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authorJakub Kicinski2021-11-19 06:21:53 -0800
committerDavid S. Miller2021-11-20 12:25:57 +0000
commitd07b26f5bbea9ade34dfd6abea7b3ca056c03cd1 (patch)
tree4a907941337e5445e0834277647ba4c04269523e /net
parent5f0b69238427f19a20063e90486754b1ea3ccd3b (diff)
dev_addr: add a modification check
netdev->dev_addr should only be modified via helpers, but someone may be casting off the const. Add a runtime check to catch abuses. Signed-off-by: Jakub Kicinski <kuba@kernel.org> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net')
-rw-r--r--net/core/dev.c1
-rw-r--r--net/core/dev_addr_lists.c19
2 files changed, 20 insertions, 0 deletions
diff --git a/net/core/dev.c b/net/core/dev.c
index 92c9258cbf28..9219e319e901 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -1377,6 +1377,7 @@ static int __dev_open(struct net_device *dev, struct netlink_ext_ack *extack)
int ret;
ASSERT_RTNL();
+ dev_addr_check(dev);
if (!netif_device_present(dev)) {
/* may be detached because parent is runtime-suspended */
diff --git a/net/core/dev_addr_lists.c b/net/core/dev_addr_lists.c
index a23a83ac18e5..969942734951 100644
--- a/net/core/dev_addr_lists.c
+++ b/net/core/dev_addr_lists.c
@@ -498,6 +498,21 @@ EXPORT_SYMBOL(__hw_addr_init);
* Device addresses handling functions
*/
+/* Check that netdev->dev_addr is not written to directly as this would
+ * break the rbtree layout. All changes should go thru dev_addr_set() and co.
+ * Remove this check in mid-2024.
+ */
+void dev_addr_check(struct net_device *dev)
+{
+ if (!memcmp(dev->dev_addr, dev->dev_addr_shadow, MAX_ADDR_LEN))
+ return;
+
+ netdev_warn(dev, "Current addr: %*ph\n", MAX_ADDR_LEN, dev->dev_addr);
+ netdev_warn(dev, "Expected addr: %*ph\n",
+ MAX_ADDR_LEN, dev->dev_addr_shadow);
+ netdev_WARN(dev, "Incorrect netdev->dev_addr\n");
+}
+
/**
* dev_addr_flush - Flush device address list
* @dev: device
@@ -509,6 +524,7 @@ EXPORT_SYMBOL(__hw_addr_init);
void dev_addr_flush(struct net_device *dev)
{
/* rtnl_mutex must be held here */
+ dev_addr_check(dev);
__hw_addr_flush(&dev->dev_addrs);
dev->dev_addr = NULL;
@@ -552,8 +568,11 @@ void dev_addr_mod(struct net_device *dev, unsigned int offset,
{
struct netdev_hw_addr *ha;
+ dev_addr_check(dev);
+
ha = container_of(dev->dev_addr, struct netdev_hw_addr, addr[0]);
memcpy(&ha->addr[offset], addr, len);
+ memcpy(&dev->dev_addr_shadow[offset], addr, len);
}
EXPORT_SYMBOL(dev_addr_mod);