tpm: use u32 instead of int for PCR index

The TPM specs defines PCR index as a positive number, and there is
no reason to use a signed number. It is also a possible security
issue as currently no functions check for a negative index,
which may become a large number when converted to u32.

Adjust the API to use u32 instead of int in all PCR related
functions.
Signed-off-by: Tomas Winkler <tomas.winkler@intel.com>
Reviewed-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Tested-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>

drivers/char/tpm/tpm-interface.c

@@ -38,7 +38,7 @@
  * recently changed pcr on suspend, so force the flush
  * with an extend to the selected _unused_ non-volatile pcr.
  */
-static int tpm_suspend_pcr;
+static u32 tpm_suspend_pcr;
 module_param_named(suspend_pcr, tpm_suspend_pcr, uint, 0644);
 MODULE_PARM_DESC(suspend_pcr,
 		 "PCR to use for dummy writes to facilitate flush on suspend.");
@@ -454,7 +454,7 @@ EXPORT_SYMBOL_GPL(tpm_is_tpm2);
  *
  * Return: same as with tpm_transmit_cmd()
  */
-int tpm_pcr_read(struct tpm_chip *chip, int pcr_idx, u8 *res_buf)
+int tpm_pcr_read(struct tpm_chip *chip, u32 pcr_idx, u8 *res_buf)
 {
 	int rc;
 
@@ -484,7 +484,7 @@ EXPORT_SYMBOL_GPL(tpm_pcr_read);
  *
  * Return: same as with tpm_transmit_cmd()
  */
-int tpm_pcr_extend(struct tpm_chip *chip, int pcr_idx, const u8 *hash)
+int tpm_pcr_extend(struct tpm_chip *chip, u32 pcr_idx, const u8 *hash)
 {
 	int rc;
 	struct tpm2_digest digest_list[ARRAY_SIZE(chip->active_banks)];

drivers/char/tpm/tpm-sysfs.c

@@ -102,7 +102,7 @@ static ssize_t pcrs_show(struct device *dev, struct device_attribute *attr,
 	cap_t cap;
 	u8 digest[TPM_DIGEST_SIZE];
 	ssize_t rc;
-	int i, j, num_pcrs;
+	u32 i, j, num_pcrs;
 	char *str = buf;
 	struct tpm_chip *chip = to_tpm_chip(dev);
 

drivers/char/tpm/tpm.h

@@ -509,14 +509,14 @@ ssize_t tpm_transmit_cmd(struct tpm_chip *chip, struct tpm_space *space,
 int tpm_get_timeouts(struct tpm_chip *);
 int tpm_auto_startup(struct tpm_chip *chip);
 
-int tpm1_pm_suspend(struct tpm_chip *chip, int tpm_suspend_pcr);
+int tpm1_pm_suspend(struct tpm_chip *chip, u32 tpm_suspend_pcr);
 int tpm1_auto_startup(struct tpm_chip *chip);
 int tpm1_do_selftest(struct tpm_chip *chip);
 int tpm1_get_timeouts(struct tpm_chip *chip);
 unsigned long tpm1_calc_ordinal_duration(struct tpm_chip *chip, u32 ordinal);
-int tpm1_pcr_extend(struct tpm_chip *chip, int pcr_idx, const u8 *hash,
+int tpm1_pcr_extend(struct tpm_chip *chip, u32 pcr_idx, const u8 *hash,
 		    const char *log_msg);
-int tpm1_pcr_read(struct tpm_chip *chip, int pcr_idx, u8 *res_buf);
+int tpm1_pcr_read(struct tpm_chip *chip, u32 pcr_idx, u8 *res_buf);
 ssize_t tpm1_getcap(struct tpm_chip *chip, u32 subcap_id, cap_t *cap,
 		    const char *desc, size_t min_cap_length);
 int tpm1_get_random(struct tpm_chip *chip, u8 *out, size_t max);
@@ -558,8 +558,8 @@ static inline u32 tpm2_rc_value(u32 rc)
 }
 
 int tpm2_get_timeouts(struct tpm_chip *chip);
-int tpm2_pcr_read(struct tpm_chip *chip, int pcr_idx, u8 *res_buf);
-int tpm2_pcr_extend(struct tpm_chip *chip, int pcr_idx, u32 count,
+int tpm2_pcr_read(struct tpm_chip *chip, u32 pcr_idx, u8 *res_buf);
+int tpm2_pcr_extend(struct tpm_chip *chip, u32 pcr_idx, u32 count,
 		    struct tpm2_digest *digests);
 int tpm2_get_random(struct tpm_chip *chip, u8 *dest, size_t max);
 void tpm2_flush_context_cmd(struct tpm_chip *chip, u32 handle,

drivers/char/tpm/tpm1-cmd.c

@@ -449,7 +449,7 @@ int tpm1_get_timeouts(struct tpm_chip *chip)
 }
 
 #define TPM_ORD_PCR_EXTEND 20
-int tpm1_pcr_extend(struct tpm_chip *chip, int pcr_idx, const u8 *hash,
+int tpm1_pcr_extend(struct tpm_chip *chip, u32 pcr_idx, const u8 *hash,
 		    const char *log_msg)
 {
 	struct tpm_buf buf;
@@ -572,7 +572,7 @@ int tpm1_get_random(struct tpm_chip *chip, u8 *dest, size_t max)
 }
 
