Root/security/keys/trusted.c

Source at commit be977234bfb4a6dca8a39e7c52165e4cd536ad71 created 9 years 5 months ago.
By Lars-Peter Clausen, jz4740: Fix compile error
1/*
2 * Copyright (C) 2010 IBM Corporation
3 *
4 * Author:
5 * David Safford <safford@us.ibm.com>
6 *
7 * This program is free software; you can redistribute it and/or modify
8 * it under the terms of the GNU General Public License as published by
9 * the Free Software Foundation, version 2 of the License.
10 *
11 * See Documentation/keys-trusted-encrypted.txt
12 */
13
14#include <linux/uaccess.h>
15#include <linux/module.h>
16#include <linux/init.h>
17#include <linux/slab.h>
18#include <linux/parser.h>
19#include <linux/string.h>
20#include <linux/err.h>
21#include <keys/user-type.h>
22#include <keys/trusted-type.h>
23#include <linux/key-type.h>
24#include <linux/rcupdate.h>
25#include <linux/crypto.h>
26#include <crypto/hash.h>
27#include <crypto/sha.h>
28#include <linux/capability.h>
29#include <linux/tpm.h>
30#include <linux/tpm_command.h>
31
32#include "trusted.h"
33
34static const char hmac_alg[] = "hmac(sha1)";
35static const char hash_alg[] = "sha1";
36
37struct sdesc {
38    struct shash_desc shash;
39    char ctx[];
40};
41
42static struct crypto_shash *hashalg;
43static struct crypto_shash *hmacalg;
44
45static struct sdesc *init_sdesc(struct crypto_shash *alg)
46{
47    struct sdesc *sdesc;
48    int size;
49
50    size = sizeof(struct shash_desc) + crypto_shash_descsize(alg);
51    sdesc = kmalloc(size, GFP_KERNEL);
52    if (!sdesc)
53        return ERR_PTR(-ENOMEM);
54    sdesc->shash.tfm = alg;
55    sdesc->shash.flags = 0x0;
56    return sdesc;
57}
58
59static int TSS_sha1(const unsigned char *data, unsigned int datalen,
60            unsigned char *digest)
61{
62    struct sdesc *sdesc;
63    int ret;
64
65    sdesc = init_sdesc(hashalg);
66    if (IS_ERR(sdesc)) {
67        pr_info("trusted_key: can't alloc %s\n", hash_alg);
68        return PTR_ERR(sdesc);
69    }
70
71    ret = crypto_shash_digest(&sdesc->shash, data, datalen, digest);
72    kfree(sdesc);
73    return ret;
74}
75
76static int TSS_rawhmac(unsigned char *digest, const unsigned char *key,
77               unsigned int keylen, ...)
78{
79    struct sdesc *sdesc;
80    va_list argp;
81    unsigned int dlen;
82    unsigned char *data;
83    int ret;
84
85    sdesc = init_sdesc(hmacalg);
86    if (IS_ERR(sdesc)) {
87        pr_info("trusted_key: can't alloc %s\n", hmac_alg);
88        return PTR_ERR(sdesc);
89    }
90
91    ret = crypto_shash_setkey(hmacalg, key, keylen);
92    if (ret < 0)
93        goto out;
94    ret = crypto_shash_init(&sdesc->shash);
95    if (ret < 0)
96        goto out;
97
98    va_start(argp, keylen);
99    for (;;) {
100        dlen = va_arg(argp, unsigned int);
101        if (dlen == 0)
102            break;
103        data = va_arg(argp, unsigned char *);
104        if (data == NULL) {
105            ret = -EINVAL;
106            break;
107        }
108        ret = crypto_shash_update(&sdesc->shash, data, dlen);
109        if (ret < 0)
110            break;
111    }
112    va_end(argp);
113    if (!ret)
114        ret = crypto_shash_final(&sdesc->shash, digest);
115out:
116    kfree(sdesc);
117    return ret;
118}
119
120/*
121 * calculate authorization info fields to send to TPM
122 */
123static int TSS_authhmac(unsigned char *digest, const unsigned char *key,
124            unsigned int keylen, unsigned char *h1,
125            unsigned char *h2, unsigned char h3, ...)
126{
127    unsigned char paramdigest[SHA1_DIGEST_SIZE];
128    struct sdesc *sdesc;
129    unsigned int dlen;
130    unsigned char *data;
131    unsigned char c;
132    int ret;
133    va_list argp;
134
135    sdesc = init_sdesc(hashalg);
136    if (IS_ERR(sdesc)) {
137        pr_info("trusted_key: can't alloc %s\n", hash_alg);
138        return PTR_ERR(sdesc);
139    }
140
141    c = h3;
142    ret = crypto_shash_init(&sdesc->shash);
143    if (ret < 0)
144        goto out;
145    va_start(argp, h3);
146    for (;;) {
147        dlen = va_arg(argp, unsigned int);
148        if (dlen == 0)
149            break;
150        data = va_arg(argp, unsigned char *);
151        if (!data) {
152            ret = -EINVAL;
153            break;
154        }
155        ret = crypto_shash_update(&sdesc->shash, data, dlen);
156        if (ret < 0)
157            break;
158    }
159    va_end(argp);
160    if (!ret)
161        ret = crypto_shash_final(&sdesc->shash, paramdigest);
162    if (!ret)
163        ret = TSS_rawhmac(digest, key, keylen, SHA1_DIGEST_SIZE,
164                  paramdigest, TPM_NONCE_SIZE, h1,
165                  TPM_NONCE_SIZE, h2, 1, &c, 0, 0);
166out:
167    kfree(sdesc);
168    return ret;
169}
170
171/*
172 * verify the AUTH1_COMMAND (Seal) result from TPM
173 */
174static int TSS_checkhmac1(unsigned char *buffer,
175              const uint32_t command,
176              const unsigned char *ononce,
177              const unsigned char *key,
178              unsigned int keylen, ...)
