linux-stable.git/drivers/video, branch v5.4.58

vgacon: Fix for missing check in scrollback handling

2020-08-11T13:33:35+00:00

commit ebfdfeeae8c01fcb2b3b74ffaf03876e20835d2d upstream.

vgacon_scrollback_update() always leaves enbough room in the scrollback
buffer for the next call, but if the console size changed that room
might not actually be enough, and so we need to re-check.

The check should be in the loop since vgacon_scrollback_cur->tail is
updated in the loop and count may be more than 1 when triggered by CSI M,
as Jiri's PoC:
#include 
#include 
#include 
#include 
#include 
#include 
#include 

int main(int argc, char** argv)
{
        int fd = open("/dev/tty1", O_RDWR);
        unsigned short size[3] = {25, 200, 0};
        ioctl(fd, 0x5609, size); // VT_RESIZE

        write(fd, "\e[1;1H", 6);
        for (int i = 0; i < 30; i++)
                write(fd, "\e[10M", 5);
}

It leads to various crashes as vgacon_scrollback_update writes out of
the buffer:
 BUG: unable to handle page fault for address: ffffc900001752a0
 #PF: supervisor write access in kernel mode
 #PF: error_code(0x0002) - not-present page
 RIP: 0010:mutex_unlock+0x13/0x30
...
 Call Trace:
  n_tty_write+0x1a0/0x4d0
  tty_write+0x1a0/0x2e0

Or to KASAN reports:
BUG: KASAN: slab-out-of-bounds in vgacon_scroll+0x57a/0x8ed

This fixes CVE-2020-14331.

Reported-by: 张云海 
Reported-by: Yang Yingliang 
Reported-by: Kyungtae Kim 
Fixes: 15bdab959c9b ([PATCH] vgacon: Add support for soft scrollback)
Cc: stable@vger.kernel.org
Cc: linux-fbdev@vger.kernel.org
Cc: Linus Torvalds 
Cc: Solar Designer 
Cc: "Srivatsa S. Bhat" 
Cc: Anthony Liguori 
Cc: Yang Yingliang 
Cc: Bartlomiej Zolnierkiewicz 
Cc: Jiri Slaby 
Signed-off-by: Yunhai Zhang 
Link: https://lore.kernel.org/r/9fb43895-ca91-9b07-ebfd-808cf854ca95@nsfocus.com
Signed-off-by: Greg Kroah-Hartman

omapfb: dss: Fix max fclk divider for omap36xx

2020-08-11T13:33:34+00:00

commit 254503a2b186caa668a188dbbd7ab0d25149c0a5 upstream.

The drm/omap driver was fixed to correct an issue where using a
divider of 32 breaks the DSS despite the TRM stating 32 is a valid
number.  Through experimentation, it appears that 31 works, and
it is consistent with the value used by the drm/omap driver.

This patch fixes the divider for fbdev driver instead of the drm.

Fixes: f76ee892a99e ("omapfb: copy omapdss & displays for omapfb")
Cc:  #4.5+
Signed-off-by: Adam Ford 
Reviewed-by: Tomi Valkeinen 
Cc: Dave Airlie 
Cc: Rob Clark 
[b.zolnierkie: mark patch as applicable to stable 4.5+ (was 4.9+)]
Signed-off-by: Bartlomiej Zolnierkiewicz 
Link: https://patchwork.freedesktop.org/patch/msgid/20200630182636.439015-1-aford173@gmail.com
Signed-off-by: Greg Kroah-Hartman

fbdev: Detect integer underflow at "struct fbcon_ops"->clear_margins.

2020-07-29T08:18:43+00:00

commit 033724d6864245a11f8e04c066002e6ad22b3fd0 upstream.

syzbot is reporting general protection fault in bitfill_aligned() [1]
caused by integer underflow in bit_clear_margins(). The cause of this
problem is when and how do_vc_resize() updates vc->vc_{cols,rows}.

