| Message ID | 20190111125552.148871-1-edumazet@google.com |
|---|---|
| State | Changes Requested |
| Delegated to: | David Miller |
| Headers | show |
| Series | [net] fou, fou6: do not assume linear skbs | expand |
On Fri, 11 Jan 2019 04:55:52 -0800 Eric Dumazet <edumazet@google.com> wrote: > Both gue_err() and gue6_err() incorrectly assume > linear skbs. Fix them to use pskb_may_pull(). Thanks for fixing this! I stupidly didn't suspect we could get non-linear skbs there. Just two things: > +++ b/net/ipv4/fou.c > @@ -1020,10 +1020,11 @@ static int gue_err(struct sk_buff *skb, u32 info) > { > int transport_offset = skb_transport_offset(skb); > struct guehdr *guehdr; > - size_t optlen; > + size_t len, optlen; > int ret; > > - if (skb->len < sizeof(struct udphdr) + sizeof(struct guehdr)) > + len = sizeof(struct udphdr) + sizeof(struct guehdr); > + if (!pskb_may_pull(skb, len)) > return -EINVAL; > > guehdr = (struct guehdr *)&udp_hdr(skb)[1]; > @@ -1058,6 +1059,10 @@ static int gue_err(struct sk_buff *skb, u32 info) > > optlen = guehdr->hlen << 2; > > + if (!pskb_may_pull(skb, len + optlen) ^ ) missing > + return -EINVAL; > + > + guehdr = (struct guehdr *)&udp_hdr(skb)[1]; > if (validate_gue_flags(guehdr, optlen)) > return -EINVAL; > > diff --git a/net/ipv6/fou6.c b/net/ipv6/fou6.c > index 7da7bf3b7fe3953eeb60addfffd6687c4da582c4..320413af4890641e7199d7d7102e7d8c2794d557 100644 > --- a/net/ipv6/fou6.c > +++ b/net/ipv6/fou6.c > @@ -90,10 +90,11 @@ static int gue6_err(struct sk_buff *skb, struct inet6_skb_parm *opt, > { > int transport_offset = skb_transport_offset(skb); > struct guehdr *guehdr; > - size_t optlen; > + size_t len, optlen; > int ret; > > - if (skb->len < sizeof(struct udphdr) + sizeof(struct guehdr)) > + len = sizeof(struct udphdr) + sizeof(struct guehdr); > + if (!pskb_may_pull(skb, len)) > return -EINVAL; > > guehdr = (struct guehdr *)&udp_hdr(skb)[1]; > @@ -128,6 +129,10 @@ static int gue6_err(struct sk_buff *skb, struct inet6_skb_parm *opt, > > optlen = guehdr->hlen << 2; > > + if (!pskb_may_pull(skb, len + optlen) ^ ) missing > + return -EINVAL; > + > + guehdr = (struct guehdr *)&udp_hdr(skb)[1]; > if (validate_gue_flags(guehdr, optlen)) > return -EINVAL; >
On Fri, Jan 11, 2019 at 6:15 AM Stefano Brivio <sbrivio@redhat.com> wrote: > > On Fri, 11 Jan 2019 04:55:52 -0800 > Eric Dumazet <edumazet@google.com> wrote: > > > Both gue_err() and gue6_err() incorrectly assume > > linear skbs. Fix them to use pskb_may_pull(). > > Thanks for fixing this! I stupidly didn't suspect we could get > non-linear skbs there. Just two things: > > + if (!pskb_may_pull(skb, len + optlen) > ^ ) missing Interesting, I had no compile error there :/ I will send a V2
On Fri, Jan 11, 2019 at 6:20 AM Eric Dumazet <edumazet@google.com> wrote: > > On Fri, Jan 11, 2019 at 6:15 AM Stefano Brivio <sbrivio@redhat.com> wrote: > > > > On Fri, 11 Jan 2019 04:55:52 -0800 > > Eric Dumazet <edumazet@google.com> wrote: > > > > > Both gue_err() and gue6_err() incorrectly assume > > > linear skbs. Fix them to use pskb_may_pull(). > > > > Thanks for fixing this! I stupidly didn't suspect we could get > > non-linear skbs there. Just two things: > > > > > + if (!pskb_may_pull(skb, len + optlen) > > ^ ) missing > > > Interesting, I had no compile error there :/ > > I will send a V2 Ah, CONFIG_NET_FOU_IP_TUNNELS was not set, of course.
