syzbot


KASAN: use-after-free Read in tcf_exts_destroy

Status: auto-obsoleted due to no activity on 2023/01/26 07:20
Reported-by: syzbot+eb33fdb680d76712f241@syzkaller.appspotmail.com
First crash: 523d, last: 523d

Sample crash report:
FAT-fs (loop5): Can't find a valid FAT filesystem
==================================================================
BUG: KASAN: use-after-free in tcf_exts_to_list include/net/pkt_cls.h:150 [inline]
BUG: KASAN: use-after-free in tcf_exts_destroy+0x280/0x2f0 net/sched/cls_api.c:897
Read of size 4 at addr ffff88804c280144 by task kworker/u4:3/324

CPU: 0 PID: 324 Comm: kworker/u4:3 Not tainted 4.14.294-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/26/2022
Workqueue: tc_filter_workqueue tcindex_destroy_rexts_work
Call Trace:
 __dump_stack lib/dump_stack.c:17 [inline]
 dump_stack+0x1b2/0x281 lib/dump_stack.c:58
 print_address_description.cold+0x54/0x1d3 mm/kasan/report.c:252
 kasan_report_error.cold+0x8a/0x191 mm/kasan/report.c:351
 kasan_report mm/kasan/report.c:409 [inline]
 __asan_report_load4_noabort+0x68/0x70 mm/kasan/report.c:429
 tcf_exts_to_list include/net/pkt_cls.h:150 [inline]
 tcf_exts_destroy+0x280/0x2f0 net/sched/cls_api.c:897
 __tcindex_destroy_rexts+0x12/0x70 net/sched/cls_tcindex.c:144
 tcindex_destroy_rexts_work+0x17/0x20 net/sched/cls_tcindex.c:154
 process_one_work+0x793/0x14a0 kernel/workqueue.c:2117
 worker_thread+0x5cc/0xff0 kernel/workqueue.c:2251
 kthread+0x30d/0x420 kernel/kthread.c:232
 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:404

Allocated by task 10353:
 save_stack mm/kasan/kasan.c:447 [inline]
 set_track mm/kasan/kasan.c:459 [inline]
 kasan_kmalloc+0xeb/0x160 mm/kasan/kasan.c:551
 __do_kmalloc mm/slab.c:3720 [inline]
 __kmalloc+0x15a/0x400 mm/slab.c:3729
 kmalloc_array include/linux/slab.h:607 [inline]
 kcalloc include/linux/slab.h:618 [inline]
 tcindex_alloc_perfect_hash+0x53/0x3c0 net/sched/cls_tcindex.c:299
 tcindex_set_parms+0x13fd/0x17c0 net/sched/cls_tcindex.c:428
 tcindex_change+0x1c1/0x2c0 net/sched/cls_tcindex.c:539
 tc_ctl_tfilter+0xb54/0x1c10 net/sched/cls_api.c:738
 rtnetlink_rcv_msg+0x3be/0xb10 net/core/rtnetlink.c:4322
 netlink_rcv_skb+0x125/0x390 net/netlink/af_netlink.c:2454
 netlink_unicast_kernel net/netlink/af_netlink.c:1296 [inline]
 netlink_unicast+0x437/0x610 net/netlink/af_netlink.c:1322
 netlink_sendmsg+0x648/0xbc0 net/netlink/af_netlink.c:1893
 sock_sendmsg_nosec net/socket.c:646 [inline]
 sock_sendmsg+0xb5/0x100 net/socket.c:656
 ___sys_sendmsg+0x6c8/0x800 net/socket.c:2062
 __sys_sendmsg+0xa3/0x120 net/socket.c:2096
 SYSC_sendmsg net/socket.c:2107 [inline]
 SyS_sendmsg+0x27/0x40 net/socket.c:2103
 do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292
 entry_SYSCALL_64_after_hwframe+0x46/0xbb

Freed by task 8370:
 save_stack mm/kasan/kasan.c:447 [inline]
 set_track mm/kasan/kasan.c:459 [inline]
 kasan_slab_free+0xc3/0x1a0 mm/kasan/kasan.c:524
 __cache_free mm/slab.c:3496 [inline]
 kfree+0xc9/0x250 mm/slab.c:3815
 __tcindex_destroy+0x2e/0x70 net/sched/cls_tcindex.c:253
 __rcu_reclaim kernel/rcu/rcu.h:195 [inline]
 rcu_do_batch kernel/rcu/tree.c:2699 [inline]
 invoke_rcu_callbacks kernel/rcu/tree.c:2962 [inline]
 __rcu_process_callbacks kernel/rcu/tree.c:2929 [inline]
 rcu_process_callbacks+0x780/0x1180 kernel/rcu/tree.c:2946
 __do_softirq+0x24d/0x9ff kernel/softirq.c:288

The buggy address belongs to the object at ffff88804c280140
 which belongs to the cache kmalloc-262144 of size 262144
The buggy address is located 4 bytes inside of
 262144-byte region [ffff88804c280140, ffff88804c2c0140)
The buggy address belongs to the page:
page:ffffea000130a000 count:1 mapcount:0 mapping:ffff88804c280140 index:0x0 compound_mapcount: 0
flags: 0xfff00000008100(slab|head)
raw: 00fff00000008100 ffff88804c280140 0000000000000000 0000000100000001
raw: ffffea0002b88020 ffff88813fe66048 ffff88813fe65800 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff88804c280000: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff88804c280080: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>ffff88804c280100: fc fc fc fc fc fc fc fc fb fb fb fb fb fb fb fb
                                           ^
 ffff88804c280180: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff88804c280200: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2022/09/28 07:20 linux-4.14.y 4edbf74132a4 75c78242 .config console log report info [disk image] [vmlinux] ci2-linux-4-14 KASAN: use-after-free Read in tcf_exts_destroy
* Struck through repros no longer work on HEAD.