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    SubjectRe: [PATCH 2/2] trusted-key: added support for loading a key blob in the TPM
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    On Wed, 2011-11-02 at 13:41 +0100, Roberto Sassu wrote:
    > The new functions 'tpm_loadkey2', 'tpm_evictkey' and 'tpm_flushspecific'
    > allow to load/unload a TPM key whose blob is provided from the userspace
    > interface and to use it for sealing or unsealing the symmetric key.

    This looks like a nice extension.
    I'll test it out thoroughly, but for now here are a couple of
    minor initial suggestions...

    dave

    >
    > Signed-off-by: Roberto Sassu <roberto.sassu@polito.it>
    > ---
    > Documentation/security/keys-trusted-encrypted.txt | 6 +-
    > include/linux/tpm_command.h | 6 +
    > security/keys/trusted.c | 203 ++++++++++++++++++++-
    > security/keys/trusted.h | 27 +++-
    > 4 files changed, 234 insertions(+), 8 deletions(-)
    >
    > diff --git a/Documentation/security/keys-trusted-encrypted.txt b/Documentation/security/keys-trusted-encrypted.txt
    > index 5f50cca..afebb58 100644
    > --- a/Documentation/security/keys-trusted-encrypted.txt
    > +++ b/Documentation/security/keys-trusted-encrypted.txt
    > @@ -27,8 +27,10 @@ Usage:
    > keyctl print keyid
    >
    > options:
    > - keyhandle= ascii hex value of sealing key default 0x40000000 (SRK)
    > - keyauth= ascii hex auth for sealing key default 0x00...i
    > + keyhandle= ascii hex value of sealing key handle default 0x40000000 (SRK)
    > + keyblob= ascii hex value of sealing key blob (no default)
    > + srkauth= ascii hex auth for SRK key default 0x00...
    > + keyauth= ascii hex auth for sealing key (not SRK) default 0x00...
    > (40 ascii zeros)
    > blobauth= ascii hex auth for sealed data default 0x00...
    > (40 ascii zeros)
    > diff --git a/include/linux/tpm_command.h b/include/linux/tpm_command.h
    > index 727512e..e3348b7 100644
    > --- a/include/linux/tpm_command.h
    > +++ b/include/linux/tpm_command.h
    > @@ -15,7 +15,10 @@
    > #define TPM_TAG_RSP_AUTH2_COMMAND 198
    >
    > /* Command Ordinals */
    > +#define TPM_ORD_EVICTKEY 34
    > +#define TPM_ORD_FLUSHSPECIFIC 186
    > #define TPM_ORD_GETRANDOM 70
    > +#define TPM_ORD_LOADKEY2 65
    > #define TPM_ORD_OSAP 11
    > #define TPM_ORD_OIAP 10
    > #define TPM_ORD_SEAL 23
    > @@ -24,5 +27,8 @@
    > /* Other constants */
    > #define SRKHANDLE 0x40000000
    > #define TPM_NONCE_SIZE 20
    > +#define TPM_RT_KEY 0x00000001
    > +#define TPM_TAG_KEY12 0x0028
    > +#define TPM_BAD_ORDINAL 10
    >
    > #endif
    > diff --git a/security/keys/trusted.c b/security/keys/trusted.c
    > index 8777015..c332e3b 100644
    > --- a/security/keys/trusted.c
    > +++ b/security/keys/trusted.c
    > @@ -688,12 +688,118 @@ static int tpm_unseal(struct tpm_buf *tb,
    > }
    >
    > /*
    > + * Load a TPM key from the blob provided by userspace
    > + */
    > +static int tpm_loadkey2(struct tpm_buf *tb,
    > + uint32_t keyhandle, unsigned char *keyauth,
    > + const unsigned char *keyblob, int keybloblen,
    > + uint32_t *newhandle)
    > +{
    > + unsigned char nonceodd[TPM_NONCE_SIZE];
    > + unsigned char enonce[TPM_NONCE_SIZE];
    > + unsigned char authdata[SHA1_DIGEST_SIZE];
    > + uint32_t authhandle = 0;
    > + unsigned char cont = 0;
    > + uint32_t ordinal;
    > + int ret;
    > +
    > + ordinal = htonl(TPM_ORD_LOADKEY2);
    > +
    > + /* session for loading the key */
    > + ret = oiap(tb, &authhandle, enonce);
    > + if (ret < 0) {
    > + pr_info("trusted_key: oiap failed (%d)\n", ret);
    > + return ret;
    > + }
    > +
    > + /* generate odd nonce */
    > + 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;
    > + }
    > +
    > + /* calculate authorization HMAC value */
    > + ret = TSS_authhmac(authdata, keyauth, SHA1_DIGEST_SIZE, enonce,
    > + nonceodd, cont, sizeof(uint32_t), &ordinal,
    > + keybloblen, keyblob, 0, 0);
    > + if (ret < 0)
    > + return ret;
    > +
    > + /* build the request buffer */
    > + INIT_BUF(tb);
    > + store16(tb, TPM_TAG_RQU_AUTH1_COMMAND);
    > + store32(tb, TPM_LOADKEY2_SIZE + keybloblen);
    > + store32(tb, TPM_ORD_LOADKEY2);
    > + store32(tb, keyhandle);
    > + storebytes(tb, keyblob, keybloblen);
    > + store32(tb, authhandle);
    > + storebytes(tb, nonceodd, TPM_NONCE_SIZE);
    > + store8(tb, cont);
    > + storebytes(tb, authdata, 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;
    > + }
    > +
    > + ret = TSS_checkhmac1(tb->data, ordinal, nonceodd, keyauth,
    > + SHA1_DIGEST_SIZE, 0, 0);
    > + if (ret < 0) {
    > + pr_info("trusted_key: TSS_checkhmac1 failed (%d)\n", ret);
    > + return ret;
    > + }
    > +
    > + *newhandle = LOAD32(tb->data, TPM_DATA_OFFSET);
    > + return 0;
    > +}
    > +
    > +/*
    > + * Execute the FlushSpecific TPM command
    > + */
    > +uint32_t tpm_flushspecific(struct tpm_buf *tb, uint32_t handle,
    > + uint32_t resourcetype)

