syzbot


KASAN: slab-out-of-bounds Read in __nla_put_nohdr

Status: fixed on 2020/02/18 14:31
Reported-by: syzbot+5af9a90dad568aa9f611@syzkaller.appspotmail.com
Fix commit: 61678d28d4a4 net_sched: fix datalen for ematch
First crash: 887d, last: 887d

Cause bisection: the issue happens on the oldest tested release (bisect log)
Crash: WARNING in sysfs_warn_dup (log)
Repro: C syz .config
similar bugs (2):
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
linux-4.14 KASAN: slab-out-of-bounds Read in __nla_put_nohdr C done 2 881d 881d 1/1 fixed on 2020/02/27 08:36
linux-4.19 KASAN: slab-out-of-bounds Read in __nla_put_nohdr C done 1 880d 880d 1/1 fixed on 2020/02/28 16:14
Patch testing requests:
Created Duration User Patch Repo Result
2020/01/22 22:04 18m xiyou.wangcong@gmail.com https://github.com/congwang/linux.git net OK

Sample crash report:
IPVS: ftp: loaded support on port[0] = 21
==================================================================
BUG: KASAN: slab-out-of-bounds in memcpy include/linux/string.h:380 [inline]
BUG: KASAN: slab-out-of-bounds in __nla_put_nohdr+0x46/0x50 lib/nlattr.c:815
Read of size 12 at addr ffff8880a76235c0 by task syz-executor141/9830

CPU: 1 PID: 9830 Comm: syz-executor141 Not tainted 5.5.0-rc7-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/0x41 mm/kasan/report.c:506
 kasan_report+0x12/0x20 mm/kasan/common.c:639
 check_memory_region_inline mm/kasan/generic.c:185 [inline]
 check_memory_region+0x134/0x1a0 mm/kasan/generic.c:192
 memcpy+0x24/0x50 mm/kasan/common.c:125
 memcpy include/linux/string.h:380 [inline]
 __nla_put_nohdr+0x46/0x50 lib/nlattr.c:815
 nla_put_nohdr+0xf9/0x140 lib/nlattr.c:881
 tcf_em_tree_dump+0x67e/0x960 net/sched/ematch.c:471
 basic_dump+0x379/0x690 net/sched/cls_basic.c:308
 tcf_fill_node+0x58b/0x970 net/sched/cls_api.c:1814
 tfilter_notify+0x134/0x290 net/sched/cls_api.c:1840
 tc_new_tfilter+0xc18/0x2590 net/sched/cls_api.c:2108
 rtnetlink_rcv_msg+0x824/0xaf0 net/core/rtnetlink.c:5415
 netlink_rcv_skb+0x177/0x450 net/netlink/af_netlink.c:2477
 rtnetlink_rcv+0x1d/0x30 net/core/rtnetlink.c:5442
 netlink_unicast_kernel net/netlink/af_netlink.c:1302 [inline]
 netlink_unicast+0x58c/0x7d0 net/netlink/af_netlink.c:1328
 netlink_sendmsg+0x91c/0xea0 net/netlink/af_netlink.c:1917
 sock_sendmsg_nosec net/socket.c:639 [inline]
 sock_sendmsg+0xd7/0x130 net/socket.c:659
 ____sys_sendmsg+0x753/0x880 net/socket.c:2330
 ___sys_sendmsg+0x100/0x170 net/socket.c:2384
 __sys_sendmsg+0x105/0x1d0 net/socket.c:2417
 __do_sys_sendmsg net/socket.c:2426 [inline]
 __se_sys_sendmsg net/socket.c:2424 [inline]
 __x64_sys_sendmsg+0x78/0xb0 net/socket.c:2424
 do_syscall_64+0xfa/0x790 arch/x86/entry/common.c:294
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x440dd9
Code: 18 89 d0 c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 00 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 10 fc ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007ffcf40c80b8 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00000000004a25b0 RCX: 0000000000440dd9
RDX: 0000000000000000 RSI: 00000000200001c0 RDI: 0000000000000003
RBP: 00000000006cc018 R08: 0000000120080522 R09: 0000000120080522
R10: 0000000120080522 R11: 0000000000000246 R12: 00000000004022e0
R13: 0000000000402370 R14: 0000000000000000 R15: 0000000000000000

