Re: [PATCH] tpm: use get_unaligned_be32 unaligned buffer access.

[Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>]

On Wed, Nov 23, 2016 at 01:04:54PM +0200, Tomas Winkler wrote:
> Use get_unaligned_be32 as b32_to_cpu doesn't work correctly on
> all platforms for unaligned access.
> 
> The fix doesn't cover all the cases as also some cast
> structures have members on unaligned addresses.
> 
> Signed-off-by: Tomas Winkler <tomas.winkler@intel.com>

This looks good to me with the exceptio that was pointed out by Jason.
CC the next version to the linux-security-module. I talked with James
about this at LPC and since this list does not have too many active
reviewers it makes sense to cycle all the non-trivial changes through
that list.

/Jarkko

> ---
>  drivers/char/tpm/tpm-interface.c    | 4 ++--
>  drivers/char/tpm/tpm-sysfs.c        | 2 +-
>  drivers/char/tpm/tpm.h              | 1 +
>  drivers/char/tpm/tpm_crb.c          | 4 ++--
>  drivers/char/tpm/tpm_i2c_infineon.c | 5 +++--
>  drivers/char/tpm/tpm_i2c_nuvoton.c  | 7 ++++---
>  drivers/char/tpm/tpm_nsc.c          | 4 +---
>  drivers/char/tpm/tpm_tis_core.c     | 4 ++--
>  8 files changed, 16 insertions(+), 15 deletions(-)
> 
> diff --git a/drivers/char/tpm/tpm-interface.c b/drivers/char/tpm/tpm-interface.c
> index 769d8b0d31a3..4cf38d00d1b3 100644
> --- a/drivers/char/tpm/tpm-interface.c
> +++ b/drivers/char/tpm/tpm-interface.c
> @@ -353,8 +353,8 @@ ssize_t tpm_transmit(struct tpm_chip *chip, const u8 *buf, size_t bufsiz,
>  	if (bufsiz > TPM_BUFSIZE)
>  		bufsiz = TPM_BUFSIZE;
>  
> -	count = be32_to_cpu(*((__be32 *) (buf + 2)));
> -	ordinal = be32_to_cpu(*((__be32 *) (buf + 6)));
> +	count = get_unaligned_be32(buf + 2);
> +	ordinal = get_unaligned_be32(buf + 6);
>  	if (count == 0)
>  		return -ENODATA;
>  	if (count > bufsiz) {
> diff --git a/drivers/char/tpm/tpm-sysfs.c b/drivers/char/tpm/tpm-sysfs.c
> index 848ad6580b46..2435d710b6af 100644
> --- a/drivers/char/tpm/tpm-sysfs.c
> +++ b/drivers/char/tpm/tpm-sysfs.c
> @@ -71,7 +71,7 @@ static ssize_t pubek_show(struct device *dev, struct device_attribute *attr,
>  		    data[12], data[13], data[14], data[15],
>  		    data[16], data[17], data[18], data[19],
>  		    data[20], data[21], data[22], data[23],
> -		    be32_to_cpu(*((__be32 *) (data + 24))));
> +		    be32_to_cpup((__be32 *)(data + 24)));
>  
>  	for (i = 0; i < 256; i++) {
>  		str += sprintf(str, "%02X ", data[i + 28]);
> diff --git a/drivers/char/tpm/tpm.h b/drivers/char/tpm/tpm.h
> index 1ae976894257..83dba0ff5ea0 100644
> --- a/drivers/char/tpm/tpm.h
> +++ b/drivers/char/tpm/tpm.h
> @@ -23,6 +23,7 @@
>  #ifndef __TPM_H__
>  #define __TPM_H__
>  
> +#include <asm/unaligned.h>
>  #include <linux/module.h>
>  #include <linux/delay.h>
>  #include <linux/fs.h>
> diff --git a/drivers/char/tpm/tpm_crb.c b/drivers/char/tpm/tpm_crb.c
> index 65040d74bb02..8067cfbfdbe2 100644
> --- a/drivers/char/tpm/tpm_crb.c
> +++ b/drivers/char/tpm/tpm_crb.c
> @@ -168,7 +168,7 @@ static u8 crb_status(struct tpm_chip *chip)
>  static int crb_recv(struct tpm_chip *chip, u8 *buf, size_t count)
>  {
>  	struct crb_priv *priv = dev_get_drvdata(&chip->dev);
> -	unsigned int expected;
> +	u32 expected;
>  
>  	/* sanity check */
>  	if (count < 6)
> @@ -178,7 +178,7 @@ static int crb_recv(struct tpm_chip *chip, u8 *buf, size_t count)
>  		return -EIO;
>  
>  	memcpy_fromio(buf, priv->rsp, 6);
> -	expected = be32_to_cpup((__be32 *) &buf[2]);
> +	expected = get_unaligned_be32(buf + 2);
>  
>  	if (expected > count)
>  		return -EIO;
> diff --git a/drivers/char/tpm/tpm_i2c_infineon.c b/drivers/char/tpm/tpm_i2c_infineon.c
