diff options
| author | Zheyu Ma <zheyuma97@gmail.com> | 2021-07-26 10:03:54 +0000 |
|---|---|---|
| committer | Sam Ravnborg <sam@ravnborg.org> | 2021-07-26 20:06:00 +0200 |
| commit | 1520b4b7ba964f8eec2e7dd14c571d50de3e5191 (patch) | |
| tree | 91ff97ec5e6128abb15f113c3c50526803156185 /drivers/video | |
| parent | b36b242d4b8ea178f7fd038965e3cac7f30c3f09 (diff) | |
video: fbdev: kyro: Error out if 'pixclock' equals zero
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 the value of 'lineclock' and
'frameclock' will be zero.
Fix this by checking whether 'pixclock' is zero in kyrofb_check_var().
The following log reveals it:
[ 103.073930] divide error: 0000 [#1] PREEMPT SMP KASAN PTI
[ 103.073942] CPU: 4 PID: 12483 Comm: syz-executor Not tainted 5.14.0-rc2-00478-g2734d6c1b1a0-dirty #118
[ 103.073959] RIP: 0010:kyrofb_set_par+0x316/0xc80
[ 103.074045] Call Trace:
[ 103.074048] ? ___might_sleep+0x1ee/0x2d0
[ 103.074060] ? kyrofb_ioctl+0x330/0x330
[ 103.074069] fb_set_var+0x5bf/0xeb0
[ 103.074078] ? fb_blank+0x1a0/0x1a0
[ 103.074085] ? lock_acquire+0x3bd/0x530
[ 103.074094] ? lock_release+0x810/0x810
[ 103.074103] ? ___might_sleep+0x1ee/0x2d0
[ 103.074114] ? __mutex_lock+0x620/0x1190
[ 103.074126] ? trace_hardirqs_on+0x6a/0x1c0
[ 103.074137] do_fb_ioctl+0x31e/0x700
[ 103.074144] ? fb_getput_cmap+0x280/0x280
[ 103.074152] ? rcu_read_lock_sched_held+0x11/0x80
[ 103.074162] ? rcu_read_lock_sched_held+0x11/0x80
[ 103.074171] ? __sanitizer_cov_trace_switch+0x67/0xf0
[ 103.074181] ? __sanitizer_cov_trace_const_cmp2+0x20/0x80
[ 103.074191] ? do_vfs_ioctl+0x14b/0x16c0
[ 103.074199] ? vfs_fileattr_set+0xb60/0xb60
[ 103.074207] ? rcu_read_lock_sched_held+0x11/0x80
[ 103.074216] ? lock_release+0x483/0x810
[ 103.074224] ? __fget_files+0x217/0x3d0
[ 103.074234] ? __fget_files+0x239/0x3d0
[ 103.074243] ? do_fb_ioctl+0x700/0x700
[ 103.074250] fb_ioctl+0xe6/0x130
Signed-off-by: Zheyu Ma <zheyuma97@gmail.com>
Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
Link: https://patchwork.freedesktop.org/patch/msgid/1627293835-17441-3-git-send-email-zheyuma97@gmail.com
Diffstat (limited to 'drivers/video')
| -rw-r--r-- | drivers/video/fbdev/kyro/fbdev.c | 3 |
1 files changed, 3 insertions, 0 deletions
diff --git a/drivers/video/fbdev/kyro/fbdev.c b/drivers/video/fbdev/kyro/fbdev.c index 4b8c7c16b1df..25801e8e3f74 100644 --- a/drivers/video/fbdev/kyro/fbdev.c +++ b/drivers/video/fbdev/kyro/fbdev.c @@ -399,6 +399,9 @@ static int kyrofb_check_var(struct fb_var_screeninfo *var, struct fb_info *info) { struct kyrofb_info *par = info->par; + if (!var->pixclock) + return -EINVAL; + if (var->bits_per_pixel != 16 && var->bits_per_pixel != 32) { printk(KERN_WARNING "kyrofb: depth not supported: %u\n", var->bits_per_pixel); return -EINVAL; |