179{
180    uint32_t bufsize;
181    uint16_t tag;
182    uint32_t ordinal;
183    uint32_t result;
184    unsigned char *enonce;
185    unsigned char *continueflag;
186    unsigned char *authdata;
187    unsigned char testhmac[SHA1_DIGEST_SIZE];
188    unsigned char paramdigest[SHA1_DIGEST_SIZE];
189    struct sdesc *sdesc;
190    unsigned int dlen;
191    unsigned int dpos;
192    va_list argp;
193    int ret;
194
195    bufsize = LOAD32(buffer, TPM_SIZE_OFFSET);
196    tag = LOAD16(buffer, 0);
197    ordinal = command;
198    result = LOAD32N(buffer, TPM_RETURN_OFFSET);
199    if (tag == TPM_TAG_RSP_COMMAND)
200        return 0;
201    if (tag != TPM_TAG_RSP_AUTH1_COMMAND)
202        return -EINVAL;
203    authdata = buffer + bufsize - SHA1_DIGEST_SIZE;
204    continueflag = authdata - 1;
205    enonce = continueflag - TPM_NONCE_SIZE;
206
207    sdesc = init_sdesc(hashalg);
208    if (IS_ERR(sdesc)) {
209        pr_info("trusted_key: can't alloc %s\n", hash_alg);
210        return PTR_ERR(sdesc);
211    }
212    ret = crypto_shash_init(&sdesc->shash);
213    if (ret < 0)
214        goto out;
215    ret = crypto_shash_update(&sdesc->shash, (const u8 *)&result,
216                  sizeof result);
217    if (ret < 0)
218        goto out;
219    ret = crypto_shash_update(&sdesc->shash, (const u8 *)&ordinal,
220                  sizeof ordinal);
221    if (ret < 0)
222        goto out;
223    va_start(argp, keylen);
224    for (;;) {
225        dlen = va_arg(argp, unsigned int);
226        if (dlen == 0)
227            break;
228        dpos = va_arg(argp, unsigned int);
229        ret = crypto_shash_update(&sdesc->shash, buffer + dpos, dlen);
230        if (ret < 0)
231            break;
232    }
233    va_end(argp);
234    if (!ret)
235        ret = crypto_shash_final(&sdesc->shash, paramdigest);
236    if (ret < 0)
237        goto out;
238
239    ret = TSS_rawhmac(testhmac, key, keylen, SHA1_DIGEST_SIZE, paramdigest,
240              TPM_NONCE_SIZE, enonce, TPM_NONCE_SIZE, ononce,
241              1, continueflag, 0, 0);
242    if (ret < 0)
243        goto out;
244
245    if (memcmp(testhmac, authdata, SHA1_DIGEST_SIZE))
246        ret = -EINVAL;
247out:
248    kfree(sdesc);
249    return ret;
250}
251
252/*
253 * verify the AUTH2_COMMAND (unseal) result from TPM
254 */
255static int TSS_checkhmac2(unsigned char *buffer,
256              const uint32_t command,
257              const unsigned char *ononce,
258              const unsigned char *key1,
259              unsigned int keylen1,
260              const unsigned char *key2,
261              unsigned int keylen2, ...)
262{
263    uint32_t bufsize;
264    uint16_t tag;
265    uint32_t ordinal;
266    uint32_t result;
267    unsigned char *enonce1;
268    unsigned char *continueflag1;
269    unsigned char *authdata1;
270    unsigned char *enonce2;
271    unsigned char *continueflag2;
272    unsigned char *authdata2;
273    unsigned char testhmac1[SHA1_DIGEST_SIZE];
274    unsigned char testhmac2[SHA1_DIGEST_SIZE];
275    unsigned char paramdigest[SHA1_DIGEST_SIZE];
276    struct sdesc *sdesc;
277    unsigned int dlen;
278    unsigned int dpos;
279    va_list argp;
280    int ret;
281
282    bufsize = LOAD32(buffer, TPM_SIZE_OFFSET);
283    tag = LOAD16(buffer, 0);
284    ordinal = command;
285    result = LOAD32N(buffer, TPM_RETURN_OFFSET);
286
287    if (tag == TPM_TAG_RSP_COMMAND)
288        return 0;
289    if (tag != TPM_TAG_RSP_AUTH2_COMMAND)
290        return -EINVAL;
291    authdata1 = buffer + bufsize - (SHA1_DIGEST_SIZE + 1
292            + SHA1_DIGEST_SIZE + SHA1_DIGEST_SIZE);
293    authdata2 = buffer + bufsize - (SHA1_DIGEST_SIZE);
294    continueflag1 = authdata1 - 1;
295    continueflag2 = authdata2 - 1;
296    enonce1 = continueflag1 - TPM_NONCE_SIZE;
297    enonce2 = continueflag2 - TPM_NONCE_SIZE;
298
299    sdesc = init_sdesc(hashalg);
300    if (IS_ERR(sdesc)) {
301        pr_info("trusted_key: can't alloc %s\n", hash_alg);
302        return PTR_ERR(sdesc);
303    }
304    ret = crypto_shash_init(&sdesc->shash);
305    if (ret < 0)
306        goto out;
307    ret = crypto_shash_update(&sdesc->shash, (const u8 *)&result,
308                  sizeof result);
309    if (ret < 0)
