linux-kernel - [PATCH] tpm, tpm_crb: fail when TPM2 ACPI table contents look corrupted

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Date:	Wed, 24 Jun 2015 17:14:55 +0300
From:	Jarkko Sakkinen <jarkko.sakkinen@...ux.intel.com>
To:	peterhuewe@....de, tpmdd-devel@...ts.sourceforge.net,
	linux-kernel@...r.kernel.org
Cc:	Jarkko Sakkinen <jarkko.sakkinen@...ux.intel.com>,
	Marcel Selhorst <tpmdd@...horst.net>,
	Jason Gunthorpe <jgunthorpe@...idianresearch.com>
Subject: [PATCH] tpm, tpm_crb: fail when TPM2 ACPI table contents look corrupted

At least some versions of AMI BIOS have corrupted contents in the TPM2
ACPI table and namely the physical address of the control area is set to
zero.

This patch changes the driver to fail gracefully  when we observe a zero
address instead of continuing to ioremap.

Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@...ux.intel.com>
---
 drivers/char/tpm/tpm_crb.c | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/drivers/char/tpm/tpm_crb.c b/drivers/char/tpm/tpm_crb.c
index b26ceee..c8fae5b 100644
--- a/drivers/char/tpm/tpm_crb.c
+++ b/drivers/char/tpm/tpm_crb.c
@@ -233,6 +233,14 @@ static int crb_acpi_add(struct acpi_device *device)
 		return -ENODEV;
 	}
 
+	/* At least some versions of AMI BIOS have a bug that TPM2 table has
+	 * zero address for the control area and therefore we must fail.
+	*/
+	if (!buf->control_area_pa) {
+		dev_err(dev, "TPM2 ACPI table has a zero address for the control area\n");
+		return -EINVAL;
+	}
+
 	if (buf->hdr.length < sizeof(struct acpi_tpm2)) {
 		dev_err(dev, "TPM2 ACPI table has wrong size");
 		return -EINVAL;
-- 
2.1.4

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