Messages in this thread | | | Date | Mon, 17 Apr 2023 19:42:21 +0200 | From | Greg Kroah-Hartman <> | Subject | Re: [PATCH] driver core: class: mark the struct class for sysfs callbacks as constant |
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On Mon, Apr 17, 2023 at 05:53:17PM +0400, Denis Efremov (Oracle) wrote: > Hello, > > On 3/25/23 12:45, Greg Kroah-Hartman wrote: > > struct class should never be modified in a sysfs callback as there is > > nothing in the structure to modify, and frankly, the structure is almost > > never used in a sysfs callback, so mark it as constant to allow struct > > class to be moved to read-only memory. > > > > While we are touching all class sysfs callbacks also mark the attribute > > as constant as it can not be modified. The bonding code still uses this > > structure so it can not be removed from the function callbacks. > > > > ... > > > diff --git a/drivers/block/zram/zram_drv.c b/drivers/block/zram/zram_drv.c > > index b7bb52f8dfbd..3feadfb96114 100644 > > --- a/drivers/block/zram/zram_drv.c > > +++ b/drivers/block/zram/zram_drv.c > > @@ -2424,8 +2424,8 @@ static int zram_remove(struct zram *zram) > > * creates a new un-initialized zram device and returns back this device's > > * device_id (or an error code if it fails to create a new device). > > */ > > -static ssize_t hot_add_show(struct class *class, > > - struct class_attribute *attr, > > +static ssize_t hot_add_show(const struct class *class, > > + const struct class_attribute *attr, > > char *buf) > > { > > int ret; > > @@ -2438,11 +2438,10 @@ static ssize_t hot_add_show(struct class *class, > > return ret; > > return scnprintf(buf, PAGE_SIZE, "%d\n", ret); > > } > > -static struct class_attribute class_attr_hot_add = > > - __ATTR(hot_add, 0400, hot_add_show, NULL); > > +static CLASS_ATTR_RO(hot_add); > > > > -static ssize_t hot_remove_store(struct class *class, > > - struct class_attribute *attr, > > +static ssize_t hot_remove_store(const struct class *class, > > + const struct class_attribute *attr, > > const char *buf, > > size_t count) > > { > > This looks like a security regression (CVE-2020-10781). > Previous fix 853eab68afc80f59f36bbdeb715e5c88c501e680.
{sigh} You would have thought I would have insisted on a big comment here about this. I'll do so this time, thanks for letting me know.
greg k-h
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