linux-kernel - [PATCH v12 5/9] tpm: tpm_tis: Rewrite "tpm_tis_req

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-Id: <20200625144650.269719-6-amirmizi6@gmail.com>
Date:   Thu, 25 Jun 2020 17:46:45 +0300
From:   amirmizi6@...il.com
To:     Eyal.Cohen@...oton.com, jarkko.sakkinen@...ux.intel.com,
        oshrialkoby85@...il.com, alexander.steffen@...ineon.com,
        robh+dt@...nel.org,
        "benoit.houyere@...com--to=mark.rutland"@arm.com,
        peterhuewe@....de, christophe-h.richard@...com, jgg@...pe.ca,
        arnd@...db.de, gregkh@...uxfoundation.org
Cc:     devicetree@...r.kernel.org, linux-kernel@...r.kernel.org,
        linux-integrity@...r.kernel.org, oshri.alkoby@...oton.com,
        tmaimon77@...il.com, gcwilson@...ibm.com, kgoldman@...ibm.com,
        Dan.Morav@...oton.com, oren.tanami@...oton.com,
        shmulik.hager@...oton.com, amir.mizinski@...oton.com,
        Amir Mizinski <amirmizi6@...il.com>
Subject: [PATCH v12 5/9] tpm: tpm_tis: Rewrite "tpm_tis_req_canceled()"

From: Amir Mizinski <amirmizi6@...il.com>

Using this function while reading/writing data resulted in an aborted
operation.
After investigating the issue according to the TCG TPM Profile (PTP)
Specifications, I found that "request to cancel" should occur only if
TPM_STS.commandReady bit is lit.
Note that i couldn't find a case where the present condition
(in the linux kernel) is valid, so I'm removing the case for
"TPM_VID_WINBOND" since we have no need for it.

Also, the default comparison is wrong. Only cmdReady bit needs to be
compared instead of the full lower status register byte.

Fixes: 1f866057291f (tpm: Fix cancellation of TPM commands (polling mode))
Signed-off-by: Amir Mizinski <amirmizi6@...il.com>
---
 drivers/char/tpm/tpm_tis_core.c | 6 ++----
 1 file changed, 2 insertions(+), 4 deletions(-)

diff --git a/drivers/char/tpm/tpm_tis_core.c b/drivers/char/tpm/tpm_tis_core.c
index 347c020..a38465f 100644
--- a/drivers/char/tpm/tpm_tis_core.c
+++ b/drivers/char/tpm/tpm_tis_core.c
@@ -701,13 +701,11 @@ static bool tpm_tis_req_canceled(struct tpm_chip *chip, u8 status)
 	struct tpm_tis_data *priv = dev_get_drvdata(&chip->dev);
 
 	switch (priv->manufacturer_id) {
-	case TPM_VID_WINBOND:
-		return ((status == TPM_STS_VALID) ||
-			(status == (TPM_STS_VALID | TPM_STS_COMMAND_READY)));
 	case TPM_VID_STM:
 		return (status == (TPM_STS_VALID | TPM_STS_COMMAND_READY));
 	default:
-		return (status == TPM_STS_COMMAND_READY);
+		return ((status & TPM_STS_COMMAND_READY) ==
+			TPM_STS_COMMAND_READY);
 	}
 }
 
-- 
2.7.4