    static?

    > +{
    > + INIT_BUF(tb);
    > + store16(tb, TPM_TAG_RQU_COMMAND);
    > + store32(tb, TPM_FLUSHSPECIFIC_SIZE);
    > + store32(tb, TPM_ORD_FLUSHSPECIFIC);
    > + store32(tb, handle);
    > + store32(tb, resourcetype);
    > +
    > + return trusted_tpm_send(TPM_ANY_NUM, tb->data, MAX_BUF_SIZE);
    > +}
    > +
    > +/*
    > + * Evict a key from the TPM
    > + */
    > +uint32_t tpm_evictkey(struct tpm_buf *tb, uint32_t keyhandle)

    static?

    > +{
    > + int ret;
    > +
    > + INIT_BUF(tb);
    > + store16(tb, TPM_TAG_RQU_COMMAND);
    > + store32(tb, TPM_EVICTKEY_SIZE);
    > + store32(tb, TPM_ORD_EVICTKEY);
    > + store32(tb, keyhandle);
    > +
    > + ret = trusted_tpm_send(TPM_ANY_NUM, tb->data, sizeof tb->data);
    > + if (ret < 0)
    > + ret = tpm_flushspecific(tb, keyhandle, TPM_RT_KEY);
    > +
    > + 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;
    > + uint32_t keyhandle;
    > + unsigned char *parentauth;
    > int ret;
    >
    > tb = kzalloc(sizeof *tb, GFP_KERNEL);
    > @@ -703,12 +809,40 @@ static int key_seal(struct trusted_key_payload *p,
    > /* 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,
    > + /* set default values */
    > + keyhandle = o->keyhandle;
    > + parentauth = o->srkauth;
    > +
    > + if (o->keytype == SEAL_keytype) {
    > + parentauth = o->keyauth;
    > + if (o->keyblob_len > 0) {
    > + ret = tpm_loadkey2(tb, SRKHANDLE, o->srkauth,
    > + o->keyblob, o->keyblob_len,
    > + &keyhandle);
    > + if (ret < 0) {
    > + pr_info("trusted_key: loadkey2 failed (%d)\n",
    > + ret);
    > + goto out;
    > + }
    > +
    > + dump_tpm_key12_handle(keyhandle);
    > + }
    > + }
    > +
    > + ret = tpm_seal(tb, o->keytype, keyhandle, parentauth,
    > 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);
    >
    > + if (o->keyblob_len > 0) {
    > + int evictret = tpm_evictkey(tb, keyhandle);
    > +
    > + if (evictret < 0)
    > + pr_info("trusted_key: evictkey failed (%d)\n",
    > + evictret);
    > + }
    > +out:
    > kfree(tb);
    > return ret;
    > }
    > @@ -720,13 +854,33 @@ static int key_unseal(struct trusted_key_payload *p,
    > struct trusted_key_options *o)
    > {
    > struct tpm_buf *tb;
    > + uint32_t keyhandle;
    > + unsigned char *parentauth;
    > 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,
    > + /* set default values */
    > + keyhandle = o->keyhandle;
    > + parentauth = o->srkauth;
    > +
    > + if (o->keytype == SEAL_keytype) {
    > + parentauth = o->keyauth;
    > + if (o->keyblob_len > 0) {
    > + ret = tpm_loadkey2(tb, SRKHANDLE, o->srkauth,
    > + o->keyblob, o->keyblob_len,
    > + &keyhandle);
    > + if (ret < 0) {
    > + pr_info("trusted_key: loadkey2 failed (%d)\n",
    > + ret);
    > + goto out;
    > + }
    > + }
    > + }
    > +
    > + ret = tpm_unseal(tb, keyhandle, parentauth, p->blob, p->blob_len,
    > o->blobauth, p->key, &p->key_len);
    > if (ret < 0)
