Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit 1e5ac630 authored by Milan Broz's avatar Milan Broz Committed by Jarkko Sakkinen
Browse files

tpm: Fix null pointer dereference on chip register error path 



If clk_enable is not defined and chip initialization
is canceled code hits null dereference.

Easily reproducible with vTPM init fail:
  swtpm chardev --tpmstate dir=nonexistent_dir --tpm2 --vtpm-proxy

BUG: kernel NULL pointer dereference, address: 00000000
...
Call Trace:
 tpm_chip_start+0x9d/0xa0 [tpm]
 tpm_chip_register+0x10/0x1a0 [tpm]
 vtpm_proxy_work+0x11/0x30 [tpm_vtpm_proxy]
 process_one_work+0x214/0x5a0
 worker_thread+0x134/0x3e0
 ? process_one_work+0x5a0/0x5a0
 kthread+0xd4/0x100
 ? process_one_work+0x5a0/0x5a0
 ? kthread_park+0x90/0x90
 ret_from_fork+0x19/0x24

Fixes: 719b7d81 ("tpm: introduce tpm_chip_start() and tpm_chip_stop()")
Cc: stable@vger.kernel.org # v5.1+
Signed-off-by: default avatarMilan Broz <gmazyland@gmail.com>
Reviewed-by: default avatarJarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Signed-off-by: default avatarJarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
parent 4b6f2316

drivers/char/tpm/tpm-chip.c

+16 −7
Original line number Diff line number Diff line
@@ -77,6 +77,18 @@ static int tpm_go_idle(struct tpm_chip *chip) 
	return chip->ops->go_idle(chip);

}



static void tpm_clk_enable(struct tpm_chip *chip)

{

	if (chip->ops->clk_enable)

		chip->ops->clk_enable(chip, true);

}



static void tpm_clk_disable(struct tpm_chip *chip)

{

	if (chip->ops->clk_enable)

		chip->ops->clk_enable(chip, false);

}



/**

 * tpm_chip_start() - power on the TPM

 * @chip:	a TPM chip to use
@@ -89,13 +101,12 @@ int tpm_chip_start(struct tpm_chip *chip) 
{

	int ret;



	if (chip->ops->clk_enable)

		chip->ops->clk_enable(chip, true);

	tpm_clk_enable(chip);



	if (chip->locality == -1) {

		ret = tpm_request_locality(chip);

		if (ret) {

			chip->ops->clk_enable(chip, false);

			tpm_clk_disable(chip);

			return ret;

		}

	}
@@ -103,8 +114,7 @@ int tpm_chip_start(struct tpm_chip *chip) 
	ret = tpm_cmd_ready(chip);

	if (ret) {

		tpm_relinquish_locality(chip);

		if (chip->ops->clk_enable)

			chip->ops->clk_enable(chip, false);

		tpm_clk_disable(chip);

		return ret;

	}
@@ -124,8 +134,7 @@ void tpm_chip_stop(struct tpm_chip *chip) 
{

	tpm_go_idle(chip);

	tpm_relinquish_locality(chip);

	if (chip->ops->clk_enable)

		chip->ops->clk_enable(chip, false);

	tpm_clk_disable(chip);

}

EXPORT_SYMBOL_GPL(tpm_chip_stop);