310        goto out;
311    ret = crypto_shash_update(&sdesc->shash, (const u8 *)&ordinal,
312                  sizeof ordinal);
313    if (ret < 0)
314        goto out;
315
316    va_start(argp, keylen2);
317    for (;;) {
318        dlen = va_arg(argp, unsigned int);
319        if (dlen == 0)
320            break;
321        dpos = va_arg(argp, unsigned int);
322        ret = crypto_shash_update(&sdesc->shash, buffer + dpos, dlen);
323        if (ret < 0)
324            break;
325    }
326    va_end(argp);
327    if (!ret)
328        ret = crypto_shash_final(&sdesc->shash, paramdigest);
329    if (ret < 0)
330        goto out;
331
332    ret = TSS_rawhmac(testhmac1, key1, keylen1, SHA1_DIGEST_SIZE,
333              paramdigest, TPM_NONCE_SIZE, enonce1,
334              TPM_NONCE_SIZE, ononce, 1, continueflag1, 0, 0);
335    if (ret < 0)
336        goto out;
337    if (memcmp(testhmac1, authdata1, SHA1_DIGEST_SIZE)) {
338        ret = -EINVAL;
339        goto out;
340    }
341    ret = TSS_rawhmac(testhmac2, key2, keylen2, SHA1_DIGEST_SIZE,
342              paramdigest, TPM_NONCE_SIZE, enonce2,
343              TPM_NONCE_SIZE, ononce, 1, continueflag2, 0, 0);
344    if (ret < 0)
345        goto out;
346    if (memcmp(testhmac2, authdata2, SHA1_DIGEST_SIZE))
347        ret = -EINVAL;
348out:
349    kfree(sdesc);
350    return ret;
351}
352
353/*
354 * For key specific tpm requests, we will generate and send our
355 * own TPM command packets using the drivers send function.
356 */
357static int trusted_tpm_send(const u32 chip_num, unsigned char *cmd,
358                size_t buflen)
359{
360    int rc;
361
362    dump_tpm_buf(cmd);
363    rc = tpm_send(chip_num, cmd, buflen);
364    dump_tpm_buf(cmd);
365    if (rc > 0)
366        /* Can't return positive return codes values to keyctl */
367        rc = -EPERM;
368    return rc;
369}
370
371/*
372 * get a random value from TPM
373 */
374static int tpm_get_random(struct tpm_buf *tb, unsigned char *buf, uint32_t len)
375{
376    int ret;
377
378    INIT_BUF(tb);
379    store16(tb, TPM_TAG_RQU_COMMAND);
380    store32(tb, TPM_GETRANDOM_SIZE);
381    store32(tb, TPM_ORD_GETRANDOM);
382    store32(tb, len);
383    ret = trusted_tpm_send(TPM_ANY_NUM, tb->data, sizeof tb->data);
384    if (!ret)
385        memcpy(buf, tb->data + TPM_GETRANDOM_SIZE, len);
386    return ret;
387}
388
389static int my_get_random(unsigned char *buf, int len)
390{
391    struct tpm_buf *tb;
392    int ret;
393
394    tb = kmalloc(sizeof *tb, GFP_KERNEL);
395    if (!tb)
396        return -ENOMEM;
397    ret = tpm_get_random(tb, buf, len);
398
399    kfree(tb);
400    return ret;
401}
402
403/*
404 * Lock a trusted key, by extending a selected PCR.
405 *
406 * Prevents a trusted key that is sealed to PCRs from being accessed.
407 * This uses the tpm driver's extend function.
408 */
409static int pcrlock(const int pcrnum)
410{
411    unsigned char hash[SHA1_DIGEST_SIZE];
412    int ret;
413
414    if (!capable(CAP_SYS_ADMIN))
415        return -EPERM;
416    ret = my_get_random(hash, SHA1_DIGEST_SIZE);
417    if (ret < 0)
418        return ret;
419    return tpm_pcr_extend(TPM_ANY_NUM, pcrnum, hash) ? -EINVAL : 0;
420}
421
422/*
423 * Create an object specific authorisation protocol (OSAP) session
424 */
425static int osap(struct tpm_buf *tb, struct osapsess *s,
426        const unsigned char *key, uint16_t type, uint32_t handle)
427{
428    unsigned char enonce[TPM_NONCE_SIZE];
429    unsigned char ononce[TPM_NONCE_SIZE];
430    int ret;
431
432    ret = tpm_get_random(tb, ononce, TPM_NONCE_SIZE);
433    if (ret < 0)
434        return ret;
435
436    INIT_BUF(tb);
437    store16(tb, TPM_TAG_RQU_COMMAND);
438    store32(tb, TPM_OSAP_SIZE);
439    store32(tb, TPM_ORD_OSAP);
440    store16(tb, type);
441    store32(tb, handle);
442    storebytes(tb, ononce, TPM_NONCE_SIZE);
443
444    ret = trusted_tpm_send(TPM_ANY_NUM, tb->data, MAX_BUF_SIZE);
445    if (ret < 0)
446        return ret;
447
448    s->handle = LOAD32(tb->data, TPM_DATA_OFFSET);
449    memcpy(s->enonce, &(tb->data[TPM_DATA_OFFSET + sizeof(uint32_t)]),
450           TPM_NONCE_SIZE);
451    memcpy(enonce, &(tb->data[TPM_DATA_OFFSET + sizeof(uint32_t) +
452                  TPM_NONCE_SIZE]), TPM_NONCE_SIZE);
