This is a note to let you know that I've just added the patch titled staging: gdm724x: check for overflow in gdm_lte_netif_rx() to the 5.13-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: staging-gdm724x-check-for-overflow-in-gdm_lte_netif_.patch and it can be found in the queue-5.13 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. commit 2e518e5aa579aff967acb2a9dba8e1e0f1fc7db1 Author: Dan Carpenter <dan.carpenter@xxxxxxxxxx> Date: Mon Jun 14 12:58:36 2021 +0300 staging: gdm724x: check for overflow in gdm_lte_netif_rx() [ Upstream commit 7002b526f4ff1f6da34356e67085caafa6be383a ] This code assumes that "len" is at least 62 bytes, but we need a check to prevent a read overflow. Fixes: 61e121047645 ("staging: gdm7240: adding LTE USB driver") Signed-off-by: Dan Carpenter <dan.carpenter@xxxxxxxxxx> Link: https://lore.kernel.org/r/YMcoTPsCYlhh2TQo@mwanda Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> diff --git a/drivers/staging/gdm724x/gdm_lte.c b/drivers/staging/gdm724x/gdm_lte.c index a41af7aa74ec..bd5f87433404 100644 --- a/drivers/staging/gdm724x/gdm_lte.c +++ b/drivers/staging/gdm724x/gdm_lte.c @@ -611,10 +611,12 @@ static void gdm_lte_netif_rx(struct net_device *dev, char *buf, * bytes (99,130,83,99 dec) */ } __packed; - void *addr = buf + sizeof(struct iphdr) + - sizeof(struct udphdr) + - offsetof(struct dhcp_packet, chaddr); - ether_addr_copy(nic->dest_mac_addr, addr); + int offset = sizeof(struct iphdr) + + sizeof(struct udphdr) + + offsetof(struct dhcp_packet, chaddr); + if (offset + ETH_ALEN > len) + return; + ether_addr_copy(nic->dest_mac_addr, buf + offset); } }