tty: vt: fix up tabstops properly

[ Upstream commit f1869a890cdedb92a3fab969db5d0fd982850273 ]

Tabs on a console with long lines do not wrap properly, so correctly
account for the line length when computing the tab placement location.

Reported-by: James Holderness <j4_james@hotmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>

diff --git a/drivers/tty/vt/vt.c b/drivers/tty/vt/vt.c
index 50b67ff2b6eaa3a44ee2d0f389d464d4741c2360..db492b4631eeeb1241c8aaf0fe66296855d16aaa 100644 (file)
--- a/drivers/tty/vt/vt.c
+++ b/drivers/tty/vt/vt.c
@@ -1711,7 +1711,7 @@ static void reset_terminal(struct vc_data *vc, int do_clear)
        default_attr(vc);
        update_attr(vc);
 
-       vc->vc_tab_stop[0]      = 0x01010100;
+       vc->vc_tab_stop[0]      =
        vc->vc_tab_stop[1]      =
        vc->vc_tab_stop[2]      =
        vc->vc_tab_stop[3]      =
@@ -1754,7 +1754,7 @@ static void do_con_trol(struct tty_struct *tty, struct vc_data *vc, int c)
                vc->vc_pos -= (vc->vc_x << 1);
                while (vc->vc_x < vc->vc_cols - 1) {
                        vc->vc_x++;
-                       if (vc->vc_tab_stop[vc->vc_x >> 5] & (1 << (vc->vc_x & 31)))
+                       if (vc->vc_tab_stop[7 & (vc->vc_x >> 5)] & (1 << (vc->vc_x & 31)))
                                break;
                }
                vc->vc_pos += (vc->vc_x << 1);
@@ -1814,7 +1814,7 @@ static void do_con_trol(struct tty_struct *tty, struct vc_data *vc, int c)
                        lf(vc);
                        return;
                case 'H':
-                       vc->vc_tab_stop[vc->vc_x >> 5] |= (1 << (vc->vc_x & 31));
+                       vc->vc_tab_stop[7 & (vc->vc_x >> 5)] |= (1 << (vc->vc_x & 31));
                        return;
                case 'Z':
                        respond_ID(tty);
@@ -2007,7 +2007,7 @@ static void do_con_trol(struct tty_struct *tty, struct vc_data *vc, int c)
                        return;
                case 'g':
                        if (!vc->vc_par[0])
-                               vc->vc_tab_stop[vc->vc_x >> 5] &= ~(1 << (vc->vc_x & 31));
+                               vc->vc_tab_stop[7 & (vc->vc_x >> 5)] &= ~(1 << (vc->vc_x & 31));
                        else if (vc->vc_par[0] == 3) {
                                vc->vc_tab_stop[0] =
                                        vc->vc_tab_stop[1] =