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tpm_tis: verify locality released before returning from release_locality

PATCH In review Jerry Snitselaar 3 participants 8 messages May 5, 2018 – May 28, 2018

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#0 lore raw

PATCH 1/1 tpm_tis: verify locality released before returning from release_locality

For certain tpm chips releasing locality can take long enough that a subsequent call to request_locality will see the locality as being active when the access register is read in check_locality. So check that the locality has been released before returning from release_locality.

---
 drivers/char/tpm/tpm_tis_core.c | 47 ++++++++++++++++++++++++++++++++++++++++-
 1 file changed, 46 insertions(+), 1 deletion(-)
drivers/char/tpm/tpm_tis_core.c +46 -1
index 5a1f47b43947..d547cd309dbd 100644
@@ -143,13 +143,58 @@ static bool check_locality(struct tpm_chip *chip, int l)
 	return false;
 }
 
+static bool locality_inactive(struct tpm_chip *chip, int l)
+{
+	struct tpm_tis_data *priv = dev_get_drvdata(&chip->dev);
+	int rc;
+	u8 access;
+
+	rc = tpm_tis_read8(priv, TPM_ACCESS(l), &access);
+	if (rc < 0)
+		return false;
+
+	if ((access & (TPM_ACCESS_VALID | TPM_ACCESS_ACTIVE_LOCALITY))
+	    == TPM_ACCESS_VALID)
+		return true;
+
+	return false;
+}
+
 static int release_locality(struct tpm_chip *chip, int l)
 {
 	struct tpm_tis_data *priv = dev_get_drvdata(&chip->dev);
+	unsigned long stop, timeout;
+	long rc;
 
 	tpm_tis_write8(priv, TPM_ACCESS(l), TPM_ACCESS_ACTIVE_LOCALITY);
 
-	return 0;
+	stop = jiffies + chip->timeout_a;
+
+	if (chip->flags & TPM_CHIP_FLAG_IRQ) {
+again:
+		timeout = stop - jiffies;
+		if ((long)timeout <= 0)
+			return -1;
+
+		rc = wait_event_interruptible_timeout(priv->int_queue,
+						      (locality_inactive(chip, l)),
+						      timeout);
+
+		if (rc > 0)
+			return 0;
+
+		if (rc == -ERESTARTSYS && freezing(current)) {
+			clear_thread_flag(TIF_SIGPENDING);
+			goto again;
+		}
+	} else {
+		do {
+			if (locality_inactive(chip, l))
+				return 0;
+			tpm_msleep(TPM_TIMEOUT);
+		} while (time_before(jiffies, stop));
+	}
+	return -1;
 }
 
 static int request_locality(struct tpm_chip *chip, int l)
Signature · 1 line
2.15.0
#1 lore raw
Quoted 82 lines · Jerry Snitselaar

For certain tpm chips releasing locality can take long enough that a subsequent call to request_locality will see the locality as being active when the access register is read in check_locality. So check that the locality has been released before returning from release_locality.

---
drivers/char/tpm/tpm_tis_core.c | 47 ++++++++++++++++++++++++++++++++++++++++-

1 file changed, 46 insertions(+), 1 deletion(-)
drivers/char/tpm/tpm_tis_core.c +46 -1
index 5a1f47b43947..d547cd309dbd 100644
@@ -143,13 +143,58 @@ static bool check_locality(struct tpm_chip *chip, int l)
 	return false;
 }
 
+static bool locality_inactive(struct tpm_chip *chip, int l)
+{
+	struct tpm_tis_data *priv = dev_get_drvdata(&chip->dev);
+	int rc;
+	u8 access;
+
+	rc = tpm_tis_read8(priv, TPM_ACCESS(l), &access);
+	if (rc < 0)
+		return false;
+
+	if ((access & (TPM_ACCESS_VALID | TPM_ACCESS_ACTIVE_LOCALITY))
+	    == TPM_ACCESS_VALID)
+		return true;
+
+	return false;
+}
+
 static int release_locality(struct tpm_chip *chip, int l)
 {
 	struct tpm_tis_data *priv = dev_get_drvdata(&chip->dev);
+	unsigned long stop, timeout;
+	long rc;
 
 	tpm_tis_write8(priv, TPM_ACCESS(l), TPM_ACCESS_ACTIVE_LOCALITY);
 
