4.19-stable review patch. If anyone has any objections, please let me know.
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From: Anastasia Kovaleva a.kovaleva@yadro.com
commit 1dae9f1187189bc09ff6d25ca97ead711f7e26f9 upstream.
The kernel may crash when deleting a genetlink family if there are still listeners for that family:
Oops: Kernel access of bad area, sig: 11 [#1] ... NIP [c000000000c080bc] netlink_update_socket_mc+0x3c/0xc0 LR [c000000000c0f764] __netlink_clear_multicast_users+0x74/0xc0 Call Trace: __netlink_clear_multicast_users+0x74/0xc0 genl_unregister_family+0xd4/0x2d0
Change the unsafe loop on the list to a safe one, because inside the loop there is an element removal from this list.
Fixes: b8273570f802 ("genetlink: fix netns vs. netlink table locking (2)") Cc: stable@vger.kernel.org Signed-off-by: Anastasia Kovaleva a.kovaleva@yadro.com Reviewed-by: Dmitry Bogdanov d.bogdanov@yadro.com Reviewed-by: Kuniyuki Iwashima kuniyu@amazon.com Link: https://patch.msgid.link/20241003104431.12391-1-a.kovaleva@yadro.com Signed-off-by: Jakub Kicinski kuba@kernel.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- include/net/sock.h | 2 ++ net/netlink/af_netlink.c | 3 ++- 2 files changed, 4 insertions(+), 1 deletion(-)
--- a/include/net/sock.h +++ b/include/net/sock.h @@ -764,6 +764,8 @@ static inline void sk_add_bind_node(stru hlist_for_each_entry_safe(__sk, tmp, list, sk_node) #define sk_for_each_bound(__sk, list) \ hlist_for_each_entry(__sk, list, sk_bind_node) +#define sk_for_each_bound_safe(__sk, tmp, list) \ + hlist_for_each_entry_safe(__sk, tmp, list, sk_bind_node)
/** * sk_for_each_entry_offset_rcu - iterate over a list at a given struct offset --- a/net/netlink/af_netlink.c +++ b/net/netlink/af_netlink.c @@ -2145,8 +2145,9 @@ void __netlink_clear_multicast_users(str { struct sock *sk; struct netlink_table *tbl = &nl_table[ksk->sk_protocol]; + struct hlist_node *tmp;
- sk_for_each_bound(sk, &tbl->mc_list) + sk_for_each_bound_safe(sk, tmp, &tbl->mc_list) netlink_update_socket_mc(nlk_sk(sk), group, 0); }