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fbmon: prevent division by zero in fb_videomode_from_videomode()
[ Upstream commit c2d953276b
]
The expression htotal * vtotal can have a zero value on
overflow. It is necessary to prevent division by zero like in
fb_var_to_videomode().
Found by Linux Verification Center (linuxtesting.org) with Svace.
Signed-off-by: Roman Smirnov <r.smirnov@omp.ru>
Reviewed-by: Sergey Shtylyov <s.shtylyov@omp.ru>
Signed-off-by: Helge Deller <deller@gmx.de>
Signed-off-by: Sasha Levin <sashal@kernel.org>
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parent
e2ce8625c3
commit
48d6bcfc31
1 changed files with 4 additions and 3 deletions
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@ -1311,7 +1311,7 @@ int fb_get_mode(int flags, u32 val, struct fb_var_screeninfo *var, struct fb_inf
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int fb_videomode_from_videomode(const struct videomode *vm,
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struct fb_videomode *fbmode)
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{
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unsigned int htotal, vtotal;
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unsigned int htotal, vtotal, total;
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fbmode->xres = vm->hactive;
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fbmode->left_margin = vm->hback_porch;
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@ -1344,8 +1344,9 @@ int fb_videomode_from_videomode(const struct videomode *vm,
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vtotal = vm->vactive + vm->vfront_porch + vm->vback_porch +
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vm->vsync_len;
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/* prevent division by zero */
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if (htotal && vtotal) {
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fbmode->refresh = vm->pixelclock / (htotal * vtotal);
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total = htotal * vtotal;
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if (total) {
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fbmode->refresh = vm->pixelclock / total;
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/* a mode must have htotal and vtotal != 0 or it is invalid */
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} else {
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fbmode->refresh = 0;
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