linux-kernel - [PATCH v2] tpm2: add longer timeout for verify signature command

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Date:   Wed, 19 May 2021 17:00:59 +0300
From:   amirmizi6@...il.com
To:     Eyal.Cohen@...oton.com, jarkko@...nel.org, peterhuewe@....de,
        jgg@...pe.ca
Cc:     linux-kernel@...r.kernel.org, linux-integrity@...r.kernel.org,
        Dan.Morav@...oton.com, oren.tanami@...oton.com,
        shmulik.hager@...oton.com, amir.mizinski@...oton.com,
        Amir Mizinski <amirmizi6@...il.com>
Subject: [PATCH v2] tpm2: add longer timeout for verify signature command

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

While running a TPM2_CC_VERIFY_SIGNATURE(0x177) operation with RSA 3070-bit
keys the TPM driver fails with the following error:
"kernel: [ 2416.187522] tpm tpm0: Operation Timed out"

Since a) the TPM PC Client specification does not specify a number for
verify signature operation timeout, and b) the duration of
TPM2_CC_VERIFY_SIGNATURE with RSA 3070-bit keys exceeds the current timeout
of TPM_LONG (2 seconds), it is preferable to pick the longest timeout
possible.
Therefore, set the duration for TPM2_CC_VERIFY_SIGNATUE to TPM_LONG_LONG
(5 minutes).

Signed-off-by: Amir Mizinski <amirmizi6@...il.com>
---
 drivers/char/tpm/tpm2-cmd.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/char/tpm/tpm2-cmd.c b/drivers/char/tpm/tpm2-cmd.c
index 7603295..e71154b 100644
--- a/drivers/char/tpm/tpm2-cmd.c
+++ b/drivers/char/tpm/tpm2-cmd.c
@@ -87,7 +87,7 @@ static u8 tpm2_ordinal_duration_index(u32 ordinal)
 		return TPM_MEDIUM;
 
 	case TPM2_CC_VERIFY_SIGNATURE:        /* 177 */
-		return TPM_LONG;
+		return TPM_LONG_LONG;
 
 	case TPM2_CC_PCR_EXTEND:              /* 182 */
 		return TPM_MEDIUM;
-- 
2.7.4