From 5355ed6388e23b69a00d48398a68d022135e6486 Mon Sep 17 00:00:00 2001 From: Eric Dumazet Date: Wed, 6 Mar 2019 10:41:00 -0800 Subject: [PATCH] fou, fou6: avoid uninit-value in gue_err() and gue6_err() My prior commit missed the fact that these functions were using udp_hdr() (aka skb_transport_header()) to get access to GUE header. Since pskb_transport_may_pull() does not exist yet, we have to add transport_offset to our pskb_may_pull() calls. BUG: KMSAN: uninit-value in gue_err+0x514/0xfa0 net/ipv4/fou.c:1032 CPU: 1 PID: 10648 Comm: syz-executor.1 Not tainted 5.0.0+ #11 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0x173/0x1d0 lib/dump_stack.c:113 kmsan_report+0x12e/0x2a0 mm/kmsan/kmsan.c:600 __msan_warning+0x82/0xf0 mm/kmsan/kmsan_instr.c:313 gue_err+0x514/0xfa0 net/ipv4/fou.c:1032 __udp4_lib_err_encap_no_sk net/ipv4/udp.c:571 [inline] __udp4_lib_err_encap net/ipv4/udp.c:626 [inline] __udp4_lib_err+0x12e6/0x1d40 net/ipv4/udp.c:665 udp_err+0x74/0x90 net/ipv4/udp.c:737 icmp_socket_deliver net/ipv4/icmp.c:767 [inline] icmp_unreach+0xb65/0x1070 net/ipv4/icmp.c:884 icmp_rcv+0x11a1/0x1950 net/ipv4/icmp.c:1066 ip_protocol_deliver_rcu+0x584/0xbb0 net/ipv4/ip_input.c:208 ip_local_deliver_finish net/ipv4/ip_input.c:234 [inline] NF_HOOK include/linux/netfilter.h:289 [inline] ip_local_deliver+0x624/0x7b0 net/ipv4/ip_input.c:255 dst_input include/net/dst.h:450 [inline] ip_rcv_finish net/ipv4/ip_input.c:414 [inline] NF_HOOK include/linux/netfilter.h:289 [inline] ip_rcv+0x6bd/0x740 net/ipv4/ip_input.c:524 __netif_receive_skb_one_core net/core/dev.c:4973 [inline] __netif_receive_skb net/core/dev.c:5083 [inline] process_backlog+0x756/0x10e0 net/core/dev.c:5923 napi_poll net/core/dev.c:6346 [inline] net_rx_action+0x78b/0x1a60 net/core/dev.c:6412 __do_softirq+0x53f/0x93a kernel/softirq.c:293 invoke_softirq kernel/softirq.c:375 [inline] irq_exit+0x214/0x250 kernel/softirq.c:416 exiting_irq+0xe/0x10 arch/x86/include/asm/apic.h:536 smp_apic_timer_interrupt+0x48/0x70 arch/x86/kernel/apic/apic.c:1064 apic_timer_interrupt+0x2e/0x40 arch/x86/entry/entry_64.S:814 RIP: 0010:finish_lock_switch+0x2b/0x40 kernel/sched/core.c:2597 Code: 48 89 e5 53 48 89 fb e8 63 e7 95 00 8b b8 88 0c 00 00 48 8b 00 48 85 c0 75 12 48 89 df e8 dd db 95 00 c6 00 00 c6 03 00 fb 5b <5d> c3 e8 4e e6 95 00 eb e7 66 90 66 2e 0f 1f 84 00 00 00 00 00 55 RSP: 0018:ffff888081a0fc80 EFLAGS: 00000296 ORIG_RAX: ffffffffffffff13 RAX: ffff88821fd6bd80 RBX: ffff888027898000 RCX: ccccccccccccd000 RDX: ffff88821fca8d80 RSI: ffff888000000000 RDI: 00000000000004a0 RBP: ffff888081a0fc80 R08: 0000000000000002 R09: ffff888081a0fb08 R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000001 R13: ffff88811130e388 R14: ffff88811130da00 R15: ffff88812fdb7d80 finish_task_switch+0xfc/0x2d0 kernel/sched/core.c:2698 context_switch kernel/sched/core.c:2851 [inline] __schedule+0x6cc/0x800 kernel/sched/core.c:3491 schedule+0x15b/0x240 kernel/sched/core.c:3535 freezable_schedule include/linux/freezer.h:172 [inline] do_nanosleep+0x2ba/0x980 kernel/time/hrtimer.c:1679 hrtimer_nanosleep kernel/time/hrtimer.c:1733 [inline] __do_sys_nanosleep kernel/time/hrtimer.c:1767 [inline] __se_sys_nanosleep+0x746/0x960 kernel/time/hrtimer.c:1754 __x64_sys_nanosleep+0x3e/0x60 kernel/time/hrtimer.c:1754 do_syscall_64+0xbc/0xf0 arch/x86/entry/common.c:291 entry_SYSCALL_64_after_hwframe+0x63/0xe7 RIP: 0033:0x4855a0 Code: 00 00 48 c7 c0 d4 ff ff ff 64 c7 00 16 00 00 00 31 c0 eb be 66 0f 1f 44 00 00 83 3d b1 11 5d 00 00 75 14 b8 23 00 00 00 0f 05 <48> 3d 01 f0 ff ff 0f 83 04 e2 f8 