| Message ID | 20220404084723.79089-7-zheyuma97@gmail.com |
|---|---|
| State | New |
| Headers | show |
| Series | Fix divide errors in fbdev drivers | expand |
diff --git a/drivers/video/fbdev/arkfb.c b/drivers/video/fbdev/arkfb.c index edf169d0816e..eb3e47c58c5f 100644 --- a/drivers/video/fbdev/arkfb.c +++ b/drivers/video/fbdev/arkfb.c @@ -566,6 +566,9 @@ static int arkfb_check_var(struct fb_var_screeninfo *var, struct fb_info *info) { int rv, mem, step; + if (!var->pixclock) + return -EINVAL; + /* Find appropriate format */ rv = svga_match_format (arkfb_formats, var, NULL); if (rv < 0)
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. The following log reveals it: [ 76.603696] divide error: 0000 [#1] PREEMPT SMP KASAN PTI [ 76.603712] RIP: 0010:arkfb_set_par+0x10fc/0x24f0 [ 76.603762] Call Trace: [ 76.603764] <TASK> [ 76.603773] fb_set_var+0x604/0xeb0 [ 76.603827] do_fb_ioctl+0x234/0x670 [ 76.603873] fb_ioctl+0xdd/0x130 [ 76.603881] do_syscall_64+0x3b/0x90 Signed-off-by: Zheyu Ma <zheyuma97@gmail.com> --- drivers/video/fbdev/arkfb.c | 3 +++ 1 file changed, 3 insertions(+)