[PATCH 4.16 11/72] dccp: initialize ireq->ir_mark

From: Greg Kroah-Hartman
Date: Mon May 14 2018 - 03:12:29 EST


4.16-stable review patch. If anyone has any objections, please let me know.

------------------

From: Eric Dumazet <edumazet@xxxxxxxxxx>

commit b855ff827476adbdc2259e9895681d82b7b26065 upstream.

syzbot reported an uninit-value read of skb->mark in iptable_mangle_hook()

Thanks to the nice report, I tracked the problem to dccp not caring
of ireq->ir_mark for passive sessions.

BUG: KMSAN: uninit-value in ipt_mangle_out net/ipv4/netfilter/iptable_mangle.c:66 [inline]
BUG: KMSAN: uninit-value in iptable_mangle_hook+0x5e5/0x720 net/ipv4/netfilter/iptable_mangle.c:84
CPU: 0 PID: 5300 Comm: syz-executor3 Not tainted 4.16.0+ #81
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
__dump_stack lib/dump_stack.c:17 [inline]
dump_stack+0x185/0x1d0 lib/dump_stack.c:53
kmsan_report+0x142/0x240 mm/kmsan/kmsan.c:1067
__msan_warning_32+0x6c/0xb0 mm/kmsan/kmsan_instr.c:676
ipt_mangle_out net/ipv4/netfilter/iptable_mangle.c:66 [inline]
iptable_mangle_hook+0x5e5/0x720 net/ipv4/netfilter/iptable_mangle.c:84
nf_hook_entry_hookfn include/linux/netfilter.h:120 [inline]
nf_hook_slow+0x158/0x3d0 net/netfilter/core.c:483
nf_hook include/linux/netfilter.h:243 [inline]
__ip_local_out net/ipv4/ip_output.c:113 [inline]
ip_local_out net/ipv4/ip_output.c:122 [inline]
ip_queue_xmit+0x1d21/0x21c0 net/ipv4/ip_output.c:504
dccp_transmit_skb+0x15eb/0x1900 net/dccp/output.c:142
dccp_xmit_packet+0x814/0x9e0 net/dccp/output.c:281
dccp_write_xmit+0x20f/0x480 net/dccp/output.c:363
dccp_sendmsg+0x12ca/0x12d0 net/dccp/proto.c:818
inet_sendmsg+0x48d/0x740 net/ipv4/af_inet.c:764
sock_sendmsg_nosec net/socket.c:630 [inline]
sock_sendmsg net/socket.c:640 [inline]
___sys_sendmsg+0xec0/0x1310 net/socket.c:2046
__sys_sendmsg net/socket.c:2080 [inline]
SYSC_sendmsg+0x2a3/0x3d0 net/socket.c:2091
SyS_sendmsg+0x54/0x80 net/socket.c:2087
do_syscall_64+0x309/0x430 arch/x86/entry/common.c:287
entry_SYSCALL_64_after_hwframe+0x3d/0xa2
RIP: 0033:0x455259
RSP: 002b:00007f1a4473dc68 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00007f1a4473e6d4 RCX: 0000000000455259
RDX: 0000000000000000 RSI: 0000000020b76fc8 RDI: 0000000000000015
RBP: 000000000072bea0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff
R13: 00000000000004f0 R14: 00000000006fa720 R15: 0000000000000000

