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: 719b7d81f204 ("tpm: introduce tpm_chip_start() and tpm_chip_stop()") Cc: stable@vger.kernel.org # v5.1+ Signed-off-by: Milan Broz gmazyland@gmail.com --- drivers/char/tpm/tpm-chip.c | 23 ++++++++++++++++------- 1 file changed, 16 insertions(+), 7 deletions(-)

diff --git a/drivers/char/tpm/tpm-chip.c b/drivers/char/tpm/tpm-chip.c index 90325e1749fb..db6ac6f83948 100644 --- a/drivers/char/tpm/tpm-chip.c +++ b/drivers/char/tpm/tpm-chip.c @@ -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);