If vc_do_resize() fails (e.g. kzalloc() fails) when var.xres or var.yres
is going to shrink, vc->vc_{cols,rows} will not be updated. This allows
bit_clear_margins() to see info->var.xres < (vc->vc_cols * cw) or
info->var.yres < (vc->vc_rows * ch). Unexpectedly large rw or bh will
try to overrun the __iomem region and causes general protection fault.

Also, vc_resize(vc, 0, 0) does not set vc->vc_{cols,rows} = 0 due to

  new_cols = (cols ? cols : vc->vc_cols);
  new_rows = (lines ? lines : vc->vc_rows);

exception. Since cols and lines are calculated as

  cols = FBCON_SWAP(ops->rotate, info->var.xres, info->var.yres);
  rows = FBCON_SWAP(ops->rotate, info->var.yres, info->var.xres);
  cols /= vc->vc_font.width;
  rows /= vc->vc_font.height;
  vc_resize(vc, cols, rows);

in fbcon_modechanged(), var.xres < vc->vc_font.width makes cols = 0
and var.yres < vc->vc_font.height makes rows = 0. This means that

  const int fd = open("/dev/fb0", O_ACCMODE);
  struct fb_var_screeninfo var = { };
  ioctl(fd, FBIOGET_VSCREENINFO, &var);
  var.xres = var.yres = 1;
  ioctl(fd, FBIOPUT_VSCREENINFO, &var);

easily reproduces integer underflow bug explained above.

Of course, callers of vc_resize() are not handling vc_do_resize() failure
is bad. But we can't avoid vc_resize(vc, 0, 0) which returns 0. Therefore,
as a band-aid workaround, this patch checks integer underflow in
"struct fbcon_ops"->clear_margins call, assuming that
vc->vc_cols * vc->vc_font.width and vc->vc_rows * vc->vc_font.heigh do not
cause integer overflow.

[1] https://syzkaller.appspot.com/bug?id=a565882df74fa76f10d3a6fec4be31098dbb37c6

Reported-and-tested-by: syzbot 
Signed-off-by: Tetsuo Handa 
Acked-by: Daniel Vetter 
Cc: stable 
Link: https://lore.kernel.org/r/20200715015102.3814-1-penguin-kernel@I-love.SAKURA.ne.jp
Signed-off-by: Greg Kroah-Hartman

backlight: lp855x: Ensure regulators are disabled on probe failure

2020-06-24T15:50:09+00:00

[ Upstream commit d8207c155a7c6015eb7f43739baa7dfb1fa638af ]

If probing the LP885x backlight fails after the regulators have been
enabled, then the following warning is seen when releasing the
regulators ...

 WARNING: CPU: 1 PID: 289 at drivers/regulator/core.c:2051 _regulator_put.part.28+0x158/0x160
 Modules linked in: tegra_xudc lp855x_bl(+) host1x pwm_tegra ip_tables x_tables ipv6 nf_defrag_ipv6
 CPU: 1 PID: 289 Comm: systemd-udevd Not tainted 5.6.0-rc2-next-20200224 #1
 Hardware name: NVIDIA Jetson TX1 Developer Kit (DT)

 ...

 Call trace:
  _regulator_put.part.28+0x158/0x160
  regulator_put+0x34/0x50
  devm_regulator_release+0x10/0x18
  release_nodes+0x12c/0x230
  devres_release_all+0x34/0x50
  really_probe+0x1c0/0x370
  driver_probe_device+0x58/0x100
  device_driver_attach+0x6c/0x78
  __driver_attach+0xb0/0xf0
  bus_for_each_dev+0x68/0xc8
  driver_attach+0x20/0x28
  bus_add_driver+0x160/0x1f0
  driver_register+0x60/0x110
  i2c_register_driver+0x40/0x80
  lp855x_driver_init+0x20/0x1000 [lp855x_bl]
  do_one_initcall+0x58/0x1a0
  do_init_module+0x54/0x1d0
  load_module+0x1d80/0x21c8
  __do_sys_finit_module+0xe8/0x100
  __arm64_sys_finit_module+0x18/0x20
  el0_svc_common.constprop.3+0xb0/0x168
  do_el0_svc+0x20/0x98
  el0_sync_handler+0xf4/0x1b0
  el0_sync+0x140/0x180

Fix this by ensuring that the regulators are disabled, if enabled, on
probe failure.

