* [syzbot] KASAN: use-after-free Write in alloc_ucounts
@ 2021-07-17 6:21 syzbot
2021-07-29 17:15 ` syzbot
[not found] ` <20210814095036.2972-1-hdanton@sina.com>
0 siblings, 2 replies; 4+ messages in thread
From: syzbot @ 2021-07-17 6:21 UTC (permalink / raw)
To: ebiederm, legion, linux-kernel, syzkaller-bugs
Hello,
syzbot found the following issue on:
HEAD commit: db503865b9ba Add linux-next specific files for 20210712
git tree: linux-next
console output: https://syzkaller.appspot.com/x/log.txt?x=155c3772300000
kernel config: https://syzkaller.appspot.com/x/.config?x=4d4d624afc208db3
dashboard link: https://syzkaller.appspot.com/bug?extid=59dd63761094a80ad06d
Unfortunately, I don't have any reproducer for this issue yet.
IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+59dd63761094a80ad06d@syzkaller.appspotmail.com
==================================================================
BUG: KASAN: use-after-free in instrument_atomic_read_write include/linux/instrumented.h:101 [inline]
BUG: KASAN: use-after-free in atomic_add_negative include/asm-generic/atomic-instrumented.h:556 [inline]
BUG: KASAN: use-after-free in get_ucounts kernel/ucount.c:152 [inline]
BUG: KASAN: use-after-free in get_ucounts kernel/ucount.c:150 [inline]
BUG: KASAN: use-after-free in alloc_ucounts+0x19b/0x5b0 kernel/ucount.c:188
Write of size 4 at addr ffff88802821e41c by task syz-executor.4/16785
CPU: 1 PID: 16785 Comm: syz-executor.4 Not tainted 5.14.0-rc1-next-20210712-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
__dump_stack lib/dump_stack.c:88 [inline]
dump_stack_lvl+0xcd/0x134 lib/dump_stack.c:105
print_address_description.constprop.0.cold+0x6c/0x309 mm/kasan/report.c:233
__kasan_report mm/kasan/report.c:419 [inline]
kasan_report.cold+0x83/0xdf mm/kasan/report.c:436
check_region_inline mm/kasan/generic.c:183 [inline]
kasan_check_range+0x13d/0x180 mm/kasan/generic.c:189
instrument_atomic_read_write include/linux/instrumented.h:101 [inline]
atomic_add_negative include/asm-generic/atomic-instrumented.h:556 [inline]
get_ucounts kernel/ucount.c:152 [inline]
get_ucounts kernel/ucount.c:150 [inline]
alloc_ucounts+0x19b/0x5b0 kernel/ucount.c:188
set_cred_ucounts+0x171/0x3a0 kernel/cred.c:684
__sys_setuid+0x285/0x400 kernel/sys.c:623
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x44/0xae
RIP: 0033:0x4665d9
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 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 73 01 c3 48 c7 c1 bc ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007fde54097188 EFLAGS: 00000246 ORIG_RAX: 0000000000000069
RAX: ffffffffffffffda RBX: 000000000056bf80 RCX: 00000000004665d9
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 00000000000000ff
RBP: 00000000004bfcb9 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 000000000056bf80
R13: 00007ffc8655740f R14: 00007fde54097300 R15: 0000000000022000
Allocated by task 16784:
kasan_save_stack+0x1b/0x40 mm/kasan/common.c:38
kasan_set_track mm/kasan/common.c:46 [inline]
set_alloc_info mm/kasan/common.c:434 [inline]
____kasan_kmalloc mm/kasan/common.c:513 [inline]
____kasan_kmalloc mm/kasan/common.c:472 [inline]
__kasan_kmalloc+0x9b/0xd0 mm/kasan/common.c:522
kmalloc include/linux/slab.h:591 [inline]
