[Patch v6 2/4] KEYS: Use common tpm_buf for trusted and asymmetric keys

From: Sumit Garg
Date: Mon Sep 16 2019 - 06:35:19 EST

Switch to utilize common heap based tpm_buf code for TPM based trusted
and asymmetric keys rather than using stack based tpm1_buf code. Also,
remove tpm1_buf code.

Suggested-by: Jarkko Sakkinen <jarkko.sakkinen@xxxxxxxxxxxxxxx>
Signed-off-by: Sumit Garg <sumit.garg@xxxxxxxxxx>
---
crypto/asymmetric_keys/asym_tpm.c | 107 ++++++++++++++++----------------------
include/keys/trusted.h | 37 +------------
security/keys/trusted.c | 98 +++++++++++++++-------------------
3 files changed, 89 insertions(+), 153 deletions(-)

diff --git a/crypto/asymmetric_keys/asym_tpm.c b/crypto/asymmetric_keys/asym_tpm.c
index b88968d..a2b2a61 100644
--- a/crypto/asymmetric_keys/asym_tpm.c
+++ b/crypto/asymmetric_keys/asym_tpm.c
@@ -21,17 +21,13 @@
#define TPM_ORD_LOADKEY2 65
#define TPM_ORD_UNBIND 30
#define TPM_ORD_SIGN 60
-#define TPM_LOADKEY2_SIZE 59
-#define TPM_FLUSHSPECIFIC_SIZE 18
-#define TPM_UNBIND_SIZE 63
-#define TPM_SIGN_SIZE 63

#define TPM_RT_KEY 0x00000001

/*
* Load a TPM key from the blob provided by userspace
*/
-static int tpm_loadkey2(struct tpm1_buf *tb,
+static int tpm_loadkey2(struct tpm_buf *tb,
uint32_t keyhandle, unsigned char *keyauth,
const unsigned char *keyblob, int keybloblen,
uint32_t *newhandle)
@@ -68,16 +64,13 @@ static int tpm_loadkey2(struct tpm1_buf *tb,
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);
+ tpm_buf_reset(tb, TPM_TAG_RQU_AUTH1_COMMAND, TPM_ORD_LOADKEY2);
+ tpm_buf_append_u32(tb, keyhandle);
+ tpm_buf_append(tb, keyblob, keybloblen);
+ tpm_buf_append_u32(tb, authhandle);
+ tpm_buf_append(tb, nonceodd, TPM_NONCE_SIZE);
+ tpm_buf_append_u8(tb, cont);
+ tpm_buf_append(tb, authdata, SHA1_DIGEST_SIZE);

ret = trusted_tpm_send(tb->data, MAX_BUF_SIZE);
if (ret < 0) {
@@ -99,14 +92,11 @@ static int tpm_loadkey2(struct tpm1_buf *tb,
/*
* Execute the FlushSpecific TPM command
*/
-static int tpm_flushspecific(struct tpm1_buf *tb, uint32_t handle)
+static int tpm_flushspecific(struct tpm_buf *tb, uint32_t handle)
{
- INIT_BUF(tb);
- store16(tb, TPM_TAG_RQU_COMMAND);
- store32(tb, TPM_FLUSHSPECIFIC_SIZE);
- store32(tb, TPM_ORD_FLUSHSPECIFIC);
- store32(tb, handle);
- store32(tb, TPM_RT_KEY);
+ tpm_buf_reset(tb, TPM_TAG_RQU_COMMAND, TPM_ORD_FLUSHSPECIFIC);
+ tpm_buf_append_u32(tb, handle);
+ tpm_buf_append_u32(tb, TPM_RT_KEY);

return trusted_tpm_send(tb->data, MAX_BUF_SIZE);
}
@@ -115,7 +105,7 @@ static int tpm_flushspecific(struct tpm1_buf *tb, uint32_t handle)
* Decrypt a blob provided by userspace using a specific key handle.
* The handle is a well known handle or previously loaded by e.g. LoadKey2
*/
-static int tpm_unbind(struct tpm1_buf *tb,
+static int tpm_unbind(struct tpm_buf *tb,
uint32_t keyhandle, unsigned char *keyauth,
const unsigned char *blob, uint32_t bloblen,
void *out, uint32_t outlen)
@@ -155,17 +145,14 @@ static int tpm_unbind(struct tpm1_buf *tb,
return ret;