453    return TSS_rawhmac(s->secret, key, SHA1_DIGEST_SIZE, TPM_NONCE_SIZE,
454               enonce, TPM_NONCE_SIZE, ononce, 0, 0);
455}
456
457/*
458 * Create an object independent authorisation protocol (oiap) session
459 */
460static int oiap(struct tpm_buf *tb, uint32_t *handle, unsigned char *nonce)
461{
462    int ret;
463
464    INIT_BUF(tb);
465    store16(tb, TPM_TAG_RQU_COMMAND);
466    store32(tb, TPM_OIAP_SIZE);
467    store32(tb, TPM_ORD_OIAP);
468    ret = trusted_tpm_send(TPM_ANY_NUM, tb->data, MAX_BUF_SIZE);
469    if (ret < 0)
470        return ret;
471
472    *handle = LOAD32(tb->data, TPM_DATA_OFFSET);
473    memcpy(nonce, &tb->data[TPM_DATA_OFFSET + sizeof(uint32_t)],
474           TPM_NONCE_SIZE);
475    return 0;
476}
477
478struct tpm_digests {
479    unsigned char encauth[SHA1_DIGEST_SIZE];
480    unsigned char pubauth[SHA1_DIGEST_SIZE];
481    unsigned char xorwork[SHA1_DIGEST_SIZE * 2];
482    unsigned char xorhash[SHA1_DIGEST_SIZE];
483    unsigned char nonceodd[TPM_NONCE_SIZE];
484};
485
486/*
487 * Have the TPM seal(encrypt) the trusted key, possibly based on
488 * Platform Configuration Registers (PCRs). AUTH1 for sealing key.
489 */
490static int tpm_seal(struct tpm_buf *tb, uint16_t keytype,
491            uint32_t keyhandle, const unsigned char *keyauth,
492            const unsigned char *data, uint32_t datalen,
493            unsigned char *blob, uint32_t *bloblen,
494            const unsigned char *blobauth,
495            const unsigned char *pcrinfo, uint32_t pcrinfosize)
496{
497    struct osapsess sess;
498    struct tpm_digests *td;
499    unsigned char cont;
500    uint32_t ordinal;
501    uint32_t pcrsize;
502    uint32_t datsize;
503    int sealinfosize;
504    int encdatasize;
505    int storedsize;
506    int ret;
507    int i;
508
509    /* alloc some work space for all the hashes */
510    td = kmalloc(sizeof *td, GFP_KERNEL);
511    if (!td)
512        return -ENOMEM;
513
514    /* get session for sealing key */
515    ret = osap(tb, &sess, keyauth, keytype, keyhandle);
516    if (ret < 0)
517        goto out;
518    dump_sess(&sess);
519
520    /* calculate encrypted authorization value */
521    memcpy(td->xorwork, sess.secret, SHA1_DIGEST_SIZE);
522    memcpy(td->xorwork + SHA1_DIGEST_SIZE, sess.enonce, SHA1_DIGEST_SIZE);
523    ret = TSS_sha1(td->xorwork, SHA1_DIGEST_SIZE * 2, td->xorhash);
524    if (ret < 0)
525        goto out;
526
527    ret = tpm_get_random(tb, td->nonceodd, TPM_NONCE_SIZE);
528    if (ret < 0)
529        goto out;
530    ordinal = htonl(TPM_ORD_SEAL);
531    datsize = htonl(datalen);
532    pcrsize = htonl(pcrinfosize);
533    cont = 0;
534
535    /* encrypt data authorization key */
536    for (i = 0; i < SHA1_DIGEST_SIZE; ++i)
537        td->encauth[i] = td->xorhash[i] ^ blobauth[i];
538
539    /* calculate authorization HMAC value */
540    if (pcrinfosize == 0) {
541        /* no pcr info specified */
542        ret = TSS_authhmac(td->pubauth, sess.secret, SHA1_DIGEST_SIZE,
543                   sess.enonce, td->nonceodd, cont,
544                   sizeof(uint32_t), &ordinal, SHA1_DIGEST_SIZE,
545                   td->encauth, sizeof(uint32_t), &pcrsize,
546                   sizeof(uint32_t), &datsize, datalen, data, 0,
547                   0);
548    } else {
549        /* pcr info specified */
550        ret = TSS_authhmac(td->pubauth, sess.secret, SHA1_DIGEST_SIZE,
551                   sess.enonce, td->nonceodd, cont,
552                   sizeof(uint32_t), &ordinal, SHA1_DIGEST_SIZE,
553                   td->encauth, sizeof(uint32_t), &pcrsize,
554                   pcrinfosize, pcrinfo, sizeof(uint32_t),
555                   &datsize, datalen, data, 0, 0);
556    }
557    if (ret < 0)
558        goto out;
559
560    /* build and send the TPM request packet */
561    INIT_BUF(tb);
562    store16(tb, TPM_TAG_RQU_AUTH1_COMMAND);
563    store32(tb, TPM_SEAL_SIZE + pcrinfosize + datalen);
564    store32(tb, TPM_ORD_SEAL);
565    store32(tb, keyhandle);
566    storebytes(tb, td->encauth, SHA1_DIGEST_SIZE);
567    store32(tb, pcrinfosize);
568    storebytes(tb, pcrinfo, pcrinfosize);
569    store32(tb, datalen);
570    storebytes(tb, data, datalen);