Finally, ensure that the vddio regulator is disabled in the driver
remove handler.

Signed-off-by: Jon Hunter 
Reviewed-by: Daniel Thompson 
Signed-off-by: Lee Jones 
Signed-off-by: Sasha Levin

video: fbdev: w100fb: Fix a potential double free.

2020-06-17T14:40:33+00:00

commit 18722d48a6bb9c2e8d046214c0a5fd19d0a7c9f6 upstream.

Some memory is vmalloc'ed in the 'w100fb_save_vidmem' function and freed in
the 'w100fb_restore_vidmem' function. (these functions are called
respectively from the 'suspend' and the 'resume' functions)

However, it is also freed in the 'remove' function.

In order to avoid a potential double free, set the corresponding pointer
to NULL once freed in the 'w100fb_restore_vidmem' function.

Fixes: aac51f09d96a ("[PATCH] w100fb: Rewrite for platform independence")
Cc: Richard Purdie 
Cc: Antonino Daplas 
Cc: Bartlomiej Zolnierkiewicz 
Cc:  # v2.6.14+
Signed-off-by: Christophe JAILLET 
Signed-off-by: Sam Ravnborg 
Link: https://patchwork.freedesktop.org/patch/msgid/20200506181902.193290-1-christophe.jaillet@wanadoo.fr
Signed-off-by: Greg Kroah-Hartman

video: vt8500lcdfb: fix fallthrough warning

2020-06-17T14:40:33+00:00

commit 1c49f35e9e9156273124a0cfd38b57f7a7d4828f upstream.

Fix following warning:
vt8500lcdfb.c: In function 'vt8500lcd_blank':
vt8500lcdfb.c:229:6: warning: this statement may fall through [-Wimplicit-fallthrough=]
      if (info->fix.visual == FB_VISUAL_PSEUDOCOLOR ||
         ^
vt8500lcdfb.c:233:2: note: here
     case FB_BLANK_UNBLANK:
     ^~~~

Adding a simple "fallthrough;" fixed the warning.
The fix was build tested.

Signed-off-by: Sam Ravnborg 
Reported-by: kbuild test robot 
Fixes: e41f1a989408 ("fbdev: Implement simple blanking in pseudocolor modes for vt8500lcdfb")
Cc: Alexey Charkov 
Cc: Paul Mundt 
Cc:  # v2.6.38+
Signed-off-by: Bartlomiej Zolnierkiewicz 
Link: https://patchwork.freedesktop.org/patch/msgid/20200412202143.GA26948@ravnborg.org
Signed-off-by: Greg Kroah-Hartman

fbmem: Adjust indentation in fb_prepare_logo and fb_blank

2020-04-23T08:36:43+00:00

commit 93166f5f2e4dc593cff8ca77ef828ac6f148b0f3 upstream.

Clang warns:

../drivers/video/fbdev/core/fbmem.c:665:3: warning: misleading
indentation; statement is not part of the previous 'else'
[-Wmisleading-indentation]
        if (fb_logo.depth > 4 && depth > 4) {
        ^
../drivers/video/fbdev/core/fbmem.c:661:2: note: previous statement is
here
        else
        ^
../drivers/video/fbdev/core/fbmem.c:1075:3: warning: misleading
indentation; statement is not part of the previous 'if'
[-Wmisleading-indentation]
        return ret;
        ^
../drivers/video/fbdev/core/fbmem.c:1072:2: note: previous statement is
here
        if (!ret)
        ^
2 warnings generated.

This warning occurs because there are spaces before the tabs on these
lines. Normalize the indentation in these functions so that it is
consistent with the Linux kernel coding style and clang no longer warns.

