| Message ID | 20250217095005.1453413-2-wwasko@nvidia.com (mailing list archive) |
|---|---|
| State | Changes Requested |
| Delegated to: | Netdev Maintainers |
| Headers | show |
| Series | Permission checks for dynamic POSIX clocks | expand |
On Mon, Feb 17 2025 at 11:50, Wojtek Wasko wrote: > File descriptor based pc_clock_*() operations of dynamic posix clocks > have access to the file pointer and implement permission checks in the > generic code before invoking the relevant dynamic clock callback. > > Character device operations (open, read, poll, ioctl) do not implement a > generic permission control and the dynamic clock callbacks have no > access to the file pointer to implement them. > > Extend struct posix_clock_context with a struct file pointer and > initialize it in posix_clock_open(), so that all dynamic clock callbacks > can access it. > > Signed-off-by: Wojtek Wasko <wwasko@nvidia.com> Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
diff --git a/include/linux/posix-clock.h b/include/linux/posix-clock.h index ef8619f48920..40fa204baafc 100644 --- a/include/linux/posix-clock.h +++ b/include/linux/posix-clock.h @@ -95,10 +95,13 @@ struct posix_clock { * struct posix_clock_context - represents clock file operations context * * @clk: Pointer to the clock + * @fp: Pointer to the file used to open the clock * @private_clkdata: Pointer to user data * * Drivers should use struct posix_clock_context during specific character - * device file operation methods to access the posix clock. + * device file operation methods to access the posix clock. In particular, + * the file pointer can be used to verify correct access mode for ioctl() + * calls. * * Drivers can store a private data structure during the open operation * if they have specific information that is required in other file @@ -106,6 +109,7 @@ struct posix_clock { */ struct posix_clock_context { struct posix_clock *clk; + struct file *fp; void *private_clkdata; }; diff --git a/kernel/time/posix-clock.c b/kernel/time/posix-clock.c index 1af0bb2cc45c..4e114e34a6e0 100644 --- a/kernel/time/posix-clock.c +++ b/kernel/time/posix-clock.c @@ -129,6 +129,7 @@ static int posix_clock_open(struct inode *inode, struct file *fp) goto out; } pccontext->clk = clk; + pccontext->fp = fp; if (clk->ops.open) { err = clk->ops.open(pccontext, fp->f_mode); if (err) {
File descriptor based pc_clock_*() operations of dynamic posix clocks have access to the file pointer and implement permission checks in the generic code before invoking the relevant dynamic clock callback. Character device operations (open, read, poll, ioctl) do not implement a generic permission control and the dynamic clock callbacks have no access to the file pointer to implement them. Extend struct posix_clock_context with a struct file pointer and initialize it in posix_clock_open(), so that all dynamic clock callbacks can access it. Signed-off-by: Wojtek Wasko <wwasko@nvidia.com> --- include/linux/posix-clock.h | 6 +++++- kernel/time/posix-clock.c | 1 + 2 files changed, 6 insertions(+), 1 deletion(-)