- 根目录:
- security
- keys
- trusted.c
/*
* Copyright (C) 2010 IBM Corporation
*
* Author:
* David Safford <safford@us.ibm.com>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, version 2 of the License.
*
* See Documentation/keys-trusted-encrypted.txt
*/
#include <linux/uaccess.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/slab.h>
#include <linux/parser.h>
#include <linux/string.h>
#include <linux/err.h>
#include <keys/user-type.h>
#include <keys/trusted-type.h>
#include <linux/key-type.h>
#include <linux/rcupdate.h>
#include <linux/crypto.h>
#include <crypto/hash.h>
#include <crypto/sha.h>
#include <linux/capability.h>
#include <linux/tpm.h>
#include <linux/tpm_command.h>
#include "trusted.h"
static const char hmac_alg[] = "hmac(sha1)";
static const char hash_alg[] = "sha1";
struct sdesc {
struct shash_desc shash;
char ctx[];
};
static struct crypto_shash *hashalg;
static struct crypto_shash *hmacalg;
static struct sdesc *init_sdesc(struct crypto_shash *alg)
{
struct sdesc *sdesc;
int size;
size = sizeof(struct shash_desc) + crypto_shash_descsize(alg);
sdesc = kmalloc(size, GFP_KERNEL);
if (!sdesc)
return ERR_PTR(-ENOMEM);
sdesc->shash.tfm = alg;
sdesc->shash.flags = 0x0;
return sdesc;
}
static int TSS_sha1(const unsigned char *data, unsigned int datalen,
unsigned char *digest)
{
struct sdesc *sdesc;
int ret;
sdesc = init_sdesc(hashalg);
if (IS_ERR(sdesc)) {
pr_info("trusted_key: can't alloc %s\n", hash_alg);
return PTR_ERR(sdesc);
}
ret = crypto_shash_digest(&sdesc->shash, data, datalen, digest);
kfree(sdesc);
return ret;
}
static int TSS_rawhmac(unsigned char *digest, const unsigned char *key,
unsigned int keylen, ...)
{
struct sdesc *sdesc;
va_list argp;
unsigned int dlen;
unsigned char *data;
int ret;
sdesc = init_sdesc(hmacalg);
if (IS_ERR(sdesc)) {
pr_info("trusted_key: can't alloc %s\n", hmac_alg);
return PTR_ERR(sdesc);
}
ret = crypto_shash_setkey(hmacalg, key, keylen);
if (ret < 0)
goto out;
ret = crypto_shash_init(&sdesc->shash);
if (ret < 0)
goto out;
va_start(argp, keylen);
for (;;) {
dlen = va_arg(argp, unsigned int);
if (dlen == 0)
break;
data = va_arg(argp, unsigned char *);
if (data == NULL) {
ret = -EINVAL;
break;
}
ret = crypto_shash_update(&sdesc->shash, data, dlen);
if (ret < 0)
break;
}
va_end(argp);
if (!ret)
ret = crypto_shash_final(&sdesc->shash, digest);
out:
kfree(sdesc);
return ret;
}
/*
* calculate authorization info fields to send to TPM
*/
static int TSS_authhmac(unsigned char *digest, const unsigned char *key,
unsigned int keylen, unsigned char *h1,
unsigned char *h2, unsigned char h3, ...)
{
unsigned char paramdigest[SHA1_DIGEST_SIZE];
struct sdesc *sdesc;
unsigned int dlen;
unsigned char *data;
unsigned char c;
int ret;
va_list argp;
sdesc = init_sdesc(hashalg);
if (IS_ERR(sdesc)) {
pr_info("trusted_key: can't alloc %s\n", hash_alg);
return PTR_ERR(sdesc);
}
c = h3;
ret = crypto_shash_init(&sdesc->shash);
if (ret < 0)
goto out;
va_start(argp, h3);
for (;;) {
dlen = va_arg(argp, unsigned int);
if (dlen == 0)
break;
data = va_arg(argp, unsigned char *);
if (!data) {
ret = -EINVAL;
break;
}
ret = crypto_shash_update(&sdesc->shash, data, dlen);
if (ret < 0)
break;
}
va_end(argp);
if (!ret)
ret = crypto_shash_final(&sdesc->shash, paramdigest);
if (!ret)
ret = TSS_rawhmac(digest, key, keylen, SHA1_DIGEST_SIZE,
paramdigest, TPM_NONCE_SIZE, h1,
TPM_NONCE_SIZE, h2, 1, &c, 0, 0);
out:
kfree(sdesc);
return ret;
}
/*
* verify the AUTH1_COMMAND (Seal) result from TPM
*/
static int TSS_checkhmac1(unsigned char *buffer,
const uint32_t command,
const unsigned char *ononce,
const unsigned char *key,
unsigned int keylen, ...)