571    store32(tb, sess.handle);
572    storebytes(tb, td->nonceodd, TPM_NONCE_SIZE);
573    store8(tb, cont);
574    storebytes(tb, td->pubauth, SHA1_DIGEST_SIZE);
575
576    ret = trusted_tpm_send(TPM_ANY_NUM, tb->data, MAX_BUF_SIZE);
577    if (ret < 0)
578        goto out;
579
580    /* calculate the size of the returned Blob */
581    sealinfosize = LOAD32(tb->data, TPM_DATA_OFFSET + sizeof(uint32_t));
582    encdatasize = LOAD32(tb->data, TPM_DATA_OFFSET + sizeof(uint32_t) +
583                 sizeof(uint32_t) + sealinfosize);
584    storedsize = sizeof(uint32_t) + sizeof(uint32_t) + sealinfosize +
585        sizeof(uint32_t) + encdatasize;
586
587    /* check the HMAC in the response */
588    ret = TSS_checkhmac1(tb->data, ordinal, td->nonceodd, sess.secret,
589                 SHA1_DIGEST_SIZE, storedsize, TPM_DATA_OFFSET, 0,
590                 0);
591
592    /* copy the returned blob to caller */
593    if (!ret) {
594        memcpy(blob, tb->data + TPM_DATA_OFFSET, storedsize);
595        *bloblen = storedsize;
596    }
597out:
598    kfree(td);
599    return ret;
600}
601
602/*
603 * use the AUTH2_COMMAND form of unseal, to authorize both key and blob
604 */
605static int tpm_unseal(struct tpm_buf *tb,
606              uint32_t keyhandle, const unsigned char *keyauth,
607              const unsigned char *blob, int bloblen,
608              const unsigned char *blobauth,
609              unsigned char *data, unsigned int *datalen)
610{
611    unsigned char nonceodd[TPM_NONCE_SIZE];
612    unsigned char enonce1[TPM_NONCE_SIZE];
613    unsigned char enonce2[TPM_NONCE_SIZE];
614    unsigned char authdata1[SHA1_DIGEST_SIZE];
615    unsigned char authdata2[SHA1_DIGEST_SIZE];
616    uint32_t authhandle1 = 0;
617    uint32_t authhandle2 = 0;
618    unsigned char cont = 0;
619    uint32_t ordinal;
620    uint32_t keyhndl;
621    int ret;
622
623    /* sessions for unsealing key and data */
624    ret = oiap(tb, &authhandle1, enonce1);
625    if (ret < 0) {
626        pr_info("trusted_key: oiap failed (%d)\n", ret);
627        return ret;
628    }
629    ret = oiap(tb, &authhandle2, enonce2);
630    if (ret < 0) {
631        pr_info("trusted_key: oiap failed (%d)\n", ret);
632        return ret;
633    }
634
635    ordinal = htonl(TPM_ORD_UNSEAL);
636    keyhndl = htonl(SRKHANDLE);
637    ret = tpm_get_random(tb, nonceodd, TPM_NONCE_SIZE);
638    if (ret < 0) {
639        pr_info("trusted_key: tpm_get_random failed (%d)\n", ret);
640        return ret;
641    }
642    ret = TSS_authhmac(authdata1, keyauth, TPM_NONCE_SIZE,
643               enonce1, nonceodd, cont, sizeof(uint32_t),
644               &ordinal, bloblen, blob, 0, 0);
645    if (ret < 0)
646        return ret;
647    ret = TSS_authhmac(authdata2, blobauth, TPM_NONCE_SIZE,
648               enonce2, nonceodd, cont, sizeof(uint32_t),
649               &ordinal, bloblen, blob, 0, 0);
650    if (ret < 0)
651        return ret;
652
653    /* build and send TPM request packet */
654    INIT_BUF(tb);
655    store16(tb, TPM_TAG_RQU_AUTH2_COMMAND);
656    store32(tb, TPM_UNSEAL_SIZE + bloblen);
657    store32(tb, TPM_ORD_UNSEAL);
658    store32(tb, keyhandle);
659    storebytes(tb, blob, bloblen);
660    store32(tb, authhandle1);
661    storebytes(tb, nonceodd, TPM_NONCE_SIZE);
662    store8(tb, cont);
663    storebytes(tb, authdata1, SHA1_DIGEST_SIZE);
664    store32(tb, authhandle2);
665    storebytes(tb, nonceodd, TPM_NONCE_SIZE);
666    store8(tb, cont);
667    storebytes(tb, authdata2, SHA1_DIGEST_SIZE);
668
669    ret = trusted_tpm_send(TPM_ANY_NUM, tb->data, MAX_BUF_SIZE);
670    if (ret < 0) {
671        pr_info("trusted_key: authhmac failed (%d)\n", ret);
672        return ret;
673    }
674
675    *datalen = LOAD32(tb->data, TPM_DATA_OFFSET);
676    ret = TSS_checkhmac2(tb->data, ordinal, nonceodd,
677                 keyauth, SHA1_DIGEST_SIZE,
678                 blobauth, SHA1_DIGEST_SIZE,
679                 sizeof(uint32_t), TPM_DATA_OFFSET,
680                 *datalen, TPM_DATA_OFFSET + sizeof(uint32_t), 0,
681                 0);
682    if (ret < 0) {
683        pr_info("trusted_key: TSS_checkhmac2 failed (%d)\n", ret);
684        return ret;
685    }
