4.14-stable review patch. If anyone has any objections, please let me know.
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From: Eric Dumazet edumazet@google.com
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@google.com Signed-off-by: David S. Miller davem@davemloft.net Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- net/ipv4/route.c | 11 ++++++----- 1 file changed, 6 insertions(+), 5 deletions(-)
--- a/net/ipv4/route.c +++ b/net/ipv4/route.c @@ -2288,13 +2288,14 @@ 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) ?