From dc3ee32e96d74dd6c80eed63af5065cb75899299 Mon Sep 17 00:00:00 2001 From: "Eric W. Biederman" Date: Fri, 13 May 2016 21:18:52 -0500 Subject: netfilter: nf_queue: Make the queue_handler pernet Florian Weber reported: > Under full load (unshare() in loop -> OOM conditions) we can > get kernel panic: > > BUG: unable to handle kernel NULL pointer dereference at 0000000000000008 > IP: [] nfqnl_nf_hook_drop+0x35/0x70 > [..] > task: ffff88012dfa3840 ti: ffff88012dffc000 task.ti: ffff88012dffc000 > RIP: 0010:[] [] nfqnl_nf_hook_drop+0x35/0x70 > RSP: 0000:ffff88012dfffd80 EFLAGS: 00010206 > RAX: 0000000000000008 RBX: ffffffff81add0c0 RCX: ffff88013fd80000 > [..] > Call Trace: > [] nf_queue_nf_hook_drop+0x18/0x20 > [] nf_unregister_net_hook+0xdb/0x150 > [] netfilter_net_exit+0x2f/0x60 > [] ops_exit_list.isra.4+0x38/0x60 > [] setup_net+0xc2/0x120 > [] copy_net_ns+0x79/0x120 > [] create_new_namespaces+0x11b/0x1e0 > [] unshare_nsproxy_namespaces+0x57/0xa0 > [] SyS_unshare+0x1b2/0x340 > [] entry_SYSCALL_64_fastpath+0x1e/0xa8 > Code: 65 00 48 89 e5 41 56 41 55 41 54 53 83 e8 01 48 8b 97 70 12 00 00 48 98 49 89 f4 4c 8b 74 c2 18 4d 8d 6e 08 49 81 c6 88 00 00 00 <49> 8b 5d 00 48 85 db 74 1a 48 89 df 4c 89 e2 48 c7 c6 90 68 47 > The simple fix for this requires a new pernet variable for struct nf_queue that indicates when it is safe to use the dynamically allocated nf_queue state. As we need a variable anyway make nf_register_queue_handler and nf_unregister_queue_handler pernet. This allows the existing logic of when it is safe to use the state from the nfnetlink_queue module to be reused with no changes except for making it per net. The syncrhonize_rcu from nf_unregister_queue_handler is moved to a new function nfnl_queue_net_exit_batch so that the worst case of having a syncrhonize_rcu in the pernet exit path is not experienced in batch mode. Reported-by: Florian Westphal Signed-off-by: "Eric W. Biederman" Acked-by: Florian Westphal Signed-off-by: Pablo Neira Ayuso --- include/net/netfilter/nf_queue.h | 4 ++-- include/net/netns/netfilter.h | 2 ++ 2 files changed, 4 insertions(+), 2 deletions(-) (limited to 'include') diff --git a/include/net/netfilter/nf_queue.h b/include/net/netfilter/nf_queue.h index 9c5638ad872e..0dbce55437f2 100644 --- a/include/net/netfilter/nf_queue.h +++ b/include/net/netfilter/nf_queue.h @@ -28,8 +28,8 @@ struct nf_queue_handler { struct nf_hook_ops *ops); }; -void nf_register_queue_handler(const struct nf_queue_handler *qh); -void nf_unregister_queue_handler(void); +void nf_register_queue_handler(struct net *net, const struct nf_queue_handler *qh); +void nf_unregister_queue_handler(struct net *net); void nf_reinject(struct nf_queue_entry *entry, unsigned int verdict); void nf_queue_entry_get_refs(struct nf_queue_entry *entry); diff --git a/include/net/netns/netfilter.h b/include/net/netns/netfilter.h index 38aa4983e2a9..36d723579af2 100644 --- a/include/net/netns/netfilter.h +++ b/include/net/netns/netfilter.h @@ -5,11 +5,13 @@ struct proc_dir_entry; struct nf_logger; +struct nf_queue_handler; struct netns_nf { #if defined CONFIG_PROC_FS struct proc_dir_entry *proc_netfilter; #endif + const struct nf_queue_handler __rcu *queue_handler; const struct nf_logger __rcu *nf_loggers[NFPROTO_NUMPROTO]; #ifdef CONFIG_SYSCTL struct ctl_table_header *nf_log_dir_header; -- cgit v1.2.3