wifi: mwifiex: Fix oob check condition in mwifiex_process_rx_packet

Only skip the code path trying to access the rfc1042 headers when the
buffer is too small, so the driver can still process packets without
rfc1042 headers.

Fixes: 119585281617 ("wifi: mwifiex: Fix OOB and integer underflow when rx packets")
Signed-off-by: Pin-yen Lin <treapking@chromium.org>
Acked-by: Brian Norris <briannorris@chromium.org>
Reviewed-by: Matthew Wang <matthewmwang@chromium.org>
Signed-off-by: Kalle Valo <kvalo@kernel.org>
Link: https://lore.kernel.org/r/20230908104308.1546501-1-treapking@chromium.org

diff --git a/drivers/net/wireless/marvell/mwifiex/sta_rx.c b/drivers/net/wireless/marvell/mwifiex/sta_rx.c
index 65420ad6741679ec7c2cd8d24004c1ab1f8334db..257737137cd70fb1ed28737db7acafd364378464 100644 (file)
--- a/drivers/net/wireless/marvell/mwifiex/sta_rx.c
+++ b/drivers/net/wireless/marvell/mwifiex/sta_rx.c
@@ -86,7 +86,8 @@ int mwifiex_process_rx_packet(struct mwifiex_private *priv,
        rx_pkt_len = le16_to_cpu(local_rx_pd->rx_pkt_length);
        rx_pkt_hdr = (void *)local_rx_pd + rx_pkt_off;
 
-       if (sizeof(*rx_pkt_hdr) + rx_pkt_off > skb->len) {
+       if (sizeof(rx_pkt_hdr->eth803_hdr) + sizeof(rfc1042_header) +
+           rx_pkt_off > skb->len) {
                mwifiex_dbg(priv->adapter, ERROR,
                            "wrong rx packet offset: len=%d, rx_pkt_off=%d\n",
                            skb->len, rx_pkt_off);
@@ -95,12 +96,13 @@ int mwifiex_process_rx_packet(struct mwifiex_private *priv,
                return -1;
        }
 
-       if ((!memcmp(&rx_pkt_hdr->rfc1042_hdr, bridge_tunnel_header,
-                    sizeof(bridge_tunnel_header))) ||
-           (!memcmp(&rx_pkt_hdr->rfc1042_hdr, rfc1042_header,
-                    sizeof(rfc1042_header)) &&
-            ntohs(rx_pkt_hdr->rfc1042_hdr.snap_type) != ETH_P_AARP &&
-            ntohs(rx_pkt_hdr->rfc1042_hdr.snap_type) != ETH_P_IPX)) {
+       if (sizeof(*rx_pkt_hdr) + rx_pkt_off <= skb->len &&
+           ((!memcmp(&rx_pkt_hdr->rfc1042_hdr, bridge_tunnel_header,
+                     sizeof(bridge_tunnel_header))) ||
+            (!memcmp(&rx_pkt_hdr->rfc1042_hdr, rfc1042_header,
+                     sizeof(rfc1042_header)) &&
+             ntohs(rx_pkt_hdr->rfc1042_hdr.snap_type) != ETH_P_AARP &&
+             ntohs(rx_pkt_hdr->rfc1042_hdr.snap_type) != ETH_P_IPX))) {
                /*
                 *  Replace the 803 header and rfc1042 header (llc/snap) with an
                 *    EthernetII header, keep the src/dst and snap_type