| Message ID | 20250211150913.772545-2-wwasko@nvidia.com (mailing list archive) |
|---|---|
| State | Superseded |
| Delegated to: | Netdev Maintainers |
| Headers | show |
| Series | Permission checks for dynamic POSIX clocks | expand |
Posix clock maintainers have not being CC-ed, adding them. The whole series is available at: https://lore.kernel.org/all/20250211150913.772545-1-wwasko@nvidia.com/ On 2/11/25 4:09 PM, Wojtek Wasko wrote: > Dynamic clocks (e.g. PTP clocks) need access to the permissions with > which the clock was opened to enforce proper access control. > > Native POSIX clocks have access to this information via > posix_clock_desc. However, it is not accessible from the implementation > of dynamic clocks. > > Add struct file* to POSIX clock context for access from dynamic clocks. > > 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(-) > > 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 for opening 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 custom > + * 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) {
On Thu, Feb 13 2025 at 12:37, Paolo Abeni wrote: > Posix clock maintainers have not being CC-ed, adding them. Tx! > $Subject: posix clocks: Store file pointer in clock context s/posix_clocks:/posix-clock:/ s/clock context/struct posix_clock_context/ >> Dynamic clocks (e.g. PTP clocks) need access to the permissions with >> which the clock was opened to enforce proper access control. >> >> Native POSIX clocks have access to this information via >> posix_clock_desc. However, it is not accessible from the implementation >> of dynamic clocks. >> Add struct file* to POSIX clock context for access from dynamic >> clocks. What is a native posix clock? posix_clock_desc is used in the context of dynamic posix clocks, no? I assume this wants to say: "The file descriptor based sys_clock_*() operations of dynamic posix clocks have access to the file pointer and implement permission checks in the generic code before invoking the relevant PTP clock callback. The character device operations (open, read, poll, ioctl) do not have a generic permission control and the PTP 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 PTP clock callbacks can access it. Or something like that, right? >> @@ -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 for opening 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 custom >> + * ioctl calls. s/custom ioctl calls/ioctl() calls/ Other than that this looks sane. Thanks, tglx
On Thu, Feb 13 2025 at 12:37, Paolo Abeni wrote: > Posix clock maintainers have not being CC-ed, adding them. Thank you! Initially this patch was fully contained in the ptp subsystem which is why I missed that. On Thu, Feb 13 2025 at 23:17, Thomas Gleixner wrote: > Other than that this looks sane. I'll wait a day to see if there's any feedback from other posix-clock maintainers and post a v3 with revised wording. Thanks, Wojtek
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 for opening 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 custom + * 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) {
Dynamic clocks (e.g. PTP clocks) need access to the permissions with which the clock was opened to enforce proper access control. Native POSIX clocks have access to this information via posix_clock_desc. However, it is not accessible from the implementation of dynamic clocks. Add struct file* to POSIX clock context for access from dynamic clocks. 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(-)