RDMA/sa_query: Use strscpy_pad instead of memcpy to copy a string

commit 64733956 upstream.

When copying the device name, the length of the data memcpy copied exceeds
the length of the source buffer, which cause the KASAN issue below.  Use
strscpy_pad() instead.

 BUG: KASAN: slab-out-of-bounds in ib_nl_set_path_rec_attrs+0x136/0x320 [ib_core]
 Read of size 64 at addr ffff88811a10f5e0 by task rping/140263
 CPU: 3 PID: 140263 Comm: rping Not tainted 5.15.0-rc1+ #1
 Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS rel-1.13.0-0-gf21b5a4aeb02-prebuilt.qemu.org 04/01/2014
 Call Trace:
  dump_stack_lvl+0x57/0x7d
  print_address_description.constprop.0+0x1d/0xa0
  kasan_report+0xcb/0x110
  kasan_check_range+0x13d/0x180
  memcpy+0x20/0x60
  ib_nl_set_path_rec_attrs+0x136/0x320 [ib_core]
  ib_nl_make_request+0x1c6/0x380 [ib_core]
  send_mad+0x20a/0x220 [ib_core]
  ib_sa_path_rec_get+0x3e3/0x800 [ib_core]
  cma_query_ib_route+0x29b/0x390 [rdma_cm]
  rdma_resolve_route+0x308/0x3e0 [rdma_cm]
  ucma_resolve_route+0xe1/0x150 [rdma_ucm]
  ucma_write+0x17b/0x1f0 [rdma_ucm]
  vfs_write+0x142/0x4d0
  ksys_write+0x133/0x160
  do_syscall_64+0x43/0x90
  entry_SYSCALL_64_after_hwframe+0x44/0xae
 RIP: 0033:0x7f26499aa90f
 Code: 89 54 24 18 48 89 74 24 10 89 7c 24 08 e8 29 fd ff ff 48 8b 54 24 18 48 8b 74 24 10 41 89 c0 8b 7c 24 08 b8 01 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 31 44 89 c7 48 89 44 24 08 e8 5c fd ff ff 48
 RSP: 002b:00007f26495f2dc0 EFLAGS: 00000293 ORIG_RAX: 0000000000000001
 RAX: ffffffffffffffda RBX: 00000000000007d0 RCX: 00007f26499aa90f
 RDX: 0000000000000010 RSI: 00007f26495f2e00 RDI: 0000000000000003
 RBP: 00005632a8315440 R08: 0000000000000000 R09: 0000000000000001
 R10: 0000000000000000 R11: 0000000000000293 R12: 00007f26495f2e00
 R13: 00005632a83154e0 R14: 00005632a8315440 R15: 00005632a830a810

 Allocated by task 131419:
  kasan_save_stack+0x1b/0x40
  __kasan_kmalloc+0x7c/0x90
  proc_self_get_link+0x8b/0x100
  pick_link+0x4f1/0x5c0
  step_into+0x2eb/0x3d0
  walk_component+0xc8/0x2c0
  link_path_walk+0x3b8/0x580
  path_openat+0x101/0x230
  do_filp_open+0x12e/0x240
  do_sys_openat2+0x115/0x280
  __x64_sys_openat+0xce/0x140
  do_syscall_64+0x43/0x90
  entry_SYSCALL_64_after_hwframe+0x44/0xae

Fixes: 2ca546b9

 ("IB/sa: Route SA pathrecord query through netlink")
Link: https://lore.kernel.org/r/72ede0f6dab61f7f23df9ac7a70666e07ef314b0.1635055496.git.leonro@nvidia.com
Signed-off-by: Mark Zhang <markzhang@nvidia.com>
Reviewed-by: Mark Bloch <mbloch@nvidia.com>
Signed-off-by: Leon Romanovsky <leonro@nvidia.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>