KASAN: invalid-free in disconnect_rio (2)

[syzbot]

Hello,

syzbot found the following crash on:

HEAD commit: e0bd8d79 usb-fuzzer: main usb gadget fuzzer driver
git tree: https://github.com/google/kasan.git usb-fuzzer
console output: https://syzkaller.appspot.com/x/log.txt?x=17d6f31d600000
kernel config: https://syzkaller.appspot.com/x/.config?x=8847e5384a16f66a
dashboard link: https://syzkaller.appspot.com/bug?extid=745b0dff8028f9488eba
compiler: gcc (GCC) 9.0.0 20181231 (experimental)
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=1009f769600000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=15b1d4b1600000

IMPORTANT: if you fix the bug, please add the following tag to the commit:
Reported-by: syzbot+745b0d...@syzkaller.appspotmail.com

usb 5-1: New USB device found, idVendor=0841, idProduct=0001,
bcdDevice=c5.d0
usb 5-1: New USB device strings: Mfr=0, Product=0, SerialNumber=0
usb 5-1: config 0 descriptor??
rio500 5-1:0.133: Second USB Rio at address 2 refused
rio500: probe of 5-1:0.133 failed with error -16
usb 3-1: USB disconnect, device number 2
==================================================================
BUG: KASAN: double-free or invalid-free in disconnect_rio+0x12b/0x1b0
drivers/usb/misc/rio500.c:525

CPU: 0 PID: 102 Comm: kworker/0:2 Not tainted 5.3.0+ #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS
Google 01/01/2011
Workqueue: usb_hub_wq hub_event
Call Trace:
__dump_stack lib/dump_stack.c:77 [inline]
dump_stack+0xca/0x13e lib/dump_stack.c:113
print_address_description+0x6a/0x32c mm/kasan/report.c:351
kasan_report_invalid_free+0x61/0xa0 mm/kasan/report.c:444
__kasan_slab_free+0x162/0x180 mm/kasan/common.c:434
slab_free_hook mm/slub.c:1423 [inline]
slab_free_freelist_hook mm/slub.c:1474 [inline]
slab_free mm/slub.c:3016 [inline]
kfree+0xe4/0x2f0 mm/slub.c:3957
disconnect_rio+0x12b/0x1b0 drivers/usb/misc/rio500.c:525
usb_unbind_interface+0x1bd/0x8a0 drivers/usb/core/driver.c:423
__device_release_driver drivers/base/dd.c:1134 [inline]
device_release_driver_internal+0x42f/0x500 drivers/base/dd.c:1165
bus_remove_device+0x2dc/0x4a0 drivers/base/bus.c:532
device_del+0x420/0xb10 drivers/base/core.c:2375
usb_disable_device+0x211/0x690 drivers/usb/core/message.c:1237
usb_disconnect+0x284/0x8d0 drivers/usb/core/hub.c:2199
hub_port_connect drivers/usb/core/hub.c:4949 [inline]
hub_port_connect_change drivers/usb/core/hub.c:5213 [inline]
port_event drivers/usb/core/hub.c:5359 [inline]
hub_event+0x1454/0x3640 drivers/usb/core/hub.c:5441
process_one_work+0x92b/0x1530 kernel/workqueue.c:2269
worker_thread+0x96/0xe20 kernel/workqueue.c:2415
kthread+0x318/0x420 kernel/kthread.c:255
ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352

Allocated by task 17:
save_stack+0x1b/0x80 mm/kasan/common.c:69
set_track mm/kasan/common.c:77 [inline]
__kasan_kmalloc mm/kasan/common.c:493 [inline]
__kasan_kmalloc.constprop.0+0xbf/0xd0 mm/kasan/common.c:466
kmalloc include/linux/slab.h:552 [inline]
probe_rio+0x135/0x248 drivers/usb/misc/rio500.c:474
usb_probe_interface+0x305/0x7a0 drivers/usb/core/driver.c:361
really_probe+0x281/0x6d0 drivers/base/dd.c:548
driver_probe_device+0x101/0x1b0 drivers/base/dd.c:721
__device_attach_driver+0x1c2/0x220 drivers/base/dd.c:828
bus_for_each_drv+0x162/0x1e0 drivers/base/bus.c:430
__device_attach+0x217/0x360 drivers/base/dd.c:894
bus_probe_device+0x1e4/0x290 drivers/base/bus.c:490
device_add+0xae6/0x16f0 drivers/base/core.c:2201
usb_set_configuration+0xdf6/0x1670 drivers/usb/core/message.c:2023
generic_probe+0x9d/0xd5 drivers/usb/core/generic.c:210
usb_probe_device+0x99/0x100 drivers/usb/core/driver.c:266
really_probe+0x281/0x6d0 drivers/base/dd.c:548
driver_probe_device+0x101/0x1b0 drivers/base/dd.c:721
__device_attach_driver+0x1c2/0x220 drivers/base/dd.c:828
bus_for_each_drv+0x162/0x1e0 drivers/base/bus.c:430
__device_attach+0x217/0x360 drivers/base/dd.c:894
bus_probe_device+0x1e4/0x290 drivers/base/bus.c:490
device_add+0xae6/0x16f0 drivers/base/core.c:2201
usb_new_device.cold+0x6a4/0xe79 drivers/usb/core/hub.c:2536
hub_port_connect drivers/usb/core/hub.c:5098 [inline]
hub_port_connect_change drivers/usb/core/hub.c:5213 [inline]
port_event drivers/usb/core/hub.c:5359 [inline]
hub_event+0x1b5c/0x3640 drivers/usb/core/hub.c:5441
process_one_work+0x92b/0x1530 kernel/workqueue.c:2269
worker_thread+0x96/0xe20 kernel/workqueue.c:2415
kthread+0x318/0x420 kernel/kthread.c:255
ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352