-	return 0;
+	stop = jiffies + chip->timeout_a;
+
+	if (chip->flags & TPM_CHIP_FLAG_IRQ) {
+again:
+		timeout = stop - jiffies;
+		if ((long)timeout <= 0)
+			return -1;
+
+		rc = wait_event_interruptible_timeout(priv->int_queue,
+						      (locality_inactive(chip, l)),
+						      timeout);
+
+		if (rc > 0)
+			return 0;
+
+		if (rc == -ERESTARTSYS && freezing(current)) {
+			clear_thread_flag(TIF_SIGPENDING);
+			goto again;
+		}
+	} else {
+		do {
+			if (locality_inactive(chip, l))
+				return 0;
+			tpm_msleep(TPM_TIMEOUT);
+		} while (time_before(jiffies, stop));
+	}
+	return -1;
 }
 
 static int request_locality(struct tpm_chip *chip, int l)
Signature · 1 line
2.15.0

Laurent,

Can you try this patch with your system since it is the one that has exhibited the problem so far. I've tested on a tpm2.0 and tpm1.2 system here.

Regards,
Jerry

#2 lore raw

Le 05/05/18 a 22:03, Jerry Snitselaar a ecrit :

Quoted 5 lines · Jerry Snitselaar
Quoted 2 lines

[...]

Laurent,

Hello Jerry,

Quoted 3 lines

Can you try this patch with your system since it is the one that has exhibited the problem so far. I've tested on a tpm2.0 and tpm1.2 system here.

I just tested the patch and the driver is loading fine again and the device in /dev is present again, so it seems to work.

But for some reason the tpm is again locked (for no visible reason) due to "dictionary attack" so I cannot test further ATM :/

Regards,

Laurent

Quoted 3 lines

Regards,
Jerry

#3 lore raw
Quoted 16 lines · Laurent Bigonville

Le 05/05/18 a 22:03, Jerry Snitselaar a ecrit :

Quoted 5 lines · Jerry Snitselaar
Quoted 2 lines

[...]

Laurent,

Hello Jerry,

Quoted 3 lines

Can you try this patch with your system since it is the one that has exhibited the problem so far. I've tested on a tpm2.0 and tpm1.2 system here.

I just tested the patch and the driver is loading fine again and the device in /dev is present again, so it seems to work.

Quoted 11 lines

But for some reason the tpm is again locked (for no visible reason) due to "dictionary attack" so I cannot test further ATM :/

Regards,

Laurent

Quoted 3 lines

Regards,
Jerry

Can you response with the tested-by tag as soon as you can? Before we have tested-by, I cannot land the fix.

/Jarkko

#4 lore raw
In reply to Jerry Snitselaar

Le 05/05/18 a 22:03, Jerry Snitselaar a ecrit :

Quoted 7 lines · Jerry Snitselaar
Quoted 6 lines

For certain tpm chips releasing locality can take long enough that a subsequent call to request_locality will see the locality as being active when the access register is read in check_locality. So check that the locality has been released before returning from release_locality.

Quoted 5 lines
Quoted 5 lines
Quoted 82 lines
Quoted 69 lines

---
drivers/char/tpm/tpm_tis_core.c | 47
++++++++++++++++++++++++++++++++++++++++-

1 file changed, 46 insertions(+), 1 deletion(-)
drivers/char/tpm/tpm_tis_core.c +46 -1
index 5a1f47b43947..d547cd309dbd 100644
@@ -143,13 +143,58 @@ static bool check_locality(struct tpm_chip 
 *chip, int l)
    return false;
 }
 
+static bool locality_inactive(struct tpm_chip *chip, int l)
+{
+    struct tpm_tis_data *priv = dev_get_drvdata(&chip->dev);
+    int rc;
+    u8 access;
+
+    rc = tpm_tis_read8(priv, TPM_ACCESS(l), &access);
+    if (rc < 0)
+        return false;
+
+    if ((access & (TPM_ACCESS_VALID | TPM_ACCESS_ACTIVE_LOCALITY))
+        == TPM_ACCESS_VALID)
+        return true;
+
+    return false;
+}
+
 static int release_locality(struct tpm_chip *chip, int l)
 {
    struct tpm_tis_data *priv = dev_get_drvdata(&chip->dev);
+    unsigned long stop, timeout;
+    long rc;
 
    tpm_tis_write8(priv, TPM_ACCESS(l), TPM_ACCESS_ACTIVE_LOCALITY);
 
