keys: add new trusted key-type

Define a new kernel key-type called 'trusted'.  Trusted keys are random
number symmetric keys, generated and RSA-sealed by the TPM.  The TPM
only unseals the keys, if the boot PCRs and other criteria match.
Userspace can only ever see encrypted blobs.

Based on suggestions by Jason Gunthorpe, several new options have been
added to support additional usages.

The new options are:
migratable=  designates that the key may/may not ever be updated
             (resealed under a new key, new pcrinfo or new auth.)

pcrlock=n    extends the designated PCR 'n' with a random value,
             so that a key sealed to that PCR may not be unsealed
             again until after a reboot.

keyhandle=   specifies the sealing/unsealing key handle.

keyauth=     specifies the sealing/unsealing key auth.

blobauth=    specifies the sealed data auth.

Implementation of a kernel reserved locality for trusted keys will be
investigated for a possible future extension.

Changelog:
- Updated and added examples to Documentation/keys-trusted-encrypted.txt
- Moved generic TPM constants to include/linux/tpm_command.h
  (David Howell's suggestion.)
- trusted_defined.c: replaced kzalloc with kmalloc, added pcrlock failure
  error handling, added const qualifiers where appropriate.
- moved to late_initcall
- updated from hash to shash (suggestion by David Howells)
- reduced worst stack usage (tpm_seal) from 530 to 312 bytes
- moved documentation to Documentation directory (suggestion by David Howells)
- all the other code cleanups suggested by David Howells
- Add pcrlock CAP_SYS_ADMIN dependency (based on comment by Jason Gunthorpe)
- New options: migratable, pcrlock, keyhandle, keyauth, blobauth (based on
  discussions with Jason Gunthorpe)
- Free payload on failure to create key(reported/fixed by Roberto Sassu)
- Updated Kconfig and other descriptions (based on Serge Hallyn's suggestion)
- Replaced kzalloc() with kmalloc() (reported by Serge Hallyn)

Signed-off-by: David Safford <safford@watson.ibm.com>
Signed-off-by: Mimi Zohar <zohar@us.ibm.com>
Signed-off-by: James Morris <jmorris@namei.org>

1 files changed, 1151 insertions, 0 deletions

diff --git a/security/keys/trusted_defined.c b/security/keys/trusted_defined.c
new file mode 100644
index 000000000000..1bec72e7596d
--- /dev/null
+++ b/security/keys/trusted_defined.c
@@ -0,0 +1,1151 @@
+/*
+ * 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 <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_defined.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, const 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,
+                       const 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)
+                        return -EINVAL;
+                ret = crypto_shash_update(&sdesc->shash, data, dlen);
+                if (ret < 0)
+                        goto out;
+        }
+        va_end(argp);
+        ret = crypto_shash_final(&sdesc->shash, digest);
+out:
+        kfree(sdesc);
+        return ret;
+}
+
+/*
+ * calculate authorization info fields to send to TPM
+ */
+static uint32_t TSS_authhmac(unsigned char *digest, const unsigned char *key,
+                             const 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 *);
+                ret = crypto_shash_update(&sdesc->shash, data, dlen);
+                if (ret < 0)
+                        goto out;
+        }
+        va_end(argp);
+        ret = crypto_shash_final(&sdesc->shash, paramdigest);
+        if (!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 uint32_t TSS_checkhmac1(unsigned char *buffer,
+                               const uint32_t command,
+                               const unsigned char *ononce,
+                               const unsigned char *key,
+                               const 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)
+                        goto out;
+        }
+        va_end(argp);
+        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 uint32_t TSS_checkhmac2(unsigned char *buffer,
+                               const uint32_t command,
+                               const unsigned char *ononce,
+                               const unsigned char *key1,
+                               const unsigned int keylen1,
+                               const unsigned char *key2,
+                               const 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)
+                        goto out;
+        }
+        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 (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 (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);
+        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 = kzalloc(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];
+
+        if (!capable(CAP_SYS_ADMIN))
+                return -EPERM;
+        my_get_random(hash, SHA1_DIGEST_SIZE);
+        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, const uint16_t type,
+                const 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);
+        ret = TSS_rawhmac(s->secret, key, SHA1_DIGEST_SIZE, TPM_NONCE_SIZE,
+                          enonce, TPM_NONCE_SIZE, ononce, 0, 0);
+        return ret;
+}
+
+/*
+ * 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 ret;
+}
+
+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, const uint16_t keytype,
+                    const uint32_t keyhandle, const unsigned char *keyauth,
+                    const unsigned char *data, const uint32_t datalen,
+                    unsigned char *blob, uint32_t *bloblen,
+                    const unsigned char *blobauth,
+                    const unsigned char *pcrinfo, const 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)
+                return ret;
+        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)
+                return ret;
+
+        ret = tpm_get_random(tb, td->nonceodd, TPM_NONCE_SIZE);
+        if (ret < 0)
+                return ret;
+        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 */
+                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 */
+                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);
+        }
+
+        /* 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)
+                return ret;
+
+        /* 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 */
+        memcpy(blob, tb->data + TPM_DATA_OFFSET, storedsize);
+        *bloblen = storedsize;
+        return ret;
+}
+
+/*
+ * use the AUTH2_COMMAND form of unseal, to authorize both key and blob
+ */
+static int tpm_unseal(struct tpm_buf *tb,
+                      const uint32_t keyhandle, const unsigned char *keyauth,
+                      const unsigned char *blob, const 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;
+        }
+        TSS_authhmac(authdata1, keyauth, TPM_NONCE_SIZE,
+                     enonce1, nonceodd, cont, sizeof(uint32_t),
+                     &ordinal, bloblen, blob, 0, 0);
+        TSS_authhmac(authdata2, blobauth, TPM_NONCE_SIZE,
+                     enonce2, nonceodd, cont, sizeof(uint32_t),
+                     &ordinal, bloblen, blob, 0, 0);
+
+        /* 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);
+        memcpy(data, tb->data + TPM_DATA_OFFSET + sizeof(uint32_t), *datalen);
+        return ret;
+}
+
+/*
+ * 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);
+        /* pull migratable flag out of sealed key */
+        p->migratable = p->key[--p->key_len];
+
+        if (ret < 0)
+                pr_info("trusted_key: srkunseal failed (%d)\n", ret);
+
+        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)
+                return 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);
+
+        /* migratable by default */
+        p->migratable = 1;
+        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,
+                               const 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,
+                          const 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;
+                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_protected(key->payload.data,
+                        rwsem_is_locked(&((struct key *)key)->sem));
+        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");