From: Roman Smirnov <r.smirnov@omp.ru>
To: Daniel Vetter <daniel@ffwll.ch>, Helge Deller <deller@gmx.de>
Cc: Roman Smirnov <r.smirnov@omp.ru>,
Thomas Zimmermann <tzimmermann@suse.de>,
Sergey Shtylyov <s.shtylyov@omp.ru>,
Karina Yankevich <k.yankevich@omp.ru>,
<linux-fbdev@vger.kernel.org>, <dri-devel@lists.freedesktop.org>,
<linux-kernel@vger.kernel.org>, <lvc-project@linuxtesting.org>
Subject: [PATCH v2] fbmon: prevent division by zero in fb_videomode_from_videomode()
Date: Tue, 5 Mar 2024 16:51:50 +0300 [thread overview]
Message-ID: <20240305135150.23240-1-r.smirnov@omp.ru> (raw)
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>
---
V1 -> V2: Replaced the code of the first version with a check.
drivers/video/fbdev/core/fbmon.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/video/fbdev/core/fbmon.c b/drivers/video/fbdev/core/fbmon.c
index 79e5bfbdd34c..b137590386da 100644
--- a/drivers/video/fbdev/core/fbmon.c
+++ b/drivers/video/fbdev/core/fbmon.c
@@ -1344,7 +1344,7 @@ int fb_videomode_from_videomode(const struct videomode *vm,
vtotal = vm->vactive + vm->vfront_porch + vm->vback_porch +
vm->vsync_len;
/* prevent division by zero */
- if (htotal && vtotal) {
+ if (htotal && vtotal && (vm->pixelclock / htotal >= vtotal)) {
fbmode->refresh = vm->pixelclock / (htotal * vtotal);
/* a mode must have htotal and vtotal != 0 or it is invalid */
} else {
--
2.34.1
next reply other threads:[~2024-03-05 13:52 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-03-05 13:51 Roman Smirnov [this message]
2024-03-15 8:44 ` [PATCH v2] fbmon: prevent division by zero in fb_videomode_from_videomode() Helge Deller
2024-03-18 8:11 ` Roman Smirnov
2024-03-18 19:15 ` Helge Deller
2024-03-19 8:12 ` Roman Smirnov
2024-03-19 8:22 ` Sergey Shtylyov
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