linux-kernel - Re: [PATCH] tpm: set TPM_CHIP_FLAG

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: <z4ggs22bzp76ire4yecy5cehlurlcll7hrf2bx4mksebtdmcmr@hpjardr6gwib>
Date: Wed, 30 Oct 2024 13:09:15 -0700
From: Jerry Snitselaar <jsnitsel@...hat.com>
To: Jarkko Sakkinen <jarkko@...nel.org>
Cc: Peter Huewe <peterhuewe@....de>, Jason Gunthorpe <jgg@...pe.ca>, 
	stable@...r.kernel.org, Mike Seo <mikeseohyungjin@...il.com>, 
	"open list:TPM DEVICE DRIVER" <linux-integrity@...r.kernel.org>, open list <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] tpm: set TPM_CHIP_FLAG_SUSPENDED early

On Wed, Oct 30, 2024 at 12:36:47AM +0200, Jarkko Sakkinen wrote:
> Setting TPM_CHIP_FLAG_SUSPENDED in the end of tpm_pm_suspend() can be racy
> according to the bug report, as this leaves window for tpm_hwrng_read() to
> be called while the operation is in progress. Move setting of the flag
> into the beginning.
> 
> Cc: stable@...r.kernel.org # v6.4+
> Fixes: 99d464506255 ("tpm: Prevent hwrng from activating during resume")
> Reported-by: Mike Seo <mikeseohyungjin@...il.com>
> Closes: https://bugzilla.kernel.org/show_bug.cgi?id=219383
> Signed-off-by: Jarkko Sakkinen <jarkko@...nel.org>
> ---
>  drivers/char/tpm/tpm-interface.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/char/tpm/tpm-interface.c b/drivers/char/tpm/tpm-interface.c
> index 8134f002b121..3f96bc8b95df 100644
> --- a/drivers/char/tpm/tpm-interface.c
> +++ b/drivers/char/tpm/tpm-interface.c
> @@ -370,6 +370,8 @@ int tpm_pm_suspend(struct device *dev)
>  	if (!chip)
>  		return -ENODEV;
>  
> +	chip->flags |= TPM_CHIP_FLAG_SUSPENDED;
> +
>  	if (chip->flags & TPM_CHIP_FLAG_ALWAYS_POWERED)
>  		goto suspended;
>  
> @@ -390,8 +392,6 @@ int tpm_pm_suspend(struct device *dev)
>  	}
>  
>  suspended:
> -	chip->flags |= TPM_CHIP_FLAG_SUSPENDED;
> -
>  	if (rc)
>  		dev_err(dev, "Ignoring error %d while suspending\n", rc);
>  	return 0;
> -- 
> 2.47.0
> 

Reviewed-by: Jerry Snitselaar <jsnitsel@...hat.com>