The permissions of the read-only or write-only sysfs files can be
changed (as root) and the user can then try to read a write-only file or
write to a read-only file which will lead to kernel crash here.
Protect against that by always validating the show/store callbacks.
Link: https://lore.kernel.org/r/d45cc26361a174ae12dbb86c994ef334d257924b.1573096807.git.viresh.kumar@linaro.org
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>
struct qib_pportdata *ppd =
container_of(kobj, struct qib_pportdata, pport_kobj);
+ if (!pattr->show)
+ return -EIO;
+
return pattr->show(ppd, buf);
}
struct qib_pportdata *ppd =
container_of(kobj, struct qib_pportdata, pport_kobj);
+ if (!pattr->store)
+ return -EIO;
+
return pattr->store(ppd, buf, len);
}