| Message ID | 20240415222041.18537-5-kuniyu@amazon.com (mailing list archive) |
|---|---|
| State | Changes Requested |
| Delegated to: | Netdev Maintainers |
| Headers | show |
| Series | ip: Fix warning in pskb_may_pull_reason() for tunnel devices. | expand |
diff --git a/net/ipv4/ipip.c b/net/ipv4/ipip.c index f2696eaadbe6..3f96364d65fd 100644 --- a/net/ipv4/ipip.c +++ b/net/ipv4/ipip.c @@ -278,11 +278,11 @@ static netdev_tx_t ipip_tunnel_xmit(struct sk_buff *skb, const struct iphdr *tiph = &tunnel->parms.iph; u8 ipproto; - if (!pskb_inet_may_pull(skb)) - goto tx_error; - switch (skb->protocol) { case htons(ETH_P_IP): + if (!pskb_network_may_pull(skb, sizeof(struct iphdr))) + goto tx_error; + ipproto = IPPROTO_IPIP; break; #if IS_ENABLED(CONFIG_MPLS)
syzkaller demonstrated the underflow in pskb_network_may_pull() by sending a crafted VLAN packet over the tunnel device. Let's check skb->protocol before pulling the next header in ipip_tunnel_xmit(). WARNING: CPU: 0 PID: 4406 at include/linux/skbuff.h:2740 pskb_may_pull_reason include/linux/skbuff.h:2740 [inline] WARNING: CPU: 0 PID: 4406 at include/linux/skbuff.h:2740 pskb_may_pull include/linux/skbuff.h:2756 [inline] WARNING: CPU: 0 PID: 4406 at include/linux/skbuff.h:2740 pskb_network_may_pull include/linux/skbuff.h:3077 [inline] WARNING: CPU: 0 PID: 4406 at include/linux/skbuff.h:2740 pskb_inet_may_pull include/net/ip_tunnels.h:361 [inline] WARNING: CPU: 0 PID: 4406 at include/linux/skbuff.h:2740 ipip_tunnel_xmit+0x2d4/0x430 net/ipv4/ipip.c:281 Modules linked in: CPU: 0 PID: 4406 Comm: syz-executor.1 Not tainted 6.8.0-12821-g537c2e91d354-dirty #11 Hardware name: linux,dummy-virt (DT) pstate: 80400005 (Nzcv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--) pc : pskb_may_pull_reason include/linux/skbuff.h:2740 [inline] pc : pskb_may_pull include/linux/skbuff.h:2756 [inline] pc : pskb_network_may_pull include/linux/skbuff.h:3077 [inline] pc : pskb_inet_may_pull include/net/ip_tunnels.h:361 [inline] pc : ipip_tunnel_xmit+0x2d4/0x430 net/ipv4/ipip.c:281 lr : pskb_may_pull_reason include/linux/skbuff.h:2740 [inline] lr : pskb_may_pull include/linux/skbuff.h:2756 [inline] lr : pskb_network_may_pull include/linux/skbuff.h:3077 [inline] lr : pskb_inet_may_pull include/net/ip_tunnels.h:361 [inline] lr : ipip_tunnel_xmit+0x2d4/0x430 net/ipv4/ipip.c:281 sp : ffff8000a82673f0 x29: ffff8000a82673f0 x28: ffff00000fc24140 x27: ffff00006ab166ba x26: 1fffe00001f8483e x25: dfff800000000000 x24: ffff00003b898080 x23: 0000000000000000 x22: 00000000fffffff6 x21: ffff00000fc241f4 x20: ffff00000fc24140 x19: ffff000046206000 x18: ffff800086d72d10 x17: 00000000008a008a x16: 008a4f8900000000 x15: 0000000000000001 x14: 1ffff00011028fbc x13: 0000000000000004 x12: 0000000000000001 x11: 0000000000040000 x10: 0000000000000f68 x9 : ffff80008d25a000 x8 : 0000000000000f69 x7 : ffff8000800477bc x6 : ffff8000800479b8 x5 : ffff0000687ca948 x4 : ffff8000a8267028 x3 : ffff800083f7f890 x2 : 0000000000000001 x1 : 00000000fffffff6 x0 : 0000000000000000 Call trace: pskb_may_pull_reason include/linux/skbuff.h:2740 [inline] pskb_may_pull include/linux/skbuff.h:2756 [inline] pskb_network_may_pull include/linux/skbuff.h:3077 [inline] pskb_inet_may_pull include/net/ip_tunnels.h:361 [inline] ipip_tunnel_xmit+0x2d4/0x430 net/ipv4/ipip.c:281 __netdev_start_xmit include/linux/netdevice.h:4903 [inline] netdev_start_xmit include/linux/netdevice.h:4917 [inline] xmit_one net/core/dev.c:3531 [inline] dev_hard_start_xmit+0x1a0/0x370 net/core/dev.c:3547 __dev_queue_xmit+0x12e8/0x2b04 net/core/dev.c:4335 dev_queue_xmit include/linux/netdevice.h:3091 [inline] packet_xmit+0x6c/0x31c net/packet/af_packet.c:276 packet_snd net/packet/af_packet.c:3081 [inline] packet_sendmsg+0x3818/0x4e50 net/packet/af_packet.c:3113 sock_sendmsg_nosec net/socket.c:730 [inline] __sock_sendmsg net/socket.c:745 [inline] __sys_sendto+0x324/0x470 net/socket.c:2191 __do_sys_sendto net/socket.c:2203 [inline] __se_sys_sendto net/socket.c:2199 [inline] __arm64_sys_sendto+0xd8/0xf8 net/socket.c:2199 __invoke_syscall arch/arm64/kernel/syscall.c:34 [inline] invoke_syscall+0x98/0x2b8 arch/arm64/kernel/syscall.c:48 el0_svc_common+0x130/0x23c arch/arm64/kernel/syscall.c:133 do_el0_svc+0x48/0x58 arch/arm64/kernel/syscall.c:152 el0_svc+0x30/0x78 arch/arm64/kernel/entry-common.c:712 el0t_64_sync_handler+0x84/0xfc arch/arm64/kernel/entry-common.c:730 el0t_64_sync+0x190/0x194 arch/arm64/kernel/entry.S:598 Reported-by: syzkaller <syzkaller@googlegroups.com> Fixes: cb9f1b783850 ("ip: validate header length on virtual device xmit") Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com> --- net/ipv4/ipip.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-)