/* build the request buffer */
- INIT_BUF(tb);
- store16(tb, TPM_TAG_RQU_AUTH1_COMMAND);
- store32(tb, TPM_UNBIND_SIZE + bloblen);
- store32(tb, TPM_ORD_UNBIND);
- store32(tb, keyhandle);
- store32(tb, bloblen);
- storebytes(tb, blob, bloblen);
- store32(tb, authhandle);
- storebytes(tb, nonceodd, TPM_NONCE_SIZE);
- store8(tb, cont);
- storebytes(tb, authdata, SHA1_DIGEST_SIZE);
+ tpm_buf_reset(tb, TPM_TAG_RQU_AUTH1_COMMAND, TPM_ORD_UNBIND);
+ tpm_buf_append_u32(tb, keyhandle);
+ tpm_buf_append_u32(tb, bloblen);
+ tpm_buf_append(tb, blob, bloblen);
+ tpm_buf_append_u32(tb, authhandle);
+ tpm_buf_append(tb, nonceodd, TPM_NONCE_SIZE);
+ tpm_buf_append_u8(tb, cont);
+ tpm_buf_append(tb, authdata, SHA1_DIGEST_SIZE);

ret = trusted_tpm_send(tb->data, MAX_BUF_SIZE);
if (ret < 0) {
@@ -201,7 +188,7 @@ static int tpm_unbind(struct tpm1_buf *tb,
* up to key_length_in_bytes - 11 and not be limited to size 20 like the
* TPM_SS_RSASSAPKCS1v15_SHA1 signature scheme.
*/
-static int tpm_sign(struct tpm1_buf *tb,
+static int tpm_sign(struct tpm_buf *tb,
uint32_t keyhandle, unsigned char *keyauth,
const unsigned char *blob, uint32_t bloblen,
void *out, uint32_t outlen)
@@ -241,17 +228,14 @@ static int tpm_sign(struct tpm1_buf *tb,
return ret;

/* build the request buffer */
- INIT_BUF(tb);
- store16(tb, TPM_TAG_RQU_AUTH1_COMMAND);
- store32(tb, TPM_SIGN_SIZE + bloblen);
- store32(tb, TPM_ORD_SIGN);
- store32(tb, keyhandle);
- store32(tb, bloblen);
- storebytes(tb, blob, bloblen);
- store32(tb, authhandle);
- storebytes(tb, nonceodd, TPM_NONCE_SIZE);
- store8(tb, cont);
- storebytes(tb, authdata, SHA1_DIGEST_SIZE);
+ tpm_buf_reset(tb, TPM_TAG_RQU_AUTH1_COMMAND, TPM_ORD_SIGN);
+ tpm_buf_append_u32(tb, keyhandle);
+ tpm_buf_append_u32(tb, bloblen);
+ tpm_buf_append(tb, blob, bloblen);
+ tpm_buf_append_u32(tb, authhandle);
+ tpm_buf_append(tb, nonceodd, TPM_NONCE_SIZE);
+ tpm_buf_append_u8(tb, cont);
+ tpm_buf_append(tb, authdata, SHA1_DIGEST_SIZE);

ret = trusted_tpm_send(tb->data, MAX_BUF_SIZE);
if (ret < 0) {
@@ -519,7 +503,7 @@ static int tpm_key_decrypt(struct tpm_key *tk,
struct kernel_pkey_params *params,
const void *in, void *out)
{
- struct tpm1_buf *tb;
+ struct tpm_buf tb;
uint32_t keyhandle;
uint8_t srkauth[SHA1_DIGEST_SIZE];
uint8_t keyauth[SHA1_DIGEST_SIZE];
@@ -533,14 +517,14 @@ static int tpm_key_decrypt(struct tpm_key *tk,
if (strcmp(params->encoding, "pkcs1"))
return -ENOPKG;

