linux-kernel.vger.kernel.org archive mirror
 help / color / mirror / Atom feed
From: amirmizi6@gmail.com
To: Eyal.Cohen@nuvoton.com, jarkko.sakkinen@linux.intel.com,
	oshrialkoby85@gmail.com, alexander.steffen@infineon.com,
	robh+dt@kernel.org, mark.rutland@arm.com, peterhuewe@gmx.de,
	jgg@ziepe.ca, arnd@arndb.de, gregkh@linuxfoundation.org
Cc: devicetree@vger.kernel.org, linux-kernel@vger.kernel.org,
	linux-integrity@vger.kernel.org, oshri.alkoby@nuvoton.com,
	tmaimon77@gmail.com, gcwilson@us.ibm.com, kgoldman@us.ibm.com,
	Dan.Morav@nuvoton.com, oren.tanami@nuvoton.com,
	shmulik.hager@nuvoton.com, amir.mizinski@nuvoton.com,
	Amir Mizinski <amirmizi6@gmail.com>
Subject: [PATCH v3 2/7] char: tpm: Add check_data handle to tpm_tis_phy_ops in order to check data integrity
Date: Mon, 10 Feb 2020 18:28:33 +0200	[thread overview]
Message-ID: <20200210162838.173903-3-amirmizi6@gmail.com> (raw)
In-Reply-To: <20200210162838.173903-1-amirmizi6@gmail.com>

From: Amir Mizinski <amirmizi6@gmail.com>

In order to compute the crc over the data sent in lower layer
 (I2C for instance), tpm_tis_check_data() calls an operation (if available)
 to check data integrity. If data integrity cannot be verified, a retry
 attempt to save the sent/received data is implemented.

The current steps are done when sending a command:
    1. Host writes to TPM_STS.commandReady.
    2. Host writes command.
    3. Host checks that TPM received data is valid.
    4. If data is currupted go to step 1.

When receiving data:
    1. Host checks that TPM_STS.dataAvail is set.
    2. Host saves received data.
    3. Host checks that received data is correct.
    4. If data is currupted Host writes to TPM_STS.responseRetry and go to
        step 1.

This commit is based on previous work by Christophe Richard.

Signed-off-by: Amir Mizinski <amirmizi6@gmail.com>
---
 drivers/char/tpm/tpm_tis_core.c | 102 +++++++++++++++++++++++++---------------
 drivers/char/tpm/tpm_tis_core.h |   3 ++
 2 files changed, 67 insertions(+), 38 deletions(-)

diff --git a/drivers/char/tpm/tpm_tis_core.c b/drivers/char/tpm/tpm_tis_core.c
index 27c6ca0..6c4f232 100644
--- a/drivers/char/tpm/tpm_tis_core.c
+++ b/drivers/char/tpm/tpm_tis_core.c
@@ -242,6 +242,15 @@ static u8 tpm_tis_status(struct tpm_chip *chip)
 	return status;
 }
 
+static bool tpm_tis_check_data(struct tpm_chip *chip, const u8 *buf, size_t len)
+{
+	struct tpm_tis_data *priv = dev_get_drvdata(&chip->dev);
+
+	if (priv->phy_ops->check_data)
+		return priv->phy_ops->check_data(priv, buf, len);
+	return true;
+}
+
 static void tpm_tis_ready(struct tpm_chip *chip)
 {
 	struct tpm_tis_data *priv = dev_get_drvdata(&chip->dev);
@@ -308,47 +317,59 @@ static int tpm_tis_recv(struct tpm_chip *chip, u8 *buf, size_t count)
 {
 	struct tpm_tis_data *priv = dev_get_drvdata(&chip->dev);
 	int size = 0;
-	int status;
+	int status, i;
 	u32 expected;
+	bool check_data = false;
 
