syzbot


KASAN: use-after-free Read in perf_trace_rpc_stats_latency

Status: fixed on 2018/05/17 10:02
Subsystems: net nfs
[Documentation on labels]
Reported-by: syzbot+27db1f90e2b972a5f2d3@syzkaller.appspotmail.com
Fix commit: 98eb6cf25f03 sunrpc: Fix latency trace point crashes
First crash: 2236d, last: 2236d
Discussions (1)
Title Replies (including bot) Last reply
KASAN: use-after-free Read in perf_trace_rpc_stats_latency 1 (2) 2018/04/30 15:39

Sample crash report:
rpcbind: RPC call returned error 22
rpcbind: RPC call returned error 22
rpcbind: RPC call returned error 22
rpcbind: RPC call returned error 22
==================================================================
BUG: KASAN: use-after-free in strlen+0x83/0xa0 lib/string.c:482
Read of size 1 at addr ffff8801d6f0a1c0 by task syz-executor7/5079

CPU: 1 PID: 5079 Comm: syz-executor7 Not tainted 4.17.0-rc2+ #16
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+0x1b9/0x294 lib/dump_stack.c:113
 print_address_description+0x6c/0x20b mm/kasan/report.c:256
 kasan_report_error mm/kasan/report.c:354 [inline]
 kasan_report.cold.7+0x242/0x2fe mm/kasan/report.c:412
 __asan_report_load1_noabort+0x14/0x20 mm/kasan/report.c:430
 strlen+0x83/0xa0 lib/string.c:482
 trace_event_get_offsets_rpc_stats_latency include/trace/events/sunrpc.h:215 [inline]
 perf_trace_rpc_stats_latency+0x318/0x10d0 include/trace/events/sunrpc.h:215
 trace_rpc_stats_latency include/trace/events/sunrpc.h:215 [inline]
 rpc_count_iostats_metrics+0x594/0x8a0 net/sunrpc/stats.c:182
 rpc_count_iostats+0x76/0x90 net/sunrpc/stats.c:195
 xprt_release+0xa3b/0x1110 net/sunrpc/xprt.c:1351
 rpc_release_resources_task+0x20/0xa0 net/sunrpc/sched.c:1024
 rpc_release_task net/sunrpc/sched.c:1068 [inline]
 __rpc_execute+0x5e9/0xf50 net/sunrpc/sched.c:833
 rpc_execute+0x37f/0x480 net/sunrpc/sched.c:852
 rpc_run_task+0x615/0x8c0 net/sunrpc/clnt.c:1053
 rpc_call_sync+0x196/0x290 net/sunrpc/clnt.c:1082
 rpc_ping+0x155/0x1f0 net/sunrpc/clnt.c:2513
 rpc_create_xprt+0x282/0x3f0 net/sunrpc/clnt.c:479
 rpc_create+0x52e/0x900 net/sunrpc/clnt.c:587
 nfs_create_rpc_client+0x63e/0x850 fs/nfs/client.c:523
 nfs_init_client+0x74/0x100 fs/nfs/client.c:634
 nfs_get_client+0x1065/0x1500 fs/nfs/client.c:425
 nfs_init_server+0x364/0xfb0 fs/nfs/client.c:670
 nfs_create_server+0x86/0x5f0 fs/nfs/client.c:953
 nfs_try_mount+0x177/0xab0 fs/nfs/super.c:1884
 nfs_fs_mount+0x17de/0x2efd fs/nfs/super.c:2695
 mount_fs+0xae/0x328 fs/super.c:1267
 vfs_kern_mount.part.34+0xd4/0x4d0 fs/namespace.c:1037
 vfs_kern_mount fs/namespace.c:1027 [inline]
 do_new_mount fs/namespace.c:2518 [inline]
 do_mount+0x564/0x3070 fs/namespace.c:2848
 ksys_mount+0x12d/0x140 fs/namespace.c:3064
 __do_sys_mount fs/namespace.c:3078 [inline]
 __se_sys_mount fs/namespace.c:3075 [inline]
 __x64_sys_mount+0xbe/0x150 fs/namespace.c:3075
 do_syscall_64+0x1b1/0x800 arch/x86/entry/common.c:287
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x455979
RSP: 002b:00007f1e2785bc68 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 00007f1e2785c6d4 RCX: 0000000000455979
RDX: 0000000020fb5ffc RSI: 0000000020343ff8 RDI: 000000002091dff8
RBP: 000000000072bf50 R08: 000000002000a000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff
R13: 0000000000000440 R14: 00000000006fa6a0 R15: 0000000000000001

