From c7ead9704249d57d4693a04697e3bbd285138fa9 Mon Sep 17 00:00:00 2001 From: Guanglei Zhu Date: Fri, 11 Sep 2026 10:17:34 +0800 Subject: [PATCH] net: wwan: t7xx: validate the netif index in t7xx_ccmni_recv_skb() The netif index carried in the DPMAIF PIT header is five bits wide, but ccmni_inst[] only has room for NIC_DEV_MAX (21) entries. t7xx_ccmni_recv_skb() indexes the array without a bounds check, so indexes 21 to 31 read past it. The out-of-bounds value lands in the callback table that follows the array, which is never NULL, so the existing !ccmni check does not catch it and the driver dereferences whatever sits there as a struct t7xx_ccmni. Drop the skb when the index is out of range. Fixes: 05d19bf500f8 ("net: wwan: t7xx: Add WWAN network interface") Cc: stable@vger.kernel.org Signed-off-by: Guanglei Zhu Verified in a QEMU guest with a fault injector setting the netif index to 25: the unpatched driver reads a value past ccmni_inst[], which lands in the callback table, and dereferences it far enough to queue the skb. With this check the packet is dropped. Well-formed traffic on index 0 is unaffected. Changes in v2: none. Link: https://patch.msgid.link/20260911021734.1396599-3-zhugl3@xiaopeng.com Signed-off-by: Jakub Kicinski --- drivers/net/wwan/t7xx/t7xx_netdev.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/drivers/net/wwan/t7xx/t7xx_netdev.c b/drivers/net/wwan/t7xx/t7xx_netdev.c index fc0a7cb181df..8f32c2d26931 100644 --- a/drivers/net/wwan/t7xx/t7xx_netdev.c +++ b/drivers/net/wwan/t7xx/t7xx_netdev.c @@ -420,6 +420,10 @@ static void t7xx_ccmni_recv_skb(struct t7xx_ccmni_ctrl *ccmni_ctlb, struct sk_bu skb_cb = T7XX_SKB_CB(skb); netif_id = skb_cb->netif_idx; + if (netif_id >= NIC_DEV_MAX) { + dev_kfree_skb(skb); + return; + } ccmni = READ_ONCE(ccmni_ctlb->ccmni_inst[netif_id]); if (!ccmni) { dev_kfree_skb(skb);