kzalloc include/linux/slab.h:721 [inline]
alloc_ucounts+0x23d/0x5b0 kernel/ucount.c:169
set_cred_ucounts+0x171/0x3a0 kernel/cred.c:684
__sys_setuid+0x285/0x400 kernel/sys.c:623
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x44/0xae
Freed by task 16785:
kasan_save_stack+0x1b/0x40 mm/kasan/common.c:38
kasan_set_track+0x1c/0x30 mm/kasan/common.c:46
kasan_set_free_info+0x20/0x30 mm/kasan/generic.c:360
____kasan_slab_free mm/kasan/common.c:366 [inline]
____kasan_slab_free mm/kasan/common.c:328 [inline]
__kasan_slab_free+0xfb/0x130 mm/kasan/common.c:374
kasan_slab_free include/linux/kasan.h:229 [inline]
slab_free_hook mm/slub.c:1650 [inline]
slab_free_freelist_hook+0xdf/0x240 mm/slub.c:1675
slab_free mm/slub.c:3235 [inline]
kfree+0xeb/0x650 mm/slub.c:4295
put_ucounts kernel/ucount.c:200 [inline]
put_ucounts+0x117/0x150 kernel/ucount.c:192
put_cred_rcu+0x27a/0x520 kernel/cred.c:124
rcu_do_batch kernel/rcu/tree.c:2550 [inline]
rcu_core+0x7ab/0x1380 kernel/rcu/tree.c:2785
__do_softirq+0x29b/0x9c2 kernel/softirq.c:558
Last potentially related work creation:
kasan_save_stack+0x1b/0x40 mm/kasan/common.c:38
kasan_record_aux_stack+0xe5/0x110 mm/kasan/generic.c:348
insert_work+0x48/0x370 kernel/workqueue.c:1332
__queue_work+0x5c1/0xed0 kernel/workqueue.c:1498
queue_work_on+0xee/0x110 kernel/workqueue.c:1525
queue_work include/linux/workqueue.h:507 [inline]
call_usermodehelper_exec+0x1f0/0x4c0 kernel/umh.c:435
kobject_uevent_env+0xf8f/0x1650 lib/kobject_uevent.c:618
netdev_queue_add_kobject net/core/net-sysfs.c:1621 [inline]
netdev_queue_update_kobjects+0x374/0x450 net/core/net-sysfs.c:1655
register_queue_kobjects net/core/net-sysfs.c:1716 [inline]
netdev_register_kobject+0x35a/0x430 net/core/net-sysfs.c:1959
register_netdevice+0xd33/0x1500 net/core/dev.c:10331
nsim_init_netdevsim drivers/net/netdevsim/netdev.c:317 [inline]
nsim_create+0x381/0x4d0 drivers/net/netdevsim/netdev.c:364
__nsim_dev_port_add+0x32e/0x830 drivers/net/netdevsim/dev.c:1295
nsim_dev_port_add_all+0x53/0x150 drivers/net/netdevsim/dev.c:1355
nsim_dev_probe+0xcb5/0x1190 drivers/net/netdevsim/dev.c:1496
call_driver_probe drivers/base/dd.c:517 [inline]
really_probe+0x23c/0xcd0 drivers/base/dd.c:595
__driver_probe_device+0x338/0x4d0 drivers/base/dd.c:747
driver_probe_device+0x4c/0x1a0 drivers/base/dd.c:777
__device_attach_driver+0x20b/0x2f0 drivers/base/dd.c:894
bus_for_each_drv+0x15f/0x1e0 drivers/base/bus.c:427
__device_attach+0x228/0x4a0 drivers/base/dd.c:965
bus_probe_device+0x1e4/0x290 drivers/base/bus.c:487
device_add+0xc2f/0x2180 drivers/base/core.c:3356
nsim_bus_dev_new drivers/net/netdevsim/bus.c:431 [inline]
new_device_store+0x436/0x710 drivers/net/netdevsim/bus.c:298
bus_attr_store+0x72/0xa0 drivers/base/bus.c:122
sysfs_kf_write+0x110/0x160 fs/sysfs/file.c:139
kernfs_fop_write_iter+0x342/0x500 fs/kernfs/file.c:296
call_write_iter include/linux/fs.h:2152 [inline]
new_sync_write+0x426/0x650 fs/read_write.c:518
vfs_write+0x75a/0xa40 fs/read_write.c:605
ksys_write+0x12d/0x250 fs/read_write.c:658
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x44/0xae
