staging: et131x: zero allocation of fbr to prevent random address access

If et131x_rx_dma_memory_alloc() allocates rx_ring->fbr[0] but fails to
allocate rx_ring->fbr[1], this leaves fbr[0]->ring_virtaddr with the
possibility of being accessed in et131x_rx_dma_memory_free() as it
contains a random value, potentially causing an oops.

Fix this by zeroing the fbr memory on allocation. Subsequent frees of
this fbr memory explicitly zeros the ring_virtaddr value.

Reported-by: Tobias Klauser <tklauser@distanz.ch>
Signed-off-by: Mark Einon <mark.einon@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/staging/et131x/et131x.c b/drivers/staging/et131x/et131x.c
index 93afd61..2889f86 100644 (file)
--- a/drivers/staging/et131x/et131x.c
+++ b/drivers/staging/et131x/et131x.c
@@ -2003,10 +2003,10 @@ static int et131x_rx_dma_memory_alloc(struct et131x_adapter *adapter)
        struct fbr_lookup *fbr;
 
        /* Alloc memory for the lookup table */
-       rx_ring->fbr[0] = kmalloc(sizeof(*fbr), GFP_KERNEL);
+       rx_ring->fbr[0] = kzalloc(sizeof(*fbr), GFP_KERNEL);
        if (rx_ring->fbr[0] == NULL)
                return -ENOMEM;
-       rx_ring->fbr[1] = kmalloc(sizeof(*fbr), GFP_KERNEL);
+       rx_ring->fbr[1] = kzalloc(sizeof(*fbr), GFP_KERNEL);
        if (rx_ring->fbr[1] == NULL)
                return -ENOMEM;