- tb = kzalloc(sizeof(*tb), GFP_KERNEL);
- if (!tb)
- return -ENOMEM;
+ r = tpm_buf_init(&tb, 0, 0);
+ if (r)
+ return r;

/* TODO: Handle a non-all zero SRK authorization */
memset(srkauth, 0, sizeof(srkauth));

- r = tpm_loadkey2(tb, SRKHANDLE, srkauth,
+ r = tpm_loadkey2(&tb, SRKHANDLE, srkauth,
tk->blob, tk->blob_len, &keyhandle);
if (r < 0) {
pr_devel("loadkey2 failed (%d)\n", r);
@@ -550,16 +534,16 @@ static int tpm_key_decrypt(struct tpm_key *tk,
/* TODO: Handle a non-all zero key authorization */
memset(keyauth, 0, sizeof(keyauth));

- r = tpm_unbind(tb, keyhandle, keyauth,
+ r = tpm_unbind(&tb, keyhandle, keyauth,
in, params->in_len, out, params->out_len);
if (r < 0)
pr_devel("tpm_unbind failed (%d)\n", r);

- if (tpm_flushspecific(tb, keyhandle) < 0)
+ if (tpm_flushspecific(&tb, keyhandle) < 0)
pr_devel("flushspecific failed (%d)\n", r);

error:
- kzfree(tb);
+ tpm_buf_destroy(&tb);
pr_devel("<==%s() = %d\n", __func__, r);
return r;
}
@@ -643,7 +627,7 @@ static int tpm_key_sign(struct tpm_key *tk,
struct kernel_pkey_params *params,
const void *in, void *out)
{
- struct tpm1_buf *tb;
+ struct tpm_buf tb;
uint32_t keyhandle;
uint8_t srkauth[SHA1_DIGEST_SIZE];
uint8_t keyauth[SHA1_DIGEST_SIZE];
@@ -681,15 +665,14 @@ static int tpm_key_sign(struct tpm_key *tk,
goto error_free_asn1_wrapped;
}

- r = -ENOMEM;
- tb = kzalloc(sizeof(*tb), GFP_KERNEL);
- if (!tb)
+ r = tpm_buf_init(&tb, 0, 0);
+ if (r)
goto error_free_asn1_wrapped;

/* TODO: Handle a non-all zero SRK authorization */
memset(srkauth, 0, sizeof(srkauth));

- r = tpm_loadkey2(tb, SRKHANDLE, srkauth,
+ r = tpm_loadkey2(&tb, SRKHANDLE, srkauth,
tk->blob, tk->blob_len, &keyhandle);
if (r < 0) {
pr_devel("loadkey2 failed (%d)\n", r);
@@ -699,15 +682,15 @@ static int tpm_key_sign(struct tpm_key *tk,
/* TODO: Handle a non-all zero key authorization */
memset(keyauth, 0, sizeof(keyauth));

- r = tpm_sign(tb, keyhandle, keyauth, in, in_len, out, params->out_len);
+ r = tpm_sign(&tb, keyhandle, keyauth, in, in_len, out, params->out_len);
if (r < 0)
pr_devel("tpm_sign failed (%d)\n", r);

- if (tpm_flushspecific(tb, keyhandle) < 0)
+ if (tpm_flushspecific(&tb, keyhandle) < 0)
pr_devel("flushspecific failed (%d)\n", r);

error_free_tb:
- kzfree(tb);
+ tpm_buf_destroy(&tb);
error_free_asn1_wrapped:
kfree(asn1_wrapped);
pr_devel("<==%s() = %d\n", __func__, r);
diff --git a/include/keys/trusted.h b/include/keys/trusted.h
index 841ae11..29e3e9b 100644
--- a/include/keys/trusted.h
+++ b/include/keys/trusted.h
@@ -5,10 +5,6 @@
/* implementation specific TPM constants */
#define MAX_BUF_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_SIZE_OFFSET 2
#define TPM_RETURN_OFFSET 6
#define TPM_DATA_OFFSET 10
@@ -17,13 +13,6 @@
#define LOAD32N(buffer, offset) (*(uint32_t *)&buffer[offset])
#define LOAD16(buffer, offset) (ntohs(*(uint16_t *)&buffer[offset]))