{
uint32_t bufsize;
uint16_t tag;
uint32_t ordinal;
uint32_t result;
unsigned char *enonce;
unsigned char *continueflag;
unsigned char *authdata;
unsigned char testhmac[SHA1_DIGEST_SIZE];
unsigned char paramdigest[SHA1_DIGEST_SIZE];
struct sdesc *sdesc;
unsigned int dlen;
unsigned int dpos;
va_list argp;
int ret;
bufsize = LOAD32(buffer, TPM_SIZE_OFFSET);
tag = LOAD16(buffer, 0);
ordinal = command;
result = LOAD32N(buffer, TPM_RETURN_OFFSET);
if (tag == TPM_TAG_RSP_COMMAND)
return 0;
if (tag != TPM_TAG_RSP_AUTH1_COMMAND)
return -EINVAL;
authdata = buffer + bufsize - SHA1_DIGEST_SIZE;
continueflag = authdata - 1;
enonce = continueflag - TPM_NONCE_SIZE;
sdesc = init_sdesc(hashalg);
if (IS_ERR(sdesc)) {
pr_info("trusted_key: can't alloc %s\n", hash_alg);
return PTR_ERR(sdesc);
}
ret = crypto_shash_init(&sdesc->shash);
if (ret < 0)
goto out;
ret = crypto_shash_update(&sdesc->shash, (const u8 *)&result,
sizeof result);
if (ret < 0)
goto out;
ret = crypto_shash_update(&sdesc->shash, (const u8 *)&ordinal,
sizeof ordinal);
if (ret < 0)
goto out;
va_start(argp, keylen);
for (;;) {
dlen = va_arg(argp, unsigned int);
if (dlen == 0)
break;
dpos = va_arg(argp, unsigned int);
ret = crypto_shash_update(&sdesc->shash, buffer + dpos, dlen);
if (ret < 0)
break;
}
va_end(argp);
if (!ret)
ret = crypto_shash_final(&sdesc->shash, paramdigest);
if (ret < 0)
goto out;
ret = TSS_rawhmac(testhmac, key, keylen, SHA1_DIGEST_SIZE, paramdigest,
TPM_NONCE_SIZE, enonce, TPM_NONCE_SIZE, ononce,
1, continueflag, 0, 0);
if (ret < 0)
goto out;
if (memcmp(testhmac, authdata, SHA1_DIGEST_SIZE))
ret = -EINVAL;
out:
kfree(sdesc);
return ret;
}
/*
* verify the AUTH2_COMMAND (unseal) result from TPM
*/
static int TSS_checkhmac2(unsigned char *buffer,
const uint32_t command,
const unsigned char *ononce,
const unsigned char *key1,
unsigned int keylen1,
const unsigned char *key2,
unsigned int keylen2, ...)
{
uint32_t bufsize;
uint16_t tag;
uint32_t ordinal;
uint32_t result;
unsigned char *enonce1;
unsigned char *continueflag1;
unsigned char *authdata1;
unsigned char *enonce2;
unsigned char *continueflag2;
unsigned char *authdata2;
unsigned char testhmac1[SHA1_DIGEST_SIZE];
unsigned char testhmac2[SHA1_DIGEST_SIZE];
unsigned char paramdigest[SHA1_DIGEST_SIZE];
struct sdesc *sdesc;
unsigned int dlen;
unsigned int dpos;
va_list argp;
int ret;
bufsize = LOAD32(buffer, TPM_SIZE_OFFSET);
tag = LOAD16(buffer, 0);
ordinal = command;
result = LOAD32N(buffer, TPM_RETURN_OFFSET);
if (tag == TPM_TAG_RSP_COMMAND)
return 0;
if (tag != TPM_TAG_RSP_AUTH2_COMMAND)
return -EINVAL;
authdata1 = buffer + bufsize - (SHA1_DIGEST_SIZE + 1
+ SHA1_DIGEST_SIZE + SHA1_DIGEST_SIZE);
authdata2 = buffer + bufsize - (SHA1_DIGEST_SIZE);
continueflag1 = authdata1 - 1;
continueflag2 = authdata2 - 1;
enonce1 = continueflag1 - TPM_NONCE_SIZE;
enonce2 = continueflag2 - TPM_NONCE_SIZE;
sdesc = init_sdesc(hashalg);
if (IS_ERR(sdesc)) {
pr_info("trusted_key: can't alloc %s\n", hash_alg);
return PTR_ERR(sdesc);
}
ret = crypto_shash_init(&sdesc->shash);
if (ret < 0)
goto out;
ret = crypto_shash_update(&sdesc->shash, (const u8 *)&result,
sizeof result);
if (ret < 0)
goto out;