diff --git a/net/ipv4/fou.c b/net/ipv4/fou.c index 632863541082230228da1e63927b9d5c72042350..02db3b0f263f7565fee53da3b8f2503ab2cd1dcb 100644 --- a/net/ipv4/fou.c +++ b/net/ipv4/fou.c @@ -1020,10 +1020,11 @@ static int gue_err(struct sk_buff *skb, u32 info) { int transport_offset = skb_transport_offset(skb); struct guehdr *guehdr; - size_t optlen; + size_t len, optlen; int ret; - if (skb->len < sizeof(struct udphdr) + sizeof(struct guehdr)) + len = sizeof(struct udphdr) + sizeof(struct guehdr); + if (!pskb_may_pull(skb, len)) return -EINVAL; guehdr = (struct guehdr *)&udp_hdr(skb)[1]; @@ -1058,6 +1059,10 @@ static int gue_err(struct sk_buff *skb, u32 info) optlen = guehdr->hlen << 2; + if (!pskb_may_pull(skb, len + optlen) + return -EINVAL; + + guehdr = (struct guehdr *)&udp_hdr(skb)[1]; if (validate_gue_flags(guehdr, optlen)) return -EINVAL; diff --git a/net/ipv6/fou6.c b/net/ipv6/fou6.c index 7da7bf3b7fe3953eeb60addfffd6687c4da582c4..320413af4890641e7199d7d7102e7d8c2794d557 100644 --- a/net/ipv6/fou6.c +++ b/net/ipv6/fou6.c @@ -90,10 +90,11 @@ static int gue6_err(struct sk_buff *skb, struct inet6_skb_parm *opt, { int transport_offset = skb_transport_offset(skb); struct guehdr *guehdr; - size_t optlen; + size_t len, optlen; int ret; - if (skb->len < sizeof(struct udphdr) + sizeof(struct guehdr)) + len = sizeof(struct udphdr) + sizeof(struct guehdr); + if (!pskb_may_pull(skb, len)) return -EINVAL; guehdr = (struct guehdr *)&udp_hdr(skb)[1]; @@ -128,6 +129,10 @@ static int gue6_err(struct sk_buff *skb, struct inet6_skb_parm *opt, optlen = guehdr->hlen << 2; + if (!pskb_may_pull(skb, len + optlen) + return -EINVAL; + + guehdr = (struct guehdr *)&udp_hdr(skb)[1]; if (validate_gue_flags(guehdr, optlen)) return -EINVAL;
Both gue_err() and gue6_err() incorrectly assume linear skbs. Fix them to use pskb_may_pull(). BUG: KMSAN: uninit-value in gue6_err+0x475/0xc40 net/ipv6/fou6.c:101 CPU: 0 PID: 18083 Comm: syz-executor1 Not tainted 5.0.0-rc1+ #7 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: <IRQ> __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 gue6_err+0x475/0xc40 net/ipv6/fou6.c:101 __udp6_lib_err_encap_no_sk net/ipv6/udp.c:434 [inline] __udp6_lib_err_encap net/ipv6/udp.c:491 [inline] __udp6_lib_err+0x18d0/0x2590 net/ipv6/udp.c:522 udplitev6_err+0x118/0x130 net/ipv6/udplite.c:27 icmpv6_notify+0x462/0x9f0 net/ipv6/icmp.c:784 icmpv6_rcv+0x18ac/0x3fa0 net/ipv6/icmp.c:872 ip6_protocol_deliver_rcu+0xb5a/0x23a0 net/ipv6/ip6_input.c:394 ip6_input_finish net/ipv6/ip6_input.c:434 [inline] NF_HOOK include/linux/netfilter.h:289 [inline] ip6_input+0x2b6/0x350 net/ipv6/ip6_input.c:443 dst_input include/net/dst.h:450 [inline] ip6_rcv_finish+0x4e7/0x6d0 net/ipv6/ip6_input.c:76 NF_HOOK include/linux/netfilter.h:289 [inline] ipv6_rcv+0x34b/0x3f0 net/ipv6/ip6_input.c:272 __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 do_softirq_own_stack+0x49/0x80 arch/x86/entry/entry_64.S:1039 </IRQ> do_softirq kernel/softirq.c:338 [inline] __local_bh_enable_ip+0x16f/0x1a0 kernel/softirq.c:190 local_bh_enable+0x36/0x40 include/linux/bottom_half.h:32 rcu_read_unlock_bh include/linux/rcupdate.h:696 [inline] ip6_finish_output2+0x1d64/0x25f0 net/ipv6/ip6_output.c:121 ip6_finish_output+0xae4/0xbc0 net/ipv6/ip6_output.c:154 NF_HOOK_COND include/linux/netfilter.h:278 [inline] ip6_output+0x5ca/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+0xfa/0x390 net/ipv6/ip6_output.c:1727 