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Date:   Tue, 23 Oct 2018 21:55:03 +0300 (EEST)
From:   Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
To:     Tomas Winkler <tomas.winkler@intel.com>
cc:     Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>,
        Jason Gunthorpe <jgg@ziepe.ca>,
        Nayna Jain <nayna@linux.vnet.ibm.com>,
        Alexander Usyskin <alexander.usyskin@intel.com>,
        Tadeusz Struk <tadeusz.struk@intel.com>,
        linux-integrity@vger.kernel.org,
        linux-security-module@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH v7 21/21] tpm: use u32 instead of int for PCR index
In-Reply-To: <20181019182307.17745-22-tomas.winkler@intel.com>
Message-ID: <alpine.DEB.2.21.1810232154130.8524@jsakkine-mobl1>
References: <20181019182307.17745-1-tomas.winkler@intel.com> <20181019182307.17745-22-tomas.winkler@intel.com>
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On Fri, 19 Oct 2018, Tomas Winkler wrote:
> 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>
> ---
> V3: New in the series.
> V4: Separate unrelated change to another patches.
> V5: Fix the commit message.
> V6: Rebased.
> V7: Resend.
>
> drivers/char/tpm/tpm-interface.c    |  6 +++---
> drivers/char/tpm/tpm-sysfs.c        |  2 +-
> drivers/char/tpm/tpm.h              | 10 +++++-----
> drivers/char/tpm/tpm1-cmd.c         |  6 +++---
> drivers/char/tpm/tpm2-cmd.c         |  5 ++---
> include/linux/tpm.h                 | 11 +++++++----
> security/integrity/ima/ima_crypto.c |  5 +++--
> 7 files changed, 24 insertions(+), 21 deletions(-)
>
> diff --git a/drivers/char/tpm/tpm-interface.c b/drivers/char/tpm/tpm-interface.c
> index acd647476ae1..d9439f9abe78 100644
> --- a/drivers/char/tpm/tpm-interface.c
> +++ b/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.");
> @@ -455,7 +455,7 @@ 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;
>
> @@ -485,7 +485,7 @@ 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)];
> diff --git a/drivers/char/tpm/tpm-sysfs.c b/drivers/char/tpm/tpm-sysfs.c
> index 96fc7433c57d..b88e08ec2c59 100644
> --- a/drivers/char/tpm/tpm-sysfs.c
> +++ b/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);
>
> diff --git a/drivers/char/tpm/tpm.h b/drivers/char/tpm/tpm.h
> index e0778d19da98..f27d1f38a93d 100644
> --- a/drivers/char/tpm/tpm.h
> +++ b/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,
> diff --git a/drivers/char/tpm/tpm1-cmd.c b/drivers/char/tpm/tpm1-cmd.c
> index 6b04648f8184..6f306338953b 100644
> --- a/drivers/char/tpm/tpm1-cmd.c
> +++ b/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;
> diff --git a/drivers/char/tpm/tpm2-cmd.c b/drivers/char/tpm/tpm2-cmd.c
> index 6ca4fc0a0d6f..ae86fb0218ab 100644
> --- a/drivers/char/tpm/tpm2-cmd.c
> +++ b/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];
> diff --git a/include/linux/tpm.h b/include/linux/tpm.h
> index 4609b94142d4..b49a55cf775f 100644
> --- a/include/linux/tpm.h
> +++ b/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;
> diff --git a/security/integrity/ima/ima_crypto.c b/security/integrity/ima/ima_crypto.c
> index 7e7e7e7c250a..959d9edc113a 100644
> --- a/security/integrity/ima/ima_crypto.c
> +++ b/security/integrity/ima/ima_crypto.c
> @@ -629,7 +629,7 @@ 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;
> @@ -645,7 +645,8 @@ 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;
>

All commits have been now applied.

/Jarkko