tpm: use struct tpm_chip for tpm_chip_find_get()
Device number (the character device index) is not a stable identifier
for a TPM chip. That is the reason why every call site passes
TPM_ANY_NUM to tpm_chip_find_get().
This commit changes the API in a way that instead a struct tpm_chip
instance is given and NULL means the default chip. In addition, this
commit refines the documentation to be up to date with the
implementation.
Suggested-by: Jason Gunthorpe <jgunthorpe@obsidianresearch.com> (@chip_num -> @chip part)
Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Reviewed-by: Jason Gunthorpe <jgg@ziepe.ca>
Tested-by: PrasannaKumar Muralidharan <prasannatsmkumar@gmail.com>
diff --git a/drivers/char/tpm/tpm-interface.c b/drivers/char/tpm/tpm-interface.c
index ebe0a1d..19f820f 100644
--- a/drivers/char/tpm/tpm-interface.c
+++ b/drivers/char/tpm/tpm-interface.c
@@ -809,19 +809,20 @@ int tpm_pcr_read_dev(struct tpm_chip *chip, int pcr_idx, u8 *res_buf)
}
/**
- * tpm_is_tpm2 - is the chip a TPM2 chip?
- * @chip_num: tpm idx # or ANY
+ * tpm_is_tpm2 - do we a have a TPM2 chip?
+ * @chip: a &struct tpm_chip instance, %NULL for the default chip
*
- * Returns < 0 on error, and 1 or 0 on success depending whether the chip
- * is a TPM2 chip.
+ * Return:
+ * 1 if we have a TPM2 chip.
+ * 0 if we don't have a TPM2 chip.
+ * A negative number for system errors (errno).
*/
-int tpm_is_tpm2(u32 chip_num)
+int tpm_is_tpm2(struct tpm_chip *chip)
{
- struct tpm_chip *chip;
int rc;
- chip = tpm_chip_find_get(chip_num);
- if (chip == NULL)
+ chip = tpm_chip_find_get(chip);
+ if (!chip)
return -ENODEV;
rc = (chip->flags & TPM_CHIP_FLAG_TPM2) != 0;
@@ -833,23 +834,19 @@ int tpm_is_tpm2(u32 chip_num)
EXPORT_SYMBOL_GPL(tpm_is_tpm2);
/**
- * tpm_pcr_read - read a pcr value
- * @chip_num: tpm idx # or ANY
- * @pcr_idx: pcr idx to retrieve
- * @res_buf: TPM_PCR value
- * size of res_buf is 20 bytes (or NULL if you don't care)
+ * tpm_pcr_read - read a PCR value from SHA1 bank
+ * @chip: a &struct tpm_chip instance, %NULL for the default chip
+ * @pcr_idx: the PCR to be retrieved
+ * @res_buf: the value of the PCR
*
- * The TPM driver should be built-in, but for whatever reason it
- * isn't, protect against the chip disappearing, by incrementing
- * the module usage count.
+ * Return: same as with tpm_transmit_cmd()
*/
-int tpm_pcr_read(u32 chip_num, int pcr_idx, u8 *res_buf)
+int tpm_pcr_read(struct tpm_chip *chip, int pcr_idx, u8 *res_buf)
{
- struct tpm_chip *chip;
int rc;
- chip = tpm_chip_find_get(chip_num);
- if (chip == NULL)
+ chip = tpm_chip_find_get(chip);
+ if (!chip)
return -ENODEV;
if (chip->flags & TPM_CHIP_FLAG_TPM2)
rc = tpm2_pcr_read(chip, pcr_idx, res_buf);
@@ -889,25 +886,26 @@ static int tpm1_pcr_extend(struct tpm_chip *chip, int pcr_idx, const u8 *hash,
}
/**
- * tpm_pcr_extend - extend pcr value with hash
- * @chip_num: tpm idx # or AN&
- * @pcr_idx: pcr idx to extend
- * @hash: hash value used to extend pcr value
+ * tpm_pcr_extend - extend a PCR value in SHA1 bank.
+ * @chip: a &struct tpm_chip instance, %NULL for the default chip
+ * @pcr_idx: the PCR to be retrieved
+ * @hash: the hash value used to extend the PCR value
*
- * The TPM driver should be built-in, but for whatever reason it
- * isn't, protect against the chip disappearing, by incrementing
- * the module usage count.
+ * Note: with TPM 2.0 extends also those banks with a known digest size to the
+ * cryto subsystem in order to prevent malicious use of those PCR banks. In the
+ * future we should dynamically determine digest sizes.
