| From 55c200a48ad45f3e2010934b266144c79a1d8a8c Mon Sep 17 00:00:00 2001 |
| From: Eric Dumazet <edumazet@google.com> |
| Date: Wed, 1 Mar 2017 14:45:06 -0800 |
| Subject: [PATCH] ipv6: orphan skbs in reassembly unit |
| |
| commit 48cac18ecf1de82f76259a54402c3adb7839ad01 upstream. |
| |
| Andrey reported a use-after-free in IPv6 stack. |
| |
| Issue here is that we free the socket while it still has skb |
| in TX path and in some queues. |
| |
| It happens here because IPv6 reassembly unit messes skb->truesize, |
| breaking skb_set_owner_w() badly. |
| |
| We fixed a similar issue for IPV4 in commit 8282f27449bf ("inet: frag: |
| Always orphan skbs inside ip_defrag()") |
| Acked-by: Joe Stringer <joe@ovn.org> |
| |
| ================================================================== |
| BUG: KASAN: use-after-free in sock_wfree+0x118/0x120 |
| Read of size 8 at addr ffff880062da0060 by task a.out/4140 |
| |
| page:ffffea00018b6800 count:1 mapcount:0 mapping: (null) |
| index:0x0 compound_mapcount: 0 |
| flags: 0x100000000008100(slab|head) |
| raw: 0100000000008100 0000000000000000 0000000000000000 0000000180130013 |
| raw: dead000000000100 dead000000000200 ffff88006741f140 0000000000000000 |
| page dumped because: kasan: bad access detected |
| |
| CPU: 0 PID: 4140 Comm: a.out Not tainted 4.10.0-rc3+ #59 |
| Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Bochs 01/01/2011 |
| Call Trace: |
| __dump_stack lib/dump_stack.c:15 |
| dump_stack+0x292/0x398 lib/dump_stack.c:51 |
| describe_address mm/kasan/report.c:262 |
| kasan_report_error+0x121/0x560 mm/kasan/report.c:370 |
| kasan_report mm/kasan/report.c:392 |
| __asan_report_load8_noabort+0x3e/0x40 mm/kasan/report.c:413 |
| sock_flag ./arch/x86/include/asm/bitops.h:324 |
| sock_wfree+0x118/0x120 net/core/sock.c:1631 |
| skb_release_head_state+0xfc/0x250 net/core/skbuff.c:655 |
| skb_release_all+0x15/0x60 net/core/skbuff.c:668 |
| __kfree_skb+0x15/0x20 net/core/skbuff.c:684 |
| kfree_skb+0x16e/0x4e0 net/core/skbuff.c:705 |
| inet_frag_destroy+0x121/0x290 net/ipv4/inet_fragment.c:304 |
| inet_frag_put ./include/net/inet_frag.h:133 |
| nf_ct_frag6_gather+0x1125/0x38b0 net/ipv6/netfilter/nf_conntrack_reasm.c:617 |
| ipv6_defrag+0x21b/0x350 net/ipv6/netfilter/nf_defrag_ipv6_hooks.c:68 |
| nf_hook_entry_hookfn ./include/linux/netfilter.h:102 |
| nf_hook_slow+0xc3/0x290 net/netfilter/core.c:310 |
| nf_hook ./include/linux/netfilter.h:212 |
| __ip6_local_out+0x52c/0xaf0 net/ipv6/output_core.c:160 |
| ip6_local_out+0x2d/0x170 net/ipv6/output_core.c:170 |
| ip6_send_skb+0xa1/0x340 net/ipv6/ip6_output.c:1722 |
| ip6_push_pending_frames+0xb3/0xe0 net/ipv6/ip6_output.c:1742 |
| rawv6_push_pending_frames net/ipv6/raw.c:613 |
| rawv6_sendmsg+0x2cff/0x4130 net/ipv6/raw.c:927 |
| inet_sendmsg+0x164/0x5b0 net/ipv4/af_inet.c:744 |
| sock_sendmsg_nosec net/socket.c:635 |
| sock_sendmsg+0xca/0x110 net/socket.c:645 |
| sock_write_iter+0x326/0x620 net/socket.c:848 |
| new_sync_write fs/read_write.c:499 |
| __vfs_write+0x483/0x760 fs/read_write.c:512 |
| vfs_write+0x187/0x530 fs/read_write.c:560 |
| SYSC_write fs/read_write.c:607 |
| SyS_write+0xfb/0x230 fs/read_write.c:599 |
| entry_SYSCALL_64_fastpath+0x1f/0xc2 arch/x86/entry/entry_64.S:203 |
| RIP: 0033:0x7ff26e6f5b79 |
| RSP: 002b:00007ff268e0ed98 EFLAGS: 00000206 ORIG_RAX: 0000000000000001 |
| RAX: ffffffffffffffda RBX: 00007ff268e0f9c0 RCX: 00007ff26e6f5b79 |
| RDX: 0000000000000010 RSI: 0000000020f50fe1 RDI: 0000000000000003 |
| RBP: 00007ff26ebc1220 R08: 0000000000000000 R09: 0000000000000000 |
| R10: 0000000000000000 R11: 0000000000000206 R12: 0000000000000000 |
| R13: 00007ff268e0f9c0 R14: 00007ff26efec040 R15: 0000000000000003 |
| |
| The buggy address belongs to the object at ffff880062da0000 |
| which belongs to the cache RAWv6 of size 1504 |
| The buggy address ffff880062da0060 is located 96 bytes inside |
| of 1504-byte region [ffff880062da0000, ffff880062da05e0) |
| |
| Freed by task 4113: |
| save_stack_trace+0x16/0x20 arch/x86/kernel/stacktrace.c:57 |
