linux-stable.git/drivers/video/fbdev/core, branch linux-4.9.y

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

2022-04-20T07:06:32+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

2021-09-22T09:43:02+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: add margin check to fb_check_caps()

2021-09-03T07:44:40+00:00

commit a49145acfb975d921464b84fe00279f99827d816 upstream.

A fb_ioctl() FBIOPUT_VSCREENINFO call with invalid xres setting
or yres setting in struct fb_var_screeninfo will result in a
KASAN: vmalloc-out-of-bounds failure in bitfill_aligned() as
the margins are being cleared. The margins are cleared in
chunks and if the xres setting or yres setting is a value of
zero upto the chunk size, the failure will occur.

Add a margin check to validate xres and yres settings.

Signed-off-by: George Kennedy 
Reported-by: syzbot+e5fd3e65515b48c02a30@syzkaller.appspotmail.com
Reviewed-by: Dan Carpenter 
Cc: Dhaval Giani 
Signed-off-by: Bartlomiej Zolnierkiewicz 
Link: https://patchwork.freedesktop.org/patch/msgid/1594149963-13801-1-git-send-email-george.kennedy@oracle.com
Signed-off-by: Greg Kroah-Hartman

fbdev: zero-fill colormap in fbcmap.c

2021-05-22T08:40:16+00:00

commit 19ab233989d0f7ab1de19a036e247afa4a0a1e9c upstream.

Use kzalloc() rather than kmalloc() for the dynamically allocated parts
of the colormap in fb_alloc_cmap_gfp, to prevent a leak of random kernel
data to userspace under certain circumstances.

Fixes a KMSAN-found infoleak bug reported by syzbot at:
https://syzkaller.appspot.com/bug?id=741578659feabd108ad9e06696f0c1f2e69c4b6e

Reported-by: syzbot+47fa9c9c648b765305b9@syzkaller.appspotmail.com
Cc: stable 
Reviewed-by: Geert Uytterhoeven 
Signed-off-by: Phillip Potter 
Link: https://lore.kernel.org/r/20210331220719.1499743-1-phil@philpotter.co.uk
Signed-off-by: Greg Kroah-Hartman 
Signed-off-by: Greg Kroah-Hartman

fbdev: potential information leak in do_fb_ioctl()

2020-04-24T05:59:14+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

fbdev: Ditch fb_edid_add_monspecs

2019-11-25T08:53:14+00:00

commit 3b8720e63f4a1fc6f422a49ecbaa3b59c86d5aaf upstream.

It's dead code ever since

commit 34280340b1dc74c521e636f45cd728f9abf56ee2
Author: Geert Uytterhoeven 
Date:   Fri Dec 4 17:01:43 2015 +0100

    fbdev: Remove unused SH-Mobile HDMI driver

Also with this gone we can remove the cea_modes db. This entire thing
is massively incomplete anyway, compared to the CEA parsing that
drm_edid.c does.

Acked-by: Linus Torvalds 
Cc: Tavis Ormandy 
Signed-off-by: Daniel Vetter 
Signed-off-by: Bartlomiej Zolnierkiewicz 
Link: https://patchwork.freedesktop.org/patch/msgid/20190721201956.941-1-daniel.vetter@ffwll.ch
Signed-off-by: Greg Kroah-Hartman

fbdev: fix WARNING in __alloc_pages_nodemask bug

2019-05-31T13:48:12+00:00

commit 8c40292be9169a9cbe19aadd1a6fc60cbd1af82f upstream.

Syzkaller hit 'WARNING in __alloc_pages_nodemask' bug.

WARNING: CPU: 1 PID: 1473 at mm/page_alloc.c:4377
__alloc_pages_nodemask+0x4da/0x2130
Kernel panic - not syncing: panic_on_warn set ...

Call Trace:
 alloc_pages_current+0xb1/0x1e0
 kmalloc_order+0x1f/0x60
 kmalloc_order_trace+0x1d/0x120
 fb_alloc_cmap_gfp+0x85/0x2b0
 fb_set_user_cmap+0xff/0x370
 do_fb_ioctl+0x949/0xa20
 fb_ioctl+0xdd/0x120
 do_vfs_ioctl+0x186/0x1070
 ksys_ioctl+0x89/0xa0
 __x64_sys_ioctl+0x74/0xb0
 do_syscall_64+0xc8/0x550
 entry_SYSCALL_64_after_hwframe+0x49/0xbe

This is a warning about order >= MAX_ORDER and the order is from
userspace ioctl. Add flag __NOWARN to silence this warning.

Signed-off-by: Jiufei Xue 
Signed-off-by: Bartlomiej Zolnierkiewicz 
Signed-off-by: Greg Kroah-Hartman

fbdev: fix divide error in fb_var_to_videomode

2019-05-31T13:48:12+00:00

commit cf84807f6dd0be5214378e66460cfc9187f532f9 upstream.

