From: Vaibhav Jain Date: Mon, 7 Sep 2020 11:05:40 +0000 (+0530) Subject: powerpc/papr_scm: Limit the readability of 'perf_stats' sysfs attribute X-Git-Tag: v5.9-rc6~19^2 X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=0460534b532e5518c657c7d6492b9337d975eaa3;p=thirdparty%2Fkernel%2Flinux.git powerpc/papr_scm: Limit the readability of 'perf_stats' sysfs attribute The newly introduced 'perf_stats' attribute uses the default access mode of 0444, allowing non-root users to access performance stats of an nvdimm and potentially force the kernel into issuing a large number of expensive hypercalls. Since the information exposed by this attribute cannot be cached it is better to ward off access to this attribute from users who don't need to access to these performance statistics. Hence update the access mode of 'perf_stats' attribute to be only readable by root users. Fixes: 2d02bf835e57 ("powerpc/papr_scm: Fetch nvdimm performance stats from PHYP") Reported-by: Aneesh Kumar K.V Signed-off-by: Vaibhav Jain Reviewed-by: Ira Weiny Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/20200907110540.21349-1-vaibhav@linux.ibm.com --- diff --git a/arch/powerpc/platforms/pseries/papr_scm.c b/arch/powerpc/platforms/pseries/papr_scm.c index f439f0dfea7d1..a88a707a608aa 100644 --- a/arch/powerpc/platforms/pseries/papr_scm.c +++ b/arch/powerpc/platforms/pseries/papr_scm.c @@ -822,7 +822,7 @@ free_stats: kfree(stats); return rc ? rc : seq_buf_used(&s); } -DEVICE_ATTR_RO(perf_stats); +DEVICE_ATTR_ADMIN_RO(perf_stats); static ssize_t flags_show(struct device *dev, struct device_attribute *attr, char *buf)