tcp: allocate tcp_death_row outside of struct netns_ipv4
I forgot tcp had per netns tracking of timewait sockets, and their sysctl to change the limit. After0dad4087a8("tcp/dccp: get rid of inet_twsk_purge()"), whole struct net can be freed before last tw socket is freed. We need to allocate a separate struct inet_timewait_death_row object per netns. tw_count becomes a refcount and gains associated debugging infrastructure. BUG: KASAN: use-after-free in inet_twsk_kill+0x358/0x3c0 net/ipv4/inet_timewait_sock.c:46 Read of size 8 at addr ffff88807d5f9f40 by task kworker/1:7/3690 CPU: 1 PID: 3690 Comm: kworker/1:7 Not tainted 5.16.0-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Workqueue: events pwq_unbound_release_workfn Call Trace: <IRQ> __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0xcd/0x134 lib/dump_stack.c:106 print_address_description.constprop.0.cold+0x8d/0x336 mm/kasan/report.c:255 __kasan_report mm/kasan/report.c:442 [inline] kasan_report.cold+0x83/0xdf mm/kasan/report.c:459 inet_twsk_kill+0x358/0x3c0 net/ipv4/inet_timewait_sock.c:46 call_timer_fn+0x1a5/0x6b0 kernel/time/timer.c:1421 expire_timers kernel/time/timer.c:1466 [inline] __run_timers.part.0+0x67c/0xa30 kernel/time/timer.c:1734 __run_timers kernel/time/timer.c:1715 [inline] run_timer_softirq+0xb3/0x1d0 kernel/time/timer.c:1747 __do_softirq+0x29b/0x9c2 kernel/softirq.c:558 invoke_softirq kernel/softirq.c:432 [inline] __irq_exit_rcu+0x123/0x180 kernel/softirq.c:637 irq_exit_rcu+0x5/0x20 kernel/softirq.c:649 sysvec_apic_timer_interrupt+0x93/0xc0 arch/x86/kernel/apic/apic.c:1097 </IRQ> <TASK> asm_sysvec_apic_timer_interrupt+0x12/0x20 arch/x86/include/asm/idtentry.h:638 RIP: 0010:lockdep_unregister_key+0x1c9/0x250 kernel/locking/lockdep.c:6328 Code: 00 00 00 48 89 ee e8 46 fd ff ff 4c 89 f7 e8 5e c9 ff ff e8 09 cc ff ff 9c 58 f6 c4 02 75 26 41 f7 c4 00 02 00 00 74 01 fb 5b <5d> 41 5c 41 5d 41 5e 41 5f e9 19 4a 08 00 0f 0b 5b 5d 41 5c 41 5d RSP: 0018:ffffc90004077cb8 EFLAGS: 00000206 RAX: 0000000000000046 RBX: ffff88807b61b498 RCX: 0000000000000001 RDX: dffffc0000000000 RSI: 0000000000000000 RDI: 0000000000000000 RBP: ffff888077027128 R08: 0000000000000001 R09: ffffffff8f1ea4fc R10: fffffbfff1ff93ee R11: 000000000000af1e R12: 0000000000000246 R13: 0000000000000000 R14: ffffffff8ffc89b8 R15: ffffffff90157fb0 wq_unregister_lockdep kernel/workqueue.c:3508 [inline] pwq_unbound_release_workfn+0x254/0x340 kernel/workqueue.c:3746 process_one_work+0x9ac/0x1650 kernel/workqueue.c:2307 worker_thread+0x657/0x1110 kernel/workqueue.c:2454 kthread+0x2e9/0x3a0 kernel/kthread.c:377 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295 </TASK> Allocated by task 3635: kasan_save_stack+0x1e/0x50 mm/kasan/common.c:38 kasan_set_track mm/kasan/common.c:46 [inline] set_alloc_info mm/kasan/common.c:437 [inline] __kasan_slab_alloc+0x90/0xc0 mm/kasan/common.c:470 kasan_slab_alloc include/linux/kasan.h:260 [inline] slab_post_alloc_hook mm/slab.h:732 [inline] slab_alloc_node mm/slub.c:3230 [inline] slab_alloc mm/slub.c:3238 [inline] kmem_cache_alloc+0x202/0x3a0 mm/slub.c:3243 kmem_cache_zalloc include/linux/slab.h:705 [inline] net_alloc net/core/net_namespace.c:407 [inline] copy_net_ns+0x125/0x760 net/core/net_namespace.c:462 create_new_namespaces+0x3f6/0xb20 kernel/nsproxy.c:110 unshare_nsproxy_namespaces+0xc1/0x1f0 kernel/nsproxy.c:226 ksys_unshare+0x445/0x920 kernel/fork.c:3048 __do_sys_unshare kernel/fork.c:3119 [inline] __se_sys_unshare kernel/fork.c:3117 [inline] __x64_sys_unshare+0x2d/0x40 kernel/fork.c:3117 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x44/0xae The buggy address belongs to the object at ffff88807d5f9a80 which belongs to the cache net_namespace of size 6528 The buggy address is located 1216 bytes inside of 6528-byte region [ffff88807d5f9a80, ffff88807d5fb400) The buggy address belongs to the page: page:ffffea0001f57e00 refcount:1 mapcount:0 mapping:0000000000000000 index:0xffff88807d5f9a80 pfn:0x7d5f8 head:ffffea0001f57e00 order:3 compound_mapcount:0 compound_pincount:0 memcg:ffff888070023001 flags: 0xfff00000010200(slab|head|node=0|zone=1|lastcpupid=0x7ff) raw: 00fff00000010200 ffff888010dd4f48 ffffea0001404e08 ffff8880118fd000 raw: ffff88807d5f9a80 0000000000040002 00000001ffffffff ffff888070023001 page dumped because: kasan: bad access detected page_owner tracks the page as allocated page last allocated via order 3, migratetype Unmovable, gfp_mask 0xd20c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 3634, ts 119694798460, free_ts 119693556950 prep_new_page