linux-stable.git/drivers/video/fbdev/core, branch v5.4.217

fbcon: Fix boundary checks for fbcon=vc:n1-n2 parameters

2022-08-25T09:17:22+00:00

commit cad564ca557f8d3bb3b1fa965d9a2b3f6490ec69 upstream.

The user may use the fbcon=vc:- option to tell fbcon to take
over the given range (n1...n2) of consoles. The value for n1 and n2
needs to be a positive number and up to (MAX_NR_CONSOLES - 1).
The given values were not fully checked against those boundaries yet.

To fix the issue, convert first_fb_vc and last_fb_vc to unsigned
integers and check them against the upper boundary, and make sure that
first_fb_vc is smaller than last_fb_vc.

Cc: stable@vger.kernel.org # v4.19+
Reviewed-by: Daniel Vetter 
Signed-off-by: Helge Deller 
Link: https://patchwork.freedesktop.org/patch/msgid/YpkYRMojilrtZIgM@p100
Signed-off-by: Greg Kroah-Hartman

fbcon: Prevent that screen size is smaller than font size

2022-07-12T14:30:47+00:00

commit e64242caef18b4a5840b0e7a9bff37abd4f4f933 upstream.

We need to prevent that users configure a screen size which is smaller than the
currently selected font size. Otherwise rendering chars on the screen will
access memory outside the graphics memory region.

This patch adds a new function fbcon_modechange_possible() which
implements this check and which later may be extended with other checks
if necessary.  The new function is called from the FBIOPUT_VSCREENINFO
ioctl handler in fbmem.c, which will return -EINVAL if userspace asked
for a too small screen size.

Signed-off-by: Helge Deller 
Reviewed-by: Geert Uytterhoeven 
Cc: stable@vger.kernel.org # v5.4+
Signed-off-by: Greg Kroah-Hartman

fbcon: Disallow setting font bigger than screen size

2022-07-12T14:30:47+00:00

commit 65a01e601dbba8b7a51a2677811f70f783766682 upstream.

Prevent that users set a font size which is bigger than the physical screen.
It's unlikely this may happen (because screens are usually much larger than the
fonts and each font char is limited to 32x32 pixels), but it may happen on
smaller screens/LCD displays.

Signed-off-by: Helge Deller 
Reviewed-by: Daniel Vetter 
Reviewed-by: Geert Uytterhoeven 
Cc: stable@vger.kernel.org # v4.14+
Signed-off-by: Greg Kroah-Hartman

fbmem: Check virtual screen sizes in fb_set_var()

2022-07-12T14:30:47+00:00

commit 6c11df58fd1ac0aefcb3b227f72769272b939e56 upstream.

Verify that the fbdev or drm driver correctly adjusted the virtual
screen sizes. On failure report the failing driver and reject the screen
size change.

Signed-off-by: Helge Deller 
Reviewed-by: Geert Uytterhoeven 
Cc: stable@vger.kernel.org # v5.4+
Signed-off-by: Greg Kroah-Hartman

fbdev: fbmem: Fix logo center image dx issue

2022-07-12T14:30:46+00:00

commit 955f04766d4e6eb94bf3baa539e096808c74ebfb upstream.

Image.dx gets wrong value because of missing '()'.

If xres == logo->width and n == 1, image.dx = -16.

Signed-off-by: Guiling Deng 
Fixes: 3d8b1933eb1c ("fbdev: fbmem: add config option to center the bootup logo")
Cc: stable@vger.kernel.org # v5.0+
Signed-off-by: Helge Deller 
Signed-off-by: Greg Kroah-Hartman

fbcon: Consistently protect deferred_takeover with console_lock()

2022-06-14T16:11:25+00:00

[ Upstream commit 43553559121ca90965b572cf8a1d6d0fd618b449 ]

This shouldn't be a problem in practice since until we've actually
taken over the console there's nothing we've registered with the
console/vt subsystem, so the exit/unbind path that check this can't
do the wrong thing. But it's confusing, so fix it by moving it a tad
later.

Acked-by: Sam Ravnborg 
Signed-off-by: Daniel Vetter 
Cc: Daniel Vetter 
Cc: Du Cheng 
Cc: Tetsuo Handa 
Cc: Claudio Suarez 
Cc: Thomas Zimmermann 
Link: https://patchwork.freedesktop.org/patch/msgid/20220405210335.3434130-14-daniel.vetter@ffwll.ch
Signed-off-by: Sasha Levin

video: fbdev: fbcvt.c: fix printing in fb_cvt_print_name()

2022-04-15T12:18:07+00:00

[ Upstream commit 78482af095abd9f4f29f1aa3fe575d25c6ae3028 ]

This code has two bugs:
1) "cnt" is 255 but the size of the buffer is 256 so the last byte is
   not used.
2) If we try to print more than 255 characters then "cnt" will be
   negative and that will trigger a WARN() in snprintf(). The fix for
   this is to use scnprintf() instead of snprintf().

We can re-write this code to be cleaner:
1) Rename "offset" to "off" because that's shorter.
2) Get rid of the "cnt" variable and just use "size - off" directly.
3) Get rid of the "read" variable and just increment "off" directly.

Fixes: 96fe6a2109db ("fbdev: Add VESA Coordinated Video Timings (CVT) support")
Signed-off-by: Dan Carpenter 
Signed-off-by: Helge Deller 
Signed-off-by: Sasha Levin

fbmem: don't allow too huge resolutions

2021-09-15T07:47:41+00:00

commit 8c28051cdcbe9dfcec6bd0a4709d67a09df6edae upstream.

syzbot is reporting page fault at vga16fb_fillrect() [1], for
vga16fb_check_var() is failing to detect multiplication overflow.

  if (vxres * vyres > maxmem) {
    vyres = maxmem / vxres;
    if (vyres < yres)
      return -ENOMEM;
  }

Since no module would accept too huge resolutions where multiplication
overflow happens, let's reject in the common path.