    > pr_info("trusted_key: srkunseal failed (%d)\n", ret);
    > @@ -734,14 +888,22 @@ static int key_unseal(struct trusted_key_payload *p,
    > /* pull migratable flag out of sealed key */
    > p->migratable = p->key[--p->key_len];
    >
    > + if (o->keyblob_len > 0) {
    > + int evictret = tpm_evictkey(tb, keyhandle);
    > +
    > + if (evictret < 0)
    > + pr_info("trusted_key: evictkey failed (%d)\n",
    > + evictret);
    > + }
    > +out:
    > kfree(tb);
    > return ret;
    > }
    >
    > enum {
    > Opt_err = -1,
    > - Opt_new, Opt_load, Opt_update,
    > - Opt_keyhandle, Opt_keyauth, Opt_blobauth,
    > + Opt_new, Opt_load, Opt_update, Opt_srkauth,
    > + Opt_keyhandle, Opt_keyblob, Opt_keyauth, Opt_blobauth,
    > Opt_pcrinfo, Opt_pcrlock, Opt_migratable
    > };
    >
    > @@ -749,7 +911,9 @@ static const match_table_t key_tokens = {
    > {Opt_new, "new"},
    > {Opt_load, "load"},
    > {Opt_update, "update"},
    > + {Opt_srkauth, "srkauth=%s"},
    > {Opt_keyhandle, "keyhandle=%s"},
    > + {Opt_keyblob, "keyblob=%s"},
    > {Opt_keyauth, "keyauth=%s"},
    > {Opt_blobauth, "blobauth=%s"},
    > {Opt_pcrinfo, "pcrinfo=%s"},
    > @@ -768,6 +932,8 @@ static int getoptions(char *c, struct trusted_key_payload *pay,
    > int res;
    > unsigned long handle;
    > unsigned long lock;
    > + uint16_t tpm_key_tag;
    > + uint32_t value;
    >
    > while ((p = strsep(&c, " \t"))) {
    > if (*p == '\0' || *p == ' ' || *p == '\t')
    > @@ -788,6 +954,35 @@ static int getoptions(char *c, struct trusted_key_payload *pay,
    > opt->keytype = SEAL_keytype;
    > opt->keyhandle = handle;
    > break;
    > + case Opt_keyblob:
    > + if (strlen(args[0].from) >= MAX_KEYBLOB_SIZE * 2)
    > + return -EINVAL;
    > + hex2bin(opt->keyblob, args[0].from, MAX_KEYBLOB_SIZE);
    > + tpm_key_tag = LOAD16(opt->keyblob, 0);
    > + if (tpm_key_tag != TPM_TAG_KEY12)
    > + return -EINVAL;
    > + opt->keytype = SEAL_keytype;
    > + opt->keyblob_len = TPM_KEY12_EXPSIZE_OFFSET;
    > + /* key exponent size */
    > + value = LOAD32(opt->keyblob, opt->keyblob_len);
    > + opt->keyblob_len += sizeof(uint32_t) + value;
    > + /* PCRINFO size */
    > + value = LOAD32(opt->keyblob, opt->keyblob_len);
    > + opt->keyblob_len += sizeof(uint32_t) + value;
    > + /* key length */
    > + value = LOAD32(opt->keyblob, opt->keyblob_len);
    > + opt->keyblob_len += sizeof(uint32_t) + value;
    > + /* enc data size */
    > + value = LOAD32(opt->keyblob, opt->keyblob_len);
    > + opt->keyblob_len += sizeof(uint32_t) + value;
    > + if (opt->keyblob_len >= MAX_KEYBLOB_SIZE)
    > + return -EINVAL;
    > + break;
    > + case Opt_srkauth:
    > + if (strlen(args[0].from) != 2 * SHA1_DIGEST_SIZE)
    > + return -EINVAL;
    > + hex2bin(opt->srkauth, args[0].from, SHA1_DIGEST_SIZE);
    > + break;
    > case Opt_keyauth:
    > if (strlen(args[0].from) != 2 * SHA1_DIGEST_SIZE)
    > return -EINVAL;
    > diff --git a/security/keys/trusted.h b/security/keys/trusted.h
