net: mana: Check if netdev/napi_alloc_frag returns single page

netdev/napi_alloc_frag() may fall back to single page which is smaller
than the requested size.
Add error checking to avoid memory overwritten.

Signed-off-by: Haiyang Zhang <haiyangz@microsoft.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

diff --git a/drivers/net/ethernet/microsoft/mana/mana_en.c b/drivers/net/ethernet/microsoft/mana/mana_en.c
index db2887e..06d6292 100644 (file)
--- a/drivers/net/ethernet/microsoft/mana/mana_en.c
+++ b/drivers/net/ethernet/microsoft/mana/mana_en.c
@@ -553,6 +553,14 @@ static int mana_pre_alloc_rxbufs(struct mana_port_context *mpc, int new_mtu)
                        va = netdev_alloc_frag(mpc->rxbpre_alloc_size);
                        if (!va)
                                goto error;
+
+                       page = virt_to_head_page(va);
+                       /* Check if the frag falls back to single page */
+                       if (compound_order(page) <
+                           get_order(mpc->rxbpre_alloc_size)) {
+                               put_page(page);
+                               goto error;
+                       }
                } else {
                        page = dev_alloc_page();
                        if (!page)
@@ -1504,6 +1512,13 @@ static void *mana_get_rxfrag(struct mana_rxq *rxq, struct device *dev,
 
                if (!va)
                        return NULL;
+
+               page = virt_to_head_page(va);
+               /* Check if the frag falls back to single page */
+               if (compound_order(page) < get_order(rxq->alloc_size)) {
+                       put_page(page);
+                       return NULL;
+               }
        } else {
                page = dev_alloc_page();
                if (!page)