fortify_panic with emulated adapter

[dkoreshkov]

A fortified Linux kernel does not like this line in LINUX/netmap_linux.c:

strcpy(((void *)attr_kind) + NLA_HDRLEN, qdisc_name);

It says:

[  440.419732] 936.282844 [ 320] generic_netmap_register   Emulated adapter for enp12s0f0 activated
[  440.419822] detected buffer overflow in strcpy
[  440.419856] ------------[ cut here ]------------
[  440.419857] Kernel BUG at fortify_panic+0xf/0x20 [verbose debug info unavailable]
[  440.419883] invalid opcode: 0000 [#1] PREEMPT SMP PTI
.......
[  440.420099] Call Trace:
[  440.420108]  <TASK>
[  440.420115]  ? die+0x2d/0x80
[  440.420126]  ? do_trap+0xe1/0x110
[  440.420136]  ? fortify_panic+0xf/0x20
[  440.420146]  ? do_error_trap+0x65/0xa0
[  440.420156]  ? fortify_panic+0xf/0x20
[  440.420166]  ? exc_invalid_op+0x49/0x70
[  440.420178]  ? fortify_panic+0xf/0x20
[  440.420188]  ? asm_exc_invalid_op+0x16/0x20
[  440.420201]  ? fortify_panic+0xf/0x20
[  440.420211]  ? fortify_panic+0xf/0x20
[  440.420222]  tc_configure+0x561/0x570 [netmap]
[  440.420257]  ? nm_os_catch_tx+0x87/0x270 [netmap]

Apparently, GCC cannot grok the destination buffer size in that case.
Temporarily fixed by a simple copy loop.