From 1e5ac6300a07ceecfc70a893ebef3352be21e6f8 Mon Sep 17 00:00:00 2001
From: Milan Broz <gmazyland@gmail.com>
Date: Thu, 4 Jul 2019 09:26:15 +0200
Subject: [PATCH] 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: 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>
Reviewed-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.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 d47ad10a35fe3..bf868260f4353 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);
--
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