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usb: idmouse: fix an uninit-value in idmouse_open

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In idmouse_create_image, if any ftip_command fails, it will
go to the reset label. However, this leads to the data in
bulk_in_buffer[HEADER..IMGSIZE] uninitialized. And the check
for valid image incurs an uninitialized dereference.

Fix this by moving the check before reset label since this
check only be valid if the data after bulk_in_buffer[HEADER]
has concrete data.

Note that this is found by KMSAN, so only kernel compilation
is tested.

Reported-by: syzbot+79832d33eb89fb3cd092@syzkaller.appspotmail.com
Signed-off-by: Dongliang Mu <mudongliangabcd@gmail.com>
Link: https://lore.kernel.org/r/20220922134847.1101921-1-dzm91@hust.edu.cn
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Dongliang Mu 2022-09-22 21:48:44 +08:00 committed by Greg Kroah-Hartman
parent 411c4597df
commit bce2b05399
1 changed files with 4 additions and 4 deletions
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8
drivers/usb/misc/idmouse.c
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@ -177,10 +177,6 @@ static int idmouse_create_image(struct usb_idmouse *dev)
bytes_read += bulk_read;
}
/* reset the device */
reset:
ftip_command(dev, FTIP_RELEASE, 0, 0);
/* check for valid image */
/* right border should be black (0x00) */
for (bytes_read = sizeof(HEADER)-1 + WIDTH-1; bytes_read < IMGSIZE; bytes_read += WIDTH)
@ -192,6 +188,10 @@ reset:
if (dev->bulk_in_buffer[bytes_read] != 0xFF)
return -EAGAIN;
/* reset the device */
reset:
ftip_command(dev, FTIP_RELEASE, 0, 0);
/* should be IMGSIZE == 65040 */
dev_dbg(&dev->interface->dev, "read %d bytes fingerprint data\n",
bytes_read);