Second to last potentially related work creation:
kasan_save_stack+0x1b/0x40 mm/kasan/common.c:38
kasan_record_aux_stack+0xe5/0x110 mm/kasan/generic.c:348
insert_work+0x48/0x370 kernel/workqueue.c:1332
__queue_work+0x5c1/0xed0 kernel/workqueue.c:1498
queue_work_on+0xee/0x110 kernel/workqueue.c:1525
queue_work include/linux/workqueue.h:507 [inline]
call_usermodehelper_exec+0x1f0/0x4c0 kernel/umh.c:435
kobject_uevent_env+0xf8f/0x1650 lib/kobject_uevent.c:618
kobject_synth_uevent+0x701/0x850 lib/kobject_uevent.c:208
uevent_store+0x20/0x50 drivers/base/core.c:2371
dev_attr_store+0x50/0x80 drivers/base/core.c:2072
sysfs_kf_write+0x110/0x160 fs/sysfs/file.c:139
kernfs_fop_write_iter+0x342/0x500 fs/kernfs/file.c:296
call_write_iter include/linux/fs.h:2152 [inline]
new_sync_write+0x426/0x650 fs/read_write.c:518
vfs_write+0x75a/0xa40 fs/read_write.c:605
ksys_write+0x12d/0x250 fs/read_write.c:658
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x44/0xae
The buggy address belongs to the object at ffff88802821e400
which belongs to the cache kmalloc-192 of size 192
The buggy address is located 28 bytes inside of
192-byte region [ffff88802821e400, ffff88802821e4c0)
The buggy address belongs to the page:
page:ffffea0000a08780 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x2821e
flags: 0xfff00000000200(slab|node=0|zone=1|lastcpupid=0x7ff)
raw: 00fff00000000200 dead000000000100 dead000000000122 ffff888010841a00
raw: 0000000000000000 0000000080100010 00000001ffffffff 0000000000000000
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 0, migratetype Unmovable, gfp_mask 0x12cc0(GFP_KERNEL|__GFP_NOWARN|__GFP_NORETRY), pid 1, ts 12874702440, free_ts 12637793385
prep_new_page mm/page_alloc.c:2433 [inline]
get_page_from_freelist+0xa72/0x2f80 mm/page_alloc.c:4166
__alloc_pages+0x1b2/0x500 mm/page_alloc.c:5374
alloc_page_interleave+0x1e/0x200 mm/mempolicy.c:2119
alloc_pages+0x238/0x2a0 mm/mempolicy.c:2242
alloc_slab_page mm/slub.c:1713 [inline]
allocate_slab+0x32b/0x4c0 mm/slub.c:1853
new_slab mm/slub.c:1916 [inline]
new_slab_objects mm/slub.c:2662 [inline]
___slab_alloc+0x4ba/0x820 mm/slub.c:2825
__slab_alloc.constprop.0+0xa7/0xf0 mm/slub.c:2865
slab_alloc_node mm/slub.c:2947 [inline]
slab_alloc mm/slub.c:2989 [inline]
__kmalloc+0x312/0x330 mm/slub.c:4133
kmalloc include/linux/slab.h:596 [inline]
kzalloc include/linux/slab.h:721 [inline]
__register_sysctl_table+0x112/0x1090 fs/proc/proc_sysctl.c:1318
rds_tcp_init_net+0x1db/0x4f0 net/rds/tcp.c:551
ops_init+0xaf/0x470 net/core/net_namespace.c:140
__register_pernet_operations net/core/net_namespace.c:1137 [inline]
register_pernet_operations+0x35a/0x850 net/core/net_namespace.c:1214
register_pernet_device+0x26/0x70 net/core/net_namespace.c:1301
rds_tcp_init+0x77/0xe0 net/rds/tcp.c:717
do_one_initcall+0x103/0x650 init/main.c:1285
do_initcall_level init/main.c:1360 [inline]
do_initcalls init/main.c:1376 [inline]
do_basic_setup init/main.c:1396 [inline]
kernel_init_freeable+0x6b8/0x741 init/main.c:1598
page last free stack trace:
reset_page_owner include/linux/page_owner.h:24 [inline]
free_pages_prepare mm/page_alloc.c:1343 [inline]
