Commit message: char/tpm: Fix unitialized usage of data buffer

This patch fixes information leakage to the userspace by initializing
the data buffer to zero.

Reported-by: Peter Huewe <huewe.external@infineon.com>
Signed-off-by: Peter Huewe <huewe.external@infineon.com>
Signed-off-by: Marcel Selhorst <m.selhorst@sirrix.com>
[ Also removed the silly "* sizeof(u8)".  If that isn't 1, we have way
  deeper problems than a simple multiplication can fix.   - Linus ]
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
CVE: CVE-2011-1160
CWE: CWE-200
Vulnerability description: The tpm_open function in drivers/char/tpm/tpm.c in the Linux kernel before 2.6.39 does not initialize a certain buffer, which allows local users to obtain potentially sensitive information from kernel memory via unspecified vectors.

Project: linux
File: tpm.c

int __tpm_pcr_read(struct tpm_chip *chip, int pcr_idx, u8 *res_buf)
{
	int rc;
	struct tpm_cmd_t cmd;

	cmd.header.in = pcrread_header;
	cmd.params.pcrread_in.pcr_idx = cpu_to_be32(pcr_idx);
	rc = transmit_cmd(chip, &cmd, READ_PCR_RESULT_SIZE,
			  "attempting to read a pcr value");

	if (rc == 0)
		memcpy(res_buf, cmd.params.pcrread_out.pcr_result,
		       TPM_DIGEST_SIZE);
	return rc;
}

Project: linux
File: tpm.c

static void timeout_work(struct work_struct *work)
{
	struct tpm_chip *chip = container_of(work, struct tpm_chip, work);

	mutex_lock(&chip->buffer_mutex);
	atomic_set(&chip->data_pending, 0);
	memset(chip->data_buffer, 0, TPM_BUFSIZE);
	mutex_unlock(&chip->buffer_mutex);
}

Project: linux
File: tpm.c

unsigned long tpm_calc_ordinal_duration(struct tpm_chip *chip,
					   u32 ordinal)
{
	int duration_idx = TPM_UNDEFINED;
	int duration = 0;

	if (ordinal < TPM_MAX_ORDINAL)
		duration_idx = tpm_ordinal_duration[ordinal];
	else if ((ordinal & TPM_PROTECTED_ORDINAL_MASK) <
		 TPM_MAX_PROTECTED_ORDINAL)
		duration_idx =
		    tpm_protected_ordinal_duration[ordinal &
						   TPM_PROTECTED_ORDINAL_MASK];

	if (duration_idx != TPM_UNDEFINED)
		duration = chip->vendor.duration[duration_idx];
	if (duration <= 0)
		return 2 * 60 * HZ;
	else
		return duration;
}

Project: linux
File: tpm.c

static struct tpm_chip *tpm_chip_find_get(int chip_num)
{
	struct tpm_chip *pos, *chip = NULL;

	rcu_read_lock();
	list_for_each_entry_rcu(pos, &tpm_chip_list, list) {
		if (chip_num != TPM_ANY_NUM && chip_num != pos->dev_num)
			continue;

		if (try_module_get(pos->dev->driver->owner)) {
			chip = pos;
			break;
		}
	}
	rcu_read_unlock();
	return chip;
}

Project: linux
File: tpm.c

void tpm_dev_release(struct device *dev)
{
	struct tpm_chip *chip = dev_get_drvdata(dev);

	tpm_dev_vendor_release(chip);

	chip->release(dev);
	kfree(chip);
}

Project: linux
File: tpm.c

void tpm_dev_vendor_release(struct tpm_chip *chip)
{
	if (chip->vendor.release)
		chip->vendor.release(chip->dev);

	clear_bit(chip->dev_num, dev_mask);
	kfree(chip->vendor.miscdev.name);
}

Project: linux
File: tpm.c

void tpm_get_timeouts(struct tpm_chip *chip)
{
	struct tpm_cmd_t tpm_cmd;
	struct timeout_t *timeout_cap;
	struct duration_t *duration_cap;
	ssize_t rc;
	u32 timeout;

	tpm_cmd.header.in = tpm_getcap_header;
	tpm_cmd.params.getcap_in.cap = TPM_CAP_PROP;
	tpm_cmd.params.getcap_in.subcap_size = cpu_to_be32(4);
	tpm_cmd.params.getcap_in.subcap = TPM_CAP_PROP_TIS_TIMEOUT;

