Re: [PATCH] staging: wicl1000: fix dereference after free in wilc_wlan_cleanup()

[Sudip Mukherjee <sudipm.mukherjee@gmail.com>]

On Tue, Sep 22, 2015 at 12:24:50PM +0200, Javier Martinez Canillas wrote:
> The wilc_wlan_cleanup() function iterates over the list of transmission
> buffers freeing all of them and then iterates over the receive buffers
> list to free all of them as well.
> 
> But on the receive loop a pointer to struct txq_entry_t is dereferenced
> instead of the pointer to a struct rxq_entry_t. This not only causes a
> dereference to a pointer already freed but also leaks the memory in the
> struct rxq_entry_t buffer.
> 
> Fixes: c5c77ba18ea6 ("staging: wilc1000: Add SDIO/SPI 802.11 driver")
> Signed-off-by: Javier Martinez Canillas <javier@osg.samsung.com>
> 
> ---
> 
>  drivers/staging/wilc1000/wilc_wlan.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/staging/wilc1000/wilc_wlan.c b/drivers/staging/wilc1000/wilc_wlan.c
> index 4c25179c2fec..c40f143b00b7 100644
> --- a/drivers/staging/wilc1000/wilc_wlan.c
> +++ b/drivers/staging/wilc1000/wilc_wlan.c
> @@ -1746,7 +1746,7 @@ static void wilc_wlan_cleanup(void)
>  		if (rqe == NULL)
>  			break;
>  #ifdef MEMORY_DYNAMIC
> -		kfree(tqe->buffer);
> +		kfree(rqe->buffer);
>  #endif
MEMORY_DYNAMIC is only used here and no where else. And buffer was
allocated in the else part of #ifdef MEMORY_STATIC.
So you should really be using #ifndef MEMORY_STATIC here instead of
#ifdef MEMORY_DYNAMIC otherwise memory leak will still remain.

regards
sudip