From 16b71fdf97599f1b1b7f38418ee9922d9f117396 Mon Sep 17 00:00:00 2001 From: Samuel CUELLA Date: Tue, 10 Mar 2009 12:56:00 -0700 Subject: [PATCH] i810: fix kernel crash fix when struct fb_var_screeninfo is supplied Prevent the kernel from being crashed by a divide-by-zero operation when supplied an incorrectly filled 'struct fb_var_screeninfo' from userland. Previously i810_main.c:1005 (i810_check_params) was using the global 'yres' symbol previously defined at i810_main.c:145 as a module parameter value holder (i810_main.c:2174). If i810fb is compiled-in or if this param doesn't get a default value, this direct usage leads to a divide-by-zero at i810_main.c:1005 (i810_check_params). The patch simply replace the 'yres' global, perhaps undefined symbol usage by a given parameter structure lookup. This problem occurs with directfb, mplayer -vo fbdev, SDL library. It was also reported ( but non solved ) at: http://mail.directfb.org/pipermail/directfb-dev/2008-March/004050.html Signed-off-by: Samuel CUELLA Cc: Jiri Kosina Cc: Krzysztof Helt Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- drivers/video/i810/i810_main.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/drivers/video/i810/i810_main.c b/drivers/video/i810/i810_main.c index a24e680..2e94019 100644 --- a/drivers/video/i810/i810_main.c +++ b/drivers/video/i810/i810_main.c @@ -993,6 +993,7 @@ static int i810_check_params(struct fb_var_screeninfo *var, struct i810fb_par *par = info->par; int line_length, vidmem, mode_valid = 0, retval = 0; u32 vyres = var->yres_virtual, vxres = var->xres_virtual; + /* * Memory limit */ @@ -1002,12 +1003,12 @@ static int i810_check_params(struct fb_var_screeninfo *var, if (vidmem > par->fb.size) { vyres = par->fb.size/line_length; if (vyres < var->yres) { - vyres = yres; + vyres = info->var.yres; vxres = par->fb.size/vyres; vxres /= var->bits_per_pixel >> 3; line_length = get_line_length(par, vxres, var->bits_per_pixel); - vidmem = line_length * yres; + vidmem = line_length * info->var.yres; if (vxres < var->xres) { printk("i810fb: required video memory, " "%d bytes, for %dx%d-%d (virtual) " -- 2.7.4