From: Zheyu Ma zheyuma97@gmail.com
commit 15cf0b82271b1823fb02ab8c377badba614d95d5 upstream.
The userspace program could pass any values to the driver through ioctl() interface. If the driver doesn't check the value of 'pixclock', it may cause divide error.
Fix this by checking whether 'pixclock' is zero in the function i740fb_check_var().
The following log reveals it:
divide error: 0000 [#1] PREEMPT SMP KASAN PTI RIP: 0010:i740fb_decode_var drivers/video/fbdev/i740fb.c:444 [inline] RIP: 0010:i740fb_set_par+0x272f/0x3bb0 drivers/video/fbdev/i740fb.c:739 Call Trace: fb_set_var+0x604/0xeb0 drivers/video/fbdev/core/fbmem.c:1036 do_fb_ioctl+0x234/0x670 drivers/video/fbdev/core/fbmem.c:1112 fb_ioctl+0xdd/0x130 drivers/video/fbdev/core/fbmem.c:1191 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:874 [inline]
Signed-off-by: Zheyu Ma zheyuma97@gmail.com Signed-off-by: Helge Deller deller@gmx.de Signed-off-by: Stefan Ghinea stefan.ghinea@windriver.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/video/fbdev/i740fb.c | 3 +++ 1 file changed, 3 insertions(+)
--- a/drivers/video/fbdev/i740fb.c +++ b/drivers/video/fbdev/i740fb.c @@ -662,6 +662,9 @@ static int i740fb_decode_var(const struc
static int i740fb_check_var(struct fb_var_screeninfo *var, struct fb_info *info) { + if (!var->pixclock) + return -EINVAL; + switch (var->bits_per_pixel) { case 8: var->red.offset = var->green.offset = var->blue.offset = 0;