4.16-stable review patch. If anyone has any objections, please let me know.
------------------
From: Eric Dumazet <edumazet@xxxxxxxxxx>
commit d0ea2b12500543535be3f54e17920fffc9bb45f6 upstream.
syzbot complained that res.type could be used while not initialized.
Using RTN_UNSPEC as initial value seems better than using garbage.
BUG: KMSAN: uninit-value in __mkroute_output net/ipv4/route.c:2200 [inline]
BUG: KMSAN: uninit-value in ip_route_output_key_hash_rcu+0x31f0/0x3940 net/ipv4/route.c:2493
CPU: 1 PID: 12207 Comm: syz-executor0 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
__mkroute_output net/ipv4/route.c:2200 [inline]
ip_route_output_key_hash_rcu+0x31f0/0x3940 net/ipv4/route.c:2493
ip_route_output_key_hash net/ipv4/route.c:2322 [inline]
__ip_route_output_key include/net/route.h:126 [inline]
ip_route_output_flow+0x1eb/0x3c0 net/ipv4/route.c:2577
raw_sendmsg+0x1861/0x3ed0 net/ipv4/raw.c:653
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]
SYSC_sendto+0x6c3/0x7e0 net/socket.c:1747
SyS_sendto+0x8a/0xb0 net/socket.c:1715
do_syscall_64+0x309/0x430 arch/x86/entry/common.c:287
entry_SYSCALL_64_after_hwframe+0x3d/0xa2
RIP: 0033:0x455259
RSP: 002b:00007fdc0625dc68 EFLAGS: 00000246 ORIG_RAX: 000000000000002c
RAX: ffffffffffffffda RBX: 00007fdc0625e6d4 RCX: 0000000000455259
RDX: 0000000000000000 RSI: 0000000020000040 RDI: 0000000000000013
RBP: 000000000072bea0 R08: 0000000020000080 R09: 0000000000000010
R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff
R13: 00000000000004f7 R14: 00000000006fa7c8 R15: 0000000000000000
Local variable description: ----res.i.i@ip_route_output_flow
Variable was created at:
ip_route_output_flow+0x75/0x3c0 net/ipv4/route.c:2576
raw_sendmsg+0x1861/0x3ed0 net/ipv4/raw.c:653
Signed-off-by: Eric Dumazet <edumazet@xxxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
net/ipv4/route.c | 11 ++++++-----
1 file changed, 6 insertions(+), 5 deletions(-)
--- a/net/ipv4/route.c
+++ b/net/ipv4/route.c
@@ -2306,13 +2306,14 @@ struct rtable *ip_route_output_key_hash(
const struct sk_buff *skb)
{
__u8 tos = RT_FL_TOS(fl4);
- struct fib_result res;
+ struct fib_result res = {
+ .type = RTN_UNSPEC,
+ .fi = NULL,
+ .table = NULL,
+ .tclassid = 0,
+ };
struct rtable *rth;
- res.tclassid = 0;
- res.fi = NULL;
- res.table = NULL;
-
fl4->flowi4_iif = LOOPBACK_IFINDEX;
fl4->flowi4_tos = tos & IPTOS_RT_MASK;
fl4->flowi4_scope = ((tos & RTO_ONLINK) ?
