Re: [PATCH] tpm: Fix auth session leak in tpm2_get_random() error path

[Jarkko Sakkinen <jarkko@kernel.org>]

On Wed, Sep 02, 2026 at 03:48:39PM +0800, Jiangshan Yi wrote:
> When tpm_buf_fill_hmac_session() fails in tpm2_get_random(), the error
> path returns without calling tpm2_end_auth_session(), leaking the auth
> session. All other error paths in the function handle this correctly.
> 
> Fixes: 3d9e043dab0a ("tpm-buf: Memory-safe allocations")
> Cc: stable@vger.kernel.org
> Signed-off-by: Jiangshan Yi <yijiangshan@kylinos.cn>
> ---
>  drivers/char/tpm/tpm2-cmd.c | 4 +++-
>  1 file changed, 3 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/char/tpm/tpm2-cmd.c b/drivers/char/tpm/tpm2-cmd.c
> index 48cec39995fe..96e0e06bbbf0 100644
> --- a/drivers/char/tpm/tpm2-cmd.c
> +++ b/drivers/char/tpm/tpm2-cmd.c
> @@ -281,8 +281,10 @@ int tpm2_get_random(struct tpm_chip *chip, u8 *dest, size_t max)
>  		}
>  		tpm_buf_append_u16(buf, num_bytes);
>  		err = tpm_buf_fill_hmac_session(chip, buf);
> -		if (err)
> +		if (err) {
> +			tpm2_end_auth_session(chip);
>  			return err;
> +		}
>  
>  		err = tpm_transmit_cmd(chip, buf,
>  				       offsetof(struct tpm2_get_random_out,
> -- 
> 2.25.1
> 

Thanks for the fix.

Reviewed-by: Jarkko Sakkinen <jarkko@kernel.org>

BR, Jarkko