ret = crypto_shash_update(&sdesc->shash, (const u8 *)&ordinal,
sizeof ordinal);
if (ret < 0)
goto out;
va_start(argp, keylen2);
for (;;) {
dlen = va_arg(argp, unsigned int);
if (dlen == 0)
break;
dpos = va_arg(argp, unsigned int);
ret = crypto_shash_update(&sdesc->shash, buffer + dpos, dlen);
if (ret < 0)
break;
}
va_end(argp);
if (!ret)
ret = crypto_shash_final(&sdesc->shash, paramdigest);
if (ret < 0)
goto out;
ret = TSS_rawhmac(testhmac1, key1, keylen1, SHA1_DIGEST_SIZE,
paramdigest, TPM_NONCE_SIZE, enonce1,
TPM_NONCE_SIZE, ononce, 1, continueflag1, 0, 0);
if (ret < 0)
goto out;
if (memcmp(testhmac1, authdata1, SHA1_DIGEST_SIZE)) {
ret = -EINVAL;
goto out;
}
ret = TSS_rawhmac(testhmac2, key2, keylen2, SHA1_DIGEST_SIZE,
paramdigest, TPM_NONCE_SIZE, enonce2,
TPM_NONCE_SIZE, ononce, 1, continueflag2, 0, 0);
if (ret < 0)
goto out;
if (memcmp(testhmac2, authdata2, SHA1_DIGEST_SIZE))
ret = -EINVAL;
out:
kfree(sdesc);
return ret;
}
/*
* For key specific tpm requests, we will generate and send our
* own TPM command packets using the drivers send function.
*/
static int trusted_tpm_send(const u32 chip_num, unsigned char *cmd,
size_t buflen)
{
int rc;
dump_tpm_buf(cmd);
rc = tpm_send(chip_num, cmd, buflen);
dump_tpm_buf(cmd);
if (rc > 0)
/* Can't return positive return codes values to keyctl */
rc = -EPERM;
return rc;
}
/*
* get a random value from TPM
*/
static int tpm_get_random(struct tpm_buf *tb, unsigned char *buf, uint32_t len)
{
int ret;
INIT_BUF(tb);
store16(tb, TPM_TAG_RQU_COMMAND);
store32(tb, TPM_GETRANDOM_SIZE);
store32(tb, TPM_ORD_GETRANDOM);
store32(tb, len);
ret = trusted_tpm_send(TPM_ANY_NUM, tb->data, sizeof tb->data);
if (!ret)
memcpy(buf, tb->data + TPM_GETRANDOM_SIZE, len);
return ret;
}
static int my_get_random(unsigned char *buf, int len)
{
struct tpm_buf *tb;
int ret;
tb = kmalloc(sizeof *tb, GFP_KERNEL);
if (!tb)
return -ENOMEM;
ret = tpm_get_random(tb, buf, len);
kfree(tb);
return ret;
}
/*
* Lock a trusted key, by extending a selected PCR.
*
* Prevents a trusted key that is sealed to PCRs from being accessed.
* This uses the tpm driver's extend function.
*/
static int pcrlock(const int pcrnum)
{
unsigned char hash[SHA1_DIGEST_SIZE];
int ret;
if (!capable(CAP_SYS_ADMIN))
return -EPERM;
ret = my_get_random(hash, SHA1_DIGEST_SIZE);
if (ret < 0)
return ret;
return tpm_pcr_extend(TPM_ANY_NUM, pcrnum, hash) ? -EINVAL : 0;
}
/*
* Create an object specific authorisation protocol (OSAP) session
*/
static int osap(struct tpm_buf *tb, struct osapsess *s,
const unsigned char *key, uint16_t type, uint32_t handle)
{
unsigned char enonce[TPM_NONCE_SIZE];
unsigned char ononce[TPM_NONCE_SIZE];
int ret;
ret = tpm_get_random(tb, ononce, TPM_NONCE_SIZE);
if (ret < 0)
return ret;
INIT_BUF(tb);
store16(tb, TPM_TAG_RQU_COMMAND);
store32(tb, TPM_OSAP_SIZE);
store32(tb, TPM_ORD_OSAP);
store16(tb, type);
store32(tb, handle);
storebytes(tb, ononce, TPM_NONCE_SIZE);
ret = trusted_tpm_send(TPM_ANY_NUM, tb->data, MAX_BUF_SIZE);
if (ret < 0)
return ret;
s->handle = LOAD32(tb->data, TPM_DATA_OFFSET);
memcpy(s->enonce, &(tb->data[TPM_DATA_OFFSET + sizeof(uint32_t)]),
TPM_NONCE_SIZE);
memcpy(enonce, &(tb->data[TPM_DATA_OFFSET + sizeof(uint32_t) +