686    memcpy(data, tb->data + TPM_DATA_OFFSET + sizeof(uint32_t), *datalen);
687    return 0;
688}
689
690/*
691 * Have the TPM seal(encrypt) the symmetric key
692 */
693static int key_seal(struct trusted_key_payload *p,
694            struct trusted_key_options *o)
695{
696    struct tpm_buf *tb;
697    int ret;
698
699    tb = kzalloc(sizeof *tb, GFP_KERNEL);
700    if (!tb)
701        return -ENOMEM;
702
703    /* include migratable flag at end of sealed key */
704    p->key[p->key_len] = p->migratable;
705
706    ret = tpm_seal(tb, o->keytype, o->keyhandle, o->keyauth,
707               p->key, p->key_len + 1, p->blob, &p->blob_len,
708               o->blobauth, o->pcrinfo, o->pcrinfo_len);
709    if (ret < 0)
710        pr_info("trusted_key: srkseal failed (%d)\n", ret);
711
712    kfree(tb);
713    return ret;
714}
715
716/*
717 * Have the TPM unseal(decrypt) the symmetric key
718 */
719static int key_unseal(struct trusted_key_payload *p,
720              struct trusted_key_options *o)
721{
722    struct tpm_buf *tb;
723    int ret;
724
725    tb = kzalloc(sizeof *tb, GFP_KERNEL);
726    if (!tb)
727        return -ENOMEM;
728
729    ret = tpm_unseal(tb, o->keyhandle, o->keyauth, p->blob, p->blob_len,
730             o->blobauth, p->key, &p->key_len);
731    if (ret < 0)
732        pr_info("trusted_key: srkunseal failed (%d)\n", ret);
733    else
734        /* pull migratable flag out of sealed key */
735        p->migratable = p->key[--p->key_len];
736
737    kfree(tb);
738    return ret;
739}
740
741enum {
742    Opt_err = -1,
743    Opt_new, Opt_load, Opt_update,
744    Opt_keyhandle, Opt_keyauth, Opt_blobauth,
745    Opt_pcrinfo, Opt_pcrlock, Opt_migratable
746};
747
748static const match_table_t key_tokens = {
749    {Opt_new, "new"},
750    {Opt_load, "load"},
751    {Opt_update, "update"},
752    {Opt_keyhandle, "keyhandle=%s"},
753    {Opt_keyauth, "keyauth=%s"},
754    {Opt_blobauth, "blobauth=%s"},
755    {Opt_pcrinfo, "pcrinfo=%s"},
756    {Opt_pcrlock, "pcrlock=%s"},
757    {Opt_migratable, "migratable=%s"},
758    {Opt_err, NULL}
759};
760
761/* can have zero or more token= options */
762static int getoptions(char *c, struct trusted_key_payload *pay,
763              struct trusted_key_options *opt)
764{
765    substring_t args[MAX_OPT_ARGS];
766    char *p = c;
767    int token;
768    int res;
769    unsigned long handle;
770    unsigned long lock;
771
772    while ((p = strsep(&c, " \t"))) {
773        if (*p == '\0' || *p == ' ' || *p == '\t')
774            continue;
775        token = match_token(p, key_tokens, args);
776
777        switch (token) {
778        case Opt_pcrinfo:
779            opt->pcrinfo_len = strlen(args[0].from) / 2;
780            if (opt->pcrinfo_len > MAX_PCRINFO_SIZE)
781                return -EINVAL;
782            hex2bin(opt->pcrinfo, args[0].from, opt->pcrinfo_len);
783            break;
784        case Opt_keyhandle:
785            res = strict_strtoul(args[0].from, 16, &handle);
786            if (res < 0)
787                return -EINVAL;
788            opt->keytype = SEAL_keytype;
789            opt->keyhandle = handle;
790            break;
791        case Opt_keyauth:
792            if (strlen(args[0].from) != 2 * SHA1_DIGEST_SIZE)
793                return -EINVAL;
794            hex2bin(opt->keyauth, args[0].from, SHA1_DIGEST_SIZE);
795            break;
796        case Opt_blobauth:
797            if (strlen(args[0].from) != 2 * SHA1_DIGEST_SIZE)
798                return -EINVAL;
799            hex2bin(opt->blobauth, args[0].from, SHA1_DIGEST_SIZE);
800            break;
801        case Opt_migratable:
802            if (*args[0].from == '0')
803                pay->migratable = 0;
804            else
805                return -EINVAL;
806            break;
807        case Opt_pcrlock:
808            res = strict_strtoul(args[0].from, 10, &lock);
809            if (res < 0)
810                return -EINVAL;
811            opt->pcrlock = lock;
812            break;
813        default:
814            return -EINVAL;
815        }
816    }
817    return 0;
818}
819
820/*
821 * datablob_parse - parse the keyctl data and fill in the
822 * payload and options structures
823 *
824 * On success returns 0, otherwise -EINVAL.