| save_stack+0x43/0xd0 mm/kasan/kasan.c:502 |
| set_track mm/kasan/kasan.c:514 |
| kasan_slab_free+0x73/0xc0 mm/kasan/kasan.c:578 |
| slab_free_hook mm/slub.c:1352 |
| slab_free_freelist_hook mm/slub.c:1374 |
| slab_free mm/slub.c:2951 |
| kmem_cache_free+0xb2/0x2c0 mm/slub.c:2973 |
| sk_prot_free net/core/sock.c:1377 |
| __sk_destruct+0x49c/0x6e0 net/core/sock.c:1452 |
| sk_destruct+0x47/0x80 net/core/sock.c:1460 |
| __sk_free+0x57/0x230 net/core/sock.c:1468 |
| sk_free+0x23/0x30 net/core/sock.c:1479 |
| sock_put ./include/net/sock.h:1638 |
| sk_common_release+0x31e/0x4e0 net/core/sock.c:2782 |
| rawv6_close+0x54/0x80 net/ipv6/raw.c:1214 |
| inet_release+0xed/0x1c0 net/ipv4/af_inet.c:425 |
| inet6_release+0x50/0x70 net/ipv6/af_inet6.c:431 |
| sock_release+0x8d/0x1e0 net/socket.c:599 |
| sock_close+0x16/0x20 net/socket.c:1063 |
| __fput+0x332/0x7f0 fs/file_table.c:208 |
| ____fput+0x15/0x20 fs/file_table.c:244 |
| task_work_run+0x19b/0x270 kernel/task_work.c:116 |
| exit_task_work ./include/linux/task_work.h:21 |
| do_exit+0x186b/0x2800 kernel/exit.c:839 |
| do_group_exit+0x149/0x420 kernel/exit.c:943 |
| SYSC_exit_group kernel/exit.c:954 |
| SyS_exit_group+0x1d/0x20 kernel/exit.c:952 |
| entry_SYSCALL_64_fastpath+0x1f/0xc2 arch/x86/entry/entry_64.S:203 |
| |
| Allocated by task 4115: |
| save_stack_trace+0x16/0x20 arch/x86/kernel/stacktrace.c:57 |
| save_stack+0x43/0xd0 mm/kasan/kasan.c:502 |
| set_track mm/kasan/kasan.c:514 |
| kasan_kmalloc+0xad/0xe0 mm/kasan/kasan.c:605 |
| kasan_slab_alloc+0x12/0x20 mm/kasan/kasan.c:544 |
| slab_post_alloc_hook mm/slab.h:432 |
| slab_alloc_node mm/slub.c:2708 |
| slab_alloc mm/slub.c:2716 |
| kmem_cache_alloc+0x1af/0x250 mm/slub.c:2721 |
| sk_prot_alloc+0x65/0x2a0 net/core/sock.c:1334 |
| sk_alloc+0x105/0x1010 net/core/sock.c:1396 |
| inet6_create+0x44d/0x1150 net/ipv6/af_inet6.c:183 |
| __sock_create+0x4f6/0x880 net/socket.c:1199 |
| sock_create net/socket.c:1239 |
| SYSC_socket net/socket.c:1269 |
| SyS_socket+0xf9/0x230 net/socket.c:1249 |
| entry_SYSCALL_64_fastpath+0x1f/0xc2 arch/x86/entry/entry_64.S:203 |
| |
| Memory state around the buggy address: |
| ffff880062d9ff00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc |
| ffff880062d9ff80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc |
| >ffff880062da0000: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb |
| ^ |
| ffff880062da0080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb |
| ffff880062da0100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb |
| ================================================================== |
| |
| Reported-by: Andrey Konovalov <andreyknvl@google.com> |
| Signed-off-by: Eric Dumazet <edumazet@google.com> |
| Signed-off-by: David S. Miller <davem@davemloft.net> |
| Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com> |
| |
| diff --git a/net/ipv6/netfilter/nf_conntrack_reasm.c b/net/ipv6/netfilter/nf_conntrack_reasm.c |
| index e4347aeb2e65..039ec11b0b04 100644 |
| --- a/net/ipv6/netfilter/nf_conntrack_reasm.c |
| +++ b/net/ipv6/netfilter/nf_conntrack_reasm.c |
| @@ -589,6 +589,7 @@ int nf_ct_frag6_gather(struct net *net, struct sk_buff *skb, u32 user) |
| hdr = ipv6_hdr(skb); |
| fhdr = (struct frag_hdr *)skb_transport_header(skb); |
| |
| + skb_orphan(skb); |
| fq = fq_find(net, fhdr->identification, user, &hdr->saddr, &hdr->daddr, |
| skb->dev ? skb->dev->ifindex : 0, ip6_frag_ecn(hdr)); |
| if (fq == NULL) { |
| diff --git a/net/openvswitch/conntrack.c b/net/openvswitch/conntrack.c |
| index 108b4a17f583..080bb24a677e 100644 |
| --- a/net/openvswitch/conntrack.c |
| +++ b/net/openvswitch/conntrack.c |
| @@ -367,7 +367,6 @@ static int handle_fragments(struct net *net, struct sw_flow_key *key, |
| } else if (key->eth.type == htons(ETH_P_IPV6)) { |
| enum ip6_defrag_users user = IP6_DEFRAG_CONNTRACK_IN + zone; |
| |
| - skb_orphan(skb); |
| memset(IP6CB(skb), 0, sizeof(struct inet6_skb_parm)); |
| err = nf_ct_frag6_gather(net, skb, user); |
| if (err) |
| -- |
| 2.12.0 |
| |
