rtnetlink: Allocate vfinfo size for VF GUIDs when supported

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

rtnetlink: Allocate vfinfo size for VF GUIDs when supported

Commit 30aad41721e0 ("net/core: Add support for getting VF GUIDs")
added support for getting VF port and node GUIDs in netlink ifinfo
messages, but their size was not taken into consideration in the
function that allocates the netlink message, causing the following
warning when a netlink message is filled with many VF port and node
GUIDs:
# echo 64 > /sys/bus/pci/devices/0000\:08\:00.0/sriov_numvfs
# ip link show dev ib0
RTNETLINK answers: Message too long
Cannot send link get request: Message too long

Kernel warning:

------------[ cut here ]------------
WARNING: CPU: 2 PID: 1930 at net/core/rtnetlink.c:4151 rtnl_getlink+0x586/0x5a0
Modules linked in: xt_conntrack xt_MASQUERADE nfnetlink xt_addrtype iptable_nat nf_nat br_netfilter overlay mlx5_ib macsec mlx5_core tls rpcrdma rdma_ucm ib_uverbs ib_iser libiscsi scsi_transport_iscsi ib_umad rdma_cm iw_cm ib_ipoib fuse ib_cm ib_core
CPU: 2 UID: 0 PID: 1930 Comm: ip Not tainted 6.14.0-rc2+ #1
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS rel-1.13.0-0-gf21b5a4aeb02-prebuilt.qemu.org 04/01/2014
RIP: 0010:rtnl_getlink+0x586/0x5a0
Code: cb 82 e8 3d af 0a 00 4d 85 ff 0f 84 08 ff ff ff 4c 89 ff 41 be ea ff ff ff e8 66 63 5b ff 49 c7 07 80 4f cb 82 e9 36 fc ff ff <0f> 0b e9 16 fe ff ff e8 de a0 56 00 66 66 2e 0f 1f 84 00 00 00 00
RSP: 0018:ffff888113557348 EFLAGS: 00010246
RAX: 00000000ffffffa6 RBX: ffff88817e87aa34 RCX: dffffc0000000000
RDX: 0000000000000003 RSI: 0000000000000000 RDI: ffff88817e87afb8
RBP: 0000000000000009 R08: ffffffff821f44aa R09: 0000000000000000
R10: ffff8881260f79a8 R11: ffff88817e87af00 R12: ffff88817e87aa00
R13: ffffffff8563d300 R14: 00000000ffffffa6 R15: 00000000ffffffff
FS: 00007f63a5dbf280(0000) GS:ffff88881ee00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f63a5ba4493 CR3: 00000001700fe002 CR4: 0000000000772eb0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
PKRU: 55555554
Call Trace:
<TASK>
? __warn+0xa5/0x230
? rtnl_getlink+0x586/0x5a0
? report_bug+0x22d/0x240
? handle_bug+0x53/0xa0
? exc_invalid_op+0x14/0x50
? asm_exc_invalid_op+0x16/0x20
? skb_trim+0x6a/0x80
? rtnl_getlink+0x586/0x5a0
? __pfx_rtnl_getlink+0x10/0x10
? rtnetlink_rcv_msg+0x1e5/0x860
? __pfx___mutex_lock+0x10/0x10
? rcu_is_watching+0x34/0x60
? __pfx_lock_acquire+0x10/0x10
? stack_trace_save+0x90/0xd0
? filter_irq_stacks+0x1d/0x70
? kasan_save_stack+0x30/0x40
? kasan_save_stack+0x20/0x40
? kasan_save_track+0x10/0x30
rtnetlink_rcv_msg+0x21c/0x860
? entry_SYSCALL_64_after_hwframe+0x76/0x7e
? __pfx_rtnetlink_rcv_msg+0x10/0x10
? arch_stack_walk+0x9e/0xf0
? rcu_is_watching+0x34/0x60
? lock_acquire+0xd5/0x410
? rcu_is_watching+0x34/0x60
netlink_rcv_skb+0xe0/0x210
? __pfx_rtnetlink_rcv_msg+0x10/0x10
? __pfx_netlink_rcv_skb+0x10/0x10
? rcu_is_watching+0x34/0x60
? __pfx___netlink_lookup+0x10/0x10
? lock_release+0x62/0x200
? netlink_deliver_tap+0xfd/0x290
? rcu_is_watching+0x34/0x60
? lock_release+0x62/0x200
? netlink_deliver_tap+0x95/0x290
netlink_unicast+0x31f/0x480
? __pfx_netlink_unicast+0x10/0x10
? rcu_is_watching+0x34/0x60
? lock_acquire+0xd5/0x410
netlink_sendmsg+0x369/0x660
? lock_release+0x62/0x200
? __pfx_netlink_sendmsg+0x10/0x10
? import_ubuf+0xb9/0xf0
? __import_iovec+0x254/0x2b0
? lock_release+0x62/0x200
? __pfx_netlink_sendmsg+0x10/0x10
____sys_sendmsg+0x559/0x5a0
? __pfx_____sys_sendmsg+0x10/0x10
? __pfx_copy_msghdr_from_user+0x10/0x10
? rcu_is_watching+0x34/0x60
? do_read_fault+0x213/0x4a0
? rcu_is_watching+0x34/0x60
___sys_sendmsg+0xe4/0x150
? __pfx____sys_sendmsg+0x10/0x10
? do_fault+0x2cc/0x6f0
? handle_pte_fault+0x2e3/0x3d0
? __pfx_handle_pte_fault+0x10/0x10
---truncated---