Commit 600dc405 authored by Greg Kroah-Hartman's avatar Greg Kroah-Hartman Committed by Paolo Abeni
Browse files

net: usb: cdc-phonet: fix skb frags[] overflow in rx_complete() 



A malicious USB device claiming to be a CDC Phonet modem can overflow
the skb_shared_info->frags[] array by sending an unbounded sequence of
full-page bulk transfers.

Drop the skb and increment the length error when the frag limit is
reached.  This matches the same fix that commit f0813bcd ("net:
wwan: t7xx: fix potential skb->frags overflow in RX path") did for the
t7xx driver.

Cc: Andrew Lunn <andrew+netdev@lunn.ch>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Eric Dumazet <edumazet@google.com>
Cc: Jakub Kicinski <kuba@kernel.org>
Cc: Paolo Abeni <pabeni@redhat.com>
Cc: stable <stable@kernel.org>
Assisted-by: gregkh_clanker_t1000
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Link: https://patch.msgid.link/2026041134-dreamboat-buddhism-d1ec@gregkh


Fixes: 87cf6560 ("USB host CDC Phonet network interface driver")
Signed-off-by: default avatarPaolo Abeni <pabeni@redhat.com>
parent ab4b6e4e

drivers/net/usb/cdc-phonet.c

+6 −1
Original line number Diff line number Diff line
@@ -157,11 +157,16 @@ static void rx_complete(struct urb *req) 
						PAGE_SIZE);

				page = NULL;

			}

		} else {

		} else if (skb_shinfo(skb)->nr_frags < MAX_SKB_FRAGS) {

			skb_add_rx_frag(skb, skb_shinfo(skb)->nr_frags,

					page, 0, req->actual_length,

					PAGE_SIZE);

			page = NULL;

		} else {

			dev_kfree_skb_any(skb);

			pnd->rx_skb = NULL;

			skb = NULL;

			dev->stats.rx_length_errors++;

		}

		if (req->actual_length < PAGE_SIZE)

			pnd->rx_skb = NULL; /* Last fragment */