-struct tpm1_buf {
- int len;
- unsigned char data[MAX_BUF_SIZE];
-};
-
-#define INIT_BUF(tb) (tb->len = 0)
-
struct osapsess {
uint32_t handle;
unsigned char secret[SHA1_DIGEST_SIZE];
@@ -46,7 +35,7 @@ int TSS_checkhmac1(unsigned char *buffer,
unsigned int keylen, ...);

int trusted_tpm_send(unsigned char *cmd, size_t buflen);
-int oiap(struct tpm1_buf *tb, uint32_t *handle, unsigned char *nonce);
+int oiap(struct tpm_buf *tb, uint32_t *handle, unsigned char *nonce);

#define TPM_DEBUG 0

@@ -109,28 +98,4 @@ static inline void dump_tpm_buf(unsigned char *buf)
{
}
#endif
-
-static inline void store8(struct tpm1_buf *buf, const unsigned char value)
-{
- buf->data[buf->len++] = value;
-}
-
-static inline void store16(struct tpm1_buf *buf, const uint16_t value)
-{
- *(uint16_t *) & buf->data[buf->len] = htons(value);
- buf->len += sizeof value;
-}
-
-static inline void store32(struct tpm1_buf *buf, const uint32_t value)
-{
- *(uint32_t *) & buf->data[buf->len] = htonl(value);
- buf->len += sizeof value;
-}
-
-static inline void storebytes(struct tpm1_buf *buf, const unsigned char *in,
- const int len)
-{
- memcpy(buf->data + buf->len, in, len);
- buf->len += len;
-}
#endif
diff --git a/security/keys/trusted.c b/security/keys/trusted.c
index 4cfae208..7071011 100644
--- a/security/keys/trusted.c
+++ b/security/keys/trusted.c
@@ -395,7 +395,7 @@ static int pcrlock(const int pcrnum)
/*
* Create an object specific authorisation protocol (OSAP) session
*/
-static int osap(struct tpm1_buf *tb, struct osapsess *s,
+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];
@@ -406,13 +406,10 @@ static int osap(struct tpm1_buf *tb, struct osapsess *s,
if (ret != TPM_NONCE_SIZE)
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);
+ tpm_buf_reset(tb, TPM_TAG_RQU_COMMAND, TPM_ORD_OSAP);
+ tpm_buf_append_u16(tb, type);
+ tpm_buf_append_u32(tb, handle);
+ tpm_buf_append(tb, ononce, TPM_NONCE_SIZE);

ret = trusted_tpm_send(tb->data, MAX_BUF_SIZE);
if (ret < 0)
@@ -430,17 +427,14 @@ static int osap(struct tpm1_buf *tb, struct osapsess *s,
/*
* Create an object independent authorisation protocol (oiap) session
*/
-int oiap(struct tpm1_buf *tb, uint32_t *handle, unsigned char *nonce)
+int oiap(struct tpm_buf *tb, uint32_t *handle, unsigned char *nonce)
{
int ret;

if (!chip)
return -ENODEV;