Freed by task 83:
save_stack+0x1b/0x80 mm/kasan/common.c:69
set_track mm/kasan/common.c:77 [inline]
__kasan_slab_free+0x130/0x180 mm/kasan/common.c:455
slab_free_hook mm/slub.c:1423 [inline]
slab_free_freelist_hook mm/slub.c:1474 [inline]
slab_free mm/slub.c:3016 [inline]
kfree+0xe4/0x2f0 mm/slub.c:3957
disconnect_rio+0x12b/0x1b0 drivers/usb/misc/rio500.c:525
usb_unbind_interface+0x1bd/0x8a0 drivers/usb/core/driver.c:423
__device_release_driver drivers/base/dd.c:1134 [inline]
device_release_driver_internal+0x42f/0x500 drivers/base/dd.c:1165
bus_remove_device+0x2dc/0x4a0 drivers/base/bus.c:532
device_del+0x420/0xb10 drivers/base/core.c:2375
usb_disable_device+0x211/0x690 drivers/usb/core/message.c:1237
usb_disconnect+0x284/0x8d0 drivers/usb/core/hub.c:2199
hub_port_connect drivers/usb/core/hub.c:4949 [inline]
hub_port_connect_change drivers/usb/core/hub.c:5213 [inline]
port_event drivers/usb/core/hub.c:5359 [inline]
hub_event+0x1454/0x3640 drivers/usb/core/hub.c:5441
process_one_work+0x92b/0x1530 kernel/workqueue.c:2269
worker_thread+0x96/0xe20 kernel/workqueue.c:2415
kthread+0x318/0x420 kernel/kthread.c:255
ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352

The buggy address belongs to the object at ffff8881d5498000
which belongs to the cache kmalloc-4k of size 4096
The buggy address is located 0 bytes inside of
4096-byte region [ffff8881d5498000, ffff8881d5499000)
The buggy address belongs to the page:
page:ffffea0007552600 refcount:1 mapcount:0 mapping:ffff8881da00c280
index:0x0 compound_mapcount: 0
flags: 0x200000000010200(slab|head)
raw: 0200000000010200 dead000000000100 dead000000000122 ffff8881da00c280
raw: 0000000000000000 0000000000070007 00000001ffffffff 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
ffff8881d5497f00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
ffff8881d5497f80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
> ffff8881d5498000: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
^
ffff8881d5498080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff8881d5498100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================


---
This bug 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 syzk...@googlegroups.com.

syzbot will keep track of this bug report. See:
https://goo.gl/tpsmEJ#status for how to communicate with syzbot.
syzbot can test patches for this bug, for details see:
https://goo.gl/tpsmEJ#testing-patches

[Andrey Konovalov]

The "USB: rio500: Fix lockdep violation" patch is in the usb-fuzzer's
tree, so this must be a different bug.

[Alan Stern]

On Thu, 19 Sep 2019, syzbot wrote:

