KMSAN reported use of uninit-value in gc_worker [1]
We need to clear ct->timeout in __nf_conntrack_alloc()
otherwise __nf_conntrack_confirm() might propagate garbage when
adding nfct_time_stamp to ct->timeout :
ct->timeout += nfct_time_stamp;
[1]
BUG: KMSAN: uninit-value in gc_worker+0x89e/0x1530 net/netfilter/nf_conntrack_core.c:1028
CPU: 1 PID: 19 Comm: kworker/1:0 Not tainted 4.18.0-rc4+ #24
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Workqueue: events_power_efficient gc_worker
Call Trace:
__dump_stack lib/dump_stack.c:77 [inline]
dump_stack+0x185/0x1e0 lib/dump_stack.c:113
kmsan_report+0x195/0x2c0 mm/kmsan/kmsan.c:1092
__msan_warning_32+0x7d/0xe0 mm/kmsan/kmsan_instr.c:640
gc_worker+0x89e/0x1530 net/netfilter/nf_conntrack_core.c:1028
process_one_work+0x1655/0x2000 kernel/workqueue.c:2153
worker_thread+0x1136/0x2490 kernel/workqueue.c:2296
kthread+0x473/0x4b0 kernel/kthread.c:247
ret_from_fork+0x35/0x40 arch/x86/entry/entry_64.S:415
Uninit was stored to memory at:
kmsan_save_stack_with_flags mm/kmsan/kmsan.c:256 [inline]
kmsan_save_stack mm/kmsan/kmsan.c:271 [inline]
kmsan_internal_chain_origin+0x13c/0x240 mm/kmsan/kmsan.c:683
__msan_chain_origin+0x76/0xd0 mm/kmsan/kmsan_instr.c:483
__nf_conntrack_confirm+0x2700/0x3f70 net/netfilter/nf_conntrack_core.c:793
nf_conntrack_confirm include/net/netfilter/nf_conntrack_core.h:71 [inline]
ipv6_confirm+0x573/0x740 net/ipv6/netfilter/nf_conntrack_l3proto_ipv6.c:165
nf_hook_entry_hookfn include/linux/netfilter.h:119 [inline]
nf_hook_slow+0x15d/0x3e0 net/netfilter/core.c:511
nf_hook include/linux/netfilter.h:242 [inline]
NF_HOOK_COND include/linux/netfilter.h:275 [inline]
ip6_output+0x37d/0x710 net/ipv6/ip6_output.c:171
dst_output include/net/dst.h:444 [inline]
ip6_local_out+0x164/0x1d0 net/ipv6/output_core.c:176
ip6_send_skb net/ipv6/ip6_output.c:1696 [inline]
ip6_push_pending_frames+0x218/0x4d0 net/ipv6/ip6_output.c:1716
rawv6_push_pending_frames net/ipv6/raw.c:616 [inline]
rawv6_sendmsg+0x45f0/0x5410 net/ipv6/raw.c:935
inet_sendmsg+0x3fc/0x760 net/ipv4/af_inet.c:798
sock_sendmsg_nosec net/socket.c:641 [inline]
sock_sendmsg net/socket.c:651 [inline]
__sys_sendto+0x798/0x8e0 net/socket.c:1797
__do_sys_sendto net/socket.c:1809 [inline]
__se_sys_sendto net/socket.c:1805 [inline]
__x64_sys_sendto+0x1a1/0x210 net/socket.c:1805
do_syscall_64+0x15b/0x230 arch/x86/entry/common.c:290
entry_SYSCALL_64_after_hwframe+0x63/0xe7
Uninit was created at:
kmsan_save_stack_with_flags mm/kmsan/kmsan.c:256 [inline]
kmsan_internal_poison_shadow+0xc8/0x1d0 mm/kmsan/kmsan.c:181
kmsan_kmalloc+0xa1/0x120 mm/kmsan/kmsan_hooks.c:91
kmem_cache_alloc+0xad2/0xbb0 mm/slub.c:2739
__nf_conntrack_alloc+0x166/0x670 net/netfilter/nf_conntrack_core.c:1137
init_conntrack+0x635/0x2840 net/netfilter/nf_conntrack_core.c:1219
resolve_normal_ct net/netfilter/nf_conntrack_core.c:1333 [inline]
nf_conntrack_in+0x1812/0x2070 net/netfilter/nf_conntrack_core.c:1416
ipv6_conntrack_local+0xc3/0xf0 net/ipv6/netfilter/nf_conntrack_l3proto_ipv6.c:179
nf_hook_entry_hookfn include/linux/netfilter.h:119 [inline]
nf_hook_slow+0x15d/0x3e0 net/netfilter/core.c:511
nf_hook include/linux/netfilter.h:242 [inline]
__ip6_local_out+0x64c/0x770 net/ipv6/output_core.c:164
ip6_local_out+0xa4/0x1d0 net/ipv6/output_core.c:174
ip6_send_skb net/ipv6/ip6_output.c:1696 [inline]
ip6_push_pending_frames+0x218/0x4d0 net/ipv6/ip6_output.c:1716
rawv6_push_pending_frames net/ipv6/raw.c:616 [inline]
rawv6_sendmsg+0x45f0/0x5410 net/ipv6/raw.c:935
inet_sendmsg+0x3fc/0x760 net/ipv4/af_inet.c:798
sock_sendmsg_nosec net/socket.c:641 [inline]
sock_sendmsg net/socket.c:651 [inline]
__sys_sendto+0x798/0x8e0 net/socket.c:1797
__do_sys_sendto net/socket.c:1809 [inline]
__se_sys_sendto net/socket.c:1805 [inline]
__x64_sys_sendto+0x1a1/0x210 net/socket.c:1805
do_syscall_64+0x15b/0x230 arch/x86/entry/common.c:290
entry_SYSCALL_64_after_hwframe+0x63/0xe7
Fixes: f330a7fdbe16 ("netfilter: conntrack: get rid of conntrack timer")
Signed-off-by: Eric Dumazet <edumazet@xxxxxxxxxx>
Cc: Pablo Neira Ayuso <pablo@xxxxxxxxxxxxx>
Cc: Florian Westphal <fw@xxxxxxxxx>
Reported-by: syzbot <syzkaller@xxxxxxxxxxxxxxxx>
---
net/netfilter/nf_conntrack_core.c | 1 +
1 file changed, 1 insertion(+)
diff --git a/net/netfilter/nf_conntrack_core.c b/net/netfilter/nf_conntrack_core.c
index 3d52804250274602c521f3cfe6c0c3b8fa9e78e9..759d09bd27140c85f1a19fdb20390558e7e8f161 100644
--- a/net/netfilter/nf_conntrack_core.c
+++ b/net/netfilter/nf_conntrack_core.c
@@ -1145,6 +1145,7 @@ __nf_conntrack_alloc(struct net *net,
/* save hash for reusing when confirming */
*(unsigned long *)(&ct->tuplehash[IP_CT_DIR_REPLY].hnnode.pprev) = hash;
ct->status = 0;
+ ct->timeout = 0;
write_pnet(&ct->ct_net, net);
memset(&ct->__nfct_init_offset[0], 0,
offsetof(struct nf_conn, proto) -
--
2.18.0.203.gfac676dfb9-goog
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