| Message ID | 1626871424-27708-1-git-send-email-zheyuma97@gmail.com (mailing list archive) |
|---|---|
| State | Superseded, archived |
| Headers | show |
| Series | video: fbdev: neofb: add a check against divide error | expand |
diff --git a/drivers/video/fbdev/neofb.c b/drivers/video/fbdev/neofb.c index c0f4f402da3f..966df2a07360 100644 --- a/drivers/video/fbdev/neofb.c +++ b/drivers/video/fbdev/neofb.c @@ -585,7 +585,7 @@ neofb_check_var(struct fb_var_screeninfo *var, struct fb_info *info) DBG("neofb_check_var"); - if (PICOS2KHZ(var->pixclock) > par->maxClock) + if (var->pixclock && PICOS2KHZ(var->pixclock) > par->maxClock) return -EINVAL; /* Is the mode larger than the LCD panel? */
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 because of the 'PICOS2KHZ' macro. Fix this by checking whether 'pixclock' is zero first. The following log reveals it: [ 53.093806] divide error: 0000 [#1] PREEMPT SMP KASAN PTI [ 53.093838] CPU: 3 PID: 11763 Comm: hang Not tainted 5.14.0-rc2-00478-g2734d6c1b1a0 #215 [ 53.093859] RIP: 0010:neofb_check_var+0x80/0xe50 [ 53.093951] Call Trace: [ 53.093956] ? neofb_setcolreg+0x2b0/0x2b0 [ 53.093968] fb_set_var+0x2e4/0xeb0 [ 53.093977] ? fb_blank+0x1a0/0x1a0 [ 53.093984] ? lock_acquire+0x1ef/0x530 [ 53.093996] ? lock_release+0x810/0x810 [ 53.094005] ? lock_is_held_type+0x100/0x140 [ 53.094016] ? ___might_sleep+0x1ee/0x2d0 [ 53.094028] ? __mutex_lock+0x620/0x1190 [ 53.094036] ? do_fb_ioctl+0x313/0x700 [ 53.094044] ? mutex_lock_io_nested+0xfa0/0xfa0 [ 53.094051] ? __this_cpu_preempt_check+0x1d/0x30 [ 53.094060] ? _raw_spin_unlock_irqrestore+0x46/0x60 [ 53.094069] ? lockdep_hardirqs_on+0x59/0x100 [ 53.094076] ? _raw_spin_unlock_irqrestore+0x46/0x60 [ 53.094085] ? trace_hardirqs_on+0x6a/0x1c0 [ 53.094096] do_fb_ioctl+0x31e/0x700 Signed-off-by: Zheyu Ma <zheyuma97@gmail.com> --- drivers/video/fbdev/neofb.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)