[PATCH v3 3/3] IB/ipoib: Log sysfs 'dev_id' accesses from userspace

Arseny Maslennikov
2018-09-03T16:13:16Z

Signed-off-by: Arseny Maslennikov <ar@cs.msu.ru>
---
drivers/infiniband/ulp/ipoib/ipoib_main.c | 38 +++++++++++++++++++++++
1 file changed, 38 insertions(+)

diff --git a/drivers/infiniband/ulp/ipoib/ipoib_main.c b/drivers/infiniband/ulp/ipoib/ipoib_main.c
index 30f840f874b3..7386e5bde3d3 100644
--- a/drivers/infiniband/ulp/ipoib/ipoib_main.c
+++ b/drivers/infiniband/ulp/ipoib/ipoib_main.c
@@ -2386,6 +2386,42 @@ int ipoib_add_pkey_attr(struct net_device *dev)
return device_create_file(&dev->dev, &dev_attr_pkey);
}

+/*
+ * We erroneously exposed the iface's port number in the dev_id
+ * sysfs field long after dev_port was introduced for that purpose[1],
+ * and we need to stop everyone from relying on that.
+ * Let's overload the shower routine for the dev_id file here
+ * to gently bring the issue up.
+ *
+ * [1] https://www.spinics.net/lists/netdev/msg272123.html
+ */
+static ssize_t dev_id_show(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ struct net_device *ndev = to_net_dev(dev);
+ ssize_t ret = -EINVAL;
+
+ if (ndev->dev_id == ndev->dev_port) {
+ netdev_info_once(ndev,
+ "\"%s\" wants to know my dev_id. "
+ "Should it look at dev_port instead?\n",
+ current->comm);
+ netdev_info_once(ndev,
+ "See Documentation/ABI/testing/sysfs-class-net for more info.\n");
+ }
+
+ ret = sprintf(buf, "%#x\n", ndev->dev_id);
+
+ return ret;
+}
+static DEVICE_ATTR_RO(dev_id);
+
+int ipoib_intercept_dev_id_attr(struct net_device *dev)
+{
+ device_remove_file(&dev->dev, &dev_attr_dev_id);
+ return device_create_file(&dev->dev, &dev_attr_dev_id);
+}
+
static struct net_device *ipoib_add_port(const char *format,
struct ib_device *hca, u8 port)
{
@@ -2427,6 +2463,8 @@ static struct net_device *ipoib_add_port(const char *format,
*/
ndev->priv_destructor = ipoib_intf_free;

+ if (ipoib_intercept_dev_id_attr(ndev))
+ goto sysfs_failed;
if (ipoib_cm_add_mode_attr(ndev))
goto sysfs_failed;
if (ipoib_add_pkey_attr(ndev))
--
2.19.0.rc1