- INIT_BUF(tb);
- store16(tb, TPM_TAG_RQU_COMMAND);
- store32(tb, TPM_OIAP_SIZE);
- store32(tb, TPM_ORD_OIAP);
+ tpm_buf_reset(tb, TPM_TAG_RQU_COMMAND, TPM_ORD_OIAP);
ret = trusted_tpm_send(tb->data, MAX_BUF_SIZE);
if (ret < 0)
return ret;
@@ -464,7 +458,7 @@ struct tpm_digests {
* Have the TPM seal(encrypt) the trusted key, possibly based on
* Platform Configuration Registers (PCRs). AUTH1 for sealing key.
*/
-static int tpm_seal(struct tpm1_buf *tb, uint16_t keytype,
+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,
@@ -535,20 +529,17 @@ static int tpm_seal(struct tpm1_buf *tb, uint16_t keytype,
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);
+ tpm_buf_reset(tb, TPM_TAG_RQU_AUTH1_COMMAND, TPM_ORD_SEAL);
+ tpm_buf_append_u32(tb, keyhandle);
+ tpm_buf_append(tb, td->encauth, SHA1_DIGEST_SIZE);
+ tpm_buf_append_u32(tb, pcrinfosize);
+ tpm_buf_append(tb, pcrinfo, pcrinfosize);
+ tpm_buf_append_u32(tb, datalen);
+ tpm_buf_append(tb, data, datalen);
+ tpm_buf_append_u32(tb, sess.handle);
+ tpm_buf_append(tb, td->nonceodd, TPM_NONCE_SIZE);
+ tpm_buf_append_u8(tb, cont);
+ tpm_buf_append(tb, td->pubauth, SHA1_DIGEST_SIZE);

ret = trusted_tpm_send(tb->data, MAX_BUF_SIZE);
if (ret < 0)
@@ -579,7 +570,7 @@ static int tpm_seal(struct tpm1_buf *tb, uint16_t keytype,
/*
* use the AUTH2_COMMAND form of unseal, to authorize both key and blob
*/
-static int tpm_unseal(struct tpm1_buf *tb,
+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,
@@ -628,20 +619,17 @@ static int tpm_unseal(struct tpm1_buf *tb,
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);
+ tpm_buf_reset(tb, TPM_TAG_RQU_AUTH2_COMMAND, TPM_ORD_UNSEAL);
+ tpm_buf_append_u32(tb, keyhandle);
+ tpm_buf_append(tb, blob, bloblen);
+ tpm_buf_append_u32(tb, authhandle1);
+ tpm_buf_append(tb, nonceodd, TPM_NONCE_SIZE);
+ tpm_buf_append_u8(tb, cont);
+ tpm_buf_append(tb, authdata1, SHA1_DIGEST_SIZE);
+ tpm_buf_append_u32(tb, authhandle2);
+ tpm_buf_append(tb, nonceodd, TPM_NONCE_SIZE);
+ tpm_buf_append_u8(tb, cont);
+ tpm_buf_append(tb, authdata2, SHA1_DIGEST_SIZE);

ret = trusted_tpm_send(tb->data, MAX_BUF_SIZE);
if (ret < 0) {
@@ -670,23 +658,23 @@ static int tpm_unseal(struct tpm1_buf *tb,
static int key_seal(struct trusted_key_payload *p,
struct trusted_key_options *o)
{
- struct tpm1_buf *tb;
+ struct tpm_buf tb;
int ret;

- tb = kzalloc(sizeof *tb, GFP_KERNEL);
- if (!tb)
- return -ENOMEM;
+ ret = tpm_buf_init(&tb, 0, 0);
+ if (ret)
+ return ret;

/* 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,
+ 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);

- kzfree(tb);
+ tpm_buf_destroy(&tb);
return ret;
}

@@ -696,14 +684,14 @@ static int key_seal(struct trusted_key_payload *p,
static int key_unseal(struct trusted_key_payload *p,
struct trusted_key_options *o)
{
- struct tpm1_buf *tb;
+ struct tpm_buf tb;
int ret;

- tb = kzalloc(sizeof *tb, GFP_KERNEL);
- if (!tb)
- return -ENOMEM;
+ ret = tpm_buf_init(&tb, 0, 0);
+ if (ret)
+ return ret;

- ret = tpm_unseal(tb, o->keyhandle, o->keyauth, p->blob, p->blob_len,
+ 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);
@@ -711,7 +699,7 @@ static int key_unseal(struct trusted_key_payload *p,
/* pull migratable flag out of sealed key */
p->migratable = p->key[--p->key_len];

- kzfree(tb);
+ tpm_buf_destroy(&tb);
return ret;
}

--
2.7.4