int, 0);
408MODULE_PARM_DESC(dbg, "Boolean to enable debugging (0/1 == off/on)");
409module_init(prng_mod_init);
410module_exit(prng_mod_fini);
generated by cgit v1.2.2 (git 2.25.0) at 2024-11-12 09:45:51 -0500