diff options
| author |   Ian Abbott <abbotti@mev.co.uk> | 2019-04-15 12:43:02 +0100 |
|---|---|---|
| committer |   Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2019-04-17 11:59:24 +0200 |
| commit | af4b54a2e5ba18259ff9aac445bf546dd60d037e (patch) | |
| tree | bfe50b627896c0c1943ff1aabd1e412e982a0430 /drivers/staging | |
| parent | staging: comedi: ni_usb6501: Fix use of uninitialized mutex (diff) | |
| download | linux-dev-af4b54a2e5ba18259ff9aac445bf546dd60d037e.tar.xz linux-dev-af4b54a2e5ba18259ff9aac445bf546dd60d037e.zip | |
staging: comedi: ni_usb6501: Fix possible double-free of ->usb_rx_buf
`ni6501_alloc_usb_buffers()` is called from `ni6501_auto_attach()` to
allocate RX and TX buffers for USB transfers. It allocates
`devpriv->usb_rx_buf` followed by `devpriv->usb_tx_buf`. If the
allocation of `devpriv->usb_tx_buf` fails, it frees
`devpriv->usb_rx_buf`, leaving the pointer set dangling, and returns an
error. Later, `ni6501_detach()` will be called from the core comedi
module code to clean up. `ni6501_detach()` also frees both
`devpriv->usb_rx_buf` and `devpriv->usb_tx_buf`, but
`devpriv->usb_rx_buf` may have already beed freed, leading to a
double-free error. Fix it bu removing the call to
`kfree(devpriv->usb_rx_buf)` from `ni6501_alloc_usb_buffers()`, relying
on `ni6501_detach()` to free the memory.
Signed-off-by: Ian Abbott <abbotti@mev.co.uk>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/staging')
| -rw-r--r-- | drivers/staging/comedi/drivers/ni_usb6501.c | 4 |
1 files changed, 1 insertions, 3 deletions
diff --git a/drivers/staging/comedi/drivers/ni_usb6501.c b/drivers/staging/comedi/drivers/ni_usb6501.c index ed5e42655821..1bb1cb651349 100644 --- a/drivers/staging/comedi/drivers/ni_usb6501.c +++ b/drivers/staging/comedi/drivers/ni_usb6501.c @@ -463,10 +463,8 @@ static int ni6501_alloc_usb_buffers(struct comedi_device *dev) size = usb_endpoint_maxp(devpriv->ep_tx); devpriv->usb_tx_buf = kzalloc(size, GFP_KERNEL); - if (!devpriv->usb_tx_buf) { - kfree(devpriv->usb_rx_buf); + if (!devpriv->usb_tx_buf) return -ENOMEM; - } return 0; } |