net: ne2000: fix bounds check in ioport operations

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: NLing Liu <liuling-it@360.cn>
Cc: qemu-stable@nongnu.org
Signed-off-by: NPrasad J Pandit <pjp@fedoraproject.org>
Signed-off-by: NJason Wang <jasowang@redhat.com>

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) <= 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) <= NE2000_MEM_SIZE)) {
         return ldl_le_p(s->mem + addr);
     } else {
         return 0xffffffff;