diff mbox series

[usb] media/pvrusb2: fix uaf in pvr2_context_set_notify

Message ID tencent_19D16EF24CA0E7F686C252C8C66D49A2AE06@qq.com (mailing list archive)
State Superseded
Headers show
Series [usb] media/pvrusb2: fix uaf in pvr2_context_set_notify | expand

Commit Message

Edward Adam Davis Feb. 16, 2024, 7:30 a.m. UTC 
[Syzbot reported]
BUG: KASAN: slab-use-after-free in pvr2_context_set_notify+0x2c4/0x310 drivers/media/usb/pvrusb2/pvrusb2-context.c:35
Read of size 4 at addr ffff888113aeb0d8 by task kworker/1:1/26

CPU: 1 PID: 26 Comm: kworker/1:1 Not tainted 6.8.0-rc1-syzkaller-00046-gf1a27f081c1f #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/25/2024
Workqueue: usb_hub_wq hub_event
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0xd9/0x1b0 lib/dump_stack.c:106
 print_address_description mm/kasan/report.c:377 [inline]
 print_report+0xc4/0x620 mm/kasan/report.c:488
 kasan_report+0xda/0x110 mm/kasan/report.c:601
 pvr2_context_set_notify+0x2c4/0x310 drivers/media/usb/pvrusb2/pvrusb2-context.c:35
 pvr2_context_notify drivers/media/usb/pvrusb2/pvrusb2-context.c:95 [inline]
 pvr2_context_disconnect+0x94/0xb0 drivers/media/usb/pvrusb2/pvrusb2-context.c:272

Freed by task 906:
kasan_save_stack+0x33/0x50 mm/kasan/common.c:47
kasan_save_track+0x14/0x30 mm/kasan/common.c:68
kasan_save_free_info+0x3f/0x60 mm/kasan/generic.c:640
poison_slab_object mm/kasan/common.c:241 [inline]
__kasan_slab_free+0x106/0x1b0 mm/kasan/common.c:257
kasan_slab_free include/linux/kasan.h:184 [inline]
slab_free_hook mm/slub.c:2121 [inline]
slab_free mm/slub.c:4299 [inline]
kfree+0x105/0x340 mm/slub.c:4409
pvr2_context_check drivers/media/usb/pvrusb2/pvrusb2-context.c:137 [inline]
pvr2_context_thread_func+0x69d/0x960 drivers/media/usb/pvrusb2/pvrusb2-context.c:158

[Analyze]
Task A set disconnect_flag = !0, which resulted in Task B's condition being met
and releasing mp, leading to this issue.

[Fix]
Place the disconnect_flag assignment operation after all code in pvr2_context_disconnect()
to avoid this issue.

Reported-and-tested-by: syzbot+ce750e124675d4599449@syzkaller.appspotmail.com
Signed-off-by: Edward Adam Davis <eadavis@qq.com>
---
 drivers/media/usb/pvrusb2/pvrusb2-context.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

Comments

Greg KH Feb. 17, 2024, 7:41 a.m. UTC | #1 
On Fri, Feb 16, 2024 at 03:30:47PM +0800, Edward Adam Davis wrote:
> [Syzbot reported]
> BUG: KASAN: slab-use-after-free in pvr2_context_set_notify+0x2c4/0x310 drivers/media/usb/pvrusb2/pvrusb2-context.c:35
> Read of size 4 at addr ffff888113aeb0d8 by task kworker/1:1/26
> 
> CPU: 1 PID: 26 Comm: kworker/1:1 Not tainted 6.8.0-rc1-syzkaller-00046-gf1a27f081c1f #0
> Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/25/2024
> Workqueue: usb_hub_wq hub_event
> Call Trace:
>  <TASK>
>  __dump_stack lib/dump_stack.c:88 [inline]
>  dump_stack_lvl+0xd9/0x1b0 lib/dump_stack.c:106
>  print_address_description mm/kasan/report.c:377 [inline]
>  print_report+0xc4/0x620 mm/kasan/report.c:488
>  kasan_report+0xda/0x110 mm/kasan/report.c:601
>  pvr2_context_set_notify+0x2c4/0x310 drivers/media/usb/pvrusb2/pvrusb2-context.c:35
>  pvr2_context_notify drivers/media/usb/pvrusb2/pvrusb2-context.c:95 [inline]
>  pvr2_context_disconnect+0x94/0xb0 drivers/media/usb/pvrusb2/pvrusb2-context.c:272
> 
> Freed by task 906:
> kasan_save_stack+0x33/0x50 mm/kasan/common.c:47
> kasan_save_track+0x14/0x30 mm/kasan/common.c:68
> kasan_save_free_info+0x3f/0x60 mm/kasan/generic.c:640
> poison_slab_object mm/kasan/common.c:241 [inline]
> __kasan_slab_free+0x106/0x1b0 mm/kasan/common.c:257
> kasan_slab_free include/linux/kasan.h:184 [inline]
> slab_free_hook mm/slub.c:2121 [inline]
> slab_free mm/slub.c:4299 [inline]
> kfree+0x105/0x340 mm/slub.c:4409
> pvr2_context_check drivers/media/usb/pvrusb2/pvrusb2-context.c:137 [inline]
> pvr2_context_thread_func+0x69d/0x960 drivers/media/usb/pvrusb2/pvrusb2-context.c:158
> 
> [Analyze]
> Task A set disconnect_flag = !0, which resulted in Task B's condition being met
> and releasing mp, leading to this issue.
> 
> [Fix]
> Place the disconnect_flag assignment operation after all code in pvr2_context_disconnect()
> to avoid this issue.
> 
> Reported-and-tested-by: syzbot+ce750e124675d4599449@syzkaller.appspotmail.com
> Signed-off-by: Edward Adam Davis <eadavis@qq.com>