mm/page_alloc.c:2434 [inline] get_page_from_freelist+0xa72/0x2f50 mm/page_alloc.c:4165 __alloc_pages+0x1b2/0x500 mm/page_alloc.c:5389 alloc_pages+0x1aa/0x310 mm/mempolicy.c:2271 alloc_slab_page mm/slub.c:1799 [inline] allocate_slab mm/slub.c:1944 [inline] new_slab+0x28a/0x3b0 mm/slub.c:2004 ___slab_alloc+0x87c/0xe90 mm/slub.c:3018 __slab_alloc.constprop.0+0x4d/0xa0 mm/slub.c:3105 slab_alloc_node mm/slub.c:3196 [inline] slab_alloc mm/slub.c:3238 [inline] kmem_cache_alloc+0x35c/0x3a0 mm/slub.c:3243 kmem_cache_zalloc include/linux/slab.h:705 [inline] net_alloc net/core/net_namespace.c:407 [inline] copy_net_ns+0x125/0x760 net/core/net_namespace.c:462 create_new_namespaces+0x3f6/0xb20 kernel/nsproxy.c:110 unshare_nsproxy_namespaces+0xc1/0x1f0 kernel/nsproxy.c:226 ksys_unshare+0x445/0x920 kernel/fork.c:3048 __do_sys_unshare kernel/fork.c:3119 [inline] __se_sys_unshare kernel/fork.c:3117 [inline] __x64_sys_unshare+0x2d/0x40 kernel/fork.c:3117 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x44/0xae page last free stack trace: reset_page_owner include/linux/page_owner.h:24 [inline] free_pages_prepare mm/page_alloc.c:1352 [inline] free_pcp_prepare+0x374/0x870 mm/page_alloc.c:1404 free_unref_page_prepare mm/page_alloc.c:3325 [inline] free_unref_page+0x19/0x690 mm/page_alloc.c:3404 skb_free_head net/core/skbuff.c:655 [inline] skb_release_data+0x65d/0x790 net/core/skbuff.c:677 skb_release_all net/core/skbuff.c:742 [inline] __kfree_skb net/core/skbuff.c:756 [inline] consume_skb net/core/skbuff.c:914 [inline] consume_skb+0xc2/0x160 net/core/skbuff.c:908 skb_free_datagram+0x1b/0x1f0 net/core/datagram.c:325 netlink_recvmsg+0x636/0xea0 net/netlink/af_netlink.c:1998 sock_recvmsg_nosec net/socket.c:948 [inline] sock_recvmsg net/socket.c:966 [inline] sock_recvmsg net/socket.c:962 [inline] ____sys_recvmsg+0x2c4/0x600 net/socket.c:2632 ___sys_recvmsg+0x127/0x200 net/socket.c:2674 __sys_recvmsg+0xe2/0x1a0 net/socket.c:2704 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x44/0xae Memory state around the buggy address: ffff88807d5f9e00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff88807d5f9e80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >ffff88807d5f9f00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff88807d5f9f80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff88807d5fa000: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb Fixes:0dad4087a8("tcp/dccp: get rid of inet_twsk_purge()") Signed-off-by: Eric Dumazet <edumazet@google.com> Reported-by: syzbot <syzkaller@googlegroups.com> Reported-by: Paolo Abeni <pabeni@redhat.com> Tested-by: Paolo Abeni <pabeni@redhat.com> Link: https://lore.kernel.org/r/20220126180714.845362-1-eric.dumazet@gmail.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
This commit is contained in:
Eric Dumazet
Jakub Kicinski
Родитель
49db8a70a0
Коммит
fbb8295248
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@ -31,18 +31,16 @@ struct ping_group_range {
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struct inet_hashinfo;
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struct inet_timewait_death_row {
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atomic_t tw_count;
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char tw_pad[L1_CACHE_BYTES - sizeof(atomic_t)];
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refcount_t tw_refcount;
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struct inet_hashinfo *hashinfo;
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struct inet_hashinfo *hashinfo ____cacheline_aligned_in_smp;
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int sysctl_max_tw_buckets;
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};
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struct tcp_fastopen_context;
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struct netns_ipv4 {
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/* Please keep tcp_death_row at first field in netns_ipv4 */
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struct inet_timewait_death_row tcp_death_row ____cacheline_aligned_in_smp;
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struct inet_timewait_death_row *tcp_death_row;
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#ifdef CONFIG_SYSCTL
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struct ctl_table_header *forw_hdr;
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@ -22,6 +22,7 @@
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#include "feat.h"
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struct inet_timewait_death_row dccp_death_row = {
