Re: [PATCH] ceph: KASAN: use-after-free Read in ceph_mdsc_destroy
On Thu, 2020-07-23 at 15:57 +0800, qiang.zh...@windriver.com wrote:
> From: Zhang Qiang
>
> When the mdsc ptr is free, we should assign "thefsc->mdsc" a null ptr,
> in ceph_mdsc_init func.
>
> CPU: 0 PID: 15653 Comm: syz-executor.3 Not tainted 5.8.0-rc5-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+0x18f/0x20d lib/dump_stack.c:118
> print_address_description.constprop.0.cold+0xae/0x436
> mm/kasan/report.c:383
> __kasan_report mm/kasan/report.c:513 [inline]
> kasan_report.cold+0x1f/0x37 mm/kasan/report.c:530
> timer_is_static_object+0x7a/0x90 kernel/time/timer.c:611
> debug_object_assert_init lib/debugobjects.c:866 [inline]
> debug_object_assert_init+0x1df/0x2e0 lib/debugobjects.c:841
> debug_timer_assert_init kernel/time/timer.c:728 [inline]
> debug_assert_init kernel/time/timer.c:773 [inline]
> del_timer+0x6d/0x110 kernel/time/timer.c:1196
> try_to_grab_pending kernel/workqueue.c:1249 [inline]
> __cancel_work_timer+0x12d/0x700 kernel/workqueue.c:3092
> ceph_mdsc_stop fs/ceph/mds_client.c:4660 [inline]
> ceph_mdsc_destroy+0x50/0x140 fs/ceph/mds_client.c:4679
> destroy_fs_client+0x13/0x200 fs/ceph/super.c:720
> ceph_get_tree+0x9e5/0x1660 fs/ceph/super.c:1110
> vfs_get_tree+0x89/0x2f0 fs/super.c:1547
> do_new_mount fs/namespace.c:2875 [inline]
> do_mount+0x1592/0x1fe0 fs/namespace.c:3200
> __do_sys_mount fs/namespace.c:3410 [inline]
> __se_sys_mount fs/namespace.c:3387 [inline]
> __x64_sys_mount+0x18f/0x230 fs/namespace.c:3387
> do_syscall_64+0x60/0xe0 arch/x86/entry/common.c:384
> entry_SYSCALL_64_after_hwframe+0x44/0xa9
> RIP: 0033:0x45c1d9
> Code: Bad RIP value.
> RSP: 002b:7f33d2bc0c78 EFLAGS: 0246 ORIG_RAX: 00a5
> RAX: ffda RBX: 0001f400 RCX: 0045c1d9
> RDX: 2140 RSI: 20c0 RDI: 25c0
> RBP: 0078bf50 R08: R09:
> R10: R11: 0246 R12: 0078bf0c
> R13: 7fffaad3cc8f R14: 7f33d2bc19c0 R15: 0078bf0c
>
> Allocated by task 15653:
> save_stack+0x1b/0x40 mm/kasan/common.c:48
> set_track mm/kasan/common.c:56 [inline]
> __kasan_kmalloc.constprop.0+0xc2/0xd0 mm/kasan/common.c:494
> kmem_cache_alloc_trace+0x14f/0x2d0 mm/slab.c:3551
> kmalloc include/linux/slab.h:555 [inline]
> kzalloc include/linux/slab.h:669 [inline]
> ceph_mdsc_init+0x47/0xf10 fs/ceph/mds_client.c:4351
> ceph_get_tree+0x4fe/0x1660 fs/ceph/super.c:1063
> vfs_get_tree+0x89/0x2f0 fs/super.c:1547
> do_new_mount fs/namespace.c:2875 [inline]
> do_mount+0x1592/0x1fe0 fs/namespace.c:3200
> __do_sys_mount fs/namespace.c:3410 [inline]
> __se_sys_mount fs/namespace.c:3387 [inline]
> __x64_sys_mount+0x18f/0x230 fs/namespace.c:3387
> do_syscall_64+0x60/0xe0 arch/x86/entry/common.c:384
> entry_SYSCALL_64_after_hwframe+0x44/0xa9
>
> Freed by task 15653:
> save_stack+0x1b/0x40 mm/kasan/common.c:48
> set_track mm/kasan/common.c:56 [inline]
> kasan_set_free_info mm/kasan/common.c:316 [inline]
> __kasan_slab_free+0xf5/0x140 mm/kasan/common.c:455
> __cache_free mm/slab.c:3426 [inline]
> kfree+0x103/0x2c0 mm/slab.c:3757
> ceph_mdsc_init+0xc64/0xf10 fs/ceph/mds_client.c:4422
