fbdev: tgafb: Fix potential divide by zero

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[ Upstream commit f90bd245de ]

fb_set_var would by called when user invokes ioctl with cmd
FBIOPUT_VSCREENINFO. User-provided data would finally reach
tgafb_check_var. In case var->pixclock is assigned to zero,
divide by zero would occur when checking whether reciprocal
of var->pixclock is too high.

Similar crashes have happened in other fbdev drivers. There
is no check and modification on var->pixclock along the call
chain to tgafb_check_var. We believe it could also be triggered
in driver tgafb from user site.

Signed-off-by: Wei Chen <harperchen1110@gmail.com>
Signed-off-by: Helge Deller <deller@gmx.de>
Signed-off-by: Sasha Levin <sashal@kernel.org>

...

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Wei Chen 2023-03-07 13:08:56 +00:00 • committed by Greg Kroah-Hartman

parent 734a3deb66

commit 1c7a897755

1 changed files with 3 additions and 0 deletions

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drivers/video/fbdev/tgafb.c

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