Link: https://syzkaller.appspot.com/bug?extid=04168c8063cfdde1db5e [1]
Reported-by: syzbot 
Debugged-by: Randy Dunlap 
Signed-off-by: Tetsuo Handa 
Reviewed-by: Geert Uytterhoeven 
Cc: stable@vger.kernel.org
Signed-off-by: Daniel Vetter 
Link: https://patchwork.freedesktop.org/patch/msgid/185175d6-227a-7b55-433d-b070929b262c@i-love.sakura.ne.jp
Signed-off-by: Greg Kroah-Hartman

fbmem: Do not delete the mode that is still in use

2021-07-20T14:10:40+00:00

commit 0af778269a522c988ef0b4188556aba97fb420cc upstream.

The execution of fb_delete_videomode() is not based on the result of the
previous fbcon_mode_deleted(). As a result, the mode is directly deleted,
regardless of whether it is still in use, which may cause UAF.

==================================================================
BUG: KASAN: use-after-free in fb_mode_is_equal+0x36e/0x5e0 \
drivers/video/fbdev/core/modedb.c:924
Read of size 4 at addr ffff88807e0ddb1c by task syz-executor.0/18962

CPU: 2 PID: 18962 Comm: syz-executor.0 Not tainted 5.10.45-rc1+ #3
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS ...
Call Trace:
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack+0x137/0x1be lib/dump_stack.c:118
 print_address_description+0x6c/0x640 mm/kasan/report.c:385
 __kasan_report mm/kasan/report.c:545 [inline]
 kasan_report+0x13d/0x1e0 mm/kasan/report.c:562
 fb_mode_is_equal+0x36e/0x5e0 drivers/video/fbdev/core/modedb.c:924
 fbcon_mode_deleted+0x16a/0x220 drivers/video/fbdev/core/fbcon.c:2746
 fb_set_var+0x1e1/0xdb0 drivers/video/fbdev/core/fbmem.c:975
 do_fb_ioctl+0x4d9/0x6e0 drivers/video/fbdev/core/fbmem.c:1108
 vfs_ioctl fs/ioctl.c:48 [inline]
 __do_sys_ioctl fs/ioctl.c:753 [inline]
 __se_sys_ioctl+0xfb/0x170 fs/ioctl.c:739
 do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

Freed by task 18960:
 kasan_save_stack mm/kasan/common.c:48 [inline]
 kasan_set_track+0x3d/0x70 mm/kasan/common.c:56
 kasan_set_free_info+0x17/0x30 mm/kasan/generic.c:355
 __kasan_slab_free+0x108/0x140 mm/kasan/common.c:422
 slab_free_hook mm/slub.c:1541 [inline]
 slab_free_freelist_hook+0xd6/0x1a0 mm/slub.c:1574
 slab_free mm/slub.c:3139 [inline]
 kfree+0xca/0x3d0 mm/slub.c:4121
 fb_delete_videomode+0x56a/0x820 drivers/video/fbdev/core/modedb.c:1104
 fb_set_var+0x1f3/0xdb0 drivers/video/fbdev/core/fbmem.c:978
 do_fb_ioctl+0x4d9/0x6e0 drivers/video/fbdev/core/fbmem.c:1108
 vfs_ioctl fs/ioctl.c:48 [inline]
 __do_sys_ioctl fs/ioctl.c:753 [inline]
 __se_sys_ioctl+0xfb/0x170 fs/ioctl.c:739
 do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

Fixes: 13ff178ccd6d ("fbcon: Call fbcon_mode_deleted/new_modelist directly")
Signed-off-by: Zhen Lei 
Cc:  # v5.3+
Signed-off-by: Daniel Vetter 
Link: https://patchwork.freedesktop.org/patch/msgid/20210712085544.2828-1-thunder.leizhen@huawei.com
Signed-off-by: Greg Kroah-Hartman

tty: vt: always invoke vc->vc_sw->con_resize callback

2021-05-26T10:05:20+00:00

commit ffb324e6f874121f7dce5bdae5e05d02baae7269 upstream.

syzbot is reporting OOB write at vga16fb_imageblit() [1], for
resize_screen() from ioctl(VT_RESIZE) returns 0 without checking whether
requested rows/columns fit the amount of memory reserved for the graphical
screen if current mode is KD_GRAPHICS.

----------
  #include 
  #include 
  #include 
  #include 
  #include 
  #include 

  int main(int argc, char *argv[])
  {
        const int fd = open("/dev/char/4:1", O_RDWR);
        struct vt_sizes vt = { 0x4100, 2 };

        ioctl(fd, KDSETMODE, KD_GRAPHICS);
        ioctl(fd, VT_RESIZE, &vt);
        ioctl(fd, KDSETMODE, KD_TEXT);
        return 0;
  }
----------

Allow framebuffer drivers to return -EINVAL, by moving vc->vc_mode !=
KD_GRAPHICS check from resize_screen() to fbcon_resize().

Link: https://syzkaller.appspot.com/bug?extid=1f29e126cf461c4de3b3 [1]
Reported-by: syzbot 
Suggested-by: Linus Torvalds 
Signed-off-by: Tetsuo Handa 
Tested-by: syzbot 
Signed-off-by: Linus Torvalds 
Signed-off-by: Greg Kroah-Hartman