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authorSamuel CUELLA <samuel.cuella@supinfo.com>2009-03-10 12:56:00 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2009-03-10 15:55:12 -0700
commit16b71fdf97599f1b1b7f38418ee9922d9f117396 (patch)
tree86ceac6117f5a678aaa177bbcdf8d84d2559010c
parent9233ecc5c4b5f31921d914b3ef3baa3dc1ae4cc6 (diff)
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 <samuel.cuella@supinfo.com> Cc: Jiri Kosina <jkosina@suse.cz> Cc: Krzysztof Helt <krzysztof.h1@poczta.fm> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
-rw-r--r--drivers/video/i810/i810_main.c5
1 files changed, 3 insertions, 2 deletions
diff --git a/drivers/video/i810/i810_main.c b/drivers/video/i810/i810_main.c
index a24e680d2b9c..2e940199fc89 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) "