On Tue, Dec 28, 2021 at 08:47:15AM +0100, Christophe JAILLET wrote: > Hi, > > (2nd try - text only format - sorry for the noise) > > > first try to use syzbot. I hope I do it right. > Discussion about the syz report can be found at > https://lore.kernel.org/linux-kernel/0000000000007d25ff059457342d@xxxxxxxxxx/ > > This patch only test if alauda_get_media_status() (and its embedded > usb_stor_ctrl_transfer()) before using the data. > In case of error, it returns USB_STOR_TRANSPORT_ERROR as done elsewhere. > > #syz test: git://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git > master > > CJ > > diff --git a/drivers/usb/storage/alauda.c b/drivers/usb/storage/alauda.c > index 20b857e97e60..6c486d964911 100644 > --- a/drivers/usb/storage/alauda.c > +++ b/drivers/usb/storage/alauda.c > @@ -318,7 +318,8 @@ static int alauda_get_media_status(struct us_data *us, unsigned char *data) > rc = usb_stor_ctrl_transfer(us, us->recv_ctrl_pipe, > command, 0xc0, 0, 1, data, 2); > > - usb_stor_dbg(us, "Media status %02X %02X\n", data[0], data[1]); > + if (rc == USB_STOR_XFER_GOOD) > + usb_stor_dbg(us, "Media status %02X %02X\n", data[0], data[1]); Instead of adding this test, you could initialize data[0] and data[1] to zero before the call to usb_stor_ctrl_transfer. > > return rc; > } > @@ -453,8 +454,11 @@ static int alauda_check_media(struct us_data *us) > { > struct alauda_info *info = (struct alauda_info *) us->extra; > unsigned char status[2]; > + int rc; > > - alauda_get_media_status(us, status); > + rc = alauda_get_media_status(us, status); > + if (rc != USB_STOR_TRANSPORT_GOOD) > + return USB_STOR_TRANSPORT_ERROR; > > /* Check for no media or door open */ > if ((status[0] & 0x80) || ((status[0] & 0x1F) == 0x10) In general this looks fine. Let us know when you are ready to submit the patch. Alan Stern
