From: Alex Guo <alexguo1023@gmail.com>
To: deller@gmx.de
Cc: alexguo1023@gmail.com, linux-fbdev@vger.kernel.org,
dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org
Subject: [PATCH] fbdev: Fix potential divide by zero
Date: Sat, 14 Jun 2025 01:29:42 -0400 [thread overview]
Message-ID: <20250614052942.3551870-1-alexguo1023@gmail.com> (raw)
Variable var->pixclock can be set by user. In case it equals to
zero, divide by zero would occur in acornfb_validate_timing.
Similar crashes have happened in other fbdev drivers. We fix this
by checking whether 'pixclock' is zero.
Similar commit: commit 16844e58704 ("video: fbdev: tridentfb:
Error out if 'pixclock' equals zero")
Signed-off-by: Alex Guo <alexguo1023@gmail.com>
---
drivers/video/fbdev/acornfb.c | 2 ++
1 file changed, 2 insertions(+)
diff --git a/drivers/video/fbdev/acornfb.c b/drivers/video/fbdev/acornfb.c
index f0600f6ca254..2dc0e64137e5 100644
--- a/drivers/video/fbdev/acornfb.c
+++ b/drivers/video/fbdev/acornfb.c
@@ -421,6 +421,8 @@ acornfb_validate_timing(struct fb_var_screeninfo *var,
* No need to do long long divisions or anything
* like that if you factor it correctly
*/
+ if (!var->pixclock)
+ return -EINVAL;
hs = 1953125000 / var->pixclock;
hs = hs * 512 /
(var->xres + var->left_margin + var->right_margin + var->hsync_len);
--
2.34.1
reply other threads:[~2025-06-14 5:29 UTC|newest]
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