linux/drivers/tty
Grzegorz Halat a1ad1cc970 vt/fbcon: deinitialize resources in visual_init() after failed memory allocation
After memory allocation failure vc_allocate() doesn't clean up data
which has been initialized in visual_init(). In case of fbcon this
leads to divide-by-0 in fbcon_init() on next open of the same tty.

memory allocation in vc_allocate() may fail here:
1097:     vc->vc_screenbuf = kzalloc(vc->vc_screenbuf_size, GFP_KERNEL);

on next open() fbcon_init() skips vc_font.data initialization:
1088:     if (!p->fontdata) {

division by zero in fbcon_init() happens here:
1149:     new_cols /= vc->vc_font.width;

Additional check is needed in fbcon_deinit() to prevent
usage of uninitialized vc_screenbuf:

1251:        if (vc->vc_hi_font_mask && vc->vc_screenbuf)
1252:                set_vc_hi_font(vc, false);

Crash:

 #6 [ffffc90001eafa60] divide_error at ffffffff81a00be4
    [exception RIP: fbcon_init+463]
    RIP: ffffffff814b860f  RSP: ffffc90001eafb18  RFLAGS: 00010246
...
 #7 [ffffc90001eafb60] visual_init at ffffffff8154c36e
 #8 [ffffc90001eafb80] vc_allocate at ffffffff8154f53c
 #9 [ffffc90001eafbc8] con_install at ffffffff8154f624
...

Signed-off-by: Grzegorz Halat <ghalat@redhat.com>
Reviewed-by: Oleksandr Natalenko <oleksandr@redhat.com>
Acked-by: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-05-24 17:08:18 +02:00
..
hvc RISC-V Patches for the 5.2 Merge Window, Part 1 v3 2019-05-19 09:56:36 -07:00
ipwireless tty: add SPDX identifiers to Kconfig and Makefiles 2019-04-04 18:48:43 +02:00
serdev tty: add SPDX identifiers to Kconfig and Makefiles 2019-04-04 18:48:43 +02:00
serial tty: max310x: Fix external crystal register setup 2019-05-21 12:18:17 +02:00
vt vt/fbcon: deinitialize resources in visual_init() after failed memory allocation 2019-05-24 17:08:18 +02:00
amiserial.c
cyclades.c
ehv_bytechan.c
goldfish.c
isicom.c
Kconfig docs: serial: convert docs to ReST and rename to *.rst 2019-04-25 11:37:42 +02:00
Makefile tty: Add NULL TTY driver 2019-04-16 15:21:34 +02:00
mips_ejtag_fdc.c
moxa.c
moxa.h
mxser.c
mxser.h
n_gsm.c
n_hdlc.c
n_null.c
n_r3964.c
n_tracerouter.c
n_tracesink.c
n_tracesink.h
n_tty.c n_tty: check for negative and zero space return from tty_write_room 2019-04-16 15:21:33 +02:00
nozomi.c
pty.c Revert "tty: pty: Fix race condition between release_one_tty and pty_write" 2019-03-29 15:47:40 +01:00
rocket_int.h
rocket.c TTY/Serial patches for 5.2-rc1 2019-05-08 10:07:28 -07:00
rocket.h tty: rocket: Remove RCPK_GET_STRUCT ioctl 2019-04-25 11:58:56 +02:00
synclink_gt.c
synclink.c
synclinkmp.c
sysrq.c panic: avoid the extra noise dmesg 2019-05-14 19:52:51 -07:00
tty_audit.c
tty_baudrate.c
tty_buffer.c
tty_io.c tty: update obsolete termios comment 2019-04-25 11:58:56 +02:00
tty_ioctl.c
tty_jobctrl.c tty: fix read of tty->pgrp outside of ctrl_lock 2019-03-28 01:28:23 +09:00
tty_ldisc.c
tty_ldsem.c
tty_mutex.c
tty_port.c Revert "tty: fix NULL pointer issue when tty_port ops is not set" 2019-04-16 15:21:34 +02:00
ttynull.c tty: Add NULL TTY driver 2019-04-16 15:21:34 +02:00
vcc.c tty: fix up a few remaining files without SPDX identifiers 2019-04-04 18:48:43 +02:00