What commit id does this fix?

And should it be cc: stable as well?

thanks,

greg k-h
Edward Adam Davis Feb. 18, 2024, 6:22 a.m. UTC | #2 
On Sat, 17 Feb 2024 08:41:33 +0100, Greg KH wrote:
> On Fri, Feb 16, 2024 at 03:30:47PM +0800, Edward Adam Davis wrote:
> > [Syzbot reported]
> > BUG: KASAN: slab-use-after-free in pvr2_context_set_notify+0x2c4/0x310 drivers/media/usb/pvrusb2/pvrusb2-context.c:35
> > Read of size 4 at addr ffff888113aeb0d8 by task kworker/1:1/26
> > 
> > CPU: 1 PID: 26 Comm: kworker/1:1 Not tainted 6.8.0-rc1-syzkaller-00046-gf1a27f081c1f #0
> > Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/25/2024
> > Workqueue: usb_hub_wq hub_event
> > Call Trace:
> >  <TASK>
> >  __dump_stack lib/dump_stack.c:88 [inline]
> >  dump_stack_lvl+0xd9/0x1b0 lib/dump_stack.c:106
> >  print_address_description mm/kasan/report.c:377 [inline]
> >  print_report+0xc4/0x620 mm/kasan/report.c:488
> >  kasan_report+0xda/0x110 mm/kasan/report.c:601
> >  pvr2_context_set_notify+0x2c4/0x310 drivers/media/usb/pvrusb2/pvrusb2-context.c:35
> >  pvr2_context_notify drivers/media/usb/pvrusb2/pvrusb2-context.c:95 [inline]
> >  pvr2_context_disconnect+0x94/0xb0 drivers/media/usb/pvrusb2/pvrusb2-context.c:272
> > 
> > Freed by task 906:
> > kasan_save_stack+0x33/0x50 mm/kasan/common.c:47
> > kasan_save_track+0x14/0x30 mm/kasan/common.c:68
> > kasan_save_free_info+0x3f/0x60 mm/kasan/generic.c:640
> > poison_slab_object mm/kasan/common.c:241 [inline]
> > __kasan_slab_free+0x106/0x1b0 mm/kasan/common.c:257
> > kasan_slab_free include/linux/kasan.h:184 [inline]
> > slab_free_hook mm/slub.c:2121 [inline]
> > slab_free mm/slub.c:4299 [inline]
> > kfree+0x105/0x340 mm/slub.c:4409
> > pvr2_context_check drivers/media/usb/pvrusb2/pvrusb2-context.c:137 [inline]
> > pvr2_context_thread_func+0x69d/0x960 drivers/media/usb/pvrusb2/pvrusb2-context.c:158
> > 
> > [Analyze]
> > Task A set disconnect_flag = !0, which resulted in Task B's condition being met
> > and releasing mp, leading to this issue.
> > 
> > [Fix]
> > Place the disconnect_flag assignment operation after all code in pvr2_context_disconnect()
> > to avoid this issue.
> > 
> > Reported-and-tested-by: syzbot+ce750e124675d4599449@syzkaller.appspotmail.com
> > Signed-off-by: Edward Adam Davis <eadavis@qq.com>
> 
> What commit id does this fix?
e5be15c63804 ("V4L/DVB (7711): pvrusb2: Fix race on module unload")
> 
> And should it be cc: stable as well?
I checked the stable git tree and it introduced e5be15c63804. I think we need to
cc stable.

thanks,
edward
diff mbox series

Patch

diff --git a/drivers/media/usb/pvrusb2/pvrusb2-context.c b/drivers/media/usb/pvrusb2/pvrusb2-context.c
index 1764674de98b..e93bca93ce4c 100644
--- a/drivers/media/usb/pvrusb2/pvrusb2-context.c
+++ b/drivers/media/usb/pvrusb2/pvrusb2-context.c
@@ -267,9 +267,9 @@  static void pvr2_context_exit(struct pvr2_context *mp)
 void pvr2_context_disconnect(struct pvr2_context *mp)
 {
 	pvr2_hdw_disconnect(mp->hdw);
-	mp->disconnect_flag = !0;
 	if (!pvr2_context_shutok())
 		pvr2_context_notify(mp);
+	mp->disconnect_flag = !0;
 }