On 4/15/19 1:12 PM, Oliver Neukum wrote: > On Fr, 2019-04-12 at 04:46 -0700, syzbot wrote: >> Hello, >> >> syzbot found the following crash on: >> >> HEAD commit: 9a33b369 usb-fuzzer: main usb gadget fuzzer driver >> git tree: https://github.com/google/kasan/tree/usb-fuzzer >> console output: https://syzkaller.appspot.com/x/log.txt?x=1643974b200000 >> kernel config: https://syzkaller.appspot.com/x/.config?x=23e37f59d94ddd15 >> dashboard link: https://syzkaller.appspot.com/bug?extid=26ec41e9f788b3eba396 >> compiler: gcc (GCC) 9.0.0 20181231 (experimental) >> syz repro: https://syzkaller.appspot.com/x/repro.syz?x=12f5efa7200000 >> C reproducer: https://syzkaller.appspot.com/x/repro.c?x=1395a0f3200000 >> >> IMPORTANT: if you fix the bug, please add the following tag to the commit: >> Reported-by: syzbot+26ec41e9f788b3eba396@xxxxxxxxxxxxxxxxxxxxxxxxx >> >> dvb-usb: schedule remote query interval to 150 msecs. >> dw2102: su3000_power_ctrl: 0, initialized 1 >> dvb-usb: TeVii S421 PCI successfully initialized and connected. >> usb 1-1: USB disconnect, device number 2 > > Hi, > > proposed fix. If nobody objects, I will submit it. > > Regards > Oliver > > From d6097d205ac61745334b79639d3b8b910ae66c71 Mon Sep 17 00:00:00 2001 > From: Oliver Neukum <oneukum@xxxxxxxx> > Date: Mon, 15 Apr 2019 13:06:01 +0200 > Subject: [PATCH] dvb: usb: fix use after free in dvb_usb_device_exit > > dvb_usb_device_exit() frees and uses teh device name in that order > Fix by storing the name in a buffer before freeing it > > Signed-off-by: Oliver Neukum <oneukum@xxxxxxxx> > Reported-by: syzbot+26ec41e9f788b3eba396@xxxxxxxxxxxxxxxxxxxxxxxxx > --- > drivers/media/usb/dvb-usb/dvb-usb-init.c | 7 ++++++- > 1 file changed, 6 insertions(+), 1 deletion(-) > > diff --git a/drivers/media/usb/dvb-usb/dvb-usb-init.c b/drivers/media/usb/dvb-usb/dvb-usb-init.c > index 99951e02a880..2e1670cc3903 100644 > --- a/drivers/media/usb/dvb-usb/dvb-usb-init.c > +++ b/drivers/media/usb/dvb-usb/dvb-usb-init.c > @@ -288,13 +288,18 @@ void dvb_usb_device_exit(struct usb_interface *intf) > { > struct dvb_usb_device *d = usb_get_intfdata(intf); > const char *name = "generic DVB-USB module"; > + char identifier[40]; > > usb_set_intfdata(intf, NULL); > if (d != NULL && d->desc != NULL) { > name = d->desc->name; > + memcpy(identifier, name, 39); > + identifier[39] = NULL; > dvb_usb_exit(d); Why not just move this to after the info()? You'll need to repeat the 'if' in that case, but that way there is no need to memcpy anything. Regards, Hans > + } else { > + memcpy(identifier, name, 39); > } > - info("%s successfully deinitialized and disconnected.", name); > + info("%s successfully deinitialized and disconnected.", identifier); > > } > EXPORT_SYMBOL(dvb_usb_device_exit); >
