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authorEric Dumazet <edumazet@google.com>2024-01-12 15:28:16 +0300
committerDavid S. Miller <davem@davemloft.net>2024-01-13 21:06:23 +0300
commit9181d6f8a2bb32d158de66a84164fac05e3ddd18 (patch)
tree68e8e620829366ecd77d1737acf3cd33c941b2c7 /include/linux/virtio_net.h
parente18405d0be8001fa4c5f9e61471f6ffd59c7a1b3 (diff)
downloadlinux-9181d6f8a2bb32d158de66a84164fac05e3ddd18.tar.xz
net: add more sanity check in virtio_net_hdr_to_skb()
syzbot/KMSAN reports access to uninitialized data from gso_features_check() [1] The repro use af_packet, injecting a gso packet and hdrlen == 0. We could fix the issue making gso_features_check() more careful while dealing with NETIF_F_TSO_MANGLEID in fast path. Or we can make sure virtio_net_hdr_to_skb() pulls minimal network and transport headers as intended. Note that for GSO packets coming from untrusted sources, SKB_GSO_DODGY bit forces a proper header validation (and pull) before the packet can hit any device ndo_start_xmit(), thus we do not need a precise disection at virtio_net_hdr_to_skb() stage. [1] BUG: KMSAN: uninit-value in skb_gso_segment include/net/gso.h:83 [inline] BUG: KMSAN: uninit-value in validate_xmit_skb+0x10f2/0x1930 net/core/dev.c:3629 skb_gso_segment include/net/gso.h:83 [inline] validate_xmit_skb+0x10f2/0x1930 net/core/dev.c:3629 __dev_queue_xmit+0x1eac/0x5130 net/core/dev.c:4341 dev_queue_xmit include/linux/netdevice.h:3134 [inline] packet_xmit+0x9c/0x6b0 net/packet/af_packet.c:276 packet_snd net/packet/af_packet.c:3087 [inline] packet_sendmsg+0x8b1d/0x9f30 net/packet/af_packet.c:3119 sock_sendmsg_nosec net/socket.c:730 [inline] __sock_sendmsg net/socket.c:745 [inline] ____sys_sendmsg+0x9c2/0xd60 net/socket.c:2584 ___sys_sendmsg+0x28d/0x3c0 net/socket.c:2638 __sys_sendmsg net/socket.c:2667 [inline] __do_sys_sendmsg net/socket.c:2676 [inline] __se_sys_sendmsg net/socket.c:2674 [inline] __x64_sys_sendmsg+0x307/0x490 net/socket.c:2674 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0x44/0x110 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x63/0x6b Uninit was created at: slab_post_alloc_hook+0x129/0xa70 mm/slab.h:768 slab_alloc_node mm/slub.c:3478 [inline] kmem_cache_alloc_node+0x5e9/0xb10 mm/slub.c:3523 kmalloc_reserve+0x13d/0x4a0 net/core/skbuff.c:560 __alloc_skb+0x318/0x740 net/core/skbuff.c:651 alloc_skb include/linux/skbuff.h:1286 [inline] alloc_skb_with_frags+0xc8/0xbd0 net/core/skbuff.c:6334 sock_alloc_send_pskb+0xa80/0xbf0 net/core/sock.c:2780 packet_alloc_skb net/packet/af_packet.c:2936 [inline] packet_snd net/packet/af_packet.c:3030 [inline] packet_sendmsg+0x70e8/0x9f30 net/packet/af_packet.c:3119 sock_sendmsg_nosec net/socket.c:730 [inline] __sock_sendmsg net/socket.c:745 [inline] ____sys_sendmsg+0x9c2/0xd60 net/socket.c:2584 ___sys_sendmsg+0x28d/0x3c0 net/socket.c:2638 __sys_sendmsg net/socket.c:2667 [inline] __do_sys_sendmsg net/socket.c:2676 [inline] __se_sys_sendmsg net/socket.c:2674 [inline] __x64_sys_sendmsg+0x307/0x490 net/socket.c:2674 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0x44/0x110 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x63/0x6b CPU: 0 PID: 5025 Comm: syz-executor279 Not tainted 6.7.0-rc7-syzkaller-00003-gfbafc3e621c3 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 11/17/2023 Reported-by: syzbot+7f4d0ea3df4d4fa9a65f@syzkaller.appspotmail.com Link: https://lore.kernel.org/netdev/0000000000005abd7b060eb160cd@google.com/ Fixes: 9274124f023b ("net: stricter validation of untrusted gso packets") Signed-off-by: Eric Dumazet <edumazet@google.com> Cc: Willem de Bruijn <willemb@google.com> Reviewed-by: Willem de Bruijn <willemb@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'include/linux/virtio_net.h')
-rw-r--r--include/linux/virtio_net.h9
1 files changed, 7 insertions, 2 deletions
diff --git a/include/linux/virtio_net.h b/include/linux/virtio_net.h
index 27cc1d464321..4dfa9b69ca8d 100644
--- a/include/linux/virtio_net.h
+++ b/include/linux/virtio_net.h
@@ -3,6 +3,8 @@
#define _LINUX_VIRTIO_NET_H
#include <linux/if_vlan.h>
+#include <linux/ip.h>
+#include <linux/ipv6.h>
#include <linux/udp.h>
#include <uapi/linux/tcp.h>
#include <uapi/linux/virtio_net.h>
@@ -49,6 +51,7 @@ static inline int virtio_net_hdr_to_skb(struct sk_buff *skb,
const struct virtio_net_hdr *hdr,
bool little_endian)
{
+ unsigned int nh_min_len = sizeof(struct iphdr);
unsigned int gso_type = 0;
unsigned int thlen = 0;
unsigned int p_off = 0;
@@ -65,6 +68,7 @@ static inline int virtio_net_hdr_to_skb(struct sk_buff *skb,
gso_type = SKB_GSO_TCPV6;
ip_proto = IPPROTO_TCP;
thlen = sizeof(struct tcphdr);
+ nh_min_len = sizeof(struct ipv6hdr);
break;
case VIRTIO_NET_HDR_GSO_UDP:
gso_type = SKB_GSO_UDP;
@@ -100,7 +104,8 @@ static inline int virtio_net_hdr_to_skb(struct sk_buff *skb,
if (!skb_partial_csum_set(skb, start, off))
return -EINVAL;
- p_off = skb_transport_offset(skb) + thlen;
+ nh_min_len = max_t(u32, nh_min_len, skb_transport_offset(skb));
+ p_off = nh_min_len + thlen;
if (!pskb_may_pull(skb, p_off))
return -EINVAL;
} else {
@@ -140,7 +145,7 @@ retry:
skb_set_transport_header(skb, keys.control.thoff);
} else if (gso_type) {
- p_off = thlen;
+ p_off = nh_min_len + thlen;
if (!pskb_may_pull(skb, p_off))
return -EINVAL;
}