-	if (count < TPM_HEADER_SIZE) {
-		size = -EIO;
-		goto out;
-	}
+	for (i = 0; i < TPM_RETRY; i++) {
+		if (count < TPM_HEADER_SIZE) {
+			size = -EIO;
+			goto out;
+		}
 
-	size = recv_data(chip, buf, TPM_HEADER_SIZE);
-	/* read first 10 bytes, including tag, paramsize, and result */
-	if (size < TPM_HEADER_SIZE) {
-		dev_err(&chip->dev, "Unable to read header\n");
-		goto out;
-	}
+		size = recv_data(chip, buf, TPM_HEADER_SIZE);
+		/* read first 10 bytes, including tag, paramsize, and result */
+		if (size < TPM_HEADER_SIZE) {
+			dev_err(&chip->dev, "Unable to read header\n");
+			goto out;
+		}
 
-	expected = be32_to_cpu(*(__be32 *) (buf + 2));
-	if (expected > count || expected < TPM_HEADER_SIZE) {
-		size = -EIO;
-		goto out;
-	}
+		expected = be32_to_cpu(*(__be32 *) (buf + 2));
+		if (expected > count || expected < TPM_HEADER_SIZE) {
+			size = -EIO;
+			goto out;
+		}
 
-	size += recv_data(chip, &buf[TPM_HEADER_SIZE],
-			  expected - TPM_HEADER_SIZE);
-	if (size < expected) {
-		dev_err(&chip->dev, "Unable to read remainder of result\n");
-		size = -ETIME;
-		goto out;
-	}
+		size += recv_data(chip, &buf[TPM_HEADER_SIZE],
+				  expected - TPM_HEADER_SIZE);
+		if (size < expected) {
+			dev_err(&chip->dev, "Unable to read remainder of result\n");
+			size = -ETIME;
+			goto out;
+		}
 
-	if (wait_for_tpm_stat(chip, TPM_STS_VALID, chip->timeout_c,
-				&priv->int_queue, false) < 0) {
-		size = -ETIME;
-		goto out;
+		if (wait_for_tpm_stat(chip, TPM_STS_VALID, chip->timeout_c,
+				      &priv->int_queue, false) < 0) {
+			size = -ETIME;
+			goto out;
+		}
+
+		status = tpm_tis_status(chip);
+		if (status & TPM_STS_DATA_AVAIL) {	/* retry? */
+			dev_err(&chip->dev, "Error left over data\n");
+			size = -EIO;
+			goto out;
+		}
+
+		check_data = tpm_tis_check_data(chip, buf, size);
+		if (!check_data)
+			tpm_tis_write8(priv, TPM_STS(priv->locality),
+				       TPM_STS_RESPONSE_RETRY);
+		else
+			break;
 	}
-	status = tpm_tis_status(chip);
-	if (status & TPM_STS_DATA_AVAIL) {	/* retry? */
-		dev_err(&chip->dev, "Error left over data\n");
+	if (!check_data)
 		size = -EIO;
-		goto out;
-	}
-
 out:
 	tpm_tis_ready(chip);
 	return size;
@@ -453,14 +474,19 @@ static void disable_interrupts(struct tpm_chip *chip)
 static int tpm_tis_send_main(struct tpm_chip *chip, const u8 *buf, size_t len)
 {
 	struct tpm_tis_data *priv = dev_get_drvdata(&chip->dev);
-	int rc;
+	int rc, i;
 	u32 ordinal;
 	unsigned long dur;
+	bool data_valid = false;
 
