| Message ID | 20250114-sysfs-const-bin_attr-cxl-v1-1-5afa23fe2a52@weissschuh.net |
|---|---|
| State | New |
| Headers | show |
| Series | cxl/port: Constify 'struct bin_attribute' | expand |
On Tue, Jan 14, 2025 at 10:25:14PM +0100, Thomas Weißschuh wrote: > The sysfs core now allows instances of 'struct bin_attribute' to be > moved into read-only memory. Make use of that to protect them against > accidental or malicious modifications. > > Signed-off-by: Thomas Weißschuh <linux@weissschuh.net> > --- > drivers/cxl/port.c | 10 +++++----- > 1 file changed, 5 insertions(+), 5 deletions(-) > > diff --git a/drivers/cxl/port.c b/drivers/cxl/port.c > index 4c83f6a22e584f1f248807c7fa4fe932d6f11d67..664fde6ff53862c6aef2a83be56c1518b6bfbadd 100644 > --- a/drivers/cxl/port.c > +++ b/drivers/cxl/port.c > @@ -153,7 +153,7 @@ static int cxl_port_probe(struct device *dev) > } > > static ssize_t CDAT_read(struct file *filp, struct kobject *kobj, > - struct bin_attribute *bin_attr, char *buf, > + const struct bin_attribute *bin_attr, char *buf, > loff_t offset, size_t count) > { > struct device *dev = kobj_to_dev(kobj); > @@ -170,7 +170,7 @@ static ssize_t CDAT_read(struct file *filp, struct kobject *kobj, > port->cdat.length); > } > > -static BIN_ATTR_ADMIN_RO(CDAT, 0); > +static const BIN_ATTR_ADMIN_RO(CDAT, 0); > > static umode_t cxl_port_bin_attr_is_visible(struct kobject *kobj, > const struct bin_attribute *attr, int i) > @@ -184,13 +184,13 @@ static umode_t cxl_port_bin_attr_is_visible(struct kobject *kobj, > return 0; > } > > -static struct bin_attribute *cxl_cdat_bin_attributes[] = { > +static const struct bin_attribute *const cxl_cdat_bin_attributes[] = { > &bin_attr_CDAT, > NULL, > }; > > -static struct attribute_group cxl_cdat_attribute_group = { > - .bin_attrs = cxl_cdat_bin_attributes, > +static const struct attribute_group cxl_cdat_attribute_group = { > + .bin_attrs_new = cxl_cdat_bin_attributes, > .is_bin_visible = cxl_port_bin_attr_is_visible, > }; What's the point of s/bin_attrs/bin_attrs_new above? --Alison > > > --- > base-commit: 7f5b6a8ec18e3add4c74682f60b90c31bdf849f2 > change-id: 20250114-sysfs-const-bin_attr-cxl-d102eab47586 > > Best regards, > -- > Thomas Weißschuh <linux@weissschuh.net> >
On 2025-01-14 15:01:22-0800, Alison Schofield wrote: > On Tue, Jan 14, 2025 at 10:25:14PM +0100, Thomas Weißschuh wrote: > > The sysfs core now allows instances of 'struct bin_attribute' to be > > moved into read-only memory. Make use of that to protect them against > > accidental or malicious modifications. > > > > Signed-off-by: Thomas Weißschuh <linux@weissschuh.net> > > --- > > drivers/cxl/port.c | 10 +++++----- > > 1 file changed, 5 insertions(+), 5 deletions(-) > > > > diff --git a/drivers/cxl/port.c b/drivers/cxl/port.c > > index 4c83f6a22e584f1f248807c7fa4fe932d6f11d67..664fde6ff53862c6aef2a83be56c1518b6bfbadd 100644 > > --- a/drivers/cxl/port.c > > +++ b/drivers/cxl/port.c > > @@ -153,7 +153,7 @@ static int cxl_port_probe(struct device *dev) > > } > > > > static ssize_t CDAT_read(struct file *filp, struct kobject *kobj, > > - struct bin_attribute *bin_attr, char *buf, > > + const struct bin_attribute *bin_attr, char *buf, > > loff_t offset, size_t count) > > { > > struct device *dev = kobj_to_dev(kobj); > > @@ -170,7 +170,7 @@ static ssize_t CDAT_read(struct file *filp, struct kobject *kobj, > > port->cdat.length); > > } > > > > -static BIN_ATTR_ADMIN_RO(CDAT, 0); > > +static const BIN_ATTR_ADMIN_RO(CDAT, 0); > > > > static umode_t cxl_port_bin_attr_is_visible(struct