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.tw_refcount = REFCOUNT_INIT(1),
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.sysctl_max_tw_buckets = NR_FILE * 2,
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.hashinfo = &dccp_hashinfo,
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};
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@ -58,7 +58,9 @@ static void inet_twsk_kill(struct inet_timewait_sock *tw)
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inet_twsk_bind_unhash(tw, hashinfo);
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spin_unlock(&bhead->lock);
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atomic_dec(&tw->tw_dr->tw_count);
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if (refcount_dec_and_test(&tw->tw_dr->tw_refcount))
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kfree(tw->tw_dr);
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inet_twsk_put(tw);
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}
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@ -157,7 +159,7 @@ struct inet_timewait_sock *inet_twsk_alloc(const struct sock *sk,
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{
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struct inet_timewait_sock *tw;
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if (atomic_read(&dr->tw_count) >= dr->sysctl_max_tw_buckets)
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if (refcount_read(&dr->tw_refcount) - 1 >= dr->sysctl_max_tw_buckets)
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return NULL;
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tw = kmem_cache_alloc(sk->sk_prot_creator->twsk_prot->twsk_slab,
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@ -249,7 +251,7 @@ void __inet_twsk_schedule(struct inet_timewait_sock *tw, int timeo, bool rearm)
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__NET_INC_STATS(twsk_net(tw), kill ? LINUX_MIB_TIMEWAITKILLED :
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LINUX_MIB_TIMEWAITED);
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BUG_ON(mod_timer(&tw->tw_timer, jiffies + timeo));
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atomic_inc(&tw->tw_dr->tw_count);
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refcount_inc(&tw->tw_dr->tw_refcount);
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} else {
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mod_timer_pending(&tw->tw_timer, jiffies + timeo);
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}
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@ -59,8 +59,8 @@ static int sockstat_seq_show(struct seq_file *seq, void *v)
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socket_seq_show(seq);
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seq_printf(seq, "TCP: inuse %d orphan %d tw %d alloc %d mem %ld\n",
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sock_prot_inuse_get(net, &tcp_prot), orphans,
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atomic_read(&net->ipv4.tcp_death_row.tw_count), sockets,
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proto_memory_allocated(&tcp_prot));
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refcount_read(&net->ipv4.tcp_death_row->tw_refcount) - 1,
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sockets, proto_memory_allocated(&tcp_prot));
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seq_printf(seq, "UDP: inuse %d mem %ld\n",
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sock_prot_inuse_get(net, &udp_prot),
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proto_memory_allocated(&udp_prot));
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@ -589,6 +589,14 @@ static struct ctl_table ipv4_table[] = {
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};
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static struct ctl_table ipv4_net_table[] = {
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/* tcp_max_tw_buckets must be first in this table. */
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{
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.procname = "tcp_max_tw_buckets",
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/* .data = &init_net.ipv4.tcp_death_row.sysctl_max_tw_buckets, */
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.maxlen = sizeof(int),
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.mode = 0644,
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.proc_handler = proc_dointvec