> ceph_get_tree+0x4fe/0x1660 fs/ceph/super.c:1063
> vfs_get_tree+0x89/0x2f0 fs/super.c:1547
> do_new_mount fs/namespace.c:2875 [inline]
> do_mount+0x1592/0x1fe0 fs/namespace.c:3200
> __do_sys_mount fs/namespace.c:3410 [inline]
> __se_sys_mount fs/namespace.c:3387 [inline]
> __x64_sys_mount+0x18f/0x230 fs/namespace.c:3387
> do_syscall_64+0x60/0xe0 arch/x86/entry/common.c:384
> entry_SYSCALL_64_after_hwframe+0x44/0xa9
>
> The buggy address belongs to the object at 88809e482000
> which belongs to the cache kmalloc-4k of size 4096
> The buggy address is located 896 bytes inside of
> 4096-byte region [88809e482000, 88809e483000)
> The buggy address belongs to the page:
> page:ea0002792080 refcount:1 mapcount:0 mapping:
> index:0x0 head:ea0002792080 order:1 compound_mapcount:0
> flags: 0xfffe010200(slab|head)
> raw: 00fffe010200 ea0002792008 ea000241dc08 8880aa002000
> raw: 88809e482000 00010001
> page dumped because: kasan: bad access detected
>
> Memory state around the buggy address:
> 88809e482280: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
> 88809e482300: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
> > 88809e482380: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>^
> 88809e482400: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
> 88809e482480: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>
> Fixes: f9009efac49c ("ceph: add dentry lease metric support")
>
> Reported-by: syzbot+b57f46d8d6ea51960...@syzkaller.appspotmail.com
> Signed-off-by: Zhang Qiang
> ---
> fs/ceph/mds_cli
[PATCH] ceph: KASAN: use-after-free Read in ceph_mdsc_destroy
From: Zhang Qiang
When the mdsc ptr is free, we should assign "thefsc->mdsc" a null ptr,
in ceph_mdsc_init func.
CPU: 0 PID: 15653 Comm: syz-executor.3 Not tainted 5.8.0-rc5-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+0x18f/0x20d lib/dump_stack.c:118
print_address_description.constprop.0.cold+0xae/0x436
mm/kasan/report.c:383
__kasan_report mm/kasan/report.c:513 [inline]
kasan_report.cold+0x1f/0x37 mm/kasan/report.c:530
timer_is_static_object+0x7a/0x90 kernel/time/timer.c:611
debug_object_assert_init lib/debugobjects.c:866 [inline]
debug_object_assert_init+0x1df/0x2e0 lib/debugobjects.c:841
debug_timer_assert_init kernel/time/timer.c:728 [inline]
debug_assert_init kernel/time/timer.c:773 [inline]
del_timer+0x6d/0x110 kernel/time/timer.c:1196
try_to_grab_pending kernel/workqueue.c:1249 [inline]
__cancel_work_timer+0x12d/0x700 kernel/workqueue.c:3092
ceph_mdsc_stop fs/ceph/mds_client.c:4660 [inline]
ceph_mdsc_destroy+0x50/0x140 fs/ceph/mds_client.c:4679
destroy_fs_client+0x13/0x200 fs/ceph/super.c:720
ceph_get_tree+0x9e5/0x1660 fs/ceph/super.c:1110
vfs_get_tree+0x89/0x2f0 fs/super.c:1547
do_new_mount fs/namespace.c:2875 [inline]
do_mount+0x1592/0x1fe0 fs/namespace.c:3200
__do_sys_mount fs/namespace.c:3410 [inline]
__se_sys_mount fs/namespace.c:3387 [inline]
__x64_sys_mount+0x18f/0x230 fs/namespace.c:3387
do_syscall_64+0x60/0xe0 arch/x86/entry/common.c:384
entry_SYSCALL_64_after_hwframe+0x44/0xa9
RIP: 0033:0x45c1d9
Code: Bad RIP value.
