summaryrefslogtreecommitdiff
path: root/drivers/video
diff options
context:
space:
mode:
authorZheyu Ma <zheyuma97@gmail.com>2021-07-21 12:43:44 +0000
committerSam Ravnborg <sam@ravnborg.org>2021-07-21 15:02:03 +0200
commit030fadb0138186cfa04492e1132a9df514d03841 (patch)
tree0e2667417713c49f563150eb8c3582e802b86f93 /drivers/video
parent99279ad8feb9142ab03f9651c2401c1b3807857b (diff)
video: fbdev: neofb: add a check against divide error
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> Signed-off-by: Sam Ravnborg <sam@ravnborg.org> Link: https://patchwork.freedesktop.org/patch/msgid/1626871424-27708-1-git-send-email-zheyuma97@gmail.com
Diffstat (limited to 'drivers/video')
-rw-r--r--drivers/video/fbdev/neofb.c2
1 files changed, 1 insertions, 1 deletions
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? */