-    return 0;
+    stop = jiffies + chip->timeout_a;
+
+    if (chip->flags & TPM_CHIP_FLAG_IRQ) {
+again:
+        timeout = stop - jiffies;
+        if ((long)timeout <= 0)
+            return -1;
+
+        rc = wait_event_interruptible_timeout(priv->int_queue,
+                              (locality_inactive(chip, l)),
+                              timeout);
+
+        if (rc > 0)
+            return 0;
+
+        if (rc == -ERESTARTSYS && freezing(current)) {
+            clear_thread_flag(TIF_SIGPENDING);
+            goto again;
+        }
+    } else {
+        do {
+            if (locality_inactive(chip, l))
+                return 0;
+            tpm_msleep(TPM_TIMEOUT);
+        } while (time_before(jiffies, stop));
+    }
+    return -1;
 }
 
Quoted 4 lines

static int request_locality(struct tpm_chip *chip, int l)

Signature · 1 line
2.15.0

Laurent,

Can you try this patch with your system since it is the one that has exhibited the problem so far. I've tested on a tpm2.0 and tpm1.2 system here.

Regards,
Jerry

#5 lore raw

Hello,

Top posting, sorry.

I don't know if I did it well to include the "Tested-by" tag because I don't see that the patch has landed in linus branch already.

And as far as I understand, this will not be in the upcoming 4.17 release as we are already late in the cycle?

Kind regards,

Laurent Bigonville

Le 11/05/18 a 21:02, Laurent Bigonville a ecrit :

Quoted 97 lines

Le 05/05/18 a 22:03, Jerry Snitselaar a ecrit :

Quoted 7 lines · Jerry Snitselaar
Quoted 6 lines

For certain tpm chips releasing locality can take long enough that a subsequent call to request_locality will see the locality as being active when the access register is read in check_locality. So check that the locality has been released before returning from release_locality.

Quoted 5 lines
Quoted 5 lines
Quoted 82 lines
Quoted 69 lines

---
drivers/char/tpm/tpm_tis_core.c | 47
++++++++++++++++++++++++++++++++++++++++-

1 file changed, 46 insertions(+), 1 deletion(-)
drivers/char/tpm/tpm_tis_core.c +46 -1
index 5a1f47b43947..d547cd309dbd 100644
@@ -143,13 +143,58 @@ static bool check_locality(struct tpm_chip 
 *chip, int l)
    return false;
 }
 
+static bool locality_inactive(struct tpm_chip *chip, int l)
+{
+    struct tpm_tis_data *priv = dev_get_drvdata(&chip->dev);
+    int rc;
+    u8 access;
+
+    rc = tpm_tis_read8(priv, TPM_ACCESS(l), &access);
+    if (rc < 0)
+        return false;
+
+    if ((access & (TPM_ACCESS_VALID | TPM_ACCESS_ACTIVE_LOCALITY))
+        == TPM_ACCESS_VALID)
+        return true;
+
+    return false;
+}
+
 static int release_locality(struct tpm_chip *chip, int l)
 {
    struct tpm_tis_data *priv = dev_get_drvdata(&chip->dev);
+    unsigned long stop, timeout;
+    long rc;
 
    tpm_tis_write8(priv, TPM_ACCESS(l), TPM_ACCESS_ACTIVE_LOCALITY);
 
-    return 0;
+    stop = jiffies + chip->timeout_a;
+
+    if (chip->flags & TPM_CHIP_FLAG_IRQ) {
+again:
+        timeout = stop - jiffies;
+        if ((long)timeout <= 0)
+            return -1;
+
+        rc = wait_event_interruptible_timeout(priv->int_queue,
+                              (locality_inactive(chip, l)),
+                              timeout);
+
+        if (rc > 0)
+            return 0;
+
+        if (rc == -ERESTARTSYS && freezing(current)) {
+            clear_thread_flag(TIF_SIGPENDING);
+            goto again;
+        }
+    } else {
+        do {
+            if (locality_inactive(chip, l))
+                return 0;
+            tpm_msleep(TPM_TIMEOUT);
+        } while (time_before(jiffies, stop));
+    }
+    return -1;
 }
 
Quoted 4 lines

static int request_locality(struct tpm_chip *chip, int l)

Signature · 1 line
2.15.0

Laurent,

Can you try this patch with your system since it is the one that has exhibited the problem so far. I've tested on a tpm2.0 and tpm1.2 system here.

