6.6-stable review patch. If anyone has any objections, please let me know.
------------------
From: Eric Dumazet edumazet@google.com
commit 031ae72825cef43e4650140b800ad58bf7a6a466 upstream.
syzbot found an use-after-free Read in ila_nf_input [1]
Issue here is that ila_xlat_exit_net() frees the rhashtable, then call nf_unregister_net_hooks().
It should be done in the reverse way, with a synchronize_rcu().
This is a good match for a pre_exit() method.
[1] BUG: KASAN: use-after-free in rht_key_hashfn include/linux/rhashtable.h:159 [inline] BUG: KASAN: use-after-free in __rhashtable_lookup include/linux/rhashtable.h:604 [inline] BUG: KASAN: use-after-free in rhashtable_lookup include/linux/rhashtable.h:646 [inline] BUG: KASAN: use-after-free in rhashtable_lookup_fast+0x77a/0x9b0 include/linux/rhashtable.h:672 Read of size 4 at addr ffff888064620008 by task ksoftirqd/0/16
CPU: 0 UID: 0 PID: 16 Comm: ksoftirqd/0 Not tainted 6.11.0-rc4-syzkaller-00238-g2ad6d23f465a #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/06/2024 Call Trace: <TASK> __dump_stack lib/dump_stack.c:93 [inline] dump_stack_lvl+0x241/0x360 lib/dump_stack.c:119 print_address_description mm/kasan/report.c:377 [inline] print_report+0x169/0x550 mm/kasan/report.c:488 kasan_report+0x143/0x180 mm/kasan/report.c:601 rht_key_hashfn include/linux/rhashtable.h:159 [inline] __rhashtable_lookup include/linux/rhashtable.h:604 [inline] rhashtable_lookup include/linux/rhashtable.h:646 [inline] rhashtable_lookup_fast+0x77a/0x9b0 include/linux/rhashtable.h:672 ila_lookup_wildcards net/ipv6/ila/ila_xlat.c:132 [inline] ila_xlat_addr net/ipv6/ila/ila_xlat.c:652 [inline] ila_nf_input+0x1fe/0x3c0 net/ipv6/ila/ila_xlat.c:190 nf_hook_entry_hookfn include/linux/netfilter.h:154 [inline] nf_hook_slow+0xc3/0x220 net/netfilter/core.c:626 nf_hook include/linux/netfilter.h:269 [inline] NF_HOOK+0x29e/0x450 include/linux/netfilter.h:312 __netif_receive_skb_one_core net/core/dev.c:5661 [inline] __netif_receive_skb+0x1ea/0x650 net/core/dev.c:5775 process_backlog+0x662/0x15b0 net/core/dev.c:6108 __napi_poll+0xcb/0x490 net/core/dev.c:6772 napi_poll net/core/dev.c:6841 [inline] net_rx_action+0x89b/0x1240 net/core/dev.c:6963 handle_softirqs+0x2c4/0x970 kernel/softirq.c:554 run_ksoftirqd+0xca/0x130 kernel/softirq.c:928 smpboot_thread_fn+0x544/0xa30 kernel/smpboot.c:164 kthread+0x2f0/0x390 kernel/kthread.c:389 ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:147 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244 </TASK>
The buggy address belongs to the physical page: page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x64620 flags: 0xfff00000000000(node=0|zone=1|lastcpupid=0x7ff) page_type: 0xbfffffff(buddy) raw: 00fff00000000000 ffffea0000959608 ffffea00019d9408 0000000000000000 raw: 0000000000000000 0000000000000003 00000000bfffffff 0000000000000000 page dumped because: kasan: bad access detected page_owner tracks the page as freed page last allocated via order 3, migratetype Unmovable, gfp_mask 0x52dc0(GFP_KERNEL|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_ZERO), pid 5242, tgid 5242 (syz-executor), ts 73611328570, free_ts 618981657187 set_page_owner include/linux/page_owner.h:32 [inline] post_alloc_hook+0x1f3/0x230 mm/page_alloc.c:1493 prep_new_page mm/page_alloc.c:1501 [inline] get_page_from_freelist+0x2e4c/0x2f10 mm/page_alloc.c:3439 __alloc_pages_noprof+0x256/0x6c0 mm/page_alloc.c:4695 __alloc_pages_node_noprof include/linux/gfp.h:269 [inline] alloc_pages_node_noprof include/linux/gfp.h:296 [inline] ___kmalloc_large_node+0x8b/0x1d0 mm/slub.c:4103 __kmalloc_large_node_noprof+0x1a/0x80 mm/slub.c:4130 __do_kmalloc_node mm/slub.c:4146 [inline] __kmalloc_node_noprof+0x2d2/0x440 mm/slub.c:4164 __kvmalloc_node_noprof+0x72/0x190 mm/util.c:650 bucket_table_alloc lib/rhashtable.c:186 [inline] rhashtable_init_noprof+0x534/0xa60 lib/rhashtable.c:1071 ila_xlat_init_net+0xa0/0x110 net/ipv6/ila/ila_xlat.c:613 ops_init+0x359/0x610 