diff options
| author |   Jakub Kicinski <kuba@kernel.org> | 2021-11-19 06:21:53 -0800 |
|---|---|---|
| committer |   David S. Miller <davem@davemloft.net> | 2021-11-20 12:25:57 +0000 |
| commit | d07b26f5bbea9ade34dfd6abea7b3ca056c03cd1 (patch) | |
| tree | 4a907941337e5445e0834277647ba4c04269523e | |
| parent | net: unexport dev_addr_init() & dev_addr_flush() (diff) | |
| download | linux-dev-d07b26f5bbea9ade34dfd6abea7b3ca056c03cd1.tar.xz linux-dev-d07b26f5bbea9ade34dfd6abea7b3ca056c03cd1.zip | |
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>
| -rw-r--r-- | include/linux/netdevice.h | 5 | ||||
| -rw-r--r-- | net/core/dev.c | 1 | ||||
| -rw-r--r-- | net/core/dev_addr_lists.c | 19 |
3 files changed, 25 insertions, 0 deletions
diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h index 2462195784a9..cb7f2661d187 100644 --- a/include/linux/netdevice.h +++ b/include/linux/netdevice.h @@ -1942,6 +1942,8 @@ enum netdev_ml_priv_type { * @unlink_list: As netif_addr_lock() can be called recursively, * keep a list of interfaces to be deleted. * + * @dev_addr_shadow: Copy of @dev_addr to catch direct writes. + * * FIXME: cleanup struct net_device such that network protocol info * moves out. */ @@ -2268,6 +2270,8 @@ struct net_device { /* protected by rtnl_lock */ struct bpf_xdp_entity xdp_state[__MAX_XDP_MODE]; + + u8 dev_addr_shadow[MAX_ADDR_LEN]; }; #define to_net_dev(d) container_of(d, struct net_device, dev) @@ -4288,6 +4292,7 @@ int dev_addr_del(struct net_device *dev, const unsigned char *addr, unsigned char addr_type); void dev_addr_flush(struct net_device *dev); int dev_addr_init(struct net_device *dev); +void dev_addr_check(struct net_device *dev); /* Functions used for unicast addresses handling */ int dev_uc_add(struct net_device *dev, const unsigned char *addr); 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); |