CVE-2022-50010

In the Linux kernel, the following vulnerability has been resolved:<br /> <br /> video: fbdev: i740fb: Check the argument of i740_calc_vclk()<br /> <br /> Since the user can control the arguments of the ioctl() from the user<br /> space, under special arguments that may result in a divide-by-zero bug.<br /> <br /> If the user provides an improper &amp;#39;pixclock&amp;#39; value that makes the argumet<br /> of i740_calc_vclk() less than &amp;#39;I740_RFREQ_FIX&amp;#39;, it will cause a<br /> divide-by-zero bug in:<br /> drivers/video/fbdev/i740fb.c:353 p_best = min(15, ilog2(I740_MAX_VCO_FREQ / (freq / I740_RFREQ_FIX)));<br /> <br /> The following log can reveal it:<br /> <br /> divide error: 0000 [#1] PREEMPT SMP KASAN PTI<br /> RIP: 0010:i740_calc_vclk drivers/video/fbdev/i740fb.c:353 [inline]<br /> RIP: 0010:i740fb_decode_var drivers/video/fbdev/i740fb.c:646 [inline]<br /> RIP: 0010:i740fb_set_par+0x163f/0x3b70 drivers/video/fbdev/i740fb.c:742<br /> Call Trace:<br /> fb_set_var+0x604/0xeb0 drivers/video/fbdev/core/fbmem.c:1034<br /> do_fb_ioctl+0x234/0x670 drivers/video/fbdev/core/fbmem.c:1110<br /> fb_ioctl+0xdd/0x130 drivers/video/fbdev/core/fbmem.c:1189<br /> <br /> Fix this by checking the argument of i740_calc_vclk() first.