> Hello,
>
> syzbot found the following crash on:
>
> HEAD commit: e0bd8d79 usb-fuzzer: main usb gadget fuzzer driver
> git tree: https://github.com/google/kasan.git usb-fuzzer
> console output: https://syzkaller.appspot.com/x/log.txt?x=17d6f31d600000
> kernel config: https://syzkaller.appspot.com/x/.config?x=8847e5384a16f66a
> dashboard link: https://syzkaller.appspot.com/bug?extid=745b0dff8028f9488eba
> compiler: gcc (GCC) 9.0.0 20181231 (experimental)
> syz repro: https://syzkaller.appspot.com/x/repro.syz?x=1009f769600000
> C reproducer: https://syzkaller.appspot.com/x/repro.c?x=15b1d4b1600000
>
> IMPORTANT: if you fix the bug, please add the following tag to the commit:
> Reported-by: syzbot+745b0d...@syzkaller.appspotmail.com
>
> usb 5-1: New USB device found, idVendor=0841, idProduct=0001,
> bcdDevice=c5.d0
> usb 5-1: New USB device strings: Mfr=0, Product=0, SerialNumber=0
> usb 5-1: config 0 descriptor??
> rio500 5-1:0.133: Second USB Rio at address 2 refused
> rio500: probe of 5-1:0.133 failed with error -16
> usb 3-1: USB disconnect, device number 2
> ==================================================================
> BUG: KASAN: double-free or invalid-free in disconnect_rio+0x12b/0x1b0
> drivers/usb/misc/rio500.c:525

All right, that was a pretty dumb mistake on my part. Checking for
whether a device has already been registered needs to be part of the
critical section.

Alan Stern

#syz test: https://github.com/google/kasan.git e0bd8d79

drivers/usb/misc/rio500.c | 34 ++++++++++++++++++----------------
1 file changed, 18 insertions(+), 16 deletions(-)

Index: usb-devel/drivers/usb/misc/rio500.c
===================================================================
--- usb-devel.orig/drivers/usb/misc/rio500.c
+++ usb-devel/drivers/usb/misc/rio500.c
@@ -454,36 +454,35 @@ static int probe_rio(struct usb_interfac
{
struct usb_device *dev = interface_to_usbdev(intf);
struct rio_usb_data *rio = &rio_instance;
- int retval = -ENOMEM;
- char *ibuf, *obuf;
+ int retval;

+ mutex_lock(&rio500_mutex);
if (rio->present) {
dev_info(&intf->dev, "Second USB Rio at address %d refused\n", dev->devnum);
- return -EBUSY;
+ retval = -EBUSY;
+ goto err_present;
}
dev_info(&intf->dev, "USB Rio found at address %d\n", dev->devnum);
+ rio->present = 1;

- obuf = kmalloc(OBUF_SIZE, GFP_KERNEL);
- if (!obuf) {
+ retval = -ENOMEM;
+ rio->obuf = kmalloc(OBUF_SIZE, GFP_KERNEL);
+ if (!rio->obuf) {
dev_err(&dev->dev,
"probe_rio: Not enough memory for the output buffer\n");
goto err_obuf;
}
- dev_dbg(&intf->dev, "obuf address: %p\n", obuf);
+ dev_dbg(&intf->dev, "obuf address: %p\n", rio->obuf);

- ibuf = kmalloc(IBUF_SIZE, GFP_KERNEL);
- if (!ibuf) {
+ rio->ibuf = kmalloc(IBUF_SIZE, GFP_KERNEL);
+ if (!rio->ibuf) {
dev_err(&dev->dev,
"probe_rio: Not enough memory for the input buffer\n");
goto err_ibuf;
}
- dev_dbg(&intf->dev, "ibuf address: %p\n", ibuf);
+ dev_dbg(&intf->dev, "ibuf address: %p\n", rio->ibuf);

- mutex_lock(&rio500_mutex);
rio->rio_dev = dev;
- rio->ibuf = ibuf;
- rio->obuf = obuf;
- rio->present = 1;
mutex_unlock(&rio500_mutex);

retval = usb_register_dev(intf, &usb_rio_class);
@@ -498,11 +497,14 @@ static int probe_rio(struct usb_interfac

err_register:
mutex_lock(&rio500_mutex);
- rio->present = 0;
- mutex_unlock(&rio500_mutex);
+ rio->rio_dev = NULL;
+ kfree(rio->ibuf);
err_ibuf:
- kfree(obuf);
+ kfree(rio->obuf);
err_obuf:
+ rio->present = 0;
+ err_present:
+ mutex_unlock(&rio500_mutex);
return retval;
}

[syzbot]

Hello,

syzbot has tested the proposed patch and the reproducer did not trigger
crash:

Reported-and-tested-by:
syzbot+745b0d...@syzkaller.appspotmail.com

Tested on:

commit: e0bd8d79 usb-fuzzer: main usb gadget fuzzer driver
git tree: https://github.com/google/kasan.git

kernel config: https://syzkaller.appspot.com/x/.config?x=8847e5384a16f66a
dashboard link: https://syzkaller.appspot.com/bug?extid=745b0dff8028f9488eba
compiler: gcc (GCC) 9.0.0 20181231 (experimental)

patch: https://syzkaller.appspot.com/x/patch.diff?x=15b3efc3600000

Note: testing is done by a robot and is best-effort only.

[Andrey Konovalov]

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#syz fix: USB: rio500: Remove Rio 500 kernel driver