Re: [Qemu-devel] [PATCH v3] net: ne2000: fix bounds check in ioport operations

[Jason Wang <jasowang@redhat.com>]

On 12/31/2015 07:35 PM, P J P wrote:
> From: Prasad J Pandit <pjp@fedoraproject.org>
>
> While doing ioport r/w operations, ne2000 device emulation suffers
> from OOB r/w errors. Update respective array bounds check to avoid
> OOB access.
>
> Reported-by: Ling Liu <liuling-it@360.cn>
> Signed-off-by: Prasad J Pandit <pjp@fedoraproject.org>
> ---
>  hw/net/ne2000.c | 10 ++++++----
>  1 file changed, 6 insertions(+), 4 deletions(-)
>
> Updated as per review in
>   -> https://lists.gnu.org/archive/html/qemu-devel/2015-12/msg04863.html
>
> diff --git a/hw/net/ne2000.c b/hw/net/ne2000.c
> index 010f9ef..9dd0c67 100644
> --- a/hw/net/ne2000.c
> +++ b/hw/net/ne2000.c
> @@ -467,8 +467,9 @@ static inline void ne2000_mem_writel(NE2000State *s, uint32_t addr,
>                                       uint32_t val)
>  {
>      addr &= ~1; /* XXX: check exact behaviour if not even */
> -    if (addr < 32 ||
> -        (addr >= NE2000_PMEM_START && addr < NE2000_MEM_SIZE)) {
> +    if (addr < 32
> +        || (addr >= NE2000_PMEM_START
> +            && addr + sizeof(uint32_t) - 1 < NE2000_MEM_SIZE)) {
>          stl_le_p(s->mem + addr, val);
>      }
>  }
> @@ -497,8 +498,9 @@ static inline uint32_t ne2000_mem_readw(NE2000State *s, uint32_t addr)
>  static inline uint32_t ne2000_mem_readl(NE2000State *s, uint32_t addr)
>  {
>      addr &= ~1; /* XXX: check exact behaviour if not even */
> -    if (addr < 32 ||
> -        (addr >= NE2000_PMEM_START && addr < NE2000_MEM_SIZE)) {
> +    if (addr < 32
> +        || (addr >= NE2000_PMEM_START
> +            && addr + sizeof(uint32_t) - 1 < NE2000_MEM_SIZE)) {
>          return ldl_le_p(s->mem + addr);
>      } else {
>          return 0xffffffff;

Applied to my -net with minor tweaks:

Change "addr + sizeof(uint32_t) - 1 < NE2000_MEM_SIZE" to "addr +
sizeof(uint32_t) <= NE2000_MEM_SIZE".

Thanks