Uninit was stored to memory at:
kmsan_save_stack_with_flags mm/kmsan/kmsan.c:278 [inline]
kmsan_save_stack mm/kmsan/kmsan.c:293 [inline]
kmsan_internal_chain_origin+0x12b/0x210 mm/kmsan/kmsan.c:684
__msan_chain_origin+0x69/0xc0 mm/kmsan/kmsan_instr.c:521
ip_queue_xmit+0x1e35/0x21c0 net/ipv4/ip_output.c:502
dccp_transmit_skb+0x15eb/0x1900 net/dccp/output.c:142
dccp_xmit_packet+0x814/0x9e0 net/dccp/output.c:281
dccp_write_xmit+0x20f/0x480 net/dccp/output.c:363
dccp_sendmsg+0x12ca/0x12d0 net/dccp/proto.c:818
inet_sendmsg+0x48d/0x740 net/ipv4/af_inet.c:764
sock_sendmsg_nosec net/socket.c:630 [inline]
sock_sendmsg net/socket.c:640 [inline]
___sys_sendmsg+0xec0/0x1310 net/socket.c:2046
__sys_sendmsg net/socket.c:2080 [inline]
SYSC_sendmsg+0x2a3/0x3d0 net/socket.c:2091
SyS_sendmsg+0x54/0x80 net/socket.c:2087
do_syscall_64+0x309/0x430 arch/x86/entry/common.c:287
entry_SYSCALL_64_after_hwframe+0x3d/0xa2
Uninit was stored to memory at:
kmsan_save_stack_with_flags mm/kmsan/kmsan.c:278 [inline]
kmsan_save_stack mm/kmsan/kmsan.c:293 [inline]
kmsan_internal_chain_origin+0x12b/0x210 mm/kmsan/kmsan.c:684
__msan_chain_origin+0x69/0xc0 mm/kmsan/kmsan_instr.c:521
inet_csk_clone_lock+0x503/0x580 net/ipv4/inet_connection_sock.c:797
dccp_create_openreq_child+0x7f/0x890 net/dccp/minisocks.c:92
dccp_v4_request_recv_sock+0x22c/0xe90 net/dccp/ipv4.c:408
dccp_v6_request_recv_sock+0x290/0x2000 net/dccp/ipv6.c:414
dccp_check_req+0x7b9/0x8f0 net/dccp/minisocks.c:197
dccp_v4_rcv+0x12e4/0x2630 net/dccp/ipv4.c:840
ip_local_deliver_finish+0x6ed/0xd40 net/ipv4/ip_input.c:216
NF_HOOK include/linux/netfilter.h:288 [inline]
ip_local_deliver+0x43c/0x4e0 net/ipv4/ip_input.c:257
dst_input include/net/dst.h:449 [inline]
ip_rcv_finish+0x1253/0x16d0 net/ipv4/ip_input.c:397
NF_HOOK include/linux/netfilter.h:288 [inline]
ip_rcv+0x119d/0x16f0 net/ipv4/ip_input.c:493
__netif_receive_skb_core+0x47cf/0x4a80 net/core/dev.c:4562
__netif_receive_skb net/core/dev.c:4627 [inline]
process_backlog+0x62d/0xe20 net/core/dev.c:5307
napi_poll net/core/dev.c:5705 [inline]
net_rx_action+0x7c1/0x1a70 net/core/dev.c:5771
__do_softirq+0x56d/0x93d kernel/softirq.c:285
Uninit was created at:
kmsan_save_stack_with_flags mm/kmsan/kmsan.c:278 [inline]
kmsan_internal_poison_shadow+0xb8/0x1b0 mm/kmsan/kmsan.c:188
kmsan_kmalloc+0x94/0x100 mm/kmsan/kmsan.c:314
kmem_cache_alloc+0xaab/0xb90 mm/slub.c:2756
reqsk_alloc include/net/request_sock.h:88 [inline]
inet_reqsk_alloc+0xc4/0x7f0 net/ipv4/tcp_input.c:6145
dccp_v4_conn_request+0x5cc/0x1770 net/dccp/ipv4.c:600
dccp_v6_conn_request+0x299/0x1880 net/dccp/ipv6.c:317
dccp_rcv_state_process+0x2ea/0x2410 net/dccp/input.c:612
dccp_v4_do_rcv+0x229/0x340 net/dccp/ipv4.c:682
dccp_v6_do_rcv+0x16d/0x1220 net/dccp/ipv6.c:578
sk_backlog_rcv include/net/sock.h:908 [inline]
__sk_receive_skb+0x60e/0xf20 net/core/sock.c:513
dccp_v4_rcv+0x24d4/0x2630 net/dccp/ipv4.c:874
ip_local_deliver_finish+0x6ed/0xd40 net/ipv4/ip_input.c:216
NF_HOOK include/linux/netfilter.h:288 [inline]
ip_local_deliver+0x43c/0x4e0 net/ipv4/ip_input.c:257
dst_input include/net/dst.h:449 [inline]
ip_rcv_finish+0x1253/0x16d0 net/ipv4/ip_input.c:397
NF_HOOK include/linux/netfilter.h:288 [inline]
ip_rcv+0x119d/0x16f0 net/ipv4/ip_input.c:493
__netif_receive_skb_core+0x47cf/0x4a80 net/core/dev.c:4562
__netif_receive_skb net/core/dev.c:4627 [inline]
process_backlog+0x62d/0xe20 net/core/dev.c:5307
napi_poll net/core/dev.c:5705 [inline]
net_rx_action+0x7c1/0x1a70 net/core/dev.c:5771
__do_softirq+0x56d/0x93d kernel/softirq.c:285

Signed-off-by: Eric Dumazet <edumazet@xxxxxxxxxx>
Reported-by: syzbot <syzkaller@xxxxxxxxxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
net/dccp/ipv4.c | 1 +
net/dccp/ipv6.c | 1 +
2 files changed, 2 insertions(+)

--- a/net/dccp/ipv4.c
+++ b/net/dccp/ipv4.c
@@ -614,6 +614,7 @@ int dccp_v4_conn_request(struct sock *sk
ireq = inet_rsk(req);
sk_rcv_saddr_set(req_to_sk(req), ip_hdr(skb)->daddr);
sk_daddr_set(req_to_sk(req), ip_hdr(skb)->saddr);
+ ireq->ir_mark = inet_request_mark(sk, skb);
ireq->ireq_family = AF_INET;
ireq->ir_iif = sk->sk_bound_dev_if;

--- a/net/dccp/ipv6.c
+++ b/net/dccp/ipv6.c
@@ -351,6 +351,7 @@ static int dccp_v6_conn_request(struct s
ireq->ir_v6_rmt_addr = ipv6_hdr(skb)->saddr;
ireq->ir_v6_loc_addr = ipv6_hdr(skb)->daddr;
ireq->ireq_family = AF_INET6;
+ ireq->ir_mark = inet_request_mark(sk, skb);

if (ipv6_opt_accepted(sk, skb, IP6CB(skb)) ||
np->rxopt.bits.rxinfo || np->rxopt.bits.rxoinfo ||