	rc = transmit_cmd(chip, &tpm_cmd, TPM_INTERNAL_RESULT_SIZE,
			"attempting to determine the timeouts");
	if (rc)
		goto duration;

	if (be32_to_cpu(tpm_cmd.header.out.length)
	    != 4 * sizeof(u32))
		goto duration;

	timeout_cap = &tpm_cmd.params.getcap_out.cap.timeout;
	/* Don't overwrite default if value is 0 */
	timeout = be32_to_cpu(timeout_cap->a);
	if (timeout)
		chip->vendor.timeout_a = usecs_to_jiffies(timeout);
	timeout = be32_to_cpu(timeout_cap->b);
	if (timeout)
		chip->vendor.timeout_b = usecs_to_jiffies(timeout);
	timeout = be32_to_cpu(timeout_cap->c);
	if (timeout)
		chip->vendor.timeout_c = usecs_to_jiffies(timeout);
	timeout = be32_to_cpu(timeout_cap->d);
	if (timeout)
		chip->vendor.timeout_d = usecs_to_jiffies(timeout);

duration:
	tpm_cmd.header.in = tpm_getcap_header;
	tpm_cmd.params.getcap_in.cap = TPM_CAP_PROP;
	tpm_cmd.params.getcap_in.subcap_size = cpu_to_be32(4);
	tpm_cmd.params.getcap_in.subcap = TPM_CAP_PROP_TIS_DURATION;

	rc = transmit_cmd(chip, &tpm_cmd, TPM_INTERNAL_RESULT_SIZE,
			"attempting to determine the durations");
	if (rc)
		return;

	if (be32_to_cpu(tpm_cmd.header.out.return_code)
	    != 3 * sizeof(u32))
		return;
	duration_cap = &tpm_cmd.params.getcap_out.cap.duration;
	chip->vendor.duration[TPM_SHORT] =
	    usecs_to_jiffies(be32_to_cpu(duration_cap->tpm_short));
	/* The Broadcom BCM0102 chipset in a Dell Latitude D820 gets the above
	 * value wrong and apparently reports msecs rather than usecs. So we
	 * fix up the resulting too-small TPM_SHORT value to make things work.
	 */
	if (chip->vendor.duration[TPM_SHORT] < (HZ/100))
		chip->vendor.duration[TPM_SHORT] = HZ;

	chip->vendor.duration[TPM_MEDIUM] =
	    usecs_to_jiffies(be32_to_cpu(duration_cap->tpm_medium));
	chip->vendor.duration[TPM_LONG] =
	    usecs_to_jiffies(be32_to_cpu(duration_cap->tpm_long));
}

Project: linux
File: tpm.c

int tpm_pcr_extend(u32 chip_num, int pcr_idx, const u8 *hash)
{
	struct tpm_cmd_t cmd;
	int rc;
	struct tpm_chip *chip;

	chip = tpm_chip_find_get(chip_num);
	if (chip == NULL)
		return -ENODEV;

	cmd.header.in = pcrextend_header;
	cmd.params.pcrextend_in.pcr_idx = cpu_to_be32(pcr_idx);
	memcpy(cmd.params.pcrextend_in.hash, hash, TPM_DIGEST_SIZE);
	rc = transmit_cmd(chip, &cmd, EXTEND_PCR_RESULT_SIZE,
			  "attempting extend a PCR value");

	tpm_chip_put(chip);
	return rc;
}

Project: linux
File: tpm.c

int tpm_pcr_read(u32 chip_num, int pcr_idx, u8 *res_buf)
{
	struct tpm_chip *chip;
	int rc;

	chip = tpm_chip_find_get(chip_num);
	if (chip == NULL)
		return -ENODEV;
	rc = __tpm_pcr_read(chip, pcr_idx, res_buf);
	tpm_chip_put(chip);
	return rc;
}

Project: linux
File: tpm.c

int tpm_pm_resume(struct device *dev)
{
	struct tpm_chip *chip = dev_get_drvdata(dev);

	if (chip == NULL)
		return -ENODEV;

	return 0;
}

Project: linux
File: tpm.c

int tpm_pm_suspend(struct device *dev, pm_message_t pm_state)
{
	struct tpm_chip *chip = dev_get_drvdata(dev);
	struct tpm_cmd_t cmd;
	int rc;

	u8 dummy_hash[TPM_DIGEST_SIZE] = { 0 };

	if (chip == NULL)
		return -ENODEV;

