CVE-2024-43817

In the Linux kernel, the following vulnerability has been resolved:<br /> <br /> net: missing check virtio<br /> <br /> Two missing check in virtio_net_hdr_to_skb() allowed syzbot<br /> to crash kernels again<br /> <br /> 1. After the skb_segment function the buffer may become non-linear<br /> (nr_frags != 0), but since the SKBTX_SHARED_FRAG flag is not set anywhere<br /> the __skb_linearize function will not be executed, then the buffer will<br /> remain non-linear. Then the condition (offset &gt;= skb_headlen(skb))<br /> becomes true, which causes WARN_ON_ONCE in skb_checksum_help.<br /> <br /> 2. The struct sk_buff and struct virtio_net_hdr members must be<br /> mathematically related.<br /> (gso_size) must be greater than (needed) otherwise WARN_ON_ONCE.<br /> (remainder) must be greater than (needed) otherwise WARN_ON_ONCE.<br /> (remainder) may be 0 if division is without remainder.<br /> <br /> offset+2 (4191) &gt; skb_headlen() (1116)<br /> WARNING: CPU: 1 PID: 5084 at net/core/dev.c:3303 skb_checksum_help+0x5e2/0x740 net/core/dev.c:3303<br /> Modules linked in:<br /> CPU: 1 PID: 5084 Comm: syz-executor336 Not tainted 6.7.0-rc3-syzkaller-00014-gdf60cee26a2e #0<br /> Hardware name: Google Compute Engine/Google Compute Engine, BIOS Google 11/10/2023<br /> RIP: 0010:skb_checksum_help+0x5e2/0x740 net/core/dev.c:3303<br /> Code: 89 e8 83 e0 07 83 c0 03 38 d0 7c 08 84 d2 0f 85 52 01 00 00 44 89 e2 2b 53 74 4c 89 ee 48 c7 c7 40 57 e9 8b e8 af 8f dd f8 90 0b 90 90 e9 87 fe ff ff e8 40 0f 6e f9 e9 4b fa ff ff 48 89 ef<br /> RSP: 0018:ffffc90003a9f338 EFLAGS: 00010286<br /> RAX: 0000000000000000 RBX: ffff888025125780 RCX: ffffffff814db209<br /> RDX: ffff888015393b80 RSI: ffffffff814db216 RDI: 0000000000000001<br /> RBP: ffff8880251257f4 R08: 0000000000000001 R09: 0000000000000000<br /> R10: 0000000000000000 R11: 0000000000000001 R12: 000000000000045c<br /> R13: 000000000000105f R14: ffff8880251257f0 R15: 000000000000105d<br /> FS: 0000555555c24380(0000) GS:ffff8880b9900000(0000) knlGS:0000000000000000<br /> CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033<br /> CR2: 000000002000f000 CR3: 0000000023151000 CR4: 00000000003506f0<br /> DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000<br /> DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400<br /> Call Trace:<br /> <br /> ip_do_fragment+0xa1b/0x18b0 net/ipv4/ip_output.c:777<br /> ip_fragment.constprop.0+0x161/0x230 net/ipv4/ip_output.c:584<br /> ip_finish_output_gso net/ipv4/ip_output.c:286 [inline]<br /> __ip_finish_output net/ipv4/ip_output.c:308 [inline]<br /> __ip_finish_output+0x49c/0x650 net/ipv4/ip_output.c:295<br /> ip_finish_output+0x31/0x310 net/ipv4/ip_output.c:323<br /> NF_HOOK_COND include/linux/netfilter.h:303 [inline]<br /> ip_output+0x13b/0x2a0 net/ipv4/ip_output.c:433<br /> dst_output include/net/dst.h:451 [inline]<br /> ip_local_out+0xaf/0x1a0 net/ipv4/ip_output.c:129<br /> iptunnel_xmit+0x5b4/0x9b0 net/ipv4/ip_tunnel_core.c:82<br /> ipip6_tunnel_xmit net/ipv6/sit.c:1034 [inline]<br /> sit_tunnel_xmit+0xed2/0x28f0 net/ipv6/sit.c:1076<br /> __netdev_start_xmit include/linux/netdevice.h:4940 [inline]<br /> netdev_start_xmit include/linux/netdevice.h:4954 [inline]<br /> xmit_one net/core/dev.c:3545 [inline]<br /> dev_hard_start_xmit+0x13d/0x6d0 net/core/dev.c:3561<br /> __dev_queue_xmit+0x7c1/0x3d60 net/core/dev.c:4346<br /> dev_queue_xmit include/linux/netdevice.h:3134 [inline]<br /> packet_xmit+0x257/0x380 net/packet/af_packet.c:276<br /> packet_snd net/packet/af_packet.c:3087 [inline]<br /> packet_sendmsg+0x24ca/0x5240 net/packet/af_packet.c:3119<br /> sock_sendmsg_nosec net/socket.c:730 [inline]<br /> __sock_sendmsg+0xd5/0x180 net/socket.c:745<br /> __sys_sendto+0x255/0x340 net/socket.c:2190<br /> __do_sys_sendto net/socket.c:2202 [inline]<br /> __se_sys_sendto net/socket.c:2198 [inline]<br /> __x64_sys_sendto+0xe0/0x1b0 net/socket.c:2198<br /> do_syscall_x64 arch/x86/entry/common.c:51 [inline]<br /> do_syscall_64+0x40/0x110 arch/x86/entry/common.c:82<br /> entry_SYSCALL_64_after_hwframe+0x63/0x6b<br /> <br /> Found by Linux Verification Center (linuxtesting.org) with Syzkaller