From: Lu Wei luwei32@huawei.com
[ Upstream commit 81225b2ea161af48e093f58e8dfee6d705b16af4 ]
If an AF_PACKET socket is used to send packets through ipvlan and the default xmit function of the AF_PACKET socket is changed from dev_queue_xmit() to packet_direct_xmit() via setsockopt() with the option name of PACKET_QDISC_BYPASS, the skb->mac_header may not be reset and remains as the initial value of 65535, this may trigger slab-out-of-bounds bugs as following:
================================================================= UG: KASAN: slab-out-of-bounds in ipvlan_xmit_mode_l2+0xdb/0x330 [ipvlan] PU: 2 PID: 1768 Comm: raw_send Kdump: loaded Not tainted 6.0.0-rc4+ #6 ardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.14.0-1.fc33 all Trace: print_address_description.constprop.0+0x1d/0x160 print_report.cold+0x4f/0x112 kasan_report+0xa3/0x130 ipvlan_xmit_mode_l2+0xdb/0x330 [ipvlan] ipvlan_start_xmit+0x29/0xa0 [ipvlan] __dev_direct_xmit+0x2e2/0x380 packet_direct_xmit+0x22/0x60 packet_snd+0x7c9/0xc40 sock_sendmsg+0x9a/0xa0 __sys_sendto+0x18a/0x230 __x64_sys_sendto+0x74/0x90 do_syscall_64+0x3b/0x90 entry_SYSCALL_64_after_hwframe+0x63/0xcd
The root cause is: 1. packet_snd() only reset skb->mac_header when sock->type is SOCK_RAW and skb->protocol is not specified as in packet_parse_headers()
2. packet_direct_xmit() doesn't reset skb->mac_header as dev_queue_xmit()
In this case, skb->mac_header is 65535 when ipvlan_xmit_mode_l2() is called. So when ipvlan_xmit_mode_l2() gets mac header with eth_hdr() which use "skb->head + skb->mac_header", out-of-bound access occurs.
This patch replaces eth_hdr() with skb_eth_hdr() in ipvlan_xmit_mode_l2() and reset mac header in multicast to solve this out-of-bound bug.
Fixes: 2ad7bf363841 ("ipvlan: Initial check-in of the IPVLAN driver.") Signed-off-by: Lu Wei luwei32@huawei.com Reviewed-by: Eric Dumazet edumazet@google.com Signed-off-by: David S. Miller davem@davemloft.net Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/net/ipvlan/ipvlan_core.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-)
diff --git a/drivers/net/ipvlan/ipvlan_core.c b/drivers/net/ipvlan/ipvlan_core.c index 6cd50106e611..d7fb6302d699 100644 --- a/drivers/net/ipvlan/ipvlan_core.c +++ b/drivers/net/ipvlan/ipvlan_core.c @@ -496,7 +496,6 @@ static int ipvlan_process_v6_outbound(struct sk_buff *skb)
static int ipvlan_process_outbound(struct sk_buff *skb) { - struct ethhdr *ethh = eth_hdr(skb); int ret = NET_XMIT_DROP;
/* The ipvlan is a pseudo-L2 device, so the packets that we receive @@ -506,6 +505,8 @@ static int ipvlan_process_outbound(struct sk_buff *skb) if (skb_mac_header_was_set(skb)) { /* In this mode we dont care about * multicast and broadcast traffic */ + struct ethhdr *ethh = eth_hdr(skb); + if (is_multicast_ether_addr(ethh->h_dest)) { pr_debug_ratelimited( "Dropped {multi|broad}cast of type=[%x]\n", @@ -590,7 +591,7 @@ static int ipvlan_xmit_mode_l3(struct sk_buff *skb, struct net_device *dev) static int ipvlan_xmit_mode_l2(struct sk_buff *skb, struct net_device *dev) { const struct ipvl_dev *ipvlan = netdev_priv(dev); - struct ethhdr *eth = eth_hdr(skb); + struct ethhdr *eth = skb_eth_hdr(skb); struct ipvl_addr *addr; void *lyr3h; int addr_type; @@ -620,6 +621,7 @@ static int ipvlan_xmit_mode_l2(struct sk_buff *skb, struct net_device *dev) return dev_forward_skb(ipvlan->phy_dev, skb);
} else if (is_multicast_ether_addr(eth->h_dest)) { + skb_reset_mac_header(skb); ipvlan_skb_crossing_ns(skb, NULL); ipvlan_multicast_enqueue(ipvlan->port, skb, true); return NET_XMIT_SUCCESS;