kobject *kobj, > > const struct bin_attribute *attr, int i) > > @@ -184,13 +184,13 @@ static umode_t cxl_port_bin_attr_is_visible(struct kobject *kobj, > > return 0; > > } > > > > -static struct bin_attribute *cxl_cdat_bin_attributes[] = { > > +static const struct bin_attribute *const cxl_cdat_bin_attributes[] = { > > &bin_attr_CDAT, > > NULL, > > }; > > > > -static struct attribute_group cxl_cdat_attribute_group = { > > - .bin_attrs = cxl_cdat_bin_attributes, > > +static const struct attribute_group cxl_cdat_attribute_group = { > > + .bin_attrs_new = cxl_cdat_bin_attributes, > > .is_bin_visible = cxl_port_bin_attr_is_visible, > > }; > > What's the point of s/bin_attrs/bin_attrs_new above? The new type of cxl_cdat_bin_attributes is not compatible with .bin_attrs. Therefore .bin_attrs_new was introduced. When all users have been migrated to the new type, .bin_attrs itself will be switched to the new type and all users moved back to bin_attr. In one big centrally managed commit to avoid annoying subsystem maintainers (even more). The same issue exists in .read_new/.write_new but in this specific case that is handled transparently in BIN_ATTR_ADMIN_RO(). > > --Alison > > > > > > > --- > > base-commit: 7f5b6a8ec18e3add4c74682f60b90c31bdf849f2 > > change-id: 20250114-sysfs-const-bin_attr-cxl-d102eab47586 > > > > Best regards, > > -- > > Thomas Weißschuh <linux@weissschuh.net> > >
On Tue, 14 Jan 2025 22:25:14 +0100 Thomas Weißschuh <linux@weissschuh.net> wrote: > The sysfs core now allows instances of 'struct bin_attribute' to be > moved into read-only memory. Make use of that to protect them against > accidental or malicious modifications. > > Signed-off-by: Thomas Weißschuh <linux@weissschuh.net> Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
diff --git a/drivers/cxl/port.c b/drivers/cxl/port.c index 4c83f6a22e584f1f248807c7fa4fe932d6f11d67..664fde6ff53862c6aef2a83be56c1518b6bfbadd 100644 --- a/drivers/cxl/port.c +++ b/drivers/cxl/port.c @@ -153,7 +153,7 @@ static int cxl_port_probe(struct device *dev) } static ssize_t CDAT_read(struct file *filp, struct kobject *kobj, - struct bin_attribute *bin_attr, char *buf, + const struct bin_attribute *bin_attr, char *buf, loff_t offset, size_t count) { struct device *dev = kobj_to_dev(kobj); @@ -170,7 +170,7 @@ static ssize_t CDAT_read(struct file *filp, struct kobject *kobj, port->cdat.length); } -static BIN_ATTR_ADMIN_RO(CDAT, 0); +static const BIN_ATTR_ADMIN_RO(CDAT, 0); static umode_t cxl_port_bin_attr_is_visible(struct kobject *kobj, const struct bin_attribute *attr, int i) @@ -184,13 +184,13 @@ static umode_t cxl_port_bin_attr_is_visible(struct kobject *kobj, return 0; } -static struct bin_attribute *cxl_cdat_bin_attributes[] = { +static const struct bin_attribute *const cxl_cdat_bin_attributes[] = { &bin_attr_CDAT, NULL, }; -static struct attribute_group cxl_cdat_attribute_group = { - .bin_attrs = cxl_cdat_bin_attributes, +static const struct attribute_group cxl_cdat_attribute_group = { + .bin_attrs_new = cxl_cdat_bin_attributes, .is_bin_visible = cxl_port_bin_attr_is_visible, };
The sysfs core now allows instances of 'struct bin_attribute' to be moved into read-only memory. Make use of that to protect them against accidental or malicious modifications. Signed-off-by: Thomas Weißschuh <linux@weissschuh.net> --- drivers/cxl/port.c | 10 +++++----- 1 file changed, 5 insertions(+), 5 deletions(-) --- base-commit: 7f5b6a8ec18e3add4c74682f60b90c31bdf849f2 change-id: 20250114-sysfs-const-bin_attr-cxl-d102eab47586 Best regards,