TPM_NONCE_SIZE]), TPM_NONCE_SIZE);
return TSS_rawhmac(s->secret, key, SHA1_DIGEST_SIZE, TPM_NONCE_SIZE,
enonce, TPM_NONCE_SIZE, ononce, 0, 0);
}
/*
* Create an object independent authorisation protocol (oiap) session
*/
static int oiap(struct tpm_buf *tb, uint32_t *handle, unsigned char *nonce)
{
int ret;
INIT_BUF(tb);
store16(tb, TPM_TAG_RQU_COMMAND);
store32(tb, TPM_OIAP_SIZE);
store32(tb, TPM_ORD_OIAP);
ret = trusted_tpm_send(TPM_ANY_NUM, tb->data, MAX_BUF_SIZE);
if (ret < 0)
return ret;
*handle = LOAD32(tb->data, TPM_DATA_OFFSET);
memcpy(nonce, &tb->data[TPM_DATA_OFFSET + sizeof(uint32_t)],
TPM_NONCE_SIZE);
return 0;
}
struct tpm_digests {
unsigned char encauth[SHA1_DIGEST_SIZE];
unsigned char pubauth[SHA1_DIGEST_SIZE];
unsigned char xorwork[SHA1_DIGEST_SIZE * 2];
unsigned char xorhash[SHA1_DIGEST_SIZE];
unsigned char nonceodd[TPM_NONCE_SIZE];
};
/*
* Have the TPM seal(encrypt) the trusted key, possibly based on
* Platform Configuration Registers (PCRs). AUTH1 for sealing key.
*/
static int tpm_seal(struct tpm_buf *tb, uint16_t keytype,
uint32_t keyhandle, const unsigned char *keyauth,
const unsigned char *data, uint32_t datalen,
unsigned char *blob, uint32_t *bloblen,
const unsigned char *blobauth,
const unsigned char *pcrinfo, uint32_t pcrinfosize)
{
struct osapsess sess;
struct tpm_digests *td;
unsigned char cont;
uint32_t ordinal;
uint32_t pcrsize;
uint32_t datsize;
int sealinfosize;
int encdatasize;
int storedsize;
int ret;
int i;
/* alloc some work space for all the hashes */
td = kmalloc(sizeof *td, GFP_KERNEL);
if (!td)
return -ENOMEM;
/* get session for sealing key */
ret = osap(tb, &sess, keyauth, keytype, keyhandle);
if (ret < 0)
goto out;
dump_sess(&sess);
/* calculate encrypted authorization value */
memcpy(td->xorwork, sess.secret, SHA1_DIGEST_SIZE);
memcpy(td->xorwork + SHA1_DIGEST_SIZE, sess.enonce, SHA1_DIGEST_SIZE);
ret = TSS_sha1(td->xorwork, SHA1_DIGEST_SIZE * 2, td->xorhash);
if (ret < 0)
goto out;
ret = tpm_get_random(tb, td->nonceodd, TPM_NONCE_SIZE);
if (ret < 0)
goto out;
ordinal = htonl(TPM_ORD_SEAL);
datsize = htonl(datalen);
pcrsize = htonl(pcrinfosize);
cont = 0;
/* encrypt data authorization key */
for (i = 0; i < SHA1_DIGEST_SIZE; ++i)
td->encauth[i] = td->xorhash[i] ^ blobauth[i];
/* calculate authorization HMAC value */
if (pcrinfosize == 0) {
/* no pcr info specified */
ret = TSS_authhmac(td->pubauth, sess.secret, SHA1_DIGEST_SIZE,
sess.enonce, td->nonceodd, cont,
sizeof(uint32_t), &ordinal, SHA1_DIGEST_SIZE,
td->encauth, sizeof(uint32_t), &pcrsize,
sizeof(uint32_t), &datsize, datalen, data, 0,
0);
} else {
/* pcr info specified */
ret = TSS_authhmac(td->pubauth, sess.secret, SHA1_DIGEST_SIZE,
sess.enonce, td->nonceodd, cont,
sizeof(uint32_t), &ordinal, SHA1_DIGEST_SIZE,
td->encauth, sizeof(uint32_t), &pcrsize,
pcrinfosize, pcrinfo, sizeof(uint32_t),
&datsize, datalen, data, 0, 0);
}
if (ret < 0)
goto out;
/* build and send the TPM request packet */
INIT_BUF(tb);
store16(tb, TPM_TAG_RQU_AUTH1_COMMAND);
store32(tb, TPM_SEAL_SIZE + pcrinfosize + datalen);
store32(tb, TPM_ORD_SEAL);
store32(tb, keyhandle);
storebytes(tb, td->encauth, SHA1_DIGEST_SIZE);
store32(tb, pcrinfosize);