    > index 3249fbd..6a9f373 100644
    > --- a/security/keys/trusted.h
    > +++ b/security/keys/trusted.h
    > @@ -3,12 +3,16 @@
    >
    > /* implementation specific TPM constants */
    > #define MAX_PCRINFO_SIZE 64
    > -#define MAX_BUF_SIZE 512
    > +#define MAX_BUF_SIZE 1024
    > +#define MAX_KEYBLOB_SIZE 1024
    > #define TPM_GETRANDOM_SIZE 14
    > #define TPM_OSAP_SIZE 36
    > #define TPM_OIAP_SIZE 10
    > #define TPM_SEAL_SIZE 87
    > #define TPM_UNSEAL_SIZE 104
    > +#define TPM_LOADKEY2_SIZE 59
    > +#define TPM_EVICTKEY_SIZE 14
    > +#define TPM_FLUSHSPECIFIC_SIZE 18
    > #define TPM_SIZE_OFFSET 2
    > #define TPM_RETURN_OFFSET 6
    > #define TPM_DATA_OFFSET 10
    > @@ -17,6 +21,8 @@
    > #define LOAD32N(buffer, offset) (*(uint32_t *)&buffer[offset])
    > #define LOAD16(buffer, offset) (ntohs(*(uint16_t *)&buffer[offset]))
    >
    > +#define TPM_KEY12_EXPSIZE_OFFSET 31
    > +
    > struct tpm_buf {
    > int len;
    > unsigned char data[MAX_BUF_SIZE];
    > @@ -39,6 +45,9 @@ enum {
    > struct trusted_key_options {
    > uint16_t keytype;
    > uint32_t keyhandle;
    > + uint32_t keyblob_len;
    > + unsigned char keyblob[MAX_KEYBLOB_SIZE];
    > + unsigned char srkauth[SHA1_DIGEST_SIZE];
    > unsigned char keyauth[SHA1_DIGEST_SIZE];
    > unsigned char blobauth[SHA1_DIGEST_SIZE];
    > uint32_t pcrinfo_len;
    > @@ -52,7 +61,12 @@ struct trusted_key_options {
    > static inline void dump_options(struct trusted_key_options *o)
    > {
    > pr_info("trusted_key: sealing key type %d\n", o->keytype);
    > - pr_info("trusted_key: sealing key handle %0X\n", o->keyhandle);
    > + if (o->keyblob_len > 0) {
    > + pr_info("trusted_key: sealing key blob %d\n", o->keyblob_len);
    > + print_hex_dump(KERN_INFO, "keyblob ", DUMP_PREFIX_NONE,
    > + 16, 1, o->keyblob, o->keyblob_len, 0);
    > + } else
    > + pr_info("trusted_key: sealing key handle %0X\n", o->keyhandle);
    > pr_info("trusted_key: pcrlock %d\n", o->pcrlock);
    > pr_info("trusted_key: pcrinfo %d\n", o->pcrinfo_len);
    > print_hex_dump(KERN_INFO, "pcrinfo ", DUMP_PREFIX_NONE,
    > @@ -90,6 +104,11 @@ static inline void dump_tpm_buf(unsigned char *buf)
    > len = LOAD32(buf, TPM_SIZE_OFFSET);
    > print_hex_dump(KERN_INFO, "", DUMP_PREFIX_NONE, 16, 1, buf, len, 0);
    > }
    > +static inline void dump_tpm_key12_handle(uint32_t handle)
    > +{
    > + print_hex_dump(KERN_INFO, "trusted-key: key handle ", DUMP_PREFIX_NONE,
    > + 16, 1, &handle, 4, 0);
    > +}
    > #else
    > static inline void dump_options(struct trusted_key_options *o)
    > {
    > @@ -106,6 +125,10 @@ static inline void dump_sess(struct osapsess *s)
    > static inline void dump_tpm_buf(unsigned char *buf)
    > {
    > }
    > +
    > +static inline void dump_tpm_key12_handle(uint32_t handle)
    > +{
    > +}
    > #endif
    >
    > static inline void store8(struct tpm_buf *buf, const unsigned char value)



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