On Tue, Jul 17, 2018 at 01:56:56PM -0700, Todd Poynor wrote:
> From: Todd Poynor <toddpoy...@google.com>
>
> Always allow root to open device for writing.
>
> Drop special-casing of ioctl permissions for root vs. owner.
>
> Reported-by: Dmitry Torokhov <d...@chromium.org>
> Signed-off-by: Zhongze Hu <fran...@chromium.org>
> Signed-off-by: Todd Poynor <toddpoy...@google.com>
> ---
> drivers/staging/gasket/apex_driver.c | 9 +--------
> drivers/staging/gasket/gasket_core.c | 8 +++++---
> drivers/staging/gasket/gasket_ioctl.c | 19 ++++++++-----------
> 3 files changed, 14 insertions(+), 22 deletions(-)
>
> diff --git a/drivers/staging/gasket/apex_driver.c
> b/drivers/staging/gasket/apex_driver.c
> index 3a83c3d4d5561..612b3ab803196 100644
> --- a/drivers/staging/gasket/apex_driver.c
> +++ b/drivers/staging/gasket/apex_driver.c
> @@ -629,14 +629,7 @@ static bool is_gcb_in_reset(struct gasket_dev
> *gasket_dev)
> */
> static uint apex_ioctl_check_permissions(struct file *filp, uint cmd)
> {
> - struct gasket_dev *gasket_dev = filp->private_data;
> - int root = capable(CAP_SYS_ADMIN);
> - int is_owner = gasket_dev->dev_info.ownership.is_owned &&
> - current->tgid == gasket_dev->dev_info.ownership.owner;
> -
> - if (root || is_owner)
> - return 1;
> - return 0;
> + return !!(filp->f_mode & FMODE_WRITE);
Shouldn't this return a boolean instead of uint?
> }
>
> /*
> diff --git a/drivers/staging/gasket/gasket_core.c
> b/drivers/staging/gasket/gasket_core.c
> index 0d5ba7359af73..947b4fcc76970 100644
> --- a/drivers/staging/gasket/gasket_core.c
> +++ b/drivers/staging/gasket/gasket_core.c
> @@ -1085,6 +1085,7 @@ static int gasket_open(struct inode *inode, struct file
> *filp)
> char task_name[TASK_COMM_LEN];
> struct gasket_cdev_info *dev_info =
> container_of(inode->i_cdev, struct gasket_cdev_info, cdev);
> + int is_root = capable(CAP_SYS_ADMIN);
>
> gasket_dev = dev_info->gasket_dev_ptr;
> driver_desc = gasket_dev->internal_desc->driver_desc;
> @@ -1098,7 +1099,7 @@ static int gasket_open(struct inode *inode, struct file
> *filp)
> "Attempting to open with tgid %u (%s) (f_mode: 0%03o, "
> "fmode_write: %d is_root: %u)",
> current->tgid, task_name, filp->f_mode,
> - (filp->f_mode & FMODE_WRITE), capable(CAP_SYS_ADMIN));
> + (filp->f_mode & FMODE_WRITE), is_root);
>
> /* Always allow non-writing accesses. */
> if (!(filp->f_mode & FMODE_WRITE)) {
> @@ -1112,8 +1113,9 @@ static int gasket_open(struct inode *inode, struct file
> *filp)
> gasket_dev, "Current owner open count (owning tgid %u): %d.",
> ownership->owner, ownership->write_open_count);
>
> - /* Opening a node owned by another TGID is an error (even root.) */
> - if (ownership->is_owned && ownership->owner != current->tgid) {
> + /* Opening a node owned by another TGID is an error (unless root) */
> + if (ownership->is_owned && ownership->owner != current->tgid &&
> + !is_root) {
> gasket_log_error(
> gasket_dev,
> "Process %u is opening a node held by %u.",
> diff --git a/drivers/staging/gasket/gasket_ioctl.c
> b/drivers/staging/gasket/gasket_ioctl.c
> index 0c2f85cf54480..d0fa05b8bf1d3 100644
> --- a/drivers/staging/gasket/gasket_ioctl.c
> +++ b/drivers/staging/gasket/gasket_ioctl.c
> @@ -171,7 +171,7 @@ long gasket_is_supported_ioctl(uint cmd)
> */
> static uint gasket_ioctl_check_permissions(struct file *filp, uint cmd)
> {
Also return bool?
> - uint alive, root, device_owner;
> + uint alive;
> fmode_t read, write;
> struct gasket_dev *gasket_dev = (struct gasket_dev *)filp->private_data;
>
> @@ -183,33 +183,30 @@ static uint gasket_ioctl_check_permissions(struct file
> *filp, uint cmd)
> alive, gasket_dev->status);
> }
>
> - root = capable(CAP_SYS_ADMIN);
> - read = filp->f_mode & FMODE_READ;
> - write = filp->f_mode & FMODE_WRITE;
> - device_owner = (gasket_dev->dev_info.ownership.is_owned &&
> - current->tgid == gasket_dev->dev_info.ownership.owner);
> + read = !!(filp->f_mode & FMODE_READ);
> + write = !!(filp->f_mode & FMODE_WRITE);
These should be bool as well, right?
I'll drop this patch, thanks.
greg k-h