free_pcp_prepare+0x312/0x7d0 mm/page_alloc.c:1394
free_unref_page_prepare mm/page_alloc.c:3329 [inline]
free_unref_page+0x19/0x690 mm/page_alloc.c:3408
__vunmap+0x783/0xb70 mm/vmalloc.c:2587
free_work+0x58/0x70 mm/vmalloc.c:82
process_one_work+0x98d/0x1630 kernel/workqueue.c:2276
worker_thread+0x658/0x11f0 kernel/workqueue.c:2422
kthread+0x3e5/0x4d0 kernel/kthread.c:319
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295
Memory state around the buggy address:
ffff88802821e300: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
ffff88802821e380: 00 00 00 00 00 fc fc fc fc fc fc fc fc fc fc fc
>ffff88802821e400: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
^
ffff88802821e480: fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc
ffff88802821e500: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
==================================================================
---
This report is generated by a bot. It may contain errors.
See https://goo.gl/tpsmEJ for more information about syzbot.
syzbot engineers can be reached at syzkaller@googlegroups.com.
syzbot will keep track of this issue. See:
https://goo.gl/tpsmEJ#status for how to communicate with syzbot.
^ permalink raw reply [flat|nested] 4+ messages in thread* Re: [syzbot] KASAN: use-after-free Write in alloc_ucounts
2021-07-17 6:21 [syzbot] KASAN: use-after-free Write in alloc_ucounts syzbot
@ 2021-07-29 17:15 ` syzbot
[not found] ` <20210814095036.2972-1-hdanton@sina.com>
1 sibling, 0 replies; 4+ messages in thread
From: syzbot @ 2021-07-29 17:15 UTC (permalink / raw)
To: ebiederm, legion, linux-kernel, syzkaller-bugs
syzbot has found a reproducer for the following issue on:
HEAD commit: 4010a528219e Merge tag 'fixes_for_v5.14-rc4' of git://git...
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=133f4a66300000
kernel config: https://syzkaller.appspot.com/x/.config?x=1dee114394f7d2c2
dashboard link: https://syzkaller.appspot.com/bug?extid=59dd63761094a80ad06d
compiler: gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.1
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=16b8851a300000
IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+59dd63761094a80ad06d@syzkaller.appspotmail.com
==================================================================
BUG: KASAN: use-after-free in instrument_atomic_read_write include/linux/instrumented.h:101 [inline]
BUG: KASAN: use-after-free in atomic_add_negative include/asm-generic/atomic-instrumented.h:556 [inline]
BUG: KASAN: use-after-free in get_ucounts kernel/ucount.c:152 [inline]
BUG: KASAN: use-after-free in get_ucounts kernel/ucount.c:150 [inline]
BUG: KASAN: use-after-free in alloc_ucounts+0x19b/0x5b0 kernel/ucount.c:188
Write of size 4 at addr ffff888017c0f61c by task syz-executor.0/12089
CPU: 1 PID: 12089 Comm: syz-executor.0 Not tainted 5.14.0-rc3-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
__dump_stack lib/dump_stack.c:88 [inline]
dump_stack_lvl+0xcd/0x134 lib/dump_stack.c:105
print_address_description.constprop.0.cold+0x6c/0x2d6 mm/kasan/report.c:233
__kasan_report mm/kasan/report.c:419 [inline]
kasan_report.cold+0x83/0xdf mm/kasan/report.c:436