	/* for buggy tpm, flush pcrs with extend to selected dummy */
	if (tpm_suspend_pcr) {
		cmd.header.in = pcrextend_header;
		cmd.params.pcrextend_in.pcr_idx = cpu_to_be32(tpm_suspend_pcr);
		memcpy(cmd.params.pcrextend_in.hash, dummy_hash,
		       TPM_DIGEST_SIZE);
		rc = transmit_cmd(chip, &cmd, EXTEND_PCR_RESULT_SIZE,
				  "extending dummy pcr before suspend");
	}

	/* now do the actual savestate */
	cmd.header.in = savestate_header;
	rc = transmit_cmd(chip, &cmd, SAVESTATE_RESULT_SIZE,
			  "sending savestate before suspend");
	return rc;
}

Project: linux
File: tpm.c

ssize_t tpm_read(struct file *file, char __user *buf,
		 size_t size, loff_t *off)
{
	struct tpm_chip *chip = file->private_data;
	ssize_t ret_size;

	del_singleshot_timer_sync(&chip->user_read_timer);
	flush_work_sync(&chip->work);
	ret_size = atomic_read(&chip->data_pending);
	atomic_set(&chip->data_pending, 0);
	if (ret_size > 0) {	/* relay data */
		if (size < ret_size)
			ret_size = size;

		mutex_lock(&chip->buffer_mutex);
		if (copy_to_user(buf, chip->data_buffer, ret_size))
			ret_size = -EFAULT;
		mutex_unlock(&chip->buffer_mutex);
	}

	return ret_size;
}

Project: linux
File: tpm.c

struct tpm_chip *tpm_register_hardware(struct device *dev,
					const struct tpm_vendor_specific *entry)
{
#define DEVNAME_SIZE 7

	char *devname;
	struct tpm_chip *chip;

	/* Driver specific per-device data */
	chip = kzalloc(sizeof(*chip), GFP_KERNEL);
	devname = kmalloc(DEVNAME_SIZE, GFP_KERNEL);

	if (chip == NULL || devname == NULL)
		goto out_free;

	mutex_init(&chip->buffer_mutex);
	mutex_init(&chip->tpm_mutex);
	INIT_LIST_HEAD(&chip->list);

	INIT_WORK(&chip->work, timeout_work);

	setup_timer(&chip->user_read_timer, user_reader_timeout,
			(unsigned long)chip);

	memcpy(&chip->vendor, entry, sizeof(struct tpm_vendor_specific));

	chip->dev_num = find_first_zero_bit(dev_mask, TPM_NUM_DEVICES);

	if (chip->dev_num >= TPM_NUM_DEVICES) {
		dev_err(dev, "No available tpm device numbers\n");
		goto out_free;
	} else if (chip->dev_num == 0)
		chip->vendor.miscdev.minor = TPM_MINOR;
	else
		chip->vendor.miscdev.minor = MISC_DYNAMIC_MINOR;

	set_bit(chip->dev_num, dev_mask);

	scnprintf(devname, DEVNAME_SIZE, "%s%d", "tpm", chip->dev_num);
	chip->vendor.miscdev.name = devname;

	chip->vendor.miscdev.parent = dev;
	chip->dev = get_device(dev);
	chip->release = dev->release;
	dev->release = tpm_dev_release;
	dev_set_drvdata(dev, chip);

	if (misc_register(&chip->vendor.miscdev)) {
		dev_err(chip->dev,
			"unable to misc_register %s, minor %d\n",
			chip->vendor.miscdev.name,
			chip->vendor.miscdev.minor);
		put_device(chip->dev);
		return NULL;
	}

	if (sysfs_create_group(&dev->kobj, chip->vendor.attr_group)) {
		misc_deregister(&chip->vendor.miscdev);
		put_device(chip->dev);

		return NULL;
	}

	chip->bios_dir = tpm_bios_log_setup(devname);