Allocated by task 9830:
 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
 __do_kmalloc mm/slab.c:3656 [inline]
 __kmalloc_track_caller+0x15f/0x760 mm/slab.c:3671
 kmemdup+0x27/0x60 mm/util.c:127
 kmemdup include/linux/string.h:453 [inline]
 em_nbyte_change+0xd6/0x150 net/sched/em_nbyte.c:32
 tcf_em_validate net/sched/ematch.c:241 [inline]
 tcf_em_tree_validate net/sched/ematch.c:359 [inline]
 tcf_em_tree_validate+0x9b5/0xf3c net/sched/ematch.c:300
 basic_set_parms net/sched/cls_basic.c:157 [inline]
 basic_change+0x513/0x14a0 net/sched/cls_basic.c:219
 tc_new_tfilter+0xbbd/0x2590 net/sched/cls_api.c:2104
 rtnetlink_rcv_msg+0x824/0xaf0 net/core/rtnetlink.c:5415
 netlink_rcv_skb+0x177/0x450 net/netlink/af_netlink.c:2477
 rtnetlink_rcv+0x1d/0x30 net/core/rtnetlink.c:5442
 netlink_unicast_kernel net/netlink/af_netlink.c:1302 [inline]
 netlink_unicast+0x58c/0x7d0 net/netlink/af_netlink.c:1328
 netlink_sendmsg+0x91c/0xea0 net/netlink/af_netlink.c:1917
 sock_sendmsg_nosec net/socket.c:639 [inline]
 sock_sendmsg+0xd7/0x130 net/socket.c:659
 ____sys_sendmsg+0x753/0x880 net/socket.c:2330
 ___sys_sendmsg+0x100/0x170 net/socket.c:2384
 __sys_sendmsg+0x105/0x1d0 net/socket.c:2417
 __do_sys_sendmsg net/socket.c:2426 [inline]
 __se_sys_sendmsg net/socket.c:2424 [inline]
 __x64_sys_sendmsg+0x78/0xb0 net/socket.c:2424
 do_syscall_64+0xfa/0x790 arch/x86/entry/common.c:294
 entry_SYSCALL_64_after_hwframe+0x49/0xbe

Freed by task 9557:
 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
 tomoyo_check_open_permission+0x19e/0x3e0 security/tomoyo/file.c:786
 tomoyo_file_open security/tomoyo/tomoyo.c:319 [inline]
 tomoyo_file_open+0xa9/0xd0 security/tomoyo/tomoyo.c:314
 security_file_open+0x71/0x300 security/security.c:1497
 do_dentry_open+0x37a/0x1380 fs/open.c:784
 vfs_open+0xa0/0xd0 fs/open.c:914
 do_last fs/namei.c:3356 [inline]
 path_openat+0x118b/0x3180 fs/namei.c:3473
 do_filp_open+0x1a1/0x280 fs/namei.c:3503
 do_sys_open+0x3fe/0x5d0 fs/open.c:1097
 __do_sys_open fs/open.c:1115 [inline]
 __se_sys_open fs/open.c:1110 [inline]
 __x64_sys_open+0x7e/0xc0 fs/open.c:1110
 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 ffff8880a76235c0
 which belongs to the cache kmalloc-32 of size 32
The buggy address is located 0 bytes inside of
 32-byte region [ffff8880a76235c0, ffff8880a76235e0)
The buggy address belongs to the page:
page:ffffea00029d88c0 refcount:1 mapcount:0 mapping:ffff8880aa4001c0 index:0xffff8880a7623fc1
raw: 00fffe0000000200 ffffea00029cb2c8 ffffea0002921dc8 ffff8880aa4001c0
raw: ffff8880a7623fc1 ffff8880a7623000 000000010000002e 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff8880a7623480: fb fb fb fb fc fc fc fc fb fb fb fb fc fc fc fc
 ffff8880a7623500: fb fb fb fb fc fc fc fc fb fb fb fb fc fc fc fc
>ffff8880a7623580: fb fb fb fb fc fc fc fc 04 fc fc fc fc fc fc fc
                                           ^
 ffff8880a7623600: fb fb fb fb fc fc fc fc fb fb fb fb fc fc fc fc
 ffff8880a7623680: fb fb fb fb fc fc fc fc fb fb fb fb fc fc fc fc
==================================================================

Crashes (4):
Manager Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Title
ci-upstream-kasan-gce 2020/01/21 21:37 upstream d96d875ef5dd 8eda0b95 .config log report syz C
ci-upstream-kasan-gce-386 2020/01/21 17:18 upstream d96d875ef5dd 8eda0b95 .config log report syz C
ci-upstream-net-this-kasan-gce 2020/01/21 13:16 net 80892772c4ed 8eda0b95 .config log report syz C
ci-upstream-net-kasan-gce 2020/01/21 14:59 net-next 17e10a15a796 8eda0b95 .config log report syz C