Fixes: 1692b37c99d5 ("fbdev: Fix logo if logo depth is less than framebuffer depth")
Link: https://github.com/ClangBuiltLinux/linux/issues/825
Signed-off-by: Nathan Chancellor 
Reviewed-by: Nick Desaulniers 
Signed-off-by: Bartlomiej Zolnierkiewicz 
Link: https://patchwork.freedesktop.org/patch/msgid/20191218030025.10064-1-natechancellor@gmail.com
Signed-off-by: Greg Kroah-Hartman

fbdev: potential information leak in do_fb_ioctl()

2020-04-23T08:36:43+00:00

commit d3d19d6fc5736a798b118971935ce274f7deaa82 upstream.

The "fix" struct has a 2 byte hole after ->ywrapstep and the
"fix = info->fix;" assignment doesn't necessarily clear it.  It depends
on the compiler.  The solution is just to replace the assignment with an
memcpy().

Fixes: 1f5e31d7e55a ("fbmem: don't call copy_from/to_user() with mutex held")
Signed-off-by: Dan Carpenter 
Cc: Andrew Morton 
Cc: Arnd Bergmann 
Cc: "Eric W. Biederman" 
Cc: Andrea Righi 
Cc: Daniel Vetter 
Cc: Sam Ravnborg 
Cc: Maarten Lankhorst 
Cc: Daniel Thompson 
Cc: Peter Rosin 
Cc: Jani Nikula 
Cc: Gerd Hoffmann 
Signed-off-by: Bartlomiej Zolnierkiewicz 
Link: https://patchwork.freedesktop.org/patch/msgid/20200113100132.ixpaymordi24n3av@kili.mountain
Signed-off-by: Greg Kroah-Hartman

fbcon: fix null-ptr-deref in fbcon_switch

2020-04-13T08:48:14+00:00

commit b139f8b00db4a8ea75a4174346eafa48041aa489 upstream.

Set logo_shown to FBCON_LOGO_CANSHOW when the vc was deallocated.

syzkaller report: https://lkml.org/lkml/2020/3/27/403
general protection fault, probably for non-canonical address
0xdffffc000000006c: 0000 [#1] SMP KASAN
KASAN: null-ptr-deref in range [0x0000000000000360-0x0000000000000367]
RIP: 0010:fbcon_switch+0x28f/0x1740
drivers/video/fbdev/core/fbcon.c:2260

Call Trace:
redraw_screen+0x2a8/0x770 drivers/tty/vt/vt.c:1008
vc_do_resize+0xfe7/0x1360 drivers/tty/vt/vt.c:1295
fbcon_init+0x1221/0x1ab0 drivers/video/fbdev/core/fbcon.c:1219
visual_init+0x305/0x5c0 drivers/tty/vt/vt.c:1062
do_bind_con_driver+0x536/0x890 drivers/tty/vt/vt.c:3542
do_take_over_console+0x453/0x5b0 drivers/tty/vt/vt.c:4122
do_fbcon_takeover+0x10b/0x210 drivers/video/fbdev/core/fbcon.c:588
fbcon_fb_registered+0x26b/0x340 drivers/video/fbdev/core/fbcon.c:3259
do_register_framebuffer drivers/video/fbdev/core/fbmem.c:1664 [inline]
register_framebuffer+0x56e/0x980 drivers/video/fbdev/core/fbmem.c:1832
dlfb_usb_probe.cold+0x1743/0x1ba3 drivers/video/fbdev/udlfb.c:1735
usb_probe_interface+0x310/0x800 drivers/usb/core/driver.c:374

accessing vc_cons[logo_shown].d->vc_top causes the bug.

Reported-by: syzbot+732528bae351682f1f27@syzkaller.appspotmail.com
Signed-off-by: Qiujun Huang 
Acked-by: Sam Ravnborg 
Cc: stable@vger.kernel.org
Signed-off-by: Daniel Vetter 
Link: https://patchwork.freedesktop.org/patch/msgid/20200329085647.25133-1-hqjagain@gmail.com
Signed-off-by: Greg Kroah-Hartman

vgacon: Fix a UAF in vgacon_invert_region

2020-03-12T12:00:19+00:00

commit 513dc792d6060d5ef572e43852683097a8420f56 upstream.