net/core/net_namespace.c:139 setup_net+0x515/0xca0 net/core/net_namespace.c:343 copy_net_ns+0x4e2/0x7b0 net/core/net_namespace.c:508 create_new_namespaces+0x425/0x7b0 kernel/nsproxy.c:110 unshare_nsproxy_namespaces+0x124/0x180 kernel/nsproxy.c:228 ksys_unshare+0x619/0xc10 kernel/fork.c:3328 __do_sys_unshare kernel/fork.c:3399 [inline] __se_sys_unshare kernel/fork.c:3397 [inline] __x64_sys_unshare+0x38/0x40 kernel/fork.c:3397 page last free pid 11846 tgid 11846 stack trace: reset_page_owner include/linux/page_owner.h:25 [inline] free_pages_prepare mm/page_alloc.c:1094 [inline] free_unref_page+0xd22/0xea0 mm/page_alloc.c:2612 __folio_put+0x2c8/0x440 mm/swap.c:128 folio_put include/linux/mm.h:1486 [inline] free_large_kmalloc+0x105/0x1c0 mm/slub.c:4565 kfree+0x1c4/0x360 mm/slub.c:4588 rhashtable_free_and_destroy+0x7c6/0x920 lib/rhashtable.c:1169 ila_xlat_exit_net+0x55/0x110 net/ipv6/ila/ila_xlat.c:626 ops_exit_list net/core/net_namespace.c:173 [inline] cleanup_net+0x802/0xcc0 net/core/net_namespace.c:640 process_one_work kernel/workqueue.c:3231 [inline] process_scheduled_works+0xa2c/0x1830 kernel/workqueue.c:3312 worker_thread+0x86d/0xd40 kernel/workqueue.c:3390 kthread+0x2f0/0x390 kernel/kthread.c:389 ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:147 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244
Memory state around the buggy address: ffff88806461ff00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffff88806461ff80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
ffff888064620000: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
^ ffff888064620080: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ffff888064620100: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
Fixes: 7f00feaf1076 ("ila: Add generic ILA translation facility") Reported-by: syzbot syzkaller@googlegroups.com Signed-off-by: Eric Dumazet edumazet@google.com Cc: Tom Herbert tom@herbertland.com Reviewed-by: Florian Westphal fw@strlen.de Link: https://patch.msgid.link/20240904144418.1162839-1-edumazet@google.com Signed-off-by: Jakub Kicinski kuba@kernel.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- net/ipv6/ila/ila.h | 1 + net/ipv6/ila/ila_main.c | 6 ++++++ net/ipv6/ila/ila_xlat.c | 13 +++++++++---- 3 files changed, 16 insertions(+), 4 deletions(-)
--- a/net/ipv6/ila/ila.h +++ b/net/ipv6/ila/ila.h @@ -108,6 +108,7 @@ int ila_lwt_init(void); void ila_lwt_fini(void);
int ila_xlat_init_net(struct net *net); +void ila_xlat_pre_exit_net(struct net *net); void ila_xlat_exit_net(struct net *net);
int ila_xlat_nl_cmd_add_mapping(struct sk_buff *skb, struct genl_info *info); --- a/net/ipv6/ila/ila_main.c +++ b/net/ipv6/ila/ila_main.c @@ -71,6 +71,11 @@ ila_xlat_init_fail: return err; }
+static __net_exit void ila_pre_exit_net(struct net *net) +{ + ila_xlat_pre_exit_net(net); +} + static __net_exit void ila_exit_net(struct net *net) { ila_xlat_exit_net(net); @@ -78,6 +83,7 @@ static __net_exit void ila_exit_net(stru
static struct pernet_operations ila_net_ops = { .init = ila_init_net, + .pre_exit = ila_pre_exit_net, .exit = ila_exit_net, .id = &ila_net_id, .size = sizeof(struct ila_net), --- a/net/ipv6/ila/ila_xlat.c +++ b/net/ipv6/ila/ila_xlat.c @@ -619,6 +619,15 @@ int ila_xlat_init_net(struct net *net) return 0; }
+void ila_xlat_pre_exit_net(struct net *net) +{ + struct ila_net *ilan = net_generic(net, ila_net_id); + + if (ilan->xlat.hooks_registered) + nf_unregister_net_hooks(net, ila_nf_hook_ops, + ARRAY_SIZE(ila_nf_hook_ops)); +} + void ila_xlat_exit_net(struct net *net) { struct ila_net *ilan = net_generic(net, ila_net_id); @@ -626,10 +635,6 @@ void ila_xlat_exit_net(struct net *net) rhashtable_free_and_destroy(&ilan->xlat.rhash_table, ila_free_cb, NULL);
free_bucket_spinlocks(ilan->xlat.locks); - - if (ilan->xlat.hooks_registered) - nf_unregister_net_hooks(net, ila_nf_hook_ops, - ARRAY_SIZE(ila_nf_hook_ops)); }
static int ila_xlat_addr(struct sk_buff *skb, bool sir2ila)