CVE-2022-49973

In the Linux kernel, the following vulnerability has been resolved:<br /> <br /> skmsg: Fix wrong last sg check in sk_msg_recvmsg()<br /> <br /> Fix one kernel NULL pointer dereference as below:<br /> <br /> [ 224.462334] Call Trace:<br /> [ 224.462394] __tcp_bpf_recvmsg+0xd3/0x380<br /> [ 224.462441] ? sock_has_perm+0x78/0xa0<br /> [ 224.462463] tcp_bpf_recvmsg+0x12e/0x220<br /> [ 224.462494] inet_recvmsg+0x5b/0xd0<br /> [ 224.462534] __sys_recvfrom+0xc8/0x130<br /> [ 224.462574] ? syscall_trace_enter+0x1df/0x2e0<br /> [ 224.462606] ? __do_page_fault+0x2de/0x500<br /> [ 224.462635] __x64_sys_recvfrom+0x24/0x30<br /> [ 224.462660] do_syscall_64+0x5d/0x1d0<br /> [ 224.462709] entry_SYSCALL_64_after_hwframe+0x65/0xca<br /> <br /> In commit 9974d37ea75f ("skmsg: Fix invalid last sg check in<br /> sk_msg_recvmsg()"), we change last sg check to sg_is_last(),<br /> but in sockmap redirection case (without stream_parser/stream_verdict/<br /> skb_verdict), we did not mark the end of the scatterlist. Check the<br /> sk_msg_alloc, sk_msg_page_add, and bpf_msg_push_data functions, they all<br /> do not mark the end of sg. They are expected to use sg.end for end<br /> judgment. So the judgment of &amp;#39;(i != msg_rx-&gt;sg.end)&amp;#39; is added back here.