[PATCH v3 3/3] KEYS: trusted: Reserve TPM for seal and unseal operations
Jarkko Sakkinen
jarkko.sakkinen at linux.intel.com
Tue Oct 13 00:28:15 UTC 2020
When TPM 2.0 trusted keys code was moved to the trusted keys subsystem,
the operations were unwrapped from tpm_try_get_ops() and tpm_put_ops(),
which are used to take temporarily the ownership of the TPM chip. The
ownership is only taken inside tpm_send(), but this is not sufficient,
as in the key load TPM2_CC_LOAD, TPM2_CC_UNSEAL and TPM2_FLUSH_CONTEXT
need to be done as a one single atom.
Fix this issue by introducting trusted_tpm_load() and trusted_tpm_new(),
which wrap these operations, and take the TPM chip ownership before
sending anything. Use tpm_transmit_cmd() to send TPM commands instead
of tpm_send(), reverting back to the old behaviour.
Fixes: 2e19e10131a0 ("KEYS: trusted: Move TPM2 trusted keys code")
Reported-by: "James E.J. Bottomley" <James.Bottomley at HansenPartnership.com>
Cc: stable at vger.kernel.org
Cc: David Howells <dhowells at redhat.com>
Cc: Mimi Zohar <zohar at linux.ibm.com>
Cc: Sumit Garg <sumit.garg at linaro.org>
Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen at linux.intel.com>
Reported-by: kernel test robot <lkp at intel.com>
---
drivers/char/tpm/tpm.h | 4 --
include/linux/tpm.h | 17 ++++-
security/keys/trusted-keys/trusted_tpm1.c | 78 +++++++++++++++--------
security/keys/trusted-keys/trusted_tpm2.c | 6 +-
4 files changed, 72 insertions(+), 33 deletions(-)
diff --git a/drivers/char/tpm/tpm.h b/drivers/char/tpm/tpm.h
index 947d1db0a5cc..283f78211c3a 100644
--- a/drivers/char/tpm/tpm.h
+++ b/drivers/char/tpm/tpm.h
@@ -164,8 +164,6 @@ extern const struct file_operations tpmrm_fops;
extern struct idr dev_nums_idr;
ssize_t tpm_transmit(struct tpm_chip *chip, u8 *buf, size_t bufsiz);
-ssize_t tpm_transmit_cmd(struct tpm_chip *chip, struct tpm_buf *buf,
- size_t min_rsp_body_length, const char *desc);
int tpm_get_timeouts(struct tpm_chip *);
int tpm_auto_startup(struct tpm_chip *chip);
@@ -194,8 +192,6 @@ static inline void tpm_msleep(unsigned int delay_msec)
int tpm_chip_start(struct tpm_chip *chip);
void tpm_chip_stop(struct tpm_chip *chip);
struct tpm_chip *tpm_find_get_ops(struct tpm_chip *chip);
-__must_check int tpm_try_get_ops(struct tpm_chip *chip);
-void tpm_put_ops(struct tpm_chip *chip);
struct tpm_chip *tpm_chip_alloc(struct device *dev,
const struct tpm_class_ops *ops);
diff --git a/include/linux/tpm.h b/include/linux/tpm.h
index 8f4ff39f51e7..f0ebce14d2f8 100644
--- a/include/linux/tpm.h
+++ b/include/linux/tpm.h
@@ -397,6 +397,10 @@ static inline u32 tpm2_rc_value(u32 rc)
#if defined(CONFIG_TCG_TPM) || defined(CONFIG_TCG_TPM_MODULE)
extern int tpm_is_tpm2(struct tpm_chip *chip);
+extern __must_check int tpm_try_get_ops(struct tpm_chip *chip);
+extern void tpm_put_ops(struct tpm_chip *chip);
+extern ssize_t tpm_transmit_cmd(struct tpm_chip *chip, struct tpm_buf *buf,
+ size_t min_rsp_body_length, const char *desc);
extern int tpm_pcr_read(struct tpm_chip *chip, u32 pcr_idx,
struct tpm_digest *digest);
extern int tpm_pcr_extend(struct tpm_chip *chip, u32 pcr_idx,
@@ -410,7 +414,18 @@ static inline int tpm_is_tpm2(struct tpm_chip *chip)
{
return -ENODEV;
}
-
+static inline int tpm_try_get_ops(struct tpm_chip *chip)
+{
+ return -ENODEV;
+}
+static inline void tpm_put_ops(struct tpm_chip *chip)
+{
+}
+static inline ssize_t tpm_transmit_cmd(struct tpm_chip *chip, struct tpm_buf *buf,
+ size_t min_rsp_body_length, const char *desc)
+{
+ return -ENODEV;
+}
static inline int tpm_pcr_read(struct tpm_chip *chip, int pcr_idx,