825 */
826static int datablob_parse(char *datablob, struct trusted_key_payload *p,
827              struct trusted_key_options *o)
828{
829    substring_t args[MAX_OPT_ARGS];
830    long keylen;
831    int ret = -EINVAL;
832    int key_cmd;
833    char *c;
834
835    /* main command */
836    c = strsep(&datablob, " \t");
837    if (!c)
838        return -EINVAL;
839    key_cmd = match_token(c, key_tokens, args);
840    switch (key_cmd) {
841    case Opt_new:
842        /* first argument is key size */
843        c = strsep(&datablob, " \t");
844        if (!c)
845            return -EINVAL;
846        ret = strict_strtol(c, 10, &keylen);
847        if (ret < 0 || keylen < MIN_KEY_SIZE || keylen > MAX_KEY_SIZE)
848            return -EINVAL;
849        p->key_len = keylen;
850        ret = getoptions(datablob, p, o);
851        if (ret < 0)
852            return ret;
853        ret = Opt_new;
854        break;
855    case Opt_load:
856        /* first argument is sealed blob */
857        c = strsep(&datablob, " \t");
858        if (!c)
859            return -EINVAL;
860        p->blob_len = strlen(c) / 2;
861        if (p->blob_len > MAX_BLOB_SIZE)
862            return -EINVAL;
863        hex2bin(p->blob, c, p->blob_len);
864        ret = getoptions(datablob, p, o);
865        if (ret < 0)
866            return ret;
867        ret = Opt_load;
868        break;
869    case Opt_update:
870        /* all arguments are options */
871        ret = getoptions(datablob, p, o);
872        if (ret < 0)
873            return ret;
874        ret = Opt_update;
875        break;
876    case Opt_err:
877        return -EINVAL;
878        break;
879    }
880    return ret;
881}
882
883static struct trusted_key_options *trusted_options_alloc(void)
884{
885    struct trusted_key_options *options;
886
887    options = kzalloc(sizeof *options, GFP_KERNEL);
888    if (options) {
889        /* set any non-zero defaults */
890        options->keytype = SRK_keytype;
891        options->keyhandle = SRKHANDLE;
892    }
893    return options;
894}
895
896static struct trusted_key_payload *trusted_payload_alloc(struct key *key)
897{
898    struct trusted_key_payload *p = NULL;
899    int ret;
900
901    ret = key_payload_reserve(key, sizeof *p);
902    if (ret < 0)
903        return p;
904    p = kzalloc(sizeof *p, GFP_KERNEL);
905    if (p)
906        p->migratable = 1; /* migratable by default */
907    return p;
908}
909
910/*
911 * trusted_instantiate - create a new trusted key
912 *
913 * Unseal an existing trusted blob or, for a new key, get a
914 * random key, then seal and create a trusted key-type key,
915 * adding it to the specified keyring.
916 *
917 * On success, return 0. Otherwise return errno.
918 */
919static int trusted_instantiate(struct key *key, const void *data,
920                   size_t datalen)
921{
922    struct trusted_key_payload *payload = NULL;
923    struct trusted_key_options *options = NULL;
924    char *datablob;
925    int ret = 0;
926    int key_cmd;
927
928    if (datalen <= 0 || datalen > 32767 || !data)
929        return -EINVAL;
930
931    datablob = kmalloc(datalen + 1, GFP_KERNEL);
932    if (!datablob)
933        return -ENOMEM;
934    memcpy(datablob, data, datalen);
935    datablob[datalen] = '\0';
936
937    options = trusted_options_alloc();
938    if (!options) {
939        ret = -ENOMEM;
940        goto out;
941    }
942    payload = trusted_payload_alloc(key);
943    if (!payload) {
944        ret = -ENOMEM;
945        goto out;
946    }
947
948    key_cmd = datablob_parse(datablob, payload, options);
949    if (key_cmd < 0) {
950        ret = key_cmd;
951        goto out;
952    }
953
954    dump_payload(payload);
955    dump_options(options);
956
957    switch (key_cmd) {
958    case Opt_load:
959        ret = key_unseal(payload, options);
960        dump_payload(payload);
961        dump_options(options);
962        if (ret < 0)
963            pr_info("trusted_key: key_unseal failed (%d)\n", ret);
964        break;
965    case Opt_new:
966        ret = my_get_random(payload->key, payload->key_len);
967        if (ret < 0) {
968            pr_info("trusted_key: key_create failed (%d)\n", ret);
969            goto out;
970        }
971        ret = key_seal(payload, options);
972        if (ret < 0)
973            pr_info("trusted_key: key_seal failed (%d)\n", ret);
974        break;
975    default:
976        ret = -EINVAL;
977        goto out;
978    }
979    if (!ret && options->pcrlock)
980        ret = pcrlock(options->pcrlock);
981out:
982    kfree(datablob);
983    kfree(options);
984    if (!ret)
985        rcu_assign_pointer(key->payload.data, payload);
986    else
987        kfree(payload);
988    return ret;
989}
990
991static void trusted_rcu_free(struct rcu_head *rcu)
992{
993    struct trusted_key_payload *p;
994
995    p = container_of(rcu, struct trusted_key_payload, rcu);
996    memset(p->key, 0, p->key_len);
997    kfree(p);
998}
999
1000/*
1001 * trusted_update - reseal an existing key with new PCR values