ff c3 48 83 ec 08 e8 3a 55 fd ff RSP: 002b:0000000000a4fd58 EFLAGS: 00000246 ORIG_RAX: 0000000000000023 RAX: ffffffffffffffda RBX: 0000000000085780 RCX: 00000000004855a0 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000a4fd60 RBP: 00000000000007ec R08: 0000000000000001 R09: 0000000000ceb940 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000008 R13: 0000000000a4fdb0 R14: 0000000000085711 R15: 0000000000a4fdc0 Uninit was created at: kmsan_save_stack_with_flags mm/kmsan/kmsan.c:205 [inline] kmsan_internal_poison_shadow+0x92/0x150 mm/kmsan/kmsan.c:159 kmsan_kmalloc+0xa6/0x130 mm/kmsan/kmsan_hooks.c:176 kmsan_slab_alloc+0xe/0x10 mm/kmsan/kmsan_hooks.c:185 slab_post_alloc_hook mm/slab.h:445 [inline] slab_alloc_node mm/slub.c:2773 [inline] __kmalloc_node_track_caller+0xe9e/0xff0 mm/slub.c:4398 __kmalloc_reserve net/core/skbuff.c:140 [inline] __alloc_skb+0x309/0xa20 net/core/skbuff.c:208 alloc_skb include/linux/skbuff.h:1012 [inline] alloc_skb_with_frags+0x186/0xa60 net/core/skbuff.c:5287 sock_alloc_send_pskb+0xafd/0x10a0 net/core/sock.c:2091 sock_alloc_send_skb+0xca/0xe0 net/core/sock.c:2108 __ip_append_data+0x34cd/0x5000 net/ipv4/ip_output.c:998 ip_append_data+0x324/0x480 net/ipv4/ip_output.c:1220 icmp_push_reply+0x23d/0x7e0 net/ipv4/icmp.c:375 __icmp_send+0x2ea3/0x30f0 net/ipv4/icmp.c:737 icmp_send include/net/icmp.h:47 [inline] ipv4_link_failure+0x6d/0x230 net/ipv4/route.c:1190 dst_link_failure include/net/dst.h:427 [inline] arp_error_report+0x106/0x1a0 net/ipv4/arp.c:297 neigh_invalidate+0x359/0x8e0 net/core/neighbour.c:992 neigh_timer_handler+0xdf2/0x1280 net/core/neighbour.c:1078 call_timer_fn+0x285/0x600 kernel/time/timer.c:1325 expire_timers kernel/time/timer.c:1362 [inline] __run_timers+0xdb4/0x11d0 kernel/time/timer.c:1681 run_timer_softirq+0x2e/0x50 kernel/time/timer.c:1694 __do_softirq+0x53f/0x93a kernel/softirq.c:293 Fixes: 26fc181e6cac ("fou, fou6: do not assume linear skbs") Signed-off-by: Eric Dumazet Reported-by: syzbot Cc: Stefano Brivio Cc: Sabrina Dubroca Acked-by: Stefano Brivio Signed-off-by: David S. Miller --- net/ipv4/fou.c | 4 ++-- net/ipv6/fou6.c | 4 ++-- 2 files changed, 4 insertions(+), 4 deletions(-) diff --git a/net/ipv4/fou.c b/net/ipv4/fou.c index 437070d1ffb1..79e98e21cdd7 100644 --- a/net/ipv4/fou.c +++ b/net/ipv4/fou.c @@ -1024,7 +1024,7 @@ static int gue_err(struct sk_buff *skb, u32 info) int ret; len = sizeof(struct udphdr) + sizeof(struct guehdr); - if (!pskb_may_pull(skb, len)) + if (!pskb_may_pull(skb, transport_offset + len)) return -EINVAL; guehdr = (struct guehdr *)&udp_hdr(skb)[1]; @@ -1059,7 +1059,7 @@ static int gue_err(struct sk_buff *skb, u32 info) optlen = guehdr->hlen << 2; - if (!pskb_may_pull(skb, len + optlen)) + if (!pskb_may_pull(skb, transport_offset + len + optlen)) return -EINVAL; guehdr = (struct guehdr *)&udp_hdr(skb)[1]; diff --git a/net/ipv6/fou6.c b/net/ipv6/fou6.c index 867474abe269..ec4e2ed95f36 100644 --- a/net/ipv6/fou6.c +++ b/net/ipv6/fou6.c @@ -94,7 +94,7 @@ static int gue6_err(struct sk_buff *skb, struct inet6_skb_parm *opt, int ret; len = sizeof(struct udphdr) + sizeof(struct guehdr); - if (!pskb_may_pull(skb, len)) + if (!pskb_may_pull(skb, transport_offset + len)) return -EINVAL; guehdr = (struct guehdr *)&udp_hdr(skb)[1]; @@ -129,7 +129,7 @@ static int gue6_err(struct sk_buff *skb, struct inet6_skb_parm *opt, optlen = guehdr->hlen << 2; - if (!pskb_may_pull(skb, len + optlen)) + if (!pskb_may_pull(skb, transport_offset + len + optlen)) return -EINVAL; guehdr = (struct guehdr *)&udp_hdr(skb)[1]; -- 2.30.2