Allocated by task 5079:
 save_stack+0x43/0xd0 mm/kasan/kasan.c:448
 set_track mm/kasan/kasan.c:460 [inline]
 kasan_kmalloc+0xc4/0xe0 mm/kasan/kasan.c:553
 __do_kmalloc mm/slab.c:3718 [inline]
 __kmalloc_track_caller+0x14a/0x760 mm/slab.c:3733
 kstrdup+0x39/0x70 mm/util.c:56
 xs_format_common_peer_ports+0x130/0x370 net/sunrpc/xprtsock.c:290
 xs_format_peer_addresses net/sunrpc/xprtsock.c:303 [inline]
 xs_setup_udp+0x5ea/0x880 net/sunrpc/xprtsock.c:3037
 xprt_create_transport+0x1d7/0x596 net/sunrpc/xprt.c:1433
 rpc_create+0x489/0x900 net/sunrpc/clnt.c:573
 nfs_create_rpc_client+0x63e/0x850 fs/nfs/client.c:523
 nfs_init_client+0x74/0x100 fs/nfs/client.c:634
 nfs_get_client+0x1065/0x1500 fs/nfs/client.c:425
 nfs_init_server+0x364/0xfb0 fs/nfs/client.c:670
 nfs_create_server+0x86/0x5f0 fs/nfs/client.c:953
 nfs_try_mount+0x177/0xab0 fs/nfs/super.c:1884
 nfs_fs_mount+0x17de/0x2efd fs/nfs/super.c:2695
 mount_fs+0xae/0x328 fs/super.c:1267
 vfs_kern_mount.part.34+0xd4/0x4d0 fs/namespace.c:1037
 vfs_kern_mount fs/namespace.c:1027 [inline]
 do_new_mount fs/namespace.c:2518 [inline]
 do_mount+0x564/0x3070 fs/namespace.c:2848
 ksys_mount+0x12d/0x140 fs/namespace.c:3064
 __do_sys_mount fs/namespace.c:3078 [inline]
 __se_sys_mount fs/namespace.c:3075 [inline]
 __x64_sys_mount+0xbe/0x150 fs/namespace.c:3075
 do_syscall_64+0x1b1/0x800 arch/x86/entry/common.c:287
 entry_SYSCALL_64_after_hwframe+0x49/0xbe

Freed by task 6:
 save_stack+0x43/0xd0 mm/kasan/kasan.c:448
 set_track mm/kasan/kasan.c:460 [inline]
 __kasan_slab_free+0x11a/0x170 mm/kasan/kasan.c:521
 kasan_slab_free+0xe/0x10 mm/kasan/kasan.c:528
 __cache_free mm/slab.c:3498 [inline]
 kfree+0xd9/0x260 mm/slab.c:3813
 xs_update_peer_port net/sunrpc/xprtsock.c:309 [inline]
 xs_set_port+0x105/0x180 net/sunrpc/xprtsock.c:1827
 rpcb_getport_done+0x224/0x2d0 net/sunrpc/rpcb_clnt.c:824
 rpc_exit_task+0xc9/0x2d0 net/sunrpc/sched.c:725
 __rpc_execute+0x28a/0xf50 net/sunrpc/sched.c:784
 rpc_async_schedule+0x16/0x20 net/sunrpc/sched.c:857
 process_one_work+0xc1e/0x1b50 kernel/workqueue.c:2145
 worker_thread+0x1cc/0x1440 kernel/workqueue.c:2279
 kthread+0x345/0x410 kernel/kthread.c:238
 ret_from_fork+0x3a/0x50 arch/x86/entry/entry_64.S:412

The buggy address belongs to the object at ffff8801d6f0a1c0
 which belongs to the cache kmalloc-32 of size 32
The buggy address is located 0 bytes inside of
 32-byte region [ffff8801d6f0a1c0, ffff8801d6f0a1e0)
The buggy address belongs to the page:
page:ffffea00075bc280 count:1 mapcount:0 mapping:ffff8801d6f0a000 index:0xffff8801d6f0afc1
flags: 0x2fffc0000000100(slab)
raw: 02fffc0000000100 ffff8801d6f0a000 ffff8801d6f0afc1 0000000100000024
raw: ffffea00075c52a0 ffff8801da801238 ffff8801da8001c0 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff8801d6f0a080: 01 fc fc fc fc fc fc fc 00 02 fc fc fc fc fc fc
 ffff8801d6f0a100: 00 02 fc fc fc fc fc fc 00 02 fc fc fc fc fc fc
>ffff8801d6f0a180: fb fb fb fb fc fc fc fc fb fb fb fb fc fc fc fc
                                           ^
 ffff8801d6f0a200: 00 02 fc fc fc fc fc fc 01 fc fc fc fc fc fc fc
 ffff8801d6f0a280: fb fb fb fb fc fc fc fc fb fb fb fb fc fc fc fc
==================================================================

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2018/04/30 05:53 bpf-next f60ad0a0c441 bb79c6ab .config console log report ci-upstream-bpf-next-kasan-gce
* Struck through repros no longer work on HEAD.