On 7/26/19 9:22 PM, Paul Bolle wrote:
Phong Tran schreef op vr 26-07-2019 om 20:35 [+0700]:
This fixed the potential reference NULL pointer while using variable
endpoint.
Reported-by: syzbot+35b1c403a14f5c89e...@syzkaller.appspotmail.com
Tested by syzbot:
https://groups.google.com/d/msg/syzkaller-bugs/wnHG8eRNWEA/Qn2HhjNdBgAJ
Signed-off-by: Phong Tran <tranmanph...@gmail.com>
---
drivers/isdn/gigaset/usb-gigaset.c | 9 +++++++++
This is now drivers/staging/isdn/gigaset/usb-gigaset.c.
this patch was created base on branch
kasan/usb-fuzzer-usb-testing-2019.07.11 [1]
I did not notice about the driver was moved to staging.
1 file changed, 9 insertions(+)
diff --git a/drivers/isdn/gigaset/usb-gigaset.c
b/drivers/isdn/gigaset/usb-gigaset.c
index 1b9b43659bdf..2e011f3db59e 100644
--- a/drivers/isdn/gigaset/usb-gigaset.c
+++ b/drivers/isdn/gigaset/usb-gigaset.c
@@ -703,6 +703,10 @@ static int gigaset_probe(struct usb_interface *interface,
usb_set_intfdata(interface, cs);
endpoint = &hostif->endpoint[0].desc;
+ if (!endpoint) {
+ dev_err(cs->dev, "Couldn't get control endpoint\n");
+ return -ENODEV;
+ }
When can this happen? Is this one of those bugs that one can only trigger with
a specially crafted (evil) usb device?
Yes, in my understanding, this only happens with random test of syzbot.
buffer_size = le16_to_cpu(endpoint->wMaxPacketSize);
ucs->bulk_out_size = buffer_size;
@@ -722,6 +726,11 @@ static int gigaset_probe(struct usb_interface *interface,
}
endpoint = &hostif->endpoint[1].desc;
+ if (!endpoint) {
+ dev_err(cs->dev, "Endpoint not available\n");
+ retval = -ENODEV;
+ goto error;
+ }
ucs->busy = 0;
Please note that I'm very close to getting cut off from the ISDN network, so
the chances of being able to testi this on a live system are getting small.
This bug can be invalid now. Do you agree?
There is an instruction to report invalid bug to syzbot [2].
Thanks,
Paul Bolle
[1]
https://github.com/google/kasan/commits/usb-fuzzer-usb-testing-2019.07.11
[2]
https://github.com/google/syzkaller/blob/master/docs/syzbot.md#communication-with-syzbot
Thanks,
Phong
