5.4-stable review patch. If anyone has any objections, please let me know.
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From: Sergey Shtylyov s.shtylyov@omp.ru
[ Upstream commit 3f6dae09fc8c306eb70fdfef70726e1f154e173a ]
In fb_find_mode_cvt(), iff mode->refresh somehow happens to be 0x80000000, cvt.f_refresh will become 0 when multiplying it by 2 due to overflow. It's then passed to fb_cvt_hperiod(), where it's used as a divider -- division by 0 will result in kernel oops. Add a sanity check for cvt.f_refresh to avoid such overflow...
Found by Linux Verification Center (linuxtesting.org) with the Svace static analysis tool.
Fixes: 96fe6a2109db ("[PATCH] fbdev: Add VESA Coordinated Video Timings (CVT) support") Signed-off-by: Sergey Shtylyov s.shtylyov@omp.ru Signed-off-by: Helge Deller deller@gmx.de Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/video/fbdev/core/fbcvt.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/video/fbdev/core/fbcvt.c b/drivers/video/fbdev/core/fbcvt.c index 64843464c6613..cd3821bd82e56 100644 --- a/drivers/video/fbdev/core/fbcvt.c +++ b/drivers/video/fbdev/core/fbcvt.c @@ -312,7 +312,7 @@ int fb_find_mode_cvt(struct fb_videomode *mode, int margins, int rb) cvt.f_refresh = cvt.refresh; cvt.interlace = 1;
- if (!cvt.xres || !cvt.yres || !cvt.refresh) { + if (!cvt.xres || !cvt.yres || !cvt.refresh || cvt.f_refresh > INT_MAX) { printk(KERN_INFO "fbcvt: Invalid input parameters\n"); return 1; }