openEuler-SA-2024-2493

Synopsis:

kernel security updateSummary:

An update for kernel is now available for openEuler-22.03-LTS-SP4Description:

The Linux Kernel, the operating system core itself.

Security Fix(es):

In the Linux kernel, the following vulnerability has been resolved:

net: missing check virtio

Two missing check in virtio_net_hdr_to_skb() allowed syzbot to crash kernels again

1. After the skb_segment function the buffer may become non-linear (nr_frags != 0), but since the SKBTX_SHARED_FRAG flag is not set anywhere the __skb_linearize function will not be executed, then the buffer will remain non-linear. Then the condition (offset >= skb_headlen(skb)) becomes true, which causes WARN_ON_ONCE in skb_checksum_help.

2. The struct sk_buff and struct virtio_net_hdr members must be mathematically related. (gso_size) must be greater than (needed) otherwise WARN_ON_ONCE. (remainder) must be greater than (needed) otherwise WARN_ON_ONCE. (remainder) may be 0 if division is without remainder.

offset+2 (4191) > skb_headlen() (1116) WARNING: CPU: 1 PID: 5084 at net/core/dev.c:3303 skb_checksum_help+0x5e2/0x740 net/core/dev.c:3303 Modules linked in: CPU: 1 PID: 5084 Comm: syz-executor336 Not tainted 6.7.0-rc3-syzkaller-00014-gdf60cee26a2e #0 Hardware name: Google Compute Engine/Google Compute Engine, BIOS Google 11/10/2023 RIP: 0010:skb_checksum_help+0x5e2/0x740 net/core/dev.c:3303 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 <0f> 0b 90 90 e9 87 fe ff ff e8 40 0f 6e f9 e9 4b fa ff ff 48 89 ef RSP: 0018:ffffc90003a9f338 EFLAGS: 00010286 RAX: 0000000000000000 RBX: ffff888025125780 RCX: ffffffff814db209 RDX: ffff888015393b80 RSI: ffffffff814db216 RDI: 0000000000000001 RBP: ffff8880251257f4 R08: 0000000000000001 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000001 R12: 000000000000045c R13: 000000000000105f R14: ffff8880251257f0 R15: 000000000000105d FS: 0000555555c24380(0000)...