From: Lino Sanfilippo <LinoSanfilippo@gmx.de>
To: peterhuewe@gmx.de, jarkko@kernel.org
Cc: jgg@ziepe.ca, stefanb@linux.vnet.ibm.com,
linux-integrity@vger.kernel.org, linux-kernel@vger.kernel.org,
LinoSanfilippo@gmx.de, Lino Sanfilippo <l.sanfilippo@kunbus.com>
Subject: [PATCH v2 3/3] tpm: in tpm2_del_space check if ops pointer is still valid
Date: Tue, 2 Feb 2021 23:09:03 +0100 [thread overview]
Message-ID: <1612303743-29017-4-git-send-email-LinoSanfilippo@gmx.de> (raw)
In-Reply-To: <1612303743-29017-1-git-send-email-LinoSanfilippo@gmx.de>
From: Lino Sanfilippo <l.sanfilippo@kunbus.com>
In tpm2_del_space() the sessions are flushed by means of the tpm_chip
operations. However the concerning operations pointer my already be NULL at
this time in case that the chip has been unregistered (see
tpm_chip_unregister() which calls tpm_del_char_device() which sets
chip->ops to NULL).
Before accessing chip->ops check if it is still valid. Skip flushing
the sessions in this case.
Signed-off-by: Lino Sanfilippo <l.sanfilippo@kunbus.com>
---
drivers/char/tpm/tpm2-space.c | 15 ++++++++++-----
1 file changed, 10 insertions(+), 5 deletions(-)
diff --git a/drivers/char/tpm/tpm2-space.c b/drivers/char/tpm/tpm2-space.c
index 784b8b3..9a29a40 100644
--- a/drivers/char/tpm/tpm2-space.c
+++ b/drivers/char/tpm/tpm2-space.c
@@ -58,12 +58,17 @@ int tpm2_init_space(struct tpm_space *space, unsigned int buf_size)
void tpm2_del_space(struct tpm_chip *chip, struct tpm_space *space)
{
- mutex_lock(&chip->tpm_mutex);
- if (!tpm_chip_start(chip)) {
- tpm2_flush_sessions(chip, space);
- tpm_chip_stop(chip);
+ down_read(&chip->ops_sem);
+ if (chip->ops) {
+ mutex_lock(&chip->tpm_mutex);
+ if (!tpm_chip_start(chip)) {
+ tpm2_flush_sessions(chip, space);
+ tpm_chip_stop(chip);
+ }
+ mutex_unlock(&chip->tpm_mutex);
}
- mutex_unlock(&chip->tpm_mutex);
+ up_read(&chip->ops_sem);
+
kfree(space->context_buf);
kfree(space->session_buf);
}
--
2.7.4
next prev parent reply other threads:[~2021-02-02 22:12 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-02-02 22:09 [PATCH v2 0/3] TPM fixes Lino Sanfilippo
2021-02-02 22:09 ` [PATCH v2 1/3] tpm: fix reference counting for struct tpm_chip Lino Sanfilippo
2021-02-03 1:09 ` Jarkko Sakkinen
2021-02-03 14:06 ` Lino Sanfilippo
2021-02-03 21:43 ` Jarkko Sakkinen
2021-02-02 22:09 ` [PATCH v2 2/3] tpm: Provide a function tpm_chip_free() to free tpm chips Lino Sanfilippo
2021-02-03 1:28 ` Jarkko Sakkinen
2021-02-03 14:09 ` Lino Sanfilippo
2021-02-02 22:09 ` Lino Sanfilippo [this message]
2021-02-03 1:17 ` [PATCH v2 3/3] tpm: in tpm2_del_space check if ops pointer is still valid Jarkko Sakkinen
2021-02-03 14:22 ` Lino Sanfilippo
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