	/* Make chip available */
	spin_lock(&driver_lock);
	list_add_rcu(&chip->list, &tpm_chip_list);
	spin_unlock(&driver_lock);

	return chip;

out_free:
	kfree(chip);
	kfree(devname);
	return NULL;
}

Project: linux
File: tpm.c

void tpm_remove_hardware(struct device *dev)
{
	struct tpm_chip *chip = dev_get_drvdata(dev);

	if (chip == NULL) {
		dev_err(dev, "No device data found\n");
		return;
	}

	spin_lock(&driver_lock);
	list_del_rcu(&chip->list);
	spin_unlock(&driver_lock);
	synchronize_rcu();

	misc_deregister(&chip->vendor.miscdev);
	sysfs_remove_group(&dev->kobj, chip->vendor.attr_group);
	tpm_bios_log_teardown(chip->bios_dir);

	/* write it this way to be explicit (chip->dev == dev) */
	put_device(chip->dev);
}

Project: linux
File: tpm.c

int tpm_send(u32 chip_num, void *cmd, size_t buflen)
{
	struct tpm_chip *chip;
	int rc;

	chip = tpm_chip_find_get(chip_num);
	if (chip == NULL)
		return -ENODEV;

	rc = transmit_cmd(chip, cmd, buflen, "attempting tpm_cmd");

	tpm_chip_put(chip);
	return rc;
}

Project: linux
File: tpm.c

ssize_t tpm_show_active(struct device * dev, struct device_attribute * attr,
			char *buf)
{
	cap_t cap;
	ssize_t rc;

	rc = tpm_getcap(dev, TPM_CAP_FLAG_PERM, &cap,
			 "attempting to determine the permanent active state");
	if (rc)
		return 0;

	rc = sprintf(buf, "%d\n", !cap.perm_flags.deactivated);
	return rc;
}

Project: linux
File: tpm.c

ssize_t tpm_show_enabled(struct device * dev, struct device_attribute * attr,
			char *buf)
{
	cap_t cap;
	ssize_t rc;

	rc = tpm_getcap(dev, TPM_CAP_FLAG_PERM, &cap,
			 "attempting to determine the permanent enabled state");
	if (rc)
		return 0;

	rc = sprintf(buf, "%d\n", !cap.perm_flags.disable);
	return rc;
}

Project: linux
File: tpm.c

ssize_t tpm_show_owned(struct device * dev, struct device_attribute * attr,
			char *buf)
{
	cap_t cap;
	ssize_t rc;

	rc = tpm_getcap(dev, TPM_CAP_PROP_OWNER, &cap,
			 "attempting to determine the owner state");
	if (rc)
		return 0;

	rc = sprintf(buf, "%d\n", cap.owned);
	return rc;
}

Project: linux
File: tpm.c

ssize_t tpm_show_pcrs(struct device *dev, struct device_attribute *attr,
		      char *buf)
{
	cap_t cap;
	u8 digest[TPM_DIGEST_SIZE];
	ssize_t rc;
	int i, j, num_pcrs;
	char *str = buf;
	struct tpm_chip *chip = dev_get_drvdata(dev);

	rc = tpm_getcap(dev, TPM_CAP_PROP_PCR, &cap,
			"attempting to determine the number of PCRS");
	if (rc)
		return 0;

	num_pcrs = be32_to_cpu(cap.num_pcrs);
	for (i = 0; i < num_pcrs; i++) {
		rc = __tpm_pcr_read(chip, i, digest);
		if (rc)
			break;
		str += sprintf(str, "PCR-%02d: ", i);
		for (j = 0; j < TPM_DIGEST_SIZE; j++)
			str += sprintf(str, "%02X ", digest[j]);
		str += sprintf(str, "\n");
	}
	return str - buf;
}

Project: linux
File: tpm.c

ssize_t tpm_show_pubek(struct device *dev, struct device_attribute *attr,
		       char *buf)
{
	u8 *data;
	struct tpm_cmd_t tpm_cmd;
	ssize_t err;
	int i, rc;
	char *str = buf;

	struct tpm_chip *chip = dev_get_drvdata(dev);

	tpm_cmd.header.in = tpm_readpubek_header;
	err = transmit_cmd(chip, &tpm_cmd, READ_PUBEK_RESULT_SIZE,
			"attempting to read the PUBEK");
	if (err)
		goto out;

