From: Florian Westphal fw@strlen.de
commit 212e7f56605ef9688d0846db60c6c6ec06544095 upstream.
An earlier commit (1b789577f655060d98d20e, "netfilter: arp_tables: init netns pointer in xt_tgchk_param struct") fixed missing net initialization for arptables, but turns out it was incomplete. We can get a very similar struct net NULL deref during error unwinding:
general protection fault: 0000 [#1] PREEMPT SMP KASAN RIP: 0010:xt_rateest_put+0xa1/0x440 net/netfilter/xt_RATEEST.c:77 xt_rateest_tg_destroy+0x72/0xa0 net/netfilter/xt_RATEEST.c:175 cleanup_entry net/ipv4/netfilter/arp_tables.c:509 [inline] translate_table+0x11f4/0x1d80 net/ipv4/netfilter/arp_tables.c:587 do_replace net/ipv4/netfilter/arp_tables.c:981 [inline] do_arpt_set_ctl+0x317/0x650 net/ipv4/netfilter/arp_tables.c:1461
Also init the netns pointer in xt_tgdtor_param struct.
Fixes: add67461240c1d ("netfilter: add struct net * to target parameters") Reported-by: syzbot+91bdd8eece0f6629ec8b@syzkaller.appspotmail.com Signed-off-by: Florian Westphal fw@strlen.de Signed-off-by: Pablo Neira Ayuso pablo@netfilter.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- net/ipv4/netfilter/arp_tables.c | 19 ++++++++++--------- 1 file changed, 10 insertions(+), 9 deletions(-)
--- a/net/ipv4/netfilter/arp_tables.c +++ b/net/ipv4/netfilter/arp_tables.c @@ -506,12 +506,13 @@ static inline int check_entry_size_and_h return 0; }
-static inline void cleanup_entry(struct arpt_entry *e) +static void cleanup_entry(struct arpt_entry *e, struct net *net) { struct xt_tgdtor_param par; struct xt_entry_target *t;
t = arpt_get_target(e); + par.net = net; par.target = t->u.kernel.target; par.targinfo = t->data; par.family = NFPROTO_ARP; @@ -601,7 +602,7 @@ static int translate_table(struct net *n xt_entry_foreach(iter, entry0, newinfo->size) { if (i-- == 0) break; - cleanup_entry(iter); + cleanup_entry(iter, net); } return ret; } @@ -926,7 +927,7 @@ static int __do_replace(struct net *net, /* Decrease module usage counts and free resource */ loc_cpu_old_entry = oldinfo->entries; xt_entry_foreach(iter, loc_cpu_old_entry, oldinfo->size) - cleanup_entry(iter); + cleanup_entry(iter, net);
xt_free_table_info(oldinfo); if (copy_to_user(counters_ptr, counters, @@ -990,7 +991,7 @@ static int do_replace(struct net *net, c
free_newinfo_untrans: xt_entry_foreach(iter, loc_cpu_entry, newinfo->size) - cleanup_entry(iter); + cleanup_entry(iter, net); free_newinfo: xt_free_table_info(newinfo); return ret; @@ -1287,7 +1288,7 @@ static int compat_do_replace(struct net
free_newinfo_untrans: xt_entry_foreach(iter, loc_cpu_entry, newinfo->size) - cleanup_entry(iter); + cleanup_entry(iter, net); free_newinfo: xt_free_table_info(newinfo); return ret; @@ -1514,7 +1515,7 @@ static int do_arpt_get_ctl(struct sock * return ret; }
-static void __arpt_unregister_table(struct xt_table *table) +static void __arpt_unregister_table(struct net *net, struct xt_table *table) { struct xt_table_info *private; void *loc_cpu_entry; @@ -1526,7 +1527,7 @@ static void __arpt_unregister_table(stru /* Decrease module usage counts and free resources */ loc_cpu_entry = private->entries; xt_entry_foreach(iter, loc_cpu_entry, private->size) - cleanup_entry(iter); + cleanup_entry(iter, net); if (private->number > private->initial_entries) module_put(table_owner); xt_free_table_info(private); @@ -1566,7 +1567,7 @@ int arpt_register_table(struct net *net,
ret = nf_register_net_hooks(net, ops, hweight32(table->valid_hooks)); if (ret != 0) { - __arpt_unregister_table(new_table); + __arpt_unregister_table(net, new_table); *res = NULL; }
@@ -1581,7 +1582,7 @@ void arpt_unregister_table(struct net *n const struct nf_hook_ops *ops) { nf_unregister_net_hooks(net, ops, hweight32(table->valid_hooks)); - __arpt_unregister_table(table); + __arpt_unregister_table(net, table); }
/* The built-in targets: standard (NULL) and error. */