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authorTadeusz Struk <tadeusz.struk@intel.com>2019-12-12 20:48:47 +0300
committerJarkko Sakkinen <jarkko.sakkinen@linux.intel.com>2019-12-17 13:20:04 +0300
commitd23d12484307b40eea549b8a858f5fffad913897 (patch)
tree40e278f20d0effbf43f8065b617459067e3a1c21 /drivers/char
parent45477b3fe3d10376b649b1b85fce72b2f9f1da84 (diff)
downloadlinux-d23d12484307b40eea549b8a858f5fffad913897.tar.xz
tpm: fix invalid locking in NONBLOCKING mode
When an application sends TPM commands in NONBLOCKING mode the driver holds chip->tpm_mutex returning from write(), which triggers: "WARNING: lock held when returning to user space". To fix this issue the driver needs to release the mutex before returning and acquire it again in tpm_dev_async_work() before sending the command. Cc: stable@vger.kernel.org Fixes: 9e1b74a63f776 (tpm: add support for nonblocking operation) Reported-by: Jeffrin Jose T <jeffrin@rajagiritech.edu.in> Tested-by: Jeffrin Jose T <jeffrin@rajagiritech.edu.in> Signed-off-by: Tadeusz Struk <tadeusz.struk@intel.com> Reviewed-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com> Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Diffstat (limited to 'drivers/char')
-rw-r--r--drivers/char/tpm/tpm-dev-common.c8
1 files changed, 8 insertions, 0 deletions
diff --git a/drivers/char/tpm/tpm-dev-common.c b/drivers/char/tpm/tpm-dev-common.c
index 2ec47a69a2a6..b23b0b999232 100644
--- a/drivers/char/tpm/tpm-dev-common.c
+++ b/drivers/char/tpm/tpm-dev-common.c
@@ -61,6 +61,12 @@ static void tpm_dev_async_work(struct work_struct *work)
mutex_lock(&priv->buffer_mutex);
priv->command_enqueued = false;
+ ret = tpm_try_get_ops(priv->chip);
+ if (ret) {
+ priv->response_length = ret;
+ goto out;
+ }
+
ret = tpm_dev_transmit(priv->chip, priv->space, priv->data_buffer,
sizeof(priv->data_buffer));
tpm_put_ops(priv->chip);
@@ -68,6 +74,7 @@ static void tpm_dev_async_work(struct work_struct *work)
priv->response_length = ret;
mod_timer(&priv->user_read_timer, jiffies + (120 * HZ));
}
+out:
mutex_unlock(&priv->buffer_mutex);
wake_up_interruptible(&priv->async_wait);
}
@@ -204,6 +211,7 @@ ssize_t tpm_common_write(struct file *file, const char __user *buf,
if (file->f_flags & O_NONBLOCK) {
priv->command_enqueued = true;
queue_work(tpm_dev_wq, &priv->async_work);
+ tpm_put_ops(priv->chip);
mutex_unlock(&priv->buffer_mutex);
return size;
}