From: Tony Battersby tonyb@cybernetics.com

stable inclusion from stable-v6.6.34 commit f07224c16678a8af54ddc059b3d2d51885d7f35e category: bugfix bugzilla: https://gitee.com/src-openeuler/kernel/issues/IA8ADY CVE: CVE-2024-39296

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=...

---------------------------

commit a45835a0bb6ef7d5ddbc0714dd760de979cb6ece upstream.

"rmmod bonding" causes an oops ever since commit cc317ea3d927 ("bonding: remove redundant NULL check in debugfs function"). Here are the relevant functions being called:

bonding_exit() bond_destroy_debugfs() debugfs_remove_recursive(bonding_debug_root); bonding_debug_root = NULL; <--------- SET TO NULL HERE bond_netlink_fini() rtnl_link_unregister() __rtnl_link_unregister() unregister_netdevice_many_notify() bond_uninit() bond_debug_unregister() (commit removed check for bonding_debug_root == NULL) debugfs_remove() simple_recursive_removal() down_write() -> OOPS

However, reverting the bad commit does not solve the problem completely because the original code contains a race that could cause the same oops, although it was much less likely to be triggered unintentionally:

CPU1 rmmod bonding bonding_exit() bond_destroy_debugfs() debugfs_remove_recursive(bonding_debug_root);

CPU2 echo -bond0 > /sys/class/net/bonding_masters bond_uninit() bond_debug_unregister() if (!bonding_debug_root)

CPU1 bonding_debug_root = NULL;

So do NOT revert the bad commit (since the removed checks were racy anyway), and instead change the order of actions taken during module removal. The same oops can also happen if there is an error during module init, so apply the same fix there.

Fixes: cc317ea3d927 ("bonding: remove redundant NULL check in debugfs function") Cc: stable@vger.kernel.org Signed-off-by: Tony Battersby tonyb@cybernetics.com Reviewed-by: Simon Horman horms@kernel.org Acked-by: Jay Vosburgh jay.vosburgh@canonical.com Link: https://lore.kernel.org/r/641f914f-3216-4eeb-87dd-91b78aa97773@cybernetics.c... Signed-off-by: Jakub Kicinski kuba@kernel.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org

Conflicts: drivers/net/bonding/bond_main.c [The conflict occurs because the commit 6263012c995d("anolis: bond: broadcast ARP or ND messages to all slaves") is not merged into mainline] Signed-off-by: Zhengchao Shao shaozhengchao@huawei.com --- drivers/net/bonding/bond_main.c | 11 +++++++---- 1 file changed, 7 insertions(+), 4 deletions(-)

diff --git a/drivers/net/bonding/bond_main.c b/drivers/net/bonding/bond_main.c index df1bc2fa6979..7da60b741c3e 100644 --- a/drivers/net/bonding/bond_main.c +++ b/drivers/net/bonding/bond_main.c @@ -6526,15 +6526,16 @@ static int __init bonding_init(void) if (res) goto out;

+ bond_create_debugfs(); + res = register_pernet_subsys(&bond_net_ops); if (res) - goto out; + goto err_net_ops;

res = bond_netlink_init(); if (res) goto err_link;

- bond_create_debugfs(); bond_create_sysctl();

for (i = 0; i < max_bonds; i++) { @@ -6551,11 +6552,12 @@ static int __init bonding_init(void) out: return res; err: - bond_destroy_debugfs(); bond_destroy_sysctl(); bond_netlink_fini(); err_link: unregister_pernet_subsys(&bond_net_ops); +err_net_ops: + bond_destroy_debugfs(); goto out;

} @@ -6564,12 +6566,13 @@ static void __exit bonding_exit(void) { unregister_netdevice_notifier(&bond_netdev_notifier);

- bond_destroy_debugfs(); bond_destroy_sysctl();

bond_netlink_fini(); unregister_pernet_subsys(&bond_net_ops);

+ bond_destroy_debugfs(); + #ifdef CONFIG_NET_POLL_CONTROLLER /* Make sure we don't have an imbalance on our netpoll blocking */ WARN_ON(atomic_read(&netpoll_block_tx));