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media: smsusb: better handle optional alignment

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Most Siano devices require an alignment for the response.

Changeset f3be52b0056a ("media: usb: siano: Fix general protection fault in smsusb")
changed the logic with gets such aligment, but it now produces a
sparce warning:

drivers/media/usb/siano/smsusb.c: In function 'smsusb_init_device':
drivers/media/usb/siano/smsusb.c:447:37: warning: 'in_maxp' may be used uninitialized in this function [-Wmaybe-uninitialized]
  447 |   dev->response_alignment = in_maxp - sizeof(struct sms_msg_hdr);
      |                             ~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~

The sparse message itself is bogus, but a broken (or fake) USB
eeprom could produce a negative value for response_alignment.

So, change the code in order to check if the result is not
negative.

Fixes: 31e0456de5 ("media: usb: siano: Fix general protection fault in smsusb")
CC: <stable@vger.kernel.org>
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Mauro Carvalho Chehab 2019-05-24 10:59:43 -04:00 committed by Greg Kroah-Hartman
parent c1a145a3ed
commit a47686636d
1 changed files with 4 additions and 4 deletions
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8
drivers/media/usb/siano/smsusb.c
View file

@ -400,7 +400,7 @@ static int smsusb_init_device(struct usb_interface *intf, int board_id)
struct smsusb_device_t *dev;
void *mdev;
int i, rc;
int in_maxp = 0;
int align = 0;
/* create device object */
dev = kzalloc(sizeof(struct smsusb_device_t), GFP_KERNEL);
@ -418,14 +418,14 @@ static int smsusb_init_device(struct usb_interface *intf, int board_id)
if (desc->bEndpointAddress & USB_DIR_IN) {
dev->in_ep = desc->bEndpointAddress;
in_maxp = usb_endpoint_maxp(desc);
align = usb_endpoint_maxp(desc) - sizeof(struct sms_msg_hdr);
} else {
dev->out_ep = desc->bEndpointAddress;
}
}
pr_debug("in_ep = %02x, out_ep = %02x\n", dev->in_ep, dev->out_ep);
if (!dev->in_ep || !dev->out_ep) { /* Missing endpoints? */
if (!dev->in_ep || !dev->out_ep || align < 0) { /* Missing endpoints? */
smsusb_term_device(intf);
return -ENODEV;
}
@ -444,7 +444,7 @@ static int smsusb_init_device(struct usb_interface *intf, int board_id)
/* fall-thru */
default:
dev->buffer_size = USB2_BUFFER_SIZE;
dev->response_alignment = in_maxp - sizeof(struct sms_msg_hdr);
dev->response_alignment = align;
params.flags |= SMS_DEVICE_FAMILY2;
break;