Commit b31c4133 authored by Xiaomeng Tong's avatar Xiaomeng Tong Committed by Greg Kroah-Hartman
Browse files

vt_ioctl: fix potential spectre v1 in VT_DISALLOCATE 



In VT_ACTIVATE an almost identical code path has been patched
with array_index_nospec. In the VT_DISALLOCATE path, the arg is
the user input from a system call argument and lately used as a index
for vc_cons[index].d access, which can be reached through path like
vt_disallocate->vc_busy or vt_disallocate->vc_deallocate.
For consistency both code paths should have the same mitigations
applied. Also, the code style is adjusted as suggested by Jiri.

Reviewed-by: default avatarJiri Slaby <jirislaby@kernel.org>
Signed-off-by: default avatarXiaomeng Tong <xiam0nd.tong@gmail.com>
Link: https://lore.kernel.org/r/20220314122921.31223-1-xiam0nd.tong@gmail.com


Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent f58c252e

drivers/tty/vt/vt_ioctl.c

+6 −4
Original line number Diff line number Diff line
@@ -898,11 +898,13 @@ int vt_ioctl(struct tty_struct *tty, 
		if (arg > MAX_NR_CONSOLES)

			return -ENXIO;



		if (arg == 0)

		if (arg == 0) {

			vt_disallocate_all();

		else

			return vt_disallocate(--arg);

			break;

		}



		arg = array_index_nospec(arg - 1, MAX_NR_CONSOLES);

		return vt_disallocate(arg);



	case VT_RESIZE:

	{