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},
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{
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.procname = "icmp_echo_ignore_all",
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.data = &init_net.ipv4.sysctl_icmp_echo_ignore_all,
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@ -1000,13 +1008,6 @@ static struct ctl_table ipv4_net_table[] = {
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.extra1 = SYSCTL_ZERO,
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.extra2 = &two,
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},
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{
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.procname = "tcp_max_tw_buckets",
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.data = &init_net.ipv4.tcp_death_row.sysctl_max_tw_buckets,
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.maxlen = sizeof(int),
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.mode = 0644,
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.proc_handler = proc_dointvec
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},
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{
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.procname = "tcp_max_syn_backlog",
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.data = &init_net.ipv4.sysctl_max_syn_backlog,
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@ -1400,7 +1401,8 @@ static __net_init int ipv4_sysctl_init_net(struct net *net)
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if (!table)
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goto err_alloc;
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for (i = 0; i < ARRAY_SIZE(ipv4_net_table) - 1; i++) {
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/* skip first entry (sysctl_max_tw_buckets) */
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for (i = 1; i < ARRAY_SIZE(ipv4_net_table) - 1; i++) {
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if (table[i].data) {
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/* Update the variables to point into
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* the current struct net
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@ -1415,6 +1417,8 @@ static __net_init int ipv4_sysctl_init_net(struct net *net)
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}
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}
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table[0].data = &net->ipv4.tcp_death_row->sysctl_max_tw_buckets;
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net->ipv4.ipv4_hdr = register_net_sysctl(net, "net/ipv4", table);
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if (!net->ipv4.ipv4_hdr)
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goto err_reg;
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@ -208,7 +208,7 @@ int tcp_v4_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len)
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struct rtable *rt;
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int err;
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struct ip_options_rcu *inet_opt;
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struct inet_timewait_death_row *tcp_death_row = &sock_net(sk)->ipv4.tcp_death_row;
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struct inet_timewait_death_row *tcp_death_row = sock_net(sk)->ipv4.tcp_death_row;
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if (addr_len < sizeof(struct sockaddr_in))
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return -EINVAL;
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@ -3117,9 +3117,13 @@ EXPORT_SYMBOL(tcp_prot);
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static void __net_exit tcp_sk_exit(struct net *net)
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{
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struct inet_timewait_death_row *tcp_death_row = net->ipv4.tcp_death_row;
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if (net->ipv4.tcp_congestion_control)
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bpf_module_put(net->ipv4.tcp_congestion_control,
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net->ipv4.tcp_congestion_control->owner);
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if (refcount_dec_and_test(&tcp_death_row->tw_refcount))
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kfree(tcp_death_row);