storebytes(tb, pcrinfo, pcrinfosize);
store32(tb, datalen);
storebytes(tb, data, datalen);
store32(tb, sess.handle);
storebytes(tb, td->nonceodd, TPM_NONCE_SIZE);
store8(tb, cont);
storebytes(tb, td->pubauth, SHA1_DIGEST_SIZE);
ret = trusted_tpm_send(TPM_ANY_NUM, tb->data, MAX_BUF_SIZE);
if (ret < 0)
goto out;
/* calculate the size of the returned Blob */
sealinfosize = LOAD32(tb->data, TPM_DATA_OFFSET + sizeof(uint32_t));
encdatasize = LOAD32(tb->data, TPM_DATA_OFFSET + sizeof(uint32_t) +
sizeof(uint32_t) + sealinfosize);
storedsize = sizeof(uint32_t) + sizeof(uint32_t) + sealinfosize +
sizeof(uint32_t) + encdatasize;
/* check the HMAC in the response */
ret = TSS_checkhmac1(tb->data, ordinal, td->nonceodd, sess.secret,
SHA1_DIGEST_SIZE, storedsize, TPM_DATA_OFFSET, 0,
0);
/* copy the returned blob to caller */
if (!ret) {
memcpy(blob, tb->data + TPM_DATA_OFFSET, storedsize);
*bloblen = storedsize;
}
out:
kfree(td);
return ret;
}
/*
* use the AUTH2_COMMAND form of unseal, to authorize both key and blob
*/
static int tpm_unseal(struct tpm_buf *tb,
uint32_t keyhandle, const unsigned char *keyauth,
const unsigned char *blob, int bloblen,
const unsigned char *blobauth,
unsigned char *data, unsigned int *datalen)
{
unsigned char nonceodd[TPM_NONCE_SIZE];
unsigned char enonce1[TPM_NONCE_SIZE];
unsigned char enonce2[TPM_NONCE_SIZE];
unsigned char authdata1[SHA1_DIGEST_SIZE];
unsigned char authdata2[SHA1_DIGEST_SIZE];
uint32_t authhandle1 = 0;
uint32_t authhandle2 = 0;
unsigned char cont = 0;
uint32_t ordinal;
uint32_t keyhndl;
int ret;
/* sessions for unsealing key and data */
ret = oiap(tb, &authhandle1, enonce1);
if (ret < 0) {
pr_info("trusted_key: oiap failed (%d)\n", ret);
return ret;
}
ret = oiap(tb, &authhandle2, enonce2);
if (ret < 0) {
pr_info("trusted_key: oiap failed (%d)\n", ret);
return ret;
}
ordinal = htonl(TPM_ORD_UNSEAL);
keyhndl = htonl(SRKHANDLE);
ret = tpm_get_random(tb, nonceodd, TPM_NONCE_SIZE);
if (ret < 0) {
pr_info("trusted_key: tpm_get_random failed (%d)\n", ret);
return ret;
}
ret = TSS_authhmac(authdata1, keyauth, TPM_NONCE_SIZE,
enonce1, nonceodd, cont, sizeof(uint32_t),
&ordinal, bloblen, blob, 0, 0);
if (ret < 0)
return ret;
ret = TSS_authhmac(authdata2, blobauth, TPM_NONCE_SIZE,
enonce2, nonceodd, cont, sizeof(uint32_t),
&ordinal, bloblen, blob, 0, 0);
if (ret < 0)
return ret;
/* build and send TPM request packet */
INIT_BUF(tb);
store16(tb, TPM_TAG_RQU_AUTH2_COMMAND);
store32(tb, TPM_UNSEAL_SIZE + bloblen);
store32(tb, TPM_ORD_UNSEAL);
store32(tb, keyhandle);
storebytes(tb, blob, bloblen);
store32(tb, authhandle1);
storebytes(tb, nonceodd, TPM_NONCE_SIZE);
store8(tb, cont);
storebytes(tb, authdata1, SHA1_DIGEST_SIZE);
store32(tb, authhandle2);
storebytes(tb, nonceodd, TPM_NONCE_SIZE);
store8(tb, cont);
storebytes(tb, authdata2, SHA1_DIGEST_SIZE);
ret = trusted_tpm_send(TPM_ANY_NUM, tb->data, MAX_BUF_SIZE);
if (ret < 0) {
pr_info("trusted_key: authhmac failed (%d)\n", ret);
return ret;
}
*datalen = LOAD32(tb->data, TPM_DATA_OFFSET);
ret = TSS_checkhmac2(tb->data, ordinal, nonceodd,
keyauth, SHA1_DIGEST_SIZE,
blobauth, SHA1_DIGEST_SIZE,
sizeof(uint32_t), TPM_DATA_OFFSET,
