From b31c41339f4f8a833cb9dc509f87aab6a159ffe4 Mon Sep 17 00:00:00 2001 From: Xiaomeng Tong Date: Mon, 14 Mar 2022 20:29:21 +0800 Subject: [PATCH] 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: Jiri Slaby Signed-off-by: Xiaomeng Tong Link: https://lore.kernel.org/r/20220314122921.31223-1-xiam0nd.tong@gmail.com Signed-off-by: Greg Kroah-Hartman --- drivers/tty/vt/vt_ioctl.c | 10 ++++++---- 1 file changed, 6 insertions(+), 4 deletions(-) diff --git a/drivers/tty/vt/vt_ioctl.c b/drivers/tty/vt/vt_ioctl.c index 58013698..8c685b5 100644 --- a/drivers/tty/vt/vt_ioctl.c +++ b/drivers/tty/vt/vt_ioctl.c @@ -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; + break; + } + + arg = array_index_nospec(arg - 1, MAX_NR_CONSOLES); + return vt_disallocate(arg); case VT_RESIZE: { -- 2.7.4