> index 62ee44e57ddc..2dd4e3bb14c7 100644
> --- a/drivers/char/tpm/tpm_i2c_infineon.c
> +++ b/drivers/char/tpm/tpm_i2c_infineon.c
> @@ -437,7 +437,8 @@ static int recv_data(struct tpm_chip *chip, u8 *buf, size_t count)
>  static int tpm_tis_i2c_recv(struct tpm_chip *chip, u8 *buf, size_t count)
>  {
>  	int size = 0;
> -	int expected, status;
> +	u32 expected;
> +	int status;
>  
>  	if (count < TPM_HEADER_SIZE) {
>  		size = -EIO;
> @@ -451,7 +452,7 @@ static int tpm_tis_i2c_recv(struct tpm_chip *chip, u8 *buf, size_t count)
>  		goto out;
>  	}
>  
> -	expected = be32_to_cpu(*(__be32 *)(buf + 2));
> +	expected = get_unaligned_be32(buf + 2);
>  	if ((size_t) expected > count) {
>  		size = -EIO;
>  		goto out;
> diff --git a/drivers/char/tpm/tpm_i2c_nuvoton.c b/drivers/char/tpm/tpm_i2c_nuvoton.c
> index e3a9155ee671..7ba9c435da4e 100644
> --- a/drivers/char/tpm/tpm_i2c_nuvoton.c
> +++ b/drivers/char/tpm/tpm_i2c_nuvoton.c
> @@ -273,7 +273,8 @@ static int i2c_nuvoton_recv(struct tpm_chip *chip, u8 *buf, size_t count)
>  	struct device *dev = chip->dev.parent;
>  	struct i2c_client *client = to_i2c_client(dev);
>  	s32 rc;
> -	int expected, status, burst_count, retries, size = 0;
> +	int status, burst_count, retries, size = 0;
> +	u32 expected;
>  
>  	if (count < TPM_HEADER_SIZE) {
>  		i2c_nuvoton_ready(chip);    /* return to idle */
> @@ -314,7 +315,7 @@ static int i2c_nuvoton_recv(struct tpm_chip *chip, u8 *buf, size_t count)
>  		 * convert number of expected bytes field from big endian 32 bit
>  		 * to machine native
>  		 */
> -		expected = be32_to_cpu(*(__be32 *) (buf + 2));
> +		expected = get_unaligned_be32(buf + 2);
>  		if (expected > count) {
>  			dev_err(dev, "%s() expected > count\n", __func__);
>  			size = -EIO;
> @@ -442,7 +443,7 @@ static int i2c_nuvoton_send(struct tpm_chip *chip, u8 *buf, size_t len)
>  		i2c_nuvoton_ready(chip);
>  		return rc;
>  	}
> -	ordinal = be32_to_cpu(*((__be32 *) (buf + 6)));
> +	ordinal = get_unaligned_be32(buf + 6);
>  	rc = i2c_nuvoton_wait_for_data_avail(chip,
>  					     tpm_calc_ordinal_duration(chip,
>  								       ordinal),
> diff --git a/drivers/char/tpm/tpm_nsc.c b/drivers/char/tpm/tpm_nsc.c
> index 9ff0e072c476..99a8ff6ea37d 100644
> --- a/drivers/char/tpm/tpm_nsc.c
> +++ b/drivers/char/tpm/tpm_nsc.c
> @@ -131,7 +131,6 @@ static int tpm_nsc_recv(struct tpm_chip *chip, u8 * buf, size_t count)
>  	u8 *buffer = buf;
>  	u8 data, *p;
>  	u32 size;
> -	__be32 *native_size;
>  
>  	if (count < 6)
>  		return -EIO;
> @@ -174,8 +173,7 @@ static int tpm_nsc_recv(struct tpm_chip *chip, u8 * buf, size_t count)
>  		return -EIO;
>  	}
>  
> -	native_size = (__force __be32 *) (buf + 2);
> -	size = be32_to_cpu(*native_size);
> +	size = get_unaligned_be32(buf + 2);
>  
>  	if (count < size)
>  		return -EIO;
> diff --git a/drivers/char/tpm/tpm_tis_core.c b/drivers/char/tpm/tpm_tis_core.c
> index 7993678954a2..5323c54dc917 100644
> --- a/drivers/char/tpm/tpm_tis_core.c
> +++ b/drivers/char/tpm/tpm_tis_core.c
> @@ -222,7 +222,7 @@ static int tpm_tis_recv(struct tpm_chip *chip, u8 *buf, size_t count)
>  		goto out;
>  	}
>  
> -	expected = be32_to_cpu(*(__be32 *) (buf + 2));
> +	expected = get_unaligned_be32(buf + 2);
>  	if (expected > count) {
>  		size = -EIO;
>  		goto out;
> @@ -371,7 +371,7 @@ static int tpm_tis_send_main(struct tpm_chip *chip, u8 *buf, size_t len)
>  		goto out_err;
>  
>  	if (chip->flags & TPM_CHIP_FLAG_IRQ) {
> -		ordinal = be32_to_cpu(*((__be32 *) (buf + 6)));
> +		ordinal = get_unaligned_be32(buf + 6);
>  
>  		if (chip->flags & TPM_CHIP_FLAG_TPM2)
>  			dur = tpm2_calc_ordinal_duration(chip, ordinal);
> -- 
> 2.7.4
>