Regards,
Jerry

#6 lore raw
Quoted 4 lines · Laurent Bigonville

Hello,

Top posting, sorry.

Quoted 8 lines

I don't know if I did it well to include the "Tested-by" tag because I don't see that the patch has landed in linus branch already.

And as far as I understand, this will not be in the upcoming 4.17 release as we are already late in the cycle?

Kind regards,

Laurent Bigonville

It should go into his branch during the merge window for 4.18.

Quoted 100 lines

Le 11/05/18 a 21:02, Laurent Bigonville a ecrit :

Quoted 97 lines

Le 05/05/18 a 22:03, Jerry Snitselaar a ecrit :

Quoted 7 lines · Jerry Snitselaar
Quoted 6 lines

For certain tpm chips releasing locality can take long enough that a subsequent call to request_locality will see the locality as being active when the access register is read in check_locality. So check that the locality has been released before returning from release_locality.

Quoted 5 lines
Quoted 5 lines
Quoted 82 lines
Quoted 69 lines

---
drivers/char/tpm/tpm_tis_core.c | 47
++++++++++++++++++++++++++++++++++++++++-

1 file changed, 46 insertions(+), 1 deletion(-)
drivers/char/tpm/tpm_tis_core.c +46 -1
index 5a1f47b43947..d547cd309dbd 100644
@@ -143,13 +143,58 @@ static bool check_locality(struct tpm_chip 
 *chip, int l)
   return false;
 }
 
+static bool locality_inactive(struct tpm_chip *chip, int l)
+{
+    struct tpm_tis_data *priv = dev_get_drvdata(&chip->dev);
+    int rc;
+    u8 access;
+
+    rc = tpm_tis_read8(priv, TPM_ACCESS(l), &access);
+    if (rc < 0)
+        return false;
+
+    if ((access & (TPM_ACCESS_VALID | TPM_ACCESS_ACTIVE_LOCALITY))
+        == TPM_ACCESS_VALID)
+        return true;
+
+    return false;
+}
+
 static int release_locality(struct tpm_chip *chip, int l)
 {
   struct tpm_tis_data *priv = dev_get_drvdata(&chip->dev);
+    unsigned long stop, timeout;
+    long rc;
 
   tpm_tis_write8(priv, TPM_ACCESS(l), TPM_ACCESS_ACTIVE_LOCALITY);
 
-    return 0;
+    stop = jiffies + chip->timeout_a;
+
+    if (chip->flags & TPM_CHIP_FLAG_IRQ) {
+again:
+        timeout = stop - jiffies;
+        if ((long)timeout <= 0)
+            return -1;
+
+        rc = wait_event_interruptible_timeout(priv->int_queue,
+                              (locality_inactive(chip, l)),
+                              timeout);
+
+        if (rc > 0)
+            return 0;
+
+        if (rc == -ERESTARTSYS && freezing(current)) {
+            clear_thread_flag(TIF_SIGPENDING);
+            goto again;
+        }
+    } else {
+        do {
+            if (locality_inactive(chip, l))
+                return 0;
+            tpm_msleep(TPM_TIMEOUT);
+        } while (time_before(jiffies, stop));
+    }
+    return -1;
 }
 
Quoted 4 lines

static int request_locality(struct tpm_chip *chip, int l)

Signature · 1 line
2.15.0

Laurent,

Can you try this patch with your system since it is the one that has exhibited the problem so far. I've tested on a tpm2.0 and tpm1.2 system here.

Regards,
Jerry

Reviewed-by on v1 1/1
#7 lore raw
In reply to Jerry Snitselaar
Quoted 11 lines · Jerry Snitselaar

For certain tpm chips releasing locality can take long enough that a subsequent call to request_locality will see the locality as being active when the access register is read in check_locality. So check that the locality has been released before returning from release_locality.

/Jarkko