check_region_inline mm/kasan/generic.c:183 [inline]
kasan_check_range+0x13d/0x180 mm/kasan/generic.c:189
instrument_atomic_read_write include/linux/instrumented.h:101 [inline]
atomic_add_negative include/asm-generic/atomic-instrumented.h:556 [inline]
get_ucounts kernel/ucount.c:152 [inline]
get_ucounts kernel/ucount.c:150 [inline]
alloc_ucounts+0x19b/0x5b0 kernel/ucount.c:188
set_cred_ucounts+0x171/0x3a0 kernel/cred.c:684
__sys_setresuid+0x62c/0x840 kernel/sys.c:702
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x44/0xae
RIP: 0033:0x4665e9
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 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 73 01 c3 48 c7 c1 bc ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f97fb5de188 EFLAGS: 00000246 ORIG_RAX: 0000000000000075
RAX: ffffffffffffffda RBX: 000000000056bf80 RCX: 00000000004665e9
RDX: 0000000000000000 RSI: 000000000000ee01 RDI: 000000000000ee01
RBP: 00000000004bfcc4 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 000000000056bf80
R13: 00007ffff4281c7f R14: 00007f97fb5de300 R15: 0000000000022000
Allocated by task 10190:
kasan_save_stack+0x1b/0x40 mm/kasan/common.c:38
kasan_set_track mm/kasan/common.c:46 [inline]
set_alloc_info mm/kasan/common.c:434 [inline]
____kasan_kmalloc mm/kasan/common.c:513 [inline]
____kasan_kmalloc mm/kasan/common.c:472 [inline]
__kasan_kmalloc+0x98/0xc0 mm/kasan/common.c:522
kasan_kmalloc include/linux/kasan.h:264 [inline]
kmem_cache_alloc_trace+0x1e4/0x480 mm/slab.c:3575
kmalloc include/linux/slab.h:591 [inline]
kzalloc include/linux/slab.h:721 [inline]
alloc_ucounts+0x23d/0x5b0 kernel/ucount.c:169
set_cred_ucounts+0x171/0x3a0 kernel/cred.c:684
__sys_setresuid+0x62c/0x840 kernel/sys.c:702
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x44/0xae
Freed by task 9890:
kasan_save_stack+0x1b/0x40 mm/kasan/common.c:38
kasan_set_track+0x1c/0x30 mm/kasan/common.c:46
kasan_set_free_info+0x20/0x30 mm/kasan/generic.c:360
____kasan_slab_free mm/kasan/common.c:366 [inline]
____kasan_slab_free mm/kasan/common.c:328 [inline]
__kasan_slab_free+0xcd/0x100 mm/kasan/common.c:374
kasan_slab_free include/linux/kasan.h:230 [inline]
__cache_free mm/slab.c:3445 [inline]
kfree+0x106/0x2c0 mm/slab.c:3803
put_ucounts kernel/ucount.c:200 [inline]
put_ucounts+0x117/0x150 kernel/ucount.c:192
put_cred_rcu+0x27a/0x520 kernel/cred.c:124
rcu_do_batch kernel/rcu/tree.c:2550 [inline]
rcu_core+0x7ab/0x1380 kernel/rcu/tree.c:2785
__do_softirq+0x29b/0x9c2 kernel/softirq.c:558
Last potentially related work creation:
kasan_save_stack+0x1b/0x40 mm/kasan/common.c:38
kasan_record_aux_stack+0xa4/0xd0 mm/kasan/generic.c:348
insert_work+0x48/0x370 kernel/workqueue.c:1332
__queue_work+0x5c1/0xed0 kernel/workqueue.c:1498
queue_work_on+0xee/0x110 kernel/workqueue.c:1525
queue_work include/linux/workqueue.h:507 [inline]
addr_event.part.0+0x31c/0x4d0 drivers/infiniband/core/roce_gid_mgmt.c:853
addr_event drivers/infiniband/core/roce_gid_mgmt.c:824 [inline]
inet6addr_event+0x13e/0x1b0 drivers/infiniband/core/roce_gid_mgmt.c:883
notifier_call_chain+0xb5/0x200 kernel/notifier.c:83
atomic_notifier_call_chain+0x70/0x180 kernel/notifier.c:217
ipv6_add_addr+0x1705/0x1f00 net/ipv6/addrconf.c:1152
