[PATCH] IB/qib: Validate ->show()/store() callbacks before calling them
From: Viresh Kumar
Date: Wed Nov 06 2019 - 22:20:37 EST
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.
Signed-off-by: Viresh Kumar <viresh.kumar@xxxxxxxxxx>
---
drivers/infiniband/hw/qib/qib_sysfs.c | 6 ++++++
1 file changed, 6 insertions(+)
diff --git a/drivers/infiniband/hw/qib/qib_sysfs.c b/drivers/infiniband/hw/qib/qib_sysfs.c
index 3926be78036e..568b21eb6ea1 100644
--- a/drivers/infiniband/hw/qib/qib_sysfs.c
+++ b/drivers/infiniband/hw/qib/qib_sysfs.c
@@ -301,6 +301,9 @@ static ssize_t qib_portattr_show(struct kobject *kobj,
struct qib_pportdata *ppd =
container_of(kobj, struct qib_pportdata, pport_kobj);
+ if (!pattr->show)
+ return -EIO;
+
return pattr->show(ppd, buf);
}
@@ -312,6 +315,9 @@ static ssize_t qib_portattr_store(struct kobject *kobj,
struct qib_pportdata *ppd =
container_of(kobj, struct qib_pportdata, pport_kobj);
+ if (!pattr->store)
+ return -EIO;
+
return pattr->store(ppd, buf, len);
}
--
2.21.0.rc0.269.g1a574e7a288b