*datalen, TPM_DATA_OFFSET + sizeof(uint32_t), 0,
0);
if (ret < 0) {
pr_info("trusted_key: TSS_checkhmac2 failed (%d)\n", ret);
return ret;
}
memcpy(data, tb->data + TPM_DATA_OFFSET + sizeof(uint32_t), *datalen);
return 0;
}
/*
* Have the TPM seal(encrypt) the symmetric key
*/
static int key_seal(struct trusted_key_payload *p,
struct trusted_key_options *o)
{
struct tpm_buf *tb;
int ret;
tb = kzalloc(sizeof *tb, GFP_KERNEL);
if (!tb)
return -ENOMEM;
/* include migratable flag at end of sealed key */
p->key[p->key_len] = p->migratable;
ret = tpm_seal(tb, o->keytype, o->keyhandle, o->keyauth,
p->key, p->key_len + 1, p->blob, &p->blob_len,
o->blobauth, o->pcrinfo, o->pcrinfo_len);
if (ret < 0)
pr_info("trusted_key: srkseal failed (%d)\n", ret);
kfree(tb);
return ret;
}
/*
* Have the TPM unseal(decrypt) the symmetric key
*/
static int key_unseal(struct trusted_key_payload *p,
struct trusted_key_options *o)
{
struct tpm_buf *tb;
int ret;
tb = kzalloc(sizeof *tb, GFP_KERNEL);
if (!tb)
return -ENOMEM;
ret = tpm_unseal(tb, o->keyhandle, o->keyauth, p->blob, p->blob_len,
o->blobauth, p->key, &p->key_len);
if (ret < 0)
pr_info("trusted_key: srkunseal failed (%d)\n", ret);
else
/* pull migratable flag out of sealed key */
p->migratable = p->key[--p->key_len];
kfree(tb);
return ret;
}
enum {
Opt_err = -1,
Opt_new, Opt_load, Opt_update,
Opt_keyhandle, Opt_keyauth, Opt_blobauth,
Opt_pcrinfo, Opt_pcrlock, Opt_migratable
};
static const match_table_t key_tokens = {
{Opt_new, "new"},
{Opt_load, "load"},
{Opt_update, "update"},
{Opt_keyhandle, "keyhandle=%s"},
{Opt_keyauth, "keyauth=%s"},
{Opt_blobauth, "blobauth=%s"},
{Opt_pcrinfo, "pcrinfo=%s"},
{Opt_pcrlock, "pcrlock=%s"},
{Opt_migratable, "migratable=%s"},
{Opt_err, NULL}
};
/* can have zero or more token= options */
static int getoptions(char *c, struct trusted_key_payload *pay,
struct trusted_key_options *opt)
{
substring_t args[MAX_OPT_ARGS];
char *p = c;
int token;
int res;
unsigned long handle;
unsigned long lock;
while ((p = strsep(&c, " \t"))) {
if (*p == '\0' || *p == ' ' || *p == '\t')
continue;
token = match_token(p, key_tokens, args);
switch (token) {
case Opt_pcrinfo:
opt->pcrinfo_len = strlen(args[0].from) / 2;
if (opt->pcrinfo_len > MAX_PCRINFO_SIZE)
return -EINVAL;
hex2bin(opt->pcrinfo, args[0].from, opt->pcrinfo_len);
break;
case Opt_keyhandle:
res = strict_strtoul(args[0].from, 16, &handle);
if (res < 0)
return -EINVAL;
opt->keytype = SEAL_keytype;
opt->keyhandle = handle;
break;
case Opt_keyauth:
if (strlen(args[0].from) != 2 * SHA1_DIGEST_SIZE)
return -EINVAL;
hex2bin(opt->keyauth, args[0].from, SHA1_DIGEST_SIZE);
break;
case Opt_blobauth:
if (strlen(args[0].from) != 2 * SHA1_DIGEST_SIZE)
return -EINVAL;
hex2bin(opt->blobauth, args[0].from, SHA1_DIGEST_SIZE);
break;
case Opt_migratable:
if (*args[0].from == '0')
pay->migratable = 0;
else
return -EINVAL;
break;
case Opt_pcrlock:
res = strict_strtoul(args[0].from, 10, &lock);
if (res < 0)
return -EINVAL;
opt->pcrlock = lock;
break;
default:
return -EINVAL;
}
}
return 0;
}
/*
* datablob_parse - parse the keyctl data and fill in the
* payload and options structures
*
* On success returns 0, otherwise -EINVAL.
