![Eric W. Biederman](/assets/img/avatar_default.png)
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: [<ffffffff81476c85>] nfqnl_nf_hook_drop+0x35/0x70 > [..] > task: ffff88012dfa3840 ti: ffff88012dffc000 task.ti: ffff88012dffc000 > RIP: 0010:[<ffffffff81476c85>] [<ffffffff81476c85>] nfqnl_nf_hook_drop+0x35/0x70 > RSP: 0000:ffff88012dfffd80 EFLAGS: 00010206 > RAX: 0000000000000008 RBX: ffffffff81add0c0 RCX: ffff88013fd80000 > [..] > Call Trace: > [<ffffffff81474d98>] nf_queue_nf_hook_drop+0x18/0x20 > [<ffffffff814738eb>] nf_unregister_net_hook+0xdb/0x150 > [<ffffffff8147398f>] netfilter_net_exit+0x2f/0x60 > [<ffffffff8141b088>] ops_exit_list.isra.4+0x38/0x60 > [<ffffffff8141b652>] setup_net+0xc2/0x120 > [<ffffffff8141bd09>] copy_net_ns+0x79/0x120 > [<ffffffff8106965b>] create_new_namespaces+0x11b/0x1e0 > [<ffffffff810698a7>] unshare_nsproxy_namespaces+0x57/0xa0 > [<ffffffff8104baa2>] SyS_unshare+0x1b2/0x340 > [<ffffffff81608276>] 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 <fw@strlen.de> Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com> Acked-by: Florian Westphal <fw@strlen.de> Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
22 lines
505 B
C
22 lines
505 B
C
#ifndef __NETNS_NETFILTER_H
|
|
#define __NETNS_NETFILTER_H
|
|
|
|
#include <linux/netfilter_defs.h>
|
|
|
|
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;
|
|
#endif
|
|
struct list_head hooks[NFPROTO_NUMPROTO][NF_MAX_HOOKS];
|
|
};
|
|
#endif
|