linux-kernel - Re: [PATCH 4.19 33/63] tpm: Fix TPM 1.2 Shutdown sequence to prevent future TPM operations

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: <20190930125712.GS8171@sasha-vm>
Date:   Mon, 30 Sep 2019 08:57:12 -0400
From:   Sasha Levin <sashal@...nel.org>
To:     Pavel Machek <pavel@....cz>
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        linux-kernel@...r.kernel.org, stable@...r.kernel.org,
        Vadim Sukhomlinov <sukhomlinov@...gle.com>,
        Douglas Anderson <dianders@...omium.org>,
        Jarkko Sakkinen <jarkko.sakkinen@...ux.intel.com>
Subject: Re: [PATCH 4.19 33/63] tpm: Fix TPM 1.2 Shutdown sequence to prevent
 future TPM operations

On Mon, Sep 30, 2019 at 08:13:46AM +0200, Pavel Machek wrote:
>> From: Vadim Sukhomlinov <sukhomlinov@...gle.com>
>>
>> commit db4d8cb9c9f2af71c4d087817160d866ed572cc9 upstream
>>
>> TPM 2.0 Shutdown involve sending TPM2_Shutdown to TPM chip and disabling
>> future TPM operations. TPM 1.2 behavior was different, future TPM
>> operations weren't disabled, causing rare issues. This patch ensures
>> that future TPM operations are disabled.
>
>> diff --git a/drivers/char/tpm/tpm-chip.c b/drivers/char/tpm/tpm-chip.c
>> index 46caadca916a0..dccc61af9ffab 100644
>> --- a/drivers/char/tpm/tpm-chip.c
>> +++ b/drivers/char/tpm/tpm-chip.c
>> @@ -187,12 +187,15 @@ static int tpm_class_shutdown(struct device *dev)
>>  {
>>  	struct tpm_chip *chip = container_of(dev, struct tpm_chip, dev);
>>
>> +	down_write(&chip->ops_sem);
>>  	if (chip->flags & TPM_CHIP_FLAG_TPM2) {
>>  		down_write(&chip->ops_sem);
>>  		tpm2_shutdown(chip, TPM2_SU_CLEAR);
>>  		chip->ops = NULL;
>>  		up_write(&chip->ops_sem);
>>  	}
>> +	chip->ops = NULL;
>> +	up_write(&chip->ops_sem);
>
>This is wrong, it takes &chip->ops_sem twice, that can't be
>good. db4d8cb9c9f2af71c4d087817160d866ed572cc9 does not have that
>problem.

I agree. I've dropped it from 4.19 and 4.14.

Jarkko, can you take a look at this again please?

--
Thanks,
Sasha