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| author | Zheyu Ma <zheyuma97@gmail.com> | 2022-08-03 17:23:12 +0800 |
|---|---|---|
| committer | Helge Deller <deller@gmx.de> | 2022-08-03 15:13:15 +0200 |
| commit | 2f1c4523f7a3aaabe7e53d3ebd378292947e95c8 (patch) | |
| tree | ad21f8e75f6d09410e326f4bf9c78f194449e91d /virt | |
| parent | c5c7502e960d9128eae1a5663fb62506d8685ac3 (diff) | |
| download | linux-2f1c4523f7a3aaabe7e53d3ebd378292947e95c8.tar.bz2 | |
video: fbdev: arkfb: Fix a divide-by-zero bug in ark_set_pixclock()
Since the user can control the arguments of the ioctl() from the user
space, under special arguments that may result in a divide-by-zero bug
in:
drivers/video/fbdev/arkfb.c:784: ark_set_pixclock(info, (hdiv * info->var.pixclock) / hmul);
with hdiv=1, pixclock=1 and hmul=2 you end up with (1*1)/2 = (int) 0.
and then in:
drivers/video/fbdev/arkfb.c:504: rv = dac_set_freq(par->dac, 0, 1000000000 / pixclock);
we'll get a division-by-zero.
The following log can reveal it:
divide error: 0000 [#1] PREEMPT SMP KASAN PTI
RIP: 0010:ark_set_pixclock drivers/video/fbdev/arkfb.c:504 [inline]
RIP: 0010:arkfb_set_par+0x10fc/0x24c0 drivers/video/fbdev/arkfb.c:784
Call Trace:
fb_set_var+0x604/0xeb0 drivers/video/fbdev/core/fbmem.c:1034
do_fb_ioctl+0x234/0x670 drivers/video/fbdev/core/fbmem.c:1110
fb_ioctl+0xdd/0x130 drivers/video/fbdev/core/fbmem.c:1189
Fix this by checking the argument of ark_set_pixclock() first.
Fixes: 681e14730c73 ("arkfb: new framebuffer driver for ARK Logic cards")
Signed-off-by: Zheyu Ma <zheyuma97@gmail.com>
Signed-off-by: Helge Deller <deller@gmx.de>
Diffstat (limited to 'virt')
0 files changed, 0 insertions, 0 deletions