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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,
	benoit.houyere@st.com, eajames@linux.ibm.com, joel@jms.id.au
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 v13 5/7] tpm: tpm_tis: verify TPM_STS register is valid after  locality request
Date: Thu, 26 Aug 2021 14:19:06 +0300	[thread overview]
Message-ID: <20210826111908.117278-6-amirmizi6@gmail.com> (raw)
In-Reply-To: <20210826111908.117278-1-amirmizi6@gmail.com>

From: Amir Mizinski <amirmizi6@gmail.com>

Issue could result when the TPM does not update TPM_STS register after
a locality request (TPM_STS Initial value = 0xFF) and a TPM_STS register
read occurs (tpm_tis_status(chip)).

Checking the next condition("if ((status & TPM_STS_COMMAND_READY) == 0)"),
the status will be at 0xFF and will be considered, wrongly, in "Ready"
state (by checking only one bit). However, at this moment the TPM is, in
fact, in "Idle" state and remains in "Idle" state because
"tpm_tis_ready(chip);" was not executed.

Suggested-by: Benoit Houyere <benoit.houyere@st.com>
Signed-off-by: Amir Mizinski <amirmizi6@gmail.com>
---
 drivers/char/tpm/tpm_tis_core.c | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/drivers/char/tpm/tpm_tis_core.c b/drivers/char/tpm/tpm_tis_core.c
index 4145758..d527c43 100644
--- a/drivers/char/tpm/tpm_tis_core.c
+++ b/drivers/char/tpm/tpm_tis_core.c
@@ -177,8 +177,14 @@ static int request_locality(struct tpm_chip *chip, int l)
 	} else {
 		/* wait for burstcount */
 		do {
-			if (check_locality(chip, l))
+			if (check_locality(chip, l)) {
+				if (tpm_tis_wait_for_stat(chip, TPM_STS_GO, 0,
+							  chip->timeout_c,
+							  &priv->int_queue,
+							  false) < 0)
+					return -ETIME;
 				return l;
+			}
 			tpm_msleep(TPM_TIMEOUT);
 		} while (time_before(jiffies, stop));
 	}
-- 
2.7.4


  parent reply	other threads:[~2021-08-26 12:18 UTC|newest]

Thread overview: 16+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-08-26 11:19 [PATCH v13 0/7] Add tpm i2c ptp driver amirmizi6
2021-08-26 11:19 ` [PATCH v13 1/7] tpm: Make read{16, 32}() and write32() in tpm_tis_phy_ops optional amirmizi6
2021-08-26 15:57   ` Jarkko Sakkinen
2021-08-26 11:19 ` [PATCH v13 2/7] tpm: tpm_tis: Fix expected bit handling and send all bytes in one shot without last byte in exception amirmizi6
2021-08-26 15:59   ` Jarkko Sakkinen
2021-08-26 11:19 ` [PATCH v13 3/7] tpm: tpm_tis: Rewrite "tpm_tis_req_canceled()" amirmizi6
2021-08-26 16:01   ` Jarkko Sakkinen
2021-08-26 11:19 ` [PATCH v13 4/7] tpm: Handle an exception for TPM Firmware Update mode amirmizi6
2021-08-26 16:02   ` Jarkko Sakkinen
2021-08-26 11:19 ` amirmizi6 [this message]
2021-08-26 16:03   ` [PATCH v13 5/7] tpm: tpm_tis: verify TPM_STS register is valid after locality request Jarkko Sakkinen
2021-08-26 11:19 ` [PATCH v13 6/7] tpm: tpm_tis: add tpm_tis_i2c driver amirmizi6
2021-08-26 16:04   ` Jarkko Sakkinen
2021-08-26 11:19 ` [PATCH v13 7/7] tpm: Add YAML schema for TPM TIS I2C options amirmizi6
2021-08-26 13:26   ` Rob Herring
2021-08-26 16:05   ` Jarkko Sakkinen

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