1002 */
1003static int trusted_update(struct key *key, const void *data, size_t datalen)
1004{
1005    struct trusted_key_payload *p = key->payload.data;
1006    struct trusted_key_payload *new_p;
1007    struct trusted_key_options *new_o;
1008    char *datablob;
1009    int ret = 0;
1010
1011    if (!p->migratable)
1012        return -EPERM;
1013    if (datalen <= 0 || datalen > 32767 || !data)
1014        return -EINVAL;
1015
1016    datablob = kmalloc(datalen + 1, GFP_KERNEL);
1017    if (!datablob)
1018        return -ENOMEM;
1019    new_o = trusted_options_alloc();
1020    if (!new_o) {
1021        ret = -ENOMEM;
1022        goto out;
1023    }
1024    new_p = trusted_payload_alloc(key);
1025    if (!new_p) {
1026        ret = -ENOMEM;
1027        goto out;
1028    }
1029
1030    memcpy(datablob, data, datalen);
1031    datablob[datalen] = '\0';
1032    ret = datablob_parse(datablob, new_p, new_o);
1033    if (ret != Opt_update) {
1034        ret = -EINVAL;
1035        kfree(new_p);
1036        goto out;
1037    }
1038    /* copy old key values, and reseal with new pcrs */
1039    new_p->migratable = p->migratable;
1040    new_p->key_len = p->key_len;
1041    memcpy(new_p->key, p->key, p->key_len);
1042    dump_payload(p);
1043    dump_payload(new_p);
1044
1045    ret = key_seal(new_p, new_o);
1046    if (ret < 0) {
1047        pr_info("trusted_key: key_seal failed (%d)\n", ret);
1048        kfree(new_p);
1049        goto out;
1050    }
1051    if (new_o->pcrlock) {
1052        ret = pcrlock(new_o->pcrlock);
1053        if (ret < 0) {
1054            pr_info("trusted_key: pcrlock failed (%d)\n", ret);
1055            kfree(new_p);
1056            goto out;
1057        }
1058    }
1059    rcu_assign_pointer(key->payload.data, new_p);
1060    call_rcu(&p->rcu, trusted_rcu_free);
1061out:
1062    kfree(datablob);
1063    kfree(new_o);
1064    return ret;
1065}
1066
1067/*
1068 * trusted_read - copy the sealed blob data to userspace in hex.
1069 * On success, return to userspace the trusted key datablob size.
1070 */
1071static long trusted_read(const struct key *key, char __user *buffer,
1072             size_t buflen)
1073{
1074    struct trusted_key_payload *p;
1075    char *ascii_buf;
1076    char *bufp;
1077    int i;
1078
1079    p = rcu_dereference_key(key);
1080    if (!p)
1081        return -EINVAL;
1082    if (!buffer || buflen <= 0)
1083        return 2 * p->blob_len;
1084    ascii_buf = kmalloc(2 * p->blob_len, GFP_KERNEL);
1085    if (!ascii_buf)
1086        return -ENOMEM;
1087
1088    bufp = ascii_buf;
1089    for (i = 0; i < p->blob_len; i++)
1090        bufp = pack_hex_byte(bufp, p->blob[i]);
1091    if ((copy_to_user(buffer, ascii_buf, 2 * p->blob_len)) != 0) {
1092        kfree(ascii_buf);
1093        return -EFAULT;
1094    }
1095    kfree(ascii_buf);
1096    return 2 * p->blob_len;
1097}
1098
1099/*
1100 * trusted_destroy - before freeing the key, clear the decrypted data
1101 */
1102static void trusted_destroy(struct key *key)
1103{
1104    struct trusted_key_payload *p = key->payload.data;
1105
1106    if (!p)
1107        return;
1108    memset(p->key, 0, p->key_len);
1109    kfree(key->payload.data);
1110}
1111
1112struct key_type key_type_trusted = {
1113    .name = "trusted",
1114    .instantiate = trusted_instantiate,
1115    .update = trusted_update,
1116    .match = user_match,
1117    .destroy = trusted_destroy,
1118    .describe = user_describe,
1119    .read = trusted_read,
1120};
1121
1122EXPORT_SYMBOL_GPL(key_type_trusted);
1123
1124static void trusted_shash_release(void)
1125{
1126    if (hashalg)
1127        crypto_free_shash(hashalg);
1128    if (hmacalg)
1129        crypto_free_shash(hmacalg);
1130}
1131
1132static int __init trusted_shash_alloc(void)
1133{
1134    int ret;
1135
1136    hmacalg = crypto_alloc_shash(hmac_alg, 0, CRYPTO_ALG_ASYNC);
1137    if (IS_ERR(hmacalg)) {
1138        pr_info("trusted_key: could not allocate crypto %s\n",
1139            hmac_alg);
1140        return PTR_ERR(hmacalg);
1141    }
1142
1143    hashalg = crypto_alloc_shash(hash_alg, 0, CRYPTO_ALG_ASYNC);
1144    if (IS_ERR(hashalg)) {
1145        pr_info("trusted_key: could not allocate crypto %s\n",
1146            hash_alg);
1147        ret = PTR_ERR(hashalg);
1148        goto hashalg_fail;
1149    }
1150
1151    return 0;
1152
1153hashalg_fail:
1154    crypto_free_shash(hmacalg);
1155    return ret;
1156}
1157
1158static int __init init_trusted(void)
1159{
1160    int ret;
1161
1162    ret = trusted_shash_alloc();
1163    if (ret < 0)
1164        return ret;
1165    ret = register_key_type(&key_type_trusted);
1166    if (ret < 0)
1167        trusted_shash_release();
1168    return ret;
1169}
1170
1171static void __exit cleanup_trusted(void)
1172{
1173    trusted_shash_release();
1174    unregister_key_type(&key_type_trusted);
1175}
1176
1177late_initcall(init_trusted);
1178module_exit(cleanup_trusted);
1179
1180MODULE_LICENSE("GPL");
1181

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