To fix following divide-by-zero error found by Syzkaller:

  divide error: 0000 [#1] SMP PTI
  CPU: 7 PID: 8447 Comm: test Kdump: loaded Not tainted 4.19.24-8.al7.x86_64 #1
  Hardware name: Alibaba Cloud Alibaba Cloud ECS, BIOS rel-1.12.0-0-ga698c8995f-prebuilt.qemu.org 04/01/2014
  RIP: 0010:fb_var_to_videomode+0xae/0xc0
  Code: 04 44 03 46 78 03 4e 7c 44 03 46 68 03 4e 70 89 ce d1 ee 69 c0 e8 03 00 00 f6 c2 01 0f 45 ce 83 e2 02 8d 34 09 0f 45 ce 31 d2 <41> f7 f0 31 d2 f7 f1 89 47 08 f3 c3 66 0f 1f 44 00 00 0f 1f 44 00
  RSP: 0018:ffffb7e189347bf0 EFLAGS: 00010246
  RAX: 00000000e1692410 RBX: ffffb7e189347d60 RCX: 0000000000000000
  RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffffb7e189347c10
  RBP: ffff99972a091c00 R08: 0000000000000000 R09: 0000000000000000
  R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000100
  R13: 0000000000010000 R14: 00007ffd66baf6d0 R15: 0000000000000000
  FS:  00007f2054d11740(0000) GS:ffff99972fbc0000(0000) knlGS:0000000000000000
  CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
  CR2: 00007f205481fd20 CR3: 00000004288a0001 CR4: 00000000001606a0
  Call Trace:
   fb_set_var+0x257/0x390
   ? lookup_fast+0xbb/0x2b0
   ? fb_open+0xc0/0x140
   ? chrdev_open+0xa6/0x1a0
   do_fb_ioctl+0x445/0x5a0
   do_vfs_ioctl+0x92/0x5f0
   ? __alloc_fd+0x3d/0x160
   ksys_ioctl+0x60/0x90
   __x64_sys_ioctl+0x16/0x20
   do_syscall_64+0x5b/0x190
   entry_SYSCALL_64_after_hwframe+0x44/0xa9
  RIP: 0033:0x7f20548258d7
  Code: 44 00 00 48 8b 05 b9 15 2d 00 64 c7 00 26 00 00 00 48 c7 c0 ff ff ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 b8 10 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 8b 0d 89 15 2d 00 f7 d8 64 89 01 48

It can be triggered easily with following test code:

  #include 
  #include 
  #include 
  int main(void)
  {
          struct fb_var_screeninfo var = {.activate = 0x100, .pixclock = 60};
          int fd = open("/dev/fb0", O_RDWR);
          if (fd < 0)
                  return 1;

          if (ioctl(fd, FBIOPUT_VSCREENINFO, &var))
                  return 1;

          return 0;
  }

Signed-off-by: Shile Zhang 
Cc: Fredrik Noring 
Cc: Daniel Vetter 
Reviewed-by: Mukesh Ojha 
Signed-off-by: Bartlomiej Zolnierkiewicz 
Signed-off-by: Greg Kroah-Hartman

fbdev: fbmem: fix memory access if logo is bigger than the screen

2019-04-05T20:29:12+00:00

[ Upstream commit a5399db139cb3ad9b8502d8b1bd02da9ce0b9df0 ]

There is no clipping on the x or y axis for logos larger that the framebuffer
size. Therefore: a logo bigger than screen size leads to invalid memory access:

[    1.254664] Backtrace:
[    1.254728] [] (cfb_imageblit) from [] (fb_show_logo+0x620/0x684)
[    1.254763]  r10:00000003 r9:00027fd8 r8:c6a40000 r7:c6a36e50 r6:00000000 r5:c06b81e4
[    1.254774]  r4:c6a3e800
[    1.254810] [] (fb_show_logo) from [] (fbcon_switch+0x3fc/0x46c)
[    1.254842]  r10:c6a3e824 r9:c6a3e800 r8:00000000 r7:c6a0c000 r6:c070b014 r5:c6a3e800
[    1.254852]  r4:c6808c00
[    1.254889] [] (fbcon_switch) from [] (redraw_screen+0xf0/0x1e8)
[    1.254918]  r10:00000000 r9:00000000 r8:00000000 r7:00000000 r6:c070d5a0 r5:00000080
[    1.254928]  r4:c6808c00
[    1.254961] [] (redraw_screen) from [] (do_bind_con_driver+0x194/0x2e4)
[    1.254991]  r9:00000000 r8:00000000 r7:00000014 r6:c070d5a0 r5:c070d5a0 r4:c070d5a0

So prevent displaying a logo bigger than screen size and avoid invalid
memory access.

Signed-off-by: Manfred Schlaegl 
Signed-off-by: Martin Kepplinger 
Cc: Daniel Vetter 
Signed-off-by: Bartlomiej Zolnierkiewicz 
Signed-off-by: Sasha Levin

fbdev: fbmem: behave better with small rotated displays and many CPUs

2019-02-12T18:44:56+00:00

[ Upstream commit f75df8d4b4fabfad7e3cba2debfad12741c6fde7 ]

Blitting an image with "negative" offsets is not working since there
is no clipping. It hopefully just crashes. For the bootup logo, there
is protection so that blitting does not happen as the image is drawn
further and further to the right (ROTATE_UR) or further and further
down (ROTATE_CW). There is however no protection when drawing in the
opposite directions (ROTATE_UD and ROTATE_CCW).

Add back this protection.

The regression is 20-odd years old but the mindless warning-killing
mentality displayed in commit 34bdb666f4b2 ("fbdev: fbmem: remove
positive test on unsigned values") is also to blame, methinks.

Fixes: 448d479747b8 ("fbdev: fb_do_show_logo() updates")
Signed-off-by: Peter Rosin 
Cc: Tomi Valkeinen 
Cc: Fabian Frederick 
Cc: Geert Uytterhoeven 
cc: Geoff Levand 
Cc: James Simmons 
Signed-off-by: Bartlomiej Zolnierkiewicz 
Signed-off-by: Sasha Levin