addrconf_add_linklocal+0x1ca/0x590 net/ipv6/addrconf.c:3182
addrconf_addr_gen+0x3a4/0x3e0 net/ipv6/addrconf.c:3313
addrconf_dev_config+0x253/0x420 net/ipv6/addrconf.c:3360
addrconf_notify+0x366/0x2400 net/ipv6/addrconf.c:3593
notifier_call_chain+0xb5/0x200 kernel/notifier.c:83
call_netdevice_notifiers_info+0xb5/0x130 net/core/dev.c:2123
netdev_state_change net/core/dev.c:1514 [inline]
netdev_state_change+0x100/0x130 net/core/dev.c:1507
linkwatch_do_dev+0x151/0x1b0 net/core/link_watch.c:167
__linkwatch_run_queue+0x1ea/0x630 net/core/link_watch.c:212
linkwatch_event+0x4a/0x60 net/core/link_watch.c:251
process_one_work+0x98d/0x1630 kernel/workqueue.c:2276
worker_thread+0x658/0x11f0 kernel/workqueue.c:2422
kthread+0x3e5/0x4d0 kernel/kthread.c:319
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295
The buggy address belongs to the object at ffff888017c0f600
which belongs to the cache kmalloc-192 of size 192
The buggy address is located 28 bytes inside of
192-byte region [ffff888017c0f600, ffff888017c0f6c0)
The buggy address belongs to the page:
page:ffffea00005f03c0 refcount:1 mapcount:0 mapping:0000000000000000 index:0xffff888017c0fb00 pfn:0x17c0f
flags: 0xfff00000000200(slab|node=0|zone=1|lastcpupid=0x7ff)
raw: 00fff00000000200 ffffea000098a7c8 ffffea0000bcb3c8 ffff888010840000
raw: ffff888017c0fb00 ffff888017c0f000 0000000100000001 0000000000000000
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 0, migratetype Unmovable, gfp_mask 0x242220(__GFP_HIGH|__GFP_ATOMIC|__GFP_NOWARN|__GFP_COMP|__GFP_THISNODE), pid 8466, ts 421925544813, free_ts 416394009964
prep_new_page mm/page_alloc.c:2436 [inline]
get_page_from_freelist+0xa72/0x2f80 mm/page_alloc.c:4169
__alloc_pages+0x1b2/0x500 mm/page_alloc.c:5391
__alloc_pages_node include/linux/gfp.h:570 [inline]
kmem_getpages mm/slab.c:1377 [inline]
cache_grow_begin+0x75/0x460 mm/slab.c:2593
cache_alloc_refill+0x27f/0x380 mm/slab.c:2965
____cache_alloc mm/slab.c:3048 [inline]
____cache_alloc mm/slab.c:3031 [inline]
__do_cache_alloc mm/slab.c:3275 [inline]
slab_alloc mm/slab.c:3316 [inline]
kmem_cache_alloc_trace+0x38c/0x480 mm/slab.c:3573
kmalloc include/linux/slab.h:591 [inline]
addr_event.part.0+0x7b/0x4d0 drivers/infiniband/core/roce_gid_mgmt.c:840
addr_event drivers/infiniband/core/roce_gid_mgmt.c:824 [inline]
inet6addr_event+0x13e/0x1b0 drivers/infiniband/core/roce_gid_mgmt.c:883
notifier_call_chain+0xb5/0x200 kernel/notifier.c:83
atomic_notifier_call_chain+0x70/0x180 kernel/notifier.c:217
ipv6_add_addr+0x1705/0x1f00 net/ipv6/addrconf.c:1152
addrconf_add_linklocal+0x1ca/0x590 net/ipv6/addrconf.c:3182
addrconf_addr_gen+0x3a4/0x3e0 net/ipv6/addrconf.c:3313
addrconf_dev_config+0x253/0x420 net/ipv6/addrconf.c:3360
addrconf_notify+0x366/0x2400 net/ipv6/addrconf.c:3593
notifier_call_chain+0xb5/0x200 kernel/notifier.c:83
call_netdevice_notifiers_info+0xb5/0x130 net/core/dev.c:2123
page last free stack trace:
reset_page_owner include/linux/page_owner.h:24 [inline]
free_pages_prepare mm/page_alloc.c:1346 [inline]
free_pcp_prepare+0x2c5/0x780 mm/page_alloc.c:1397
free_unref_page_prepare mm/page_alloc.c:3332 [inline]