*/
static int datablob_parse(char *datablob, struct trusted_key_payload *p,
struct trusted_key_options *o)
{
substring_t args[MAX_OPT_ARGS];
long keylen;
int ret = -EINVAL;
int key_cmd;
char *c;
/* main command */
c = strsep(&datablob, " \t");
if (!c)
return -EINVAL;
key_cmd = match_token(c, key_tokens, args);
switch (key_cmd) {
case Opt_new:
/* first argument is key size */
c = strsep(&datablob, " \t");
if (!c)
return -EINVAL;
ret = strict_strtol(c, 10, &keylen);
if (ret < 0 || keylen < MIN_KEY_SIZE || keylen > MAX_KEY_SIZE)
return -EINVAL;
p->key_len = keylen;
ret = getoptions(datablob, p, o);
if (ret < 0)
return ret;
ret = Opt_new;
break;
case Opt_load:
/* first argument is sealed blob */
c = strsep(&datablob, " \t");
if (!c)
return -EINVAL;
p->blob_len = strlen(c) / 2;
if (p->blob_len > MAX_BLOB_SIZE)
return -EINVAL;
hex2bin(p->blob, c, p->blob_len);
ret = getoptions(datablob, p, o);
if (ret < 0)
return ret;
ret = Opt_load;
break;
case Opt_update:
/* all arguments are options */
ret = getoptions(datablob, p, o);
if (ret < 0)
return ret;
ret = Opt_update;
break;
case Opt_err:
return -EINVAL;
break;
}
return ret;
}
static struct trusted_key_options *trusted_options_alloc(void)
{
struct trusted_key_options *options;
options = kzalloc(sizeof *options, GFP_KERNEL);
if (options) {
/* set any non-zero defaults */
options->keytype = SRK_keytype;
options->keyhandle = SRKHANDLE;
}
return options;
}
static struct trusted_key_payload *trusted_payload_alloc(struct key *key)
{
struct trusted_key_payload *p = NULL;
int ret;
ret = key_payload_reserve(key, sizeof *p);
if (ret < 0)
return p;
p = kzalloc(sizeof *p, GFP_KERNEL);
if (p)
p->migratable = 1; /* migratable by default */
return p;
}
/*
* trusted_instantiate - create a new trusted key
*
* Unseal an existing trusted blob or, for a new key, get a
* random key, then seal and create a trusted key-type key,
* adding it to the specified keyring.
*
* On success, return 0. Otherwise return errno.
*/
static int trusted_instantiate(struct key *key, const void *data,
size_t datalen)
{
struct trusted_key_payload *payload = NULL;
struct trusted_key_options *options = NULL;
char *datablob;
int ret = 0;
int key_cmd;
if (datalen <= 0 || datalen > 32767 || !data)
return -EINVAL;
datablob = kmalloc(datalen + 1, GFP_KERNEL);
if (!datablob)
return -ENOMEM;
memcpy(datablob, data, datalen);
datablob[datalen] = '\0';
options = trusted_options_alloc();
if (!options) {
ret = -ENOMEM;
goto out;
}
payload = trusted_payload_alloc(key);
if (!payload) {
ret = -ENOMEM;
goto out;
}
key_cmd = datablob_parse(datablob, payload, options);
if (key_cmd < 0) {
ret = key_cmd;
goto out;
}
dump_payload(payload);
dump_options(options);
switch (key_cmd) {
case Opt_load:
ret = key_unseal(payload, options);
dump_payload(payload);
dump_options(options);
if (ret < 0)
pr_info("trusted_key: key_unseal failed (%d)\n", ret);
break;
case Opt_new:
ret = my_get_random(payload->key, payload->key_len);
if (ret < 0) {
pr_info("trusted_key: key_create failed (%d)\n", ret);
goto out;
}
ret = key_seal(payload, options);
if (ret < 0)
pr_info("trusted_key: key_seal failed (%d)\n", ret);
break;
default:
ret = -EINVAL;
goto out;
}
if (!ret && options->pcrlock)
ret = pcrlock(options->pcrlock);
out:
kfree(datablob);
kfree(options);
if (!ret)
rcu_assign_pointer(key->payload.data, payload);
else
kfree(payload);
return ret;
}
static void trusted_rcu_free(struct rcu_head *rcu)
{
struct trusted_key_payload *p;
p = container_of(rcu, struct trusted_key_payload, rcu);
memset(p->key, 0, p->key_len);
kfree(p);
}
/*