RSP: 002b:7f33d2bc0c78 EFLAGS: 0246 ORIG_RAX: 00a5
RAX: ffda RBX: 0001f400 RCX: 0045c1d9
RDX: 2140 RSI: 20c0 RDI: 25c0
RBP: 0078bf50 R08: R09:
R10: R11: 0246 R12: 0078bf0c
R13: 7fffaad3cc8f R14: 7f33d2bc19c0 R15: 0078bf0c
Allocated by task 15653:
save_stack+0x1b/0x40 mm/kasan/common.c:48
set_track mm/kasan/common.c:56 [inline]
__kasan_kmalloc.constprop.0+0xc2/0xd0 mm/kasan/common.c:494
kmem_cache_alloc_trace+0x14f/0x2d0 mm/slab.c:3551
kmalloc include/linux/slab.h:555 [inline]
kzalloc include/linux/slab.h:669 [inline]
ceph_mdsc_init+0x47/0xf10 fs/ceph/mds_client.c:4351
ceph_get_tree+0x4fe/0x1660 fs/ceph/super.c:1063
vfs_get_tree+0x89/0x2f0 fs/super.c:1547
do_new_mount fs/namespace.c:2875 [inline]
do_mount+0x1592/0x1fe0 fs/namespace.c:3200
__do_sys_mount fs/namespace.c:3410 [inline]
__se_sys_mount fs/namespace.c:3387 [inline]
__x64_sys_mount+0x18f/0x230 fs/namespace.c:3387
do_syscall_64+0x60/0xe0 arch/x86/entry/common.c:384
entry_SYSCALL_64_after_hwframe+0x44/0xa9
Freed by task 15653:
save_stack+0x1b/0x40 mm/kasan/common.c:48
set_track mm/kasan/common.c:56 [inline]
kasan_set_free_info mm/kasan/common.c:316 [inline]
__kasan_slab_free+0xf5/0x140 mm/kasan/common.c:455
__cache_free mm/slab.c:3426 [inline]
kfree+0x103/0x2c0 mm/slab.c:3757
ceph_mdsc_init+0xc64/0xf10 fs/ceph/mds_client.c:4422
ceph_get_tree+0x4fe/0x1660 fs/ceph/super.c:1063
vfs_get_tree+0x89/0x2f0 fs/super.c:1547
do_new_mount fs/namespace.c:2875 [inline]
do_mount+0x1592/0x1fe0 fs/namespace.c:3200
__do_sys_mount fs/namespace.c:3410 [inline]
__se_sys_mount fs/namespace.c:3387 [inline]
__x64_sys_mount+0x18f/0x230 fs/namespace.c:3387
do_syscall_64+0x60/0xe0 arch/x86/entry/common.c:384
entry_SYSCALL_64_after_hwframe+0x44/0xa9
The buggy address belongs to the object at 88809e482000
which belongs to the cache kmalloc-4k of size 4096
The buggy address is located 896 bytes inside of
4096-byte region [88809e482000, 88809e483000)
The buggy address belongs to the page:
page:ea0002792080 refcount:1 mapcount:0 mapping:
index:0x0 head:ea0002792080 order:1 compound_mapcount:0
flags: 0xfffe010200(slab|head)
raw: 00fffe010200 ea0002792008 ea000241dc08 8880aa002000
raw: 88809e482000 00010001
page dumped because: kasan: bad access detected
Memory state around the buggy address:
88809e482280: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
88809e482300: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>88809e482380: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
^
88809e482400: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
88809e482480: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
Fixes: f9009efac49c ("ceph: add dentry lease metric support")
Reported-by: syzbot+b57f46d8d6ea51960...@syzkaller.appspotmail.com
Signed-off-by: Zhang Qiang
---
fs/ceph/mds_client.c | 1 +
1 file changed, 1 insertion(+)
diff --git a/fs/ceph/mds_client.c b/fs/ceph/mds_client.c
index a50497142e59..6d819c285b05 100644
--- a/fs/ceph/mds_client.c
+++ b/fs/ceph/mds_client.c
@@ -4420,6 +4420,7 @@ int ceph_mdsc_init(struct ceph_fs_client *fsc)
kfree(md