free_unref_page+0x19/0x690 mm/page_alloc.c:3411
slab_destroy mm/slab.c:1627 [inline]
slabs_destroy+0x89/0xc0 mm/slab.c:1647
cache_flusharray mm/slab.c:3418 [inline]
___cache_free+0x4ba/0x600 mm/slab.c:3480
qlink_free mm/kasan/quarantine.c:146 [inline]
qlist_free_all+0x4e/0x110 mm/kasan/quarantine.c:165
kasan_quarantine_reduce+0x180/0x200 mm/kasan/quarantine.c:272
__kasan_slab_alloc+0x8b/0xa0 mm/kasan/common.c:444
kasan_slab_alloc include/linux/kasan.h:254 [inline]
slab_post_alloc_hook mm/slab.h:519 [inline]
slab_alloc mm/slab.c:3323 [inline]
kmem_cache_alloc+0x25f/0x540 mm/slab.c:3507
prepare_kernel_cred+0x27/0x8a0 kernel/cred.c:724
call_usermodehelper_exec_async+0x10e/0x580 kernel/umh.c:91
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295
Memory state around the buggy address:
ffff888017c0f500: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff888017c0f580: fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc
>ffff888017c0f600: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
^
ffff888017c0f680: fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc
ffff888017c0f700: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================
^ permalink raw reply [flat|nested] 4+ messages in thread[parent not found: <20210814095036.2972-1-hdanton@sina.com>]
* Re: [syzbot] KASAN: use-after-free Write in alloc_ucounts
[not found] ` <20210814095036.2972-1-hdanton@sina.com>
@ 2021-08-14 10:31 ` Alexey Gladkov
2021-08-14 13:50 ` syzbot
1 sibling, 0 replies; 4+ messages in thread
From: Alexey Gladkov @ 2021-08-14 10:31 UTC (permalink / raw)
To: Hillf Danton; +Cc: syzbot, ebiederm, linux-kernel, syzkaller-bugs
On Sat, Aug 14, 2021 at 05:50:36PM +0800, Hillf Danton wrote:
> On Thu, 29 Jul 2021 10:15:28 -0700
> > syzbot has found a reproducer for the following issue on:
> >
> > HEAD commit: 4010a528219e Merge tag 'fixes_for_v5.14-rc4' of git://git...
> > git tree: upstream
> > console output: https://syzkaller.appspot.com/x/log.txt?x=133f4a66300000
> > kernel config: https://syzkaller.appspot.com/x/.config?x=1dee114394f7d2c2
> > dashboard link: https://syzkaller.appspot.com/bug?extid=59dd63761094a80ad06d
> > compiler: gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.1
> > syz repro: https://syzkaller.appspot.com/x/repro.syz?x=16b8851a300000
> >
> > IMPORTANT: if you fix the issue, please add the following tag to the commit:
> > Reported-by: syzbot+59dd63761094a80ad06d@syzkaller.appspotmail.com
> >
> > ==================================================================
> > BUG: KASAN: use-after-free in instrument_atomic_read_write include/linux/instrumented.h:101 [inline]
> > BUG: KASAN: use-after-free in atomic_add_negative include/asm-generic/atomic-instrumented.h:556 [inline]
> > BUG: KASAN: use-after-free in get_ucounts kernel/ucount.c:152 [inline]
> > BUG: KASAN: use-after-free in get_ucounts kernel/ucount.c:150 [inline]
> > BUG: KASAN: use-after-free in alloc_ucounts+0x19b/0x5b0 kernel/ucount.c:188
> > Write of size 4 at addr ffff888017c0f61c by task syz-executor.0/12089
This is outdated report. It was sent before the fix was landed [1]. After
the fix, there were no reports about ucounts.
