Improper Input Validation Affecting bpftool package, versions <0:4.18.0-553.8.1.el8_10

Note: Versions mentioned in the description apply only to the upstream bpftool package and not the bpftool package as distributed by Centos. See How to fix? for Centos:8 relevant fixed versions and status.

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

tipc: fix kernel warning when sending SYN message

When sending a SYN message, this kernel stack trace is observed:

... [ 13.396352] RIP: 0010:_copy_from_iter+0xb4/0x550 ... [ 13.398494] Call Trace: [ 13.398630] <TASK> [ 13.398630] ? __alloc_skb+0xed/0x1a0 [ 13.398630] tipc_msg_build+0x12c/0x670 [tipc] [ 13.398630] ? shmem_add_to_page_cache.isra.71+0x151/0x290 [ 13.398630] __tipc_sendmsg+0x2d1/0x710 [tipc] [ 13.398630] ? tipc_connect+0x1d9/0x230 [tipc] [ 13.398630] ? __local_bh_enable_ip+0x37/0x80 [ 13.398630] tipc_connect+0x1d9/0x230 [tipc] [ 13.398630] ? __sys_connect+0x9f/0xd0 [ 13.398630] __sys_connect+0x9f/0xd0 [ 13.398630] ? preempt_count_add+0x4d/0xa0 [ 13.398630] ? fpregs_assert_state_consistent+0x22/0x50 [ 13.398630] __x64_sys_connect+0x16/0x20 [ 13.398630] do_syscall_64+0x42/0x90 [ 13.398630] entry_SYSCALL_64_after_hwframe+0x63/0xcd

It is because commit a41dad905e5a ("iov_iter: saner checks for attempt to copy to/from iterator") has introduced sanity check for copying from/to iov iterator. Lacking of copy direction from the iterator viewpoint would lead to kernel stack trace like above.

This commit fixes this issue by initializing the iov iterator with the correct copy direction when sending SYN or ACK without data.

• https://access.redhat.com/security/cve/CVE-2023-52700
• https://git.kernel.org/stable/c/11a4d6f67cf55883dc78e31c247d1903ed7feccc
• https://git.kernel.org/stable/c/54b6082aec178f16ad6d193b4ecdc9c4823d9a32