+ *
+ * Return: same as with tpm_transmit_cmd()
*/
-int tpm_pcr_extend(u32 chip_num, int pcr_idx, const u8 *hash)
+int tpm_pcr_extend(struct tpm_chip *chip, int pcr_idx, const u8 *hash)
{
int rc;
- struct tpm_chip *chip;
struct tpm2_digest digest_list[ARRAY_SIZE(chip->active_banks)];
u32 count = 0;
int i;
- chip = tpm_chip_find_get(chip_num);
- if (chip == NULL)
+ chip = tpm_chip_find_get(chip);
+ if (!chip)
return -ENODEV;
if (chip->flags & TPM_CHIP_FLAG_TPM2) {
@@ -1019,17 +1017,24 @@ int tpm1_auto_startup(struct tpm_chip *chip)
return rc;
}
-int tpm_send(u32 chip_num, void *cmd, size_t buflen)
+/**
+ * tpm_send - send a TPM command
+ * @chip: a &struct tpm_chip instance, %NULL for the default chip
+ * @cmd: a TPM command buffer
+ * @buflen: the length of the TPM command buffer
+ *
+ * Return: same as with tpm_transmit_cmd()
+ */
+int tpm_send(struct tpm_chip *chip, void *cmd, size_t buflen)
{
- struct tpm_chip *chip;
int rc;
- chip = tpm_chip_find_get(chip_num);
- if (chip == NULL)
+ chip = tpm_chip_find_get(chip);
+ if (!chip)
return -ENODEV;
rc = tpm_transmit_cmd(chip, NULL, cmd, buflen, 0, 0,
- "attempting tpm_cmd");
+ "attempting to a send a command");
tpm_put_ops(chip);
return rc;
}
@@ -1127,16 +1132,15 @@ static const struct tpm_input_header tpm_getrandom_header = {
};
/**
- * tpm_get_random() - Get random bytes from the tpm's RNG
- * @chip_num: A specific chip number for the request or TPM_ANY_NUM
- * @out: destination buffer for the random bytes
- * @max: the max number of bytes to write to @out
+ * tpm_get_random() - get random bytes from the TPM's RNG
+ * @chip: a &struct tpm_chip instance, %NULL for the default chip
+ * @out: destination buffer for the random bytes
+ * @max: the max number of bytes to write to @out
*
- * Returns < 0 on error and the number of bytes read on success
+ * Return: same as with tpm_transmit_cmd()
*/
-int tpm_get_random(u32 chip_num, u8 *out, size_t max)
+int tpm_get_random(struct tpm_chip *chip, u8 *out, size_t max)
{
- struct tpm_chip *chip;
struct tpm_cmd_t tpm_cmd;
u32 recd, num_bytes = min_t(u32, max, TPM_MAX_RNG_DATA), rlength;
int err, total = 0, retries = 5;
@@ -1145,8 +1149,8 @@ int tpm_get_random(u32 chip_num, u8 *out, size_t max)
if (!out || !num_bytes || max > TPM_MAX_RNG_DATA)
return -EINVAL;
- chip = tpm_chip_find_get(chip_num);
- if (chip == NULL)
+ chip = tpm_chip_find_get(chip);
+ if (!chip)
return -ENODEV;
if (chip->flags & TPM_CHIP_FLAG_TPM2) {
@@ -1188,22 +1192,23 @@ int tpm_get_random(u32 chip_num, u8 *out, size_t max)
EXPORT_SYMBOL_GPL(tpm_get_random);
/**
- * tpm_seal_trusted() - seal a trusted key
- * @chip_num: A specific chip number for the request or TPM_ANY_NUM
- * @options: authentication values and other options
- * @payload: the key data in clear and encrypted form
+ * tpm_seal_trusted() - seal a trusted key payload
+ * @chip: a &struct tpm_chip instance, %NULL for the default chip
+ * @options: authentication values and other options
+ * @payload: the key data in clear and encrypted form
*
- * Returns < 0 on error and 0 on success. At the moment, only TPM 2.0 chips
- * are supported.
+ * Note: only TPM 2.0 chip are supported. TPM 1.x implementation is located in
+ * the keyring subsystem.
+ *
+ * Return: same as with tpm_transmit_cmd()
*/
-int tpm_seal_trusted(u32 chip_num, struct trusted_key_payload *payload,
+int tpm_seal_trusted(struct tpm_chip *chip, struct trusted_key_payload *payload,
struct trusted_key_options *options)
{
- struct tpm_chip *chip;
int rc;
- chip = tpm_chip_find_get(chip_num);
- if (chip == NULL || !(chip->flags & TPM_CHIP_FLAG_TPM2))
+ chip = tpm_chip_find_get(chip);
+ if (!chip || !(chip->flags & TPM_CHIP_FLAG_TPM2))
return -ENODEV;
rc = tpm2_seal_trusted(chip, payload, options);
@@ -1215,21 +1220,23 @@ EXPORT_SYMBOL_GPL(tpm_seal_trusted);
/**
* tpm_unseal_trusted() - unseal a trusted key
- * @chip_num: A specific chip number for the request or TPM_ANY_NUM
- * @options: authentication values and other options
- * @payload: the key data in clear and encrypted form
+ * @chip: a &struct tpm_chip instance, %NULL for the default chip
+ * @options: authentication values and other options
+ * @payload: the key data in clear and encrypted form
*
- * Returns < 0 on error and 0 on success. At the moment, only TPM 2.0 chips
- * are supported.
+ * Note: only TPM 2.0 chip are supported. TPM 1.x implementation is located in
+ * the keyring subsystem.
+ *
+ * Return: same as with tpm_transmit_cmd()
*/
-int tpm_unseal_trusted(u32 chip_num, struct trusted_key_payload *payload,
+int tpm_unseal_trusted(struct tpm_chip *chip,
+ struct trusted_key_payload *payload,
struct trusted_key_options *options)
{
- struct tpm_chip *chip;
int rc;
- chip = tpm_chip_find_get(chip_num);
- if (chip == NULL || !(chip->flags & TPM_CHIP_FLAG_TPM2))
+ chip = tpm_chip_find_get(chip);
+ if (!chip || !(chip->flags & TPM_CHIP_FLAG_TPM2))
return -ENODEV;
rc = tpm2_unseal_trusted(chip, payload, options);