 #define TPM_ORD_PCRREAD 21
-int tpm1_pcr_read(struct tpm_chip *chip, int pcr_idx, u8 *res_buf)
+int tpm1_pcr_read(struct tpm_chip *chip, u32 pcr_idx, u8 *res_buf)
 {
 	struct tpm_buf buf;
 	int rc;
@@ -729,7 +729,7 @@ int tpm1_auto_startup(struct tpm_chip *chip)
  * * 0 on success,
  * * < 0 on error.
  */
-int tpm1_pm_suspend(struct tpm_chip *chip, int tpm_suspend_pcr)
+int tpm1_pm_suspend(struct tpm_chip *chip, u32 tpm_suspend_pcr)
 {
 	u8 dummy_hash[TPM_DIGEST_SIZE] = { 0 };
 	struct tpm_buf buf;

drivers/char/tpm/tpm2-cmd.c

@@ -175,7 +175,7 @@ struct tpm2_pcr_read_out {
  *
  * Return: Same as with tpm_transmit_cmd.
  */
-int tpm2_pcr_read(struct tpm_chip *chip, int pcr_idx, u8 *res_buf)
+int tpm2_pcr_read(struct tpm_chip *chip, u32 pcr_idx, u8 *res_buf)
 {
 	int rc;
 	struct tpm_buf buf;
@@ -225,7 +225,7 @@ struct tpm2_null_auth_area {
  *
  * Return: Same as with tpm_transmit_cmd.
  */
-int tpm2_pcr_extend(struct tpm_chip *chip, int pcr_idx, u32 count,
+int tpm2_pcr_extend(struct tpm_chip *chip, u32 pcr_idx, u32 count,
 		    struct tpm2_digest *digests)
 {
 	struct tpm_buf buf;
@@ -272,7 +272,6 @@ int tpm2_pcr_extend(struct tpm_chip *chip, int pcr_idx, u32 count,
 	return rc;
 }
 
-
 struct tpm2_get_random_out {
 	__be16 size;
 	u8 buffer[TPM_MAX_RNG_DATA];

include/linux/tpm.h

@@ -53,8 +53,8 @@ struct tpm_class_ops {
 #if defined(CONFIG_TCG_TPM) || defined(CONFIG_TCG_TPM_MODULE)
 
 extern int tpm_is_tpm2(struct tpm_chip *chip);
-extern int tpm_pcr_read(struct tpm_chip *chip, int pcr_idx, u8 *res_buf);
-extern int tpm_pcr_extend(struct tpm_chip *chip, int pcr_idx, const u8 *hash);
+extern int tpm_pcr_read(struct tpm_chip *chip, u32 pcr_idx, u8 *res_buf);
+extern int tpm_pcr_extend(struct tpm_chip *chip, u32 pcr_idx, const u8 *hash);
 extern int tpm_send(struct tpm_chip *chip, void *cmd, size_t buflen);
 extern int tpm_get_random(struct tpm_chip *chip, u8 *data, size_t max);
 extern int tpm_seal_trusted(struct tpm_chip *chip,
@@ -69,15 +69,18 @@ static inline int tpm_is_tpm2(struct tpm_chip *chip)
 {
 	return -ENODEV;
 }
-static inline int tpm_pcr_read(struct tpm_chip *chip, int pcr_idx, u8 *res_buf)
+
+static inline int tpm_pcr_read(struct tpm_chip *chip, u32 pcr_idx, u8 *res_buf)
 {
 	return -ENODEV;
 }
-static inline int tpm_pcr_extend(struct tpm_chip *chip, int pcr_idx,
+
+static inline int tpm_pcr_extend(struct tpm_chip *chip, u32 pcr_idx,
 				 const u8 *hash)
 {
 	return -ENODEV;
 }
+
 static inline int tpm_send(struct tpm_chip *chip, void *cmd, size_t buflen)
 {
 	return -ENODEV;

security/integrity/ima/ima_crypto.c

@@ -643,7 +643,7 @@ int ima_calc_buffer_hash(const void *buf, loff_t len,
 	return calc_buffer_shash(buf, len, hash);
 }
 
-static void __init ima_pcrread(int idx, u8 *pcr)
+static void __init ima_pcrread(u32 idx, u8 *pcr)
 {
 	if (!ima_tpm_chip)
 		return;
@@ -659,7 +659,8 @@ static int __init ima_calc_boot_aggregate_tfm(char *digest,
 					      struct crypto_shash *tfm)
 {
 	u8 pcr_i[TPM_DIGEST_SIZE];
-	int rc, i;
+	int rc;
+	u32 i;
 	SHASH_DESC_ON_STACK(shash, tfm);
 
 	shash->tfm = tfm;