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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: 719b7d81f2 ("tpm: introduce tpm_chip_start() and tpm_chip_stop()")
Cc: stable@vger.kernel.org # v5.1+
Signed-off-by: Milan Broz <gmazyland@gmail.com>
Reviewed-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
This commit is contained in:
Milan Broz 2019-07-04 09:26:15 +02:00 committed by Jarkko Sakkinen
parent 4b6f23161b
commit 1e5ac6300a
1 changed files with 16 additions and 7 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

23
drivers/char/tpm/tpm-chip.c
View File

@ -77,6 +77,18 @@ static int tpm_go_idle(struct tpm_chip *chip)
return chip->ops->go_idle(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 * tpm_chip_start() - power on the TPM
* @chip: a TPM chip to use * @chip: a TPM chip to use
@ -89,13 +101,12 @@ int tpm_chip_start(struct tpm_chip *chip)
{ {
int ret; int ret;
if (chip->ops->clk_enable) tpm_clk_enable(chip);
chip->ops->clk_enable(chip, true);
if (chip->locality == -1) { if (chip->locality == -1) {
ret = tpm_request_locality(chip); ret = tpm_request_locality(chip);
if (ret) { if (ret) {
chip->ops->clk_enable(chip, false); tpm_clk_disable(chip);
return ret; return ret;
} }
} }
@ -103,8 +114,7 @@ int tpm_chip_start(struct tpm_chip *chip)
ret = tpm_cmd_ready(chip); ret = tpm_cmd_ready(chip);
if (ret) { if (ret) {
tpm_relinquish_locality(chip); tpm_relinquish_locality(chip);
if (chip->ops->clk_enable) tpm_clk_disable(chip);
chip->ops->clk_enable(chip, false);
return ret; return ret;
} }
@ -124,8 +134,7 @@ void tpm_chip_stop(struct tpm_chip *chip)
{ {
tpm_go_idle(chip); tpm_go_idle(chip);
tpm_relinquish_locality(chip); tpm_relinquish_locality(chip);
if (chip->ops->clk_enable) tpm_clk_disable(chip);
chip->ops->clk_enable(chip, false);
} }
EXPORT_SYMBOL_GPL(tpm_chip_stop); EXPORT_SYMBOL_GPL(tpm_chip_stop);