From 9981159fc3b677b357f84e069a11de5a5ec8a2a8 Mon Sep 17 00:00:00 2001 From: Eric Dumazet Date: Tue, 4 Feb 2020 22:17:25 +0100 Subject: [PATCH] wireguard: allowedips: fix use-after-free in root_remove_peer_lists In the unlikely case a new node could not be allocated, we need to remove @newnode from @peer->allowedips_list before freeing it. syzbot reported: BUG: KASAN: use-after-free in __list_del_entry_valid+0xdc/0xf5 lib/list_debug.c:54 Read of size 8 at addr ffff88809881a538 by task syz-executor.4/30133 CPU: 0 PID: 30133 Comm: syz-executor.4 Not tainted 5.5.0-syzkaller #0 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+0x197/0x210 lib/dump_stack.c:118 print_address_description.constprop.0.cold+0xd4/0x30b mm/kasan/report.c:374 __kasan_report.cold+0x1b/0x32 mm/kasan/report.c:506 kasan_report+0x12/0x20 mm/kasan/common.c:639 __asan_report_load8_noabort+0x14/0x20 mm/kasan/generic_report.c:135 __list_del_entry_valid+0xdc/0xf5 lib/list_debug.c:54 __list_del_entry include/linux/list.h:132 [inline] list_del include/linux/list.h:146 [inline] root_remove_peer_lists+0x24f/0x4b0 drivers/net/wireguard/allowedips.c:65 wg_allowedips_free+0x232/0x390 drivers/net/wireguard/allowedips.c:300 wg_peer_remove_all+0xd5/0x620 drivers/net/wireguard/peer.c:187 wg_set_device+0xd01/0x1350 drivers/net/wireguard/netlink.c:542 genl_family_rcv_msg_doit net/netlink/genetlink.c:672 [inline] genl_family_rcv_msg net/netlink/genetlink.c:717 [inline] genl_rcv_msg+0x67d/0xea0 net/netlink/genetlink.c:734 netlink_rcv_skb+0x177/0x450 net/netlink/af_netlink.c:2477 genl_rcv+0x29/0x40 net/netlink/genetlink.c:745 netlink_unicast_kernel net/netlink/af_netlink.c:1302 [inline] netlink_unicast+0x59e/0x7e0 net/netlink/af_netlink.c:1328 netlink_sendmsg+0x91c/0xea0 net/netlink/af_netlink.c:1917 sock_sendmsg_nosec net/socket.c:652 [inline] sock_sendmsg+0xd7/0x130 net/socket.c:672 ____sys_sendmsg+0x753/0x880 net/socket.c:2343 ___sys_sendmsg+0x100/0x170 net/socket.c:2397 __sys_sendmsg+0x105/0x1d0 net/socket.c:2430 __do_sys_sendmsg net/socket.c:2439 [inline] __se_sys_sendmsg net/socket.c:2437 [inline] __x64_sys_sendmsg+0x78/0xb0 net/socket.c:2437 do_syscall_64+0xfa/0x790 arch/x86/entry/common.c:294 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x45b399 Code: ad b6 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 7b b6 fb ff c3 66 2e 0f 1f 84 00 00 00 00 RSP: 002b:00007f99a9bcdc78 EFLAGS: 00000246 ORIG_RAX: 000000000000002e RAX: ffffffffffffffda RBX: 00007f99a9bce6d4 RCX: 000000000045b399 RDX: 0000000000000000 RSI: 0000000020001340 RDI: 0000000000000003 RBP: 000000000075bf20 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000004 R13: 00000000000009ba R14: 00000000004cb2b8 R15: 0000000000000009 Allocated by task 30103: save_stack+0x23/0x90 mm/kasan/common.c:72 set_track mm/kasan/common.c:80 [inline] __kasan_kmalloc mm/kasan/common.c:513 [inline] __kasan_kmalloc.constprop.0+0xcf/0xe0 mm/kasan/common.c:486 kasan_kmalloc+0x9/0x10 mm/kasan/common.c:527 kmem_cache_alloc_trace+0x158/0x790 mm/slab.c:3551 kmalloc include/linux/slab.h:556 [inline] kzalloc include/linux/slab.h:670 [inline] add+0x70a/0x1970 drivers/net/wireguard/allowedips.c:236 wg_allowedips_insert_v4+0xf6/0x160 drivers/net/wireguard/allowedips.c:320 set_allowedip drivers/net/wireguard/netlink.c:343 [inline] set_peer+0xfb9/0x1150 drivers/net/wireguard/netlink.c:468 wg_set_device+0xbd4/0x1350 drivers/net/wireguard/netlink.c:591 genl_family_rcv_msg_doit net/netlink/genetlink.c:672 [inline] genl_family_rcv_msg net/netlink/genetlink.c:717 [inline] genl_rcv_msg+0x67d/0xea0 net/netlink/genetlink.c:734 netlink_rcv_skb+0x177/0x450 net/netlink/af_netlink.c:2477 genl_rcv+0x29/0x40 net/netlink/genetlink.c:745 netlink_unicast_kernel net/netlink/af_netlink.c:1302 [inline] netlink_unicast+0x59e/0x7e0 net/netlink/af_netlink.c:1328 netlink_sendmsg+0x91c/0xea0 net/netlink/af_netlink.c:1917 sock_sendmsg_nosec net/socket.c:652 [inline] sock_sendmsg+0xd7/0x130 net/socket.c:672 ____sys_sendmsg+0x753/0x880 net/socket.c:2343 ___sys_sendmsg+0x100/0x170 net/socket.c:2397 __sys_sendmsg+0x105/0x1d0 net/socket.c:2430 __do_sys_sendmsg net/socket.c:2439 [inline] __se_sys_sendmsg net/socket.c:2437 [inline] __x64_sys_sendmsg+0x78/0xb0 net/socket.c:2437 do_syscall_64+0xfa/0x790 arch/x86/entry/common.c:294 entry_SYSCALL_64_after_hwframe+0x49/0xbe Freed by task 30103: save_stack+0x23/0x90 mm/kasan/common.c:72 set_track mm/kasan/common.c:80 [inline] kasan_set_free_info mm/kasan/common.c:335 [inline] __kasan_slab_free+0x102/0x150 mm/kasan/common.c:474 kasan_slab_free+0xe/0x10 mm/kasan/common.c:483 __cache_free mm/slab.c:3426 [inline] kfree+0x10a/0x2c0 mm/slab.c:3757 add+0x12d2/0x1970 drivers/net/wireguard/allowedips.c:266 wg_allowedips_insert_v4+0xf6/0x160 drivers/net/wireguard/allowedips.c:320 set_allowedip drivers/net/wireguard/netlink.c:343 [inline] set_peer+0xfb9/0x1150 drivers/net/wireguard/netlink.c:468 wg_set_device+0xbd4/0x1350 drivers/net/wireguard/netlink.c:591 genl_family_rcv_msg_doit net/netlink/genetlink.c:672 [inline] genl_family_rcv_msg net/netlink/genetlink.c:717 [inline] genl_rcv_msg+0x67d/0xea0 net/netlink/genetlink.c:734 netlink_rcv_skb+0x177/0x450 net/netlink/af_netlink.c:2477 genl_rcv+0x29/0x40 net/netlink/genetlink.c:745 netlink_unicast_kernel net/netlink/af_netlink.c:1302 [inline] netlink_unicast+0x59e/0x7e0 net/netlink/af_netlink.c:1328 netlink_sendmsg+0x91c/0xea0 net/netlink/af_netlink.c:1917 sock_sendmsg_nosec net/socket.c:652 [inline] sock_sendmsg+0xd7/0x130 net/socket.c:672 ____sys_sendmsg+0x753/0x880 net/socket.c:2343 ___sys_sendmsg+0x100/0x170 net/socket.c:2397 __sys_sendmsg+0x105/0x1d0 net/socket.c:2430 __do_sys_sendmsg net/socket.c:2439 [inline] __se_sys_sendmsg net/socket.c:2437 [inline] __x64_sys_sendmsg+0x78/0xb0 net/socket.c:2437 do_syscall_64+0xfa/0x790 arch/x86/entry/common.c:294 entry_SYSCALL_64_after_hwframe+0x49/0xbe The buggy address belongs to the object at ffff88809881a500 which belongs to the cache kmalloc-64 of size 64 The buggy address is located 56 bytes inside of 64-byte region [ffff88809881a500, ffff88809881a540) The buggy address belongs to the page: page:ffffea0002620680 refcount:1 mapcount:0 mapping:ffff8880aa400380 index:0x0 raw: 00fffe0000000200 ffffea000250b748 ffffea000254bac8 ffff8880aa400380 raw: 0000000000000000 ffff88809881a000 0000000100000020 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff88809881a400: fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc ffff88809881a480: 00 00 00 00 00 fc fc fc fc fc fc fc fc fc fc fc >ffff88809881a500: fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc ^ ffff88809881a580: fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc ffff88809881a600: 00 00 00 00 00 00 fc fc fc fc fc fc fc fc fc fc Fixes: e7096c131e51 ("net: WireGuard secure network tunnel") Signed-off-by: Eric Dumazet Reported-by: syzbot Cc: Jason A. Donenfeld Cc: wireguard@lists.zx2c4.com Signed-off-by: Jason A. Donenfeld Signed-off-by: David S. Miller --- drivers/net/wireguard/allowedips.c | 1 + 1 file changed, 1 insertion(+) diff --git a/drivers/net/wireguard/allowedips.c b/drivers/net/wireguard/allowedips.c index 121d9ea0f135..3725e9cd85f4 100644 --- a/drivers/net/wireguard/allowedips.c +++ b/drivers/net/wireguard/allowedips.c @@ -263,6 +263,7 @@ static int add(struct allowedips_node __rcu **trie, u8 bits, const u8 *key, } else { node = kzalloc(sizeof(*node), GFP_KERNEL); if (unlikely(!node)) { + list_del(&newnode->peer_list); kfree(newnode); return -ENOMEM; }