diff options
| author | Ian Abbott <abbotti@mev.co.uk> | 2019-04-15 12:43:02 +0100 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2019-04-27 09:34:01 +0200 |
| commit | 0241c6f9f56cafbcb3087d680efe454acdf658cd (patch) | |
| tree | ac3e26c264a1300d5a0782dd5ad312066557341a | |
| parent | 9f2bf97bb6c36793bc782fd71098e4ebfff9723d (diff) | |
staging: comedi: ni_usb6501: Fix possible double-free of ->usb_rx_buf
commit af4b54a2e5ba18259ff9aac445bf546dd60d037e upstream.
`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>
| -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 83a7eb894c86..6778e2b73667 100644 --- a/drivers/staging/comedi/drivers/ni_usb6501.c +++ b/drivers/staging/comedi/drivers/ni_usb6501.c @@ -472,10 +472,8 @@ static int ni6501_alloc_usb_buffers(struct comedi_device *dev) size = le16_to_cpu(devpriv->ep_tx->wMaxPacketSize); 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; } |