* trusted_update - reseal an existing key with new PCR values
*/
static int trusted_update(struct key *key, const void *data, size_t datalen)
{
struct trusted_key_payload *p = key->payload.data;
struct trusted_key_payload *new_p;
struct trusted_key_options *new_o;
char *datablob;
int ret = 0;
if (!p->migratable)
return -EPERM;
if (datalen <= 0 || datalen > 32767 || !data)
return -EINVAL;
datablob = kmalloc(datalen + 1, GFP_KERNEL);
if (!datablob)
return -ENOMEM;
new_o = trusted_options_alloc();
if (!new_o) {
ret = -ENOMEM;
goto out;
}
new_p = trusted_payload_alloc(key);
if (!new_p) {
ret = -ENOMEM;
goto out;
}
memcpy(datablob, data, datalen);
datablob[datalen] = '\0';
ret = datablob_parse(datablob, new_p, new_o);
if (ret != Opt_update) {
ret = -EINVAL;
kfree(new_p);
goto out;
}
/* copy old key values, and reseal with new pcrs */
new_p->migratable = p->migratable;
new_p->key_len = p->key_len;
memcpy(new_p->key, p->key, p->key_len);
dump_payload(p);
dump_payload(new_p);
ret = key_seal(new_p, new_o);
if (ret < 0) {
pr_info("trusted_key: key_seal failed (%d)\n", ret);
kfree(new_p);
goto out;
}
if (new_o->pcrlock) {
ret = pcrlock(new_o->pcrlock);
if (ret < 0) {
pr_info("trusted_key: pcrlock failed (%d)\n", ret);
kfree(new_p);
goto out;
}
}
rcu_assign_pointer(key->payload.data, new_p);
call_rcu(&p->rcu, trusted_rcu_free);
out:
kfree(datablob);
kfree(new_o);
return ret;
}
/*
* trusted_read - copy the sealed blob data to userspace in hex.
* On success, return to userspace the trusted key datablob size.
*/
static long trusted_read(const struct key *key, char __user *buffer,
size_t buflen)
{
struct trusted_key_payload *p;
char *ascii_buf;
char *bufp;
int i;
p = rcu_dereference_key(key);
if (!p)
return -EINVAL;
if (!buffer || buflen <= 0)
return 2 * p->blob_len;
ascii_buf = kmalloc(2 * p->blob_len, GFP_KERNEL);
if (!ascii_buf)
return -ENOMEM;
bufp = ascii_buf;
for (i = 0; i < p->blob_len; i++)
bufp = pack_hex_byte(bufp, p->blob[i]);
if ((copy_to_user(buffer, ascii_buf, 2 * p->blob_len)) != 0) {
kfree(ascii_buf);
return -EFAULT;
}
kfree(ascii_buf);
return 2 * p->blob_len;
}
/*
* trusted_destroy - before freeing the key, clear the decrypted data
*/
static void trusted_destroy(struct key *key)
{
struct trusted_key_payload *p = key->payload.data;
if (!p)
return;
memset(p->key, 0, p->key_len);
kfree(key->payload.data);
}
struct key_type key_type_trusted = {
.name = "trusted",
.instantiate = trusted_instantiate,
.update = trusted_update,
.match = user_match,
.destroy = trusted_destroy,
.describe = user_describe,
.read = trusted_read,
};
EXPORT_SYMBOL_GPL(key_type_trusted);
static void trusted_shash_release(void)
{
if (hashalg)
crypto_free_shash(hashalg);
if (hmacalg)
crypto_free_shash(hmacalg);
}
static int __init trusted_shash_alloc(void)
{
int ret;
hmacalg = crypto_alloc_shash(hmac_alg, 0, CRYPTO_ALG_ASYNC);
if (IS_ERR(hmacalg)) {
pr_info("trusted_key: could not allocate crypto %s\n",
hmac_alg);
return PTR_ERR(hmacalg);
}
hashalg = crypto_alloc_shash(hash_alg, 0, CRYPTO_ALG_ASYNC);
if (IS_ERR(hashalg)) {
pr_info("trusted_key: could not allocate crypto %s\n",
hash_alg);
ret = PTR_ERR(hashalg);
goto hashalg_fail;
}
return 0;
hashalg_fail:
crypto_free_shash(hmacalg);
return ret;
}
static int __init init_trusted(void)
{
int ret;
ret = trusted_shash_alloc();
if (ret < 0)
return ret;
ret = register_key_type(&key_type_trusted);
if (ret < 0)
trusted_shash_release();
return ret;
}
static void __exit cleanup_trusted(void)
{
trusted_shash_release();
unregister_key_type(&key_type_trusted);
}
late_initcall(init_trusted);
module_exit(cleanup_trusted);
MODULE_LICENSE("GPL");