udp_v6_send_skb+0x1733/0x1d20 net/ipv6/udp.c:1169 udpv6_sendmsg+0x424e/0x45d0 net/ipv6/udp.c:1466 inet_sendmsg+0x54a/0x720 net/ipv4/af_inet.c:798 sock_sendmsg_nosec net/socket.c:621 [inline] sock_sendmsg net/socket.c:631 [inline] ___sys_sendmsg+0xdb9/0x11b0 net/socket.c:2116 __sys_sendmmsg+0x580/0xad0 net/socket.c:2211 __do_sys_sendmmsg net/socket.c:2240 [inline] __se_sys_sendmmsg+0xbd/0xe0 net/socket.c:2237 __x64_sys_sendmmsg+0x56/0x70 net/socket.c:2237 do_syscall_64+0xbc/0xf0 arch/x86/entry/common.c:291 entry_SYSCALL_64_after_hwframe+0x63/0xe7 RIP: 0033:0x457ec9 Code: 6d b7 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 0f 83 3b b7 fb ff c3 66 2e 0f 1f 84 00 00 00 00 RSP: 002b:00007f4a5204fc78 EFLAGS: 00000246 ORIG_RAX: 0000000000000133 RAX: ffffffffffffffda RBX: 0000000000000004 RCX: 0000000000457ec9 RDX: 00000000040001ab RSI: 0000000020000240 RDI: 0000000000000003 RBP: 000000000073bf00 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00007f4a520506d4 R13: 00000000004c4ce5 R14: 00000000004d85d8 R15: 00000000ffffffff 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:446 [inline] slab_alloc_node mm/slub.c:2754 [inline] __kmalloc_node_track_caller+0xe9e/0xff0 mm/slub.c:4377 __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+0x1c7/0xac0 net/core/skbuff.c:5288 sock_alloc_send_pskb+0xafd/0x10a0 net/core/sock.c:2091 sock_alloc_send_skb+0xca/0xe0 net/core/sock.c:2108 __ip6_append_data+0x42ed/0x5dc0 net/ipv6/ip6_output.c:1443 ip6_append_data+0x3c2/0x650 net/ipv6/ip6_output.c:1619 icmp6_send+0x2f5c/0x3c40 net/ipv6/icmp.c:574 icmpv6_send+0xe5/0x110 net/ipv6/ip6_icmp.c:43 ip6_link_failure+0x5c/0x2c0 net/ipv6/route.c:2231 dst_link_failure include/net/dst.h:427 [inline] vti_xmit net/ipv4/ip_vti.c:229 [inline] vti_tunnel_xmit+0xf3b/0x1ea0 net/ipv4/ip_vti.c:265 __netdev_start_xmit include/linux/netdevice.h:4382 [inline] netdev_start_xmit include/linux/netdevice.h:4391 [inline] xmit_one net/core/dev.c:3278 [inline] dev_hard_start_xmit+0x604/0xc40 net/core/dev.c:3294 __dev_queue_xmit+0x2e48/0x3b80 net/core/dev.c:3864 dev_queue_xmit+0x4b/0x60 net/core/dev.c:3897 neigh_direct_output+0x42/0x50 net/core/neighbour.c:1511 neigh_output include/net/neighbour.h:508 [inline] ip6_finish_output2+0x1d4e/0x25f0 net/ipv6/ip6_output.c:120 ip6_finish_output+0xae4/0xbc0 net/ipv6/ip6_output.c:154 NF_HOOK_COND include/linux/netfilter.h:278 [inline] ip6_output+0x5ca/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+0xfa/0x390 net/ipv6/ip6_output.c:1727 udp_v6_send_skb+0x1733/0x1d20 net/ipv6/udp.c:1169 udpv6_sendmsg+0x424e/0x45d0 net/ipv6/udp.c:1466 inet_sendmsg+0x54a/0x720 net/ipv4/af_inet.c:798 sock_sendmsg_nosec net/socket.c:621 [inline] sock_sendmsg net/socket.c:631 [inline] ___sys_sendmsg+0xdb9/0x11b0 net/socket.c:2116 __sys_sendmmsg+0x580/0xad0 net/socket.c:2211 __do_sys_sendmmsg net/socket.c:2240 [inline] __se_sys_sendmmsg+0xbd/0xe0 net/socket.c:2237 __x64_sys_sendmmsg+0x56/0x70 net/socket.c:2237 do_syscall_64+0xbc/0xf0 arch/x86/entry/common.c:291 entry_SYSCALL_64_after_hwframe+0x63/0xe7 Fixes: b8a51b38e4d4 ("fou, fou6: ICMP error handlers for FoU and GUE") Signed-off-by: Eric Dumazet <edumazet@google.com> Reported-by: syzbot <syzkaller@googlegroups.com> Cc: Stefano Brivio <sbrivio@redhat.com> Cc: Sabrina Dubroca <sd@queasysnail.net> --- net/ipv4/fou.c | 9 +++++++-- net/ipv6/fou6.c | 9 +++++++-- 2 files changed, 14 insertions(+), 4 deletions(-)