[1] https://lore.kernel.org/lkml/87a6lvak43.fsf@disp2133/
> In bid to fix the uaf, make get_ucounts() able to detect count underflow in
> addition to overflow by replacing atomic_add_negative() with
> atomic_try_cmpxchg(). Because the cmpxchg itself can not do the job without
> checking xflow, try to bump up count until xflow is detected.
The cmpxchg is much more expensive.
> #syz test git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git 4010a528219e
>
> --- x/kernel/ucount.c
> +++ y/kernel/ucount.c
> @@ -149,11 +149,18 @@ static void hlist_add_ucounts(struct uco
>
> struct ucounts *get_ucounts(struct ucounts *ucounts)
> {
> - if (ucounts && atomic_add_negative(1, &ucounts->count)) {
> - put_ucounts(ucounts);
> - ucounts = NULL;
> + int count;
> +
> + if (!ucounts)
> + return NULL;
> +
> + count = atomic_read(&ucounts->count);
> +
> + while (count > 0 && count + 1 > count) {
> + if (atomic_try_cmpxchg(&ucounts->count, &count, count + 1))
> + return ucounts;
> }
> - return ucounts;
> + return NULL;
> }
>
> struct ucounts *alloc_ucounts(struct user_namespace *ns, kuid_t uid)
> @@ -184,8 +191,8 @@ struct ucounts *alloc_ucounts(struct use
> return new;
> }
> }
> - spin_unlock_irq(&ucounts_lock);
> ucounts = get_ucounts(ucounts);
> + spin_unlock_irq(&ucounts_lock);
> return ucounts;
> }
I see that your patch is not for the most recent code. You are using the
old version of code.
--
Rgrds, legion
^ permalink raw reply [flat|nested] 4+ messages in thread* Re: [syzbot] KASAN: use-after-free Write in alloc_ucounts
[not found] ` <20210814095036.2972-1-hdanton@sina.com>
2021-08-14 10:31 ` Alexey Gladkov
@ 2021-08-14 13:50 ` syzbot
1 sibling, 0 replies; 4+ messages in thread
From: syzbot @ 2021-08-14 13:50 UTC (permalink / raw)
To: ebiederm, hdanton, legion, linux-kernel, syzkaller-bugs
Hello,
syzbot has tested the proposed patch and the reproducer did not trigger any issue:
Reported-and-tested-by: syzbot+59dd63761094a80ad06d@syzkaller.appspotmail.com
Tested on:
commit: 4010a528 Merge tag 'fixes_for_v5.14-rc4' of git://git...
git tree: git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel config: https://syzkaller.appspot.com/x/.config?x=1dee114394f7d2c2
dashboard link: https://syzkaller.appspot.com/bug?extid=59dd63761094a80ad06d
compiler: gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.1
patch: https://syzkaller.appspot.com/x/patch.diff?x=16a86b4e300000
Note: testing is done by a robot and is best-effort only.
^ permalink raw reply [flat|nested] 4+ messages in thread
end of thread, other threads:[~2021-08-14 13:50 UTC | newest]
Thread overview: 4+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2021-07-17 6:21 [syzbot] KASAN: use-after-free Write in alloc_ucounts syzbot
2021-07-29 17:15 ` syzbot
[not found] ` <20210814095036.2972-1-hdanton@sina.com>
2021-08-14 10:31 ` Alexey Gladkov
2021-08-14 13:50 ` syzbot
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