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}
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static int __net_init tcp_sk_init(struct net *net)
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@ -3151,9 +3155,13 @@ static int __net_init tcp_sk_init(struct net *net)
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net->ipv4.sysctl_tcp_tw_reuse = 2;
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net->ipv4.sysctl_tcp_no_ssthresh_metrics_save = 1;
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net->ipv4.tcp_death_row = kzalloc(sizeof(struct inet_timewait_death_row), GFP_KERNEL);
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if (!net->ipv4.tcp_death_row)
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return -ENOMEM;
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refcount_set(&net->ipv4.tcp_death_row->tw_refcount, 1);
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cnt = tcp_hashinfo.ehash_mask + 1;
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net->ipv4.tcp_death_row.sysctl_max_tw_buckets = cnt / 2;
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net->ipv4.tcp_death_row.hashinfo = &tcp_hashinfo;
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net->ipv4.tcp_death_row->sysctl_max_tw_buckets = cnt / 2;
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net->ipv4.tcp_death_row->hashinfo = &tcp_hashinfo;
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net->ipv4.sysctl_max_syn_backlog = max(128, cnt / 128);
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net->ipv4.sysctl_tcp_sack = 1;
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@ -248,7 +248,7 @@ void tcp_time_wait(struct sock *sk, int state, int timeo)
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const struct inet_connection_sock *icsk = inet_csk(sk);
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const struct tcp_sock *tp = tcp_sk(sk);
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struct inet_timewait_sock *tw;
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struct inet_timewait_death_row *tcp_death_row = &sock_net(sk)->ipv4.tcp_death_row;
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struct inet_timewait_death_row *tcp_death_row = sock_net(sk)->ipv4.tcp_death_row;
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tw = inet_twsk_alloc(sk, tcp_death_row, state);
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@ -148,6 +148,7 @@ static int tcp_v6_connect(struct sock *sk, struct sockaddr *uaddr,
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struct sockaddr_in6 *usin = (struct sockaddr_in6 *) uaddr;
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struct inet_sock *inet = inet_sk(sk);
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struct inet_connection_sock *icsk = inet_csk(sk);
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struct inet_timewait_death_row *tcp_death_row;
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struct ipv6_pinfo *np = tcp_inet6_sk(sk);
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struct tcp_sock *tp = tcp_sk(sk);
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struct in6_addr *saddr = NULL, *final_p, final;
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@ -156,7 +157,6 @@ static int tcp_v6_connect(struct sock *sk, struct sockaddr *uaddr,
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struct dst_entry *dst;
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int addr_type;
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int err;
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struct inet_timewait_death_row *tcp_death_row = &sock_net(sk)->ipv4.tcp_death_row;
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if (addr_len < SIN6_LEN_RFC2133)
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return -EINVAL;
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@ -308,6 +308,7 @@ static int tcp_v6_connect(struct sock *sk, struct sockaddr *uaddr,
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inet->inet_dport = usin->sin6_port;
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tcp_set_state(sk, TCP_SYN_SENT);
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tcp_death_row = sock_net(sk)->ipv4.tcp_death_row;
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err = inet6_hash_connect(tcp_death_row, sk);
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if (err)
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goto late_failure;
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