-	rc = tpm_tis_send_data(chip, buf, len);
-	if (rc < 0)
-		return rc;
-
+	for (i = 0; i < TPM_RETRY && !data_valid; i++) {
+		rc = tpm_tis_send_data(chip, buf, len);
+		if (rc < 0)
+			return rc;
+		data_valid = tpm_tis_check_data(chip, buf, len);
+	}
+	if (!data_valid)
+		return -EIO;
 	/* go and do it */
 	rc = tpm_tis_write8(priv, TPM_STS(priv->locality), TPM_STS_GO);
 	if (rc < 0)
diff --git a/drivers/char/tpm/tpm_tis_core.h b/drivers/char/tpm/tpm_tis_core.h
index d06c65b..486c2e9 100644
--- a/drivers/char/tpm/tpm_tis_core.h
+++ b/drivers/char/tpm/tpm_tis_core.h
@@ -34,6 +34,7 @@ enum tis_status {
 	TPM_STS_GO = 0x20,
 	TPM_STS_DATA_AVAIL = 0x10,
 	TPM_STS_DATA_EXPECT = 0x08,
+	TPM_STS_RESPONSE_RETRY = 0x02,
 };
 
 enum tis_int_flags {
@@ -106,6 +107,8 @@ struct tpm_tis_phy_ops {
 	int (*read16)(struct tpm_tis_data *data, u32 addr, u16 *result);
 	int (*read32)(struct tpm_tis_data *data, u32 addr, u32 *result);
 	int (*write32)(struct tpm_tis_data *data, u32 addr, u32 src);
+	bool (*check_data)(struct tpm_tis_data *data, const u8 *buf,
+			   size_t len);
 };
 
 static inline int tpm_tis_read_bytes(struct tpm_tis_data *data, u32 addr,
-- 
2.7.4


  parent reply	other threads:[~2020-02-10 17:10 UTC|newest]

Thread overview: 11+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-02-10 16:28 [PATCH v3 0/7] add tpm i2c ptp driver amirmizi6
2020-02-10 16:28 ` [PATCH v3 1/7] char: tpm: Make implementation of read16 read32 write32 optional amirmizi6
2020-02-12 15:07   ` Jarkko Sakkinen
2020-02-10 16:28 ` amirmizi6 [this message]
2020-02-10 16:28 ` [PATCH v3 3/7] char: tpm: rewrite "tpm_tis_req_canceled()" amirmizi6
2020-02-10 16:28 ` [PATCH v3 4/7] char: tpm: Fix expected bit handling and send all bytes in one shot without last byte in exception amirmizi6
2020-02-10 16:28 ` [PATCH v3 5/7] tpm: Handle an exception for TPM Firmware Update mode amirmizi6
2020-02-10 16:28 ` [PATCH v3 6/7] dt-bindings: tpm: Add YAML schema for TPM TIS I2C options amirmizi6
2020-02-12  1:59   ` Rob Herring
2020-02-10 16:28 ` [PATCH v3 7/7] char: tpm: add tpm_tis_i2c driver amirmizi6
2020-02-13 22:56   ` Eddie James

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20200210162838.173903-3-amirmizi6@gmail.com \
    --to=amirmizi6@gmail.com \
    --cc=Dan.Morav@nuvoton.com \
    --cc=Eyal.Cohen@nuvoton.com \
    --cc=alexander.steffen@infineon.com \
    --cc=amir.mizinski@nuvoton.com \
    --cc=arnd@arndb.de \
    --cc=devicetree@vger.kernel.org \
    --cc=gcwilson@us.ibm.com \
    --cc=gregkh@linuxfoundation.org \
    --cc=jarkko.sakkinen@linux.intel.com \
    --cc=jgg@ziepe.ca \
    --cc=kgoldman@us.ibm.com \
    --cc=linux-integrity@vger.kernel.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=mark.rutland@arm.com \
    --cc=oren.tanami@nuvoton.com \
    --cc=oshri.alkoby@nuvoton.com \
    --cc=oshrialkoby85@gmail.com \
    --cc=peterhuewe@gmx.de \
    --cc=robh+dt@kernel.org \
    --cc=shmulik.hager@nuvoton.com \
    --cc=tmaimon77@gmail.com \
    --subject='Re: [PATCH v3 2/7] char: tpm: Add check_data handle to tpm_tis_phy_ops in order to check data integrity' \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link

This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).