When syzkaller tests, there is a UAF:
  BUG: KASan: use after free in vgacon_invert_region+0x9d/0x110 at addr
    ffff880000100000
  Read of size 2 by task syz-executor.1/16489
  page:ffffea0000004000 count:0 mapcount:-127 mapping:          (null)
  index:0x0
  page flags: 0xfffff00000000()
  page dumped because: kasan: bad access detected
  CPU: 1 PID: 16489 Comm: syz-executor.1 Not tainted
  Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS
  rel-1.9.3-0-ge2fc41e-prebuilt.qemu-project.org 04/01/2014
  Call Trace:
    [] dump_stack+0x1e/0x20
    [] kasan_report+0x577/0x950
    [] __asan_load2+0x62/0x80
    [] vgacon_invert_region+0x9d/0x110
    [] invert_screen+0xe5/0x470
    [] set_selection+0x44b/0x12f0
    [] tioclinux+0xee/0x490
    [] vt_ioctl+0xff4/0x2670
    [] tty_ioctl+0x46a/0x1a10
    [] do_vfs_ioctl+0x5bd/0xc40
    [] SyS_ioctl+0x132/0x170
    [] system_call_fastpath+0x22/0x27
    Memory state around the buggy address:
     ffff8800000fff00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00
     00 00
     ffff8800000fff80: 00 00 00 00 00 00 00 00 00 00 00 00 00
     00 00 00
    >ffff880000100000: ff ff ff ff ff ff ff ff ff ff ff ff ff
     ff ff ff

It can be reproduce in the linux mainline by the program:
  #include 
  #include 
  #include 
  #include 
  #include 
  #include 
  #include 
  #include 

  struct tiocl_selection {
    unsigned short xs;      /* X start */
    unsigned short ys;      /* Y start */
    unsigned short xe;      /* X end */
    unsigned short ye;      /* Y end */
    unsigned short sel_mode; /* selection mode */
  };

  #define TIOCL_SETSEL    2
  struct tiocl {
    unsigned char type;
    unsigned char pad;
    struct tiocl_selection sel;
  };

  int main()
  {
    int fd = 0;
    const char *dev = "/dev/char/4:1";

    struct vt_consize v = {0};
    struct tiocl tioc = {0};

    fd = open(dev, O_RDWR, 0);

    v.v_rows = 3346;
    ioctl(fd, VT_RESIZEX, &v);

    tioc.type = TIOCL_SETSEL;
    ioctl(fd, TIOCLINUX, &tioc);

    return 0;
  }

When resize the screen, update the 'vc->vc_size_row' to the new_row_size,
but when 'set_origin' in 'vgacon_set_origin', vgacon use 'vga_vram_base'
for 'vc_origin' and 'vc_visible_origin', not 'vc_screenbuf'. It maybe
smaller than 'vc_screenbuf'. When TIOCLINUX, use the new_row_size to calc
the offset, it maybe larger than the vga_vram_size in vgacon driver, then
bad access.
Also, if set an larger screenbuf firstly, then set an more larger
screenbuf, when copy old_origin to new_origin, a bad access may happen.

So, If the screen size larger than vga_vram, resize screen should be
failed. This alse fix CVE-2020-8649 and CVE-2020-8647.

Linus pointed out that overflow checking seems absent. We're saved by
the existing bounds checks in vc_do_resize() with rather strict
limits:

	if (cols > VC_RESIZE_MAXCOL || lines > VC_RESIZE_MAXROW)
		return -EINVAL;

Fixes: 0aec4867dca14 ("[PATCH] SVGATextMode fix")
Reference: CVE-2020-8647 and CVE-2020-8649
Reported-by: Hulk Robot 
Signed-off-by: Zhang Xiaoxu 
[danvet: augment commit message to point out overflow safety]
Cc: stable@vger.kernel.org
Signed-off-by: Daniel Vetter 
Link: https://patchwork.freedesktop.org/patch/msgid/20200304022429.37738-1-zhangxiaoxu5@huawei.com
Signed-off-by: Greg Kroah-Hartman