	/* 
	   ignore header 10 bytes
	   algorithm 32 bits (1 == RSA )
	   encscheme 16 bits
	   sigscheme 16 bits
	   parameters (RSA 12->bytes: keybit, #primes, expbit)  
	   keylenbytes 32 bits
	   256 byte modulus
	   ignore checksum 20 bytes
	 */
	data = tpm_cmd.params.readpubek_out_buffer;
	str +=
	    sprintf(str,
		    "Algorithm: %02X %02X %02X %02X\nEncscheme: %02X %02X\n"
		    "Sigscheme: %02X %02X\nParameters: %02X %02X %02X %02X"
		    " %02X %02X %02X %02X %02X %02X %02X %02X\n"
		    "Modulus length: %d\nModulus: \n",
		    data[10], data[11], data[12], data[13], data[14],
		    data[15], data[16], data[17], data[22], data[23],
		    data[24], data[25], data[26], data[27], data[28],
		    data[29], data[30], data[31], data[32], data[33],
		    be32_to_cpu(*((__be32 *) (data + 34))));

	for (i = 0; i < 256; i++) {
		str += sprintf(str, "%02X ", data[i + 38]);
		if ((i + 1) % 16 == 0)
			str += sprintf(str, "\n");
	}
out:
	rc = str - buf;
	return rc;
}

Project: linux
File: tpm.c

ssize_t tpm_show_temp_deactivated(struct device * dev,
				struct device_attribute * attr, char *buf)
{
	cap_t cap;
	ssize_t rc;

	rc = tpm_getcap(dev, TPM_CAP_FLAG_VOL, &cap,
			 "attempting to determine the temporary state");
	if (rc)
		return 0;

	rc = sprintf(buf, "%d\n", cap.stclear_flags.deactivated);
	return rc;
}

Project: linux
File: tpm.c

ssize_t tpm_store_cancel(struct device *dev, struct device_attribute *attr,
			const char *buf, size_t count)
{
	struct tpm_chip *chip = dev_get_drvdata(dev);
	if (chip == NULL)
		return 0;

	chip->vendor.cancel(chip);
	return count;
}

Project: linux
File: tpm.c

static ssize_t tpm_transmit(struct tpm_chip *chip, const char *buf,
			    size_t bufsiz)
{
	ssize_t rc;
	u32 count, ordinal;
	unsigned long stop;

	count = be32_to_cpu(*((__be32 *) (buf + 2)));
	ordinal = be32_to_cpu(*((__be32 *) (buf + 6)));
	if (count == 0)
		return -ENODATA;
	if (count > bufsiz) {
		dev_err(chip->dev,
			"invalid count value %x %zx \n", count, bufsiz);
		return -E2BIG;
	}

	mutex_lock(&chip->tpm_mutex);

	if ((rc = chip->vendor.send(chip, (u8 *) buf, count)) < 0) {
		dev_err(chip->dev,
			"tpm_transmit: tpm_send: error %zd\n", rc);
		goto out;
	}

	if (chip->vendor.irq)
		goto out_recv;

	stop = jiffies + tpm_calc_ordinal_duration(chip, ordinal);
	do {
		u8 status = chip->vendor.status(chip);
		if ((status & chip->vendor.req_complete_mask) ==
		    chip->vendor.req_complete_val)
			goto out_recv;

		if ((status == chip->vendor.req_canceled)) {
			dev_err(chip->dev, "Operation Canceled\n");
			rc = -ECANCELED;
			goto out;
		}

		msleep(TPM_TIMEOUT);	/* CHECK */
		rmb();
	} while (time_before(jiffies, stop));

	chip->vendor.cancel(chip);
	dev_err(chip->dev, "Operation Timed out\n");
	rc = -ETIME;
	goto out;

out_recv:
	rc = chip->vendor.recv(chip, (u8 *) buf, bufsiz);
	if (rc < 0)
		dev_err(chip->dev,
			"tpm_transmit: tpm_recv: error %zd\n", rc);
out:
	mutex_unlock(&chip->tpm_mutex);
	return rc;
}

Project: linux
File: tpm.c

static ssize_t transmit_cmd(struct tpm_chip *chip, struct tpm_cmd_t *cmd,
			    int len, const char *desc)
{
	int err;

	len = tpm_transmit(chip,(u8 *) cmd, len);
	if (len <  0)
		return len;
	if (len == TPM_ERROR_SIZE) {
		err = be32_to_cpu(cmd->header.out.return_code);
		dev_dbg(chip->dev, "A TPM error (%d) occurred %s\n", err, desc);
		return err;
	}
	return 0;
}

Project: linux
File: tpm.c

static void user_reader_timeout(unsigned long ptr)
{
	struct tpm_chip *chip = (struct tpm_chip *) ptr;

	schedule_work(&chip->work);
}