Messages in this thread Patch in this message | | | From | Xiaomeng Tong <> | Subject | [RESEND PATCH v2] vt_ioctl: fix potential spectre v1 in VT_DISALLOCATE | Date | Mon, 14 Mar 2022 20:29:21 +0800 |
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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 <jirislaby@kernel.org> Signed-off-by: Xiaomeng Tong <xiam0nd.tong@gmail.com>
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v1 -> v2: - Add Reviewed-by https://lore.kernel.org/lkml/20220222081101.21233-1-xiam0nd.tong@gmail.com/
RFC -> v1: - Adjust code style [Jiri Slaby] https://lore.kernel.org/lkml/20220222073954.20212-1-xiam0nd.tong@gmail.com/
RFC: https://lore.kernel.org/lkml/20220222035648.17984-1-xiam0nd.tong@gmail.com/
--- 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 580136986..8c685b501 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: { -- 2.17.1
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