struct tpm_digest *digest)
{
diff --git a/security/keys/trusted-keys/trusted_tpm1.c b/security/keys/trusted-keys/trusted_tpm1.c
index 7a937c3c5283..20ca18e17437 100644
--- a/security/keys/trusted-keys/trusted_tpm1.c
+++ b/security/keys/trusted-keys/trusted_tpm1.c
@@ -950,6 +950,51 @@ static struct trusted_key_payload *trusted_payload_alloc(struct key *key)
return p;
}
+static int trusted_tpm_load(struct tpm_chip *chip,
+ struct trusted_key_payload *payload,
+ struct trusted_key_options *options)
+{
+ int ret;
+
+ if (tpm_is_tpm2(chip)) {
+ ret = tpm_try_get_ops(chip);
+ if (!ret) {
+ ret = tpm2_unseal_trusted(chip, payload, options);
+ tpm_put_ops(chip);
+ }
+ } else {
+ ret = key_unseal(payload, options);
+ }
+
+ return ret;
+}
+
+static int trusted_tpm_new(struct tpm_chip *chip,
+ struct trusted_key_payload *payload,
+ struct trusted_key_options *options)
+{
+ int ret;
+
+ ret = tpm_get_random(chip, payload->key, payload->key_len);
+ if (ret < 0)
+ return ret;
+
+ if (ret != payload->key_len)
+ return -EIO;
+
+ if (tpm_is_tpm2(chip)) {
+ ret = tpm_try_get_ops(chip);
+ if (!ret) {
+ ret = tpm2_seal_trusted(chip, payload, options);
+ tpm_put_ops(chip);
+ }
+ } else {
+ ret = key_seal(payload, options);
+ }
+
+ return ret;
+}
+
/*
* trusted_instantiate - create a new trusted key
*
@@ -968,12 +1013,6 @@ static int trusted_instantiate(struct key *key,
char *datablob;
int ret = 0;
int key_cmd;
- size_t key_len;
- int tpm2;
-
- tpm2 = tpm_is_tpm2(chip);
- if (tpm2 < 0)
- return tpm2;
if (datalen <= 0 || datalen > 32767 || !prep->data)
return -EINVAL;
@@ -1011,32 +1050,21 @@ static int trusted_instantiate(struct key *key,
switch (key_cmd) {
case Opt_load:
- if (tpm2)
- ret = tpm2_unseal_trusted(chip, payload, options);
- else
- ret = key_unseal(payload, options);
+ ret = trusted_tpm_load(chip, payload, options);
+
dump_payload(payload);
dump_options(options);
+
if (ret < 0)
- pr_info("trusted_key: key_unseal failed (%d)\n", ret);
+ pr_info("%s: load failed (%d)\n", __func__, ret);
+
break;
case Opt_new:
- key_len = payload->key_len;
- ret = tpm_get_random(chip, payload->key, key_len);
- if (ret < 0)
- goto out;
+ ret = trusted_tpm_new(chip, payload, options);
- if (ret != key_len) {
- pr_info("trusted_key: key_create failed (%d)\n", ret);
- ret = -EIO;
- goto out;
- }
- if (tpm2)
- ret = tpm2_seal_trusted(chip, payload, options);
- else
- ret = key_seal(payload, options);
if (ret < 0)
- pr_info("trusted_key: key_seal failed (%d)\n", ret);
+ pr_info("%s: new failed (%d)\n", __func__, ret);
+
break;
default:
ret = -EINVAL;
diff --git a/security/keys/trusted-keys/trusted_tpm2.c b/security/keys/trusted-keys/trusted_tpm2.c
index 08ec7f48f01d..effdb67fac6d 100644
--- a/security/keys/trusted-keys/trusted_tpm2.c
+++ b/security/keys/trusted-keys/trusted_tpm2.c
@@ -130,7 +130,7 @@ int tpm2_seal_trusted(struct tpm_chip *chip,
goto out;
}
- rc = tpm_send(chip, buf.data, tpm_buf_length(&buf));
+ rc = tpm_transmit_cmd(chip, &buf, 4, "sealing data");
if (rc)
goto out;
@@ -211,7 +211,7 @@ static int tpm2_load_cmd(struct tpm_chip *chip,
goto out;
}
- rc = tpm_send(chip, buf.data, tpm_buf_length(&buf));
+ rc = tpm_transmit_cmd(chip, &buf, 4, "loading blob");
if (!rc)
*blob_handle = be32_to_cpup(
(__be32 *) &buf.data[TPM_HEADER_SIZE]);
@@ -260,7 +260,7 @@ static int tpm2_unseal_cmd(struct tpm_chip *chip,
options->blobauth /* hmac */,
TPM_DIGEST_SIZE);
- rc = tpm_send(chip, buf.data, tpm_buf_length(&buf));
+ rc = tpm_transmit_cmd(chip, &buf, 6, "unsealing");
if (rc > 0)
rc = -EPERM;
--
2.25.1
More information about the Linux-security-module-archive
mailing list