linux-kernel - [PATCH] tpm: Don't make vendor check required for probe

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Message-ID: <20230818181516.19167-1-mario.limonciello@amd.com>
Date:   Fri, 18 Aug 2023 13:15:16 -0500
From:   Mario Limonciello <mario.limonciello@....com>
To:     <jarkko@...nel.org>
CC:     <linux-integrity@...r.kernel.org>, <linux-kernel@...r.kernel.org>,
        Thorsten Leemhuis <regressions@...mhuis.info>,
        <charles.d.prestopine@...el.com>, <rafael.j.wysocki@...el.com>,
        <len.brown@...el.com>,
        Mario Limonciello <mario.limonciello@....com>,
        <stable@...r.kernel.org>, Todd Brandt <todd.e.brandt@...el.com>
Subject: [PATCH] tpm: Don't make vendor check required for probe

The vendor check introduced by commit 554b841d4703 ("tpm: Disable RNG for
all AMD fTPMs") doesn't work properly on Intel fTPM.  The TPM doesn't reply
at bootup and returns back the command code.

As this isn't crucial for anything but AMD fTPM and AMD fTPM works, throw
away the error code to let Intel fTPM continue to work.

Cc: stable@...r.kernel.org
Fixes: 554b841d4703 ("tpm: Disable RNG for all AMD fTPMs")
Reported-by: Todd Brandt <todd.e.brandt@...el.com>
Closes: https://bugzilla.kernel.org/show_bug.cgi?id=217804
Signed-off-by: Mario Limonciello <mario.limonciello@....com>
---
 drivers/char/tpm/tpm_crb.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/drivers/char/tpm/tpm_crb.c b/drivers/char/tpm/tpm_crb.c
index 9eb1a18590123..b0e9931fe436c 100644
--- a/drivers/char/tpm/tpm_crb.c
+++ b/drivers/char/tpm/tpm_crb.c
@@ -472,8 +472,7 @@ static int crb_check_flags(struct tpm_chip *chip)
 	if (ret)
 		return ret;
 
-	ret = tpm2_get_tpm_pt(chip, TPM2_PT_MANUFACTURER, &val, NULL);
-	if (ret)
+	if (tpm2_get_tpm_pt(chip, TPM2_PT_MANUFACTURER, &val, NULL))
 		goto release;
 
 	if (val == 0x414D4400U /* AMD */)
-- 
2.34.1