CVE-2022-50365

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

skbuff: Account for tail adjustment during pull operations

Extending the tail can have some unexpected side effects if a program uses a helper like BPF_FUNC_skb_pull_data to read partial content beyond the head skb headlen when all the skbs in the gso frag_list are linear with no head_frag -

kernel BUG at net/core/skbuff.c:4219! pc : skb_segment+0xcf4/0xd2c lr : skb_segment+0x63c/0xd2c Call trace: skb_segment+0xcf4/0xd2c __udp_gso_segment+0xa4/0x544 udp4_ufo_fragment+0x184/0x1c0 inet_gso_segment+0x16c/0x3a4 skb_mac_gso_segment+0xd4/0x1b0 __skb_gso_segment+0xcc/0x12c udp_rcv_segment+0x54/0x16c udp_queue_rcv_skb+0x78/0x144 udp_unicast_rcv_skb+0x8c/0xa4 __udp4_lib_rcv+0x490/0x68c udp_rcv+0x20/0x30 ip_protocol_deliver_rcu+0x1b0/0x33c ip_local_deliver+0xd8/0x1f0 ip_rcv+0x98/0x1a4 deliver_ptype_list_skb+0x98/0x1ec __netif_receive_skb_core+0x978/0xc60

Fix this by marking these skbs as GSO_DODGY so segmentation can handle the tail updates accordingly.

Affected Software

References

• https://git.kernel.org/stable/c/2d59f0ca153e9573ec4f140988c0ccca0eb4181b
• https://git.kernel.org/stable/c/2d7afdcbc9d32423f177ee12b7c93783aea338fb
• https://git.kernel.org/stable/c/331615d837f4979eb91a336a223a5c7f7886ecd5
• https://git.kernel.org/stable/c/668dc454bcbd1da73605201ff43f988c70848215
• https://git.kernel.org/stable/c/6ac417d71b80e74b002313fcd73f7e9008e8e457
• https://git.kernel.org/stable/c/821be5a5ab09a40ba09cb5ba354f18cf7996fea0
• https://git.kernel.org/stable/c/8fb773eed4909ef5dc1bbeb3629a337d3336df7e
• https://git.kernel.org/stable/c/946dd5dc4fcc4123cdfe3942b20012c4448cf89a
• https://git.kernel.org/stable/c/ff3743d00f41d803e6ab9334962b674f3b7fd0cb