diff options
| author | Eric Dumazet <edumazet@google.com> | 2024-02-13 06:32:38 +0000 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2024-02-14 11:20:13 +0000 |
| commit | c7d52737e7ebd31cc5fef46380d94b58becf9479 (patch) | |
| tree | 4bd56292d5714b0bea521695b95ae8c445c6fd13 | |
| parent | 12692e3df2dacf2993c56aa23b6d3de921a5bdff (diff) | |
net-sysfs: use dev_addr_sem to remove races in address_show()
Using dev_base_lock is not preventing from reading garbage.
Use dev_addr_sem instead.
v4: place dev_addr_sem extern in net/core/dev.h (Jakub Kicinski)
Link: https://lore.kernel.org/netdev/20240212175845.10f6680a@kernel.org/
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
| -rw-r--r-- | net/core/dev.c | 2 | ||||
| -rw-r--r-- | net/core/dev.h | 3 | ||||
| -rw-r--r-- | net/core/net-sysfs.c | 10 |
3 files changed, 11 insertions, 4 deletions
diff --git a/net/core/dev.c b/net/core/dev.c index 9c95cae9d6ab..26f93446b743 100644 --- a/net/core/dev.c +++ b/net/core/dev.c @@ -8993,7 +8993,7 @@ int dev_set_mac_address(struct net_device *dev, struct sockaddr *sa, } EXPORT_SYMBOL(dev_set_mac_address); -static DECLARE_RWSEM(dev_addr_sem); +DECLARE_RWSEM(dev_addr_sem); int dev_set_mac_address_user(struct net_device *dev, struct sockaddr *sa, struct netlink_ext_ack *extack) diff --git a/net/core/dev.h b/net/core/dev.h index a43dfe3de50e..45892267848d 100644 --- a/net/core/dev.h +++ b/net/core/dev.h @@ -3,6 +3,7 @@ #define _NET_CORE_DEV_H #include <linux/types.h> +#include <linux/rwsem.h> struct net; struct net_device; @@ -46,6 +47,8 @@ extern int weight_p; extern int dev_weight_rx_bias; extern int dev_weight_tx_bias; +extern struct rw_semaphore dev_addr_sem; + /* rtnl helpers */ extern struct list_head net_todo_list; void netdev_run_todo(void); diff --git a/net/core/net-sysfs.c b/net/core/net-sysfs.c index 678e4be69082..23ef2df549c3 100644 --- a/net/core/net-sysfs.c +++ b/net/core/net-sysfs.c @@ -142,17 +142,21 @@ static ssize_t name_assign_type_show(struct device *dev, } static DEVICE_ATTR_RO(name_assign_type); -/* use same locking rules as GIFHWADDR ioctl's */ +/* use same locking rules as GIFHWADDR ioctl's (dev_get_mac_address()) */ static ssize_t address_show(struct device *dev, struct device_attribute *attr, char *buf) { struct net_device *ndev = to_net_dev(dev); ssize_t ret = -EINVAL; - read_lock(&dev_base_lock); + down_read(&dev_addr_sem); + + rcu_read_lock(); if (dev_isalive(ndev)) ret = sysfs_format_mac(buf, ndev->dev_addr, ndev->addr_len); - read_unlock(&dev_base_lock); + rcu_read_unlock(); + + up_read(&dev_addr_sem); return ret; } static DEVICE_ATTR_RO(address); |