video: fbdev: vt8623fb: Check the size of screen before memset_io()

Vulnerability Description

In the Linux kernel, the following vulnerability has been resolved: video: fbdev: vt8623fb: Check the size of screen before memset_io() In the function vt8623fb_set_par(), the value of 'screen_size' is calculated by the user input. If the user provides the improper value, the value of 'screen_size' may larger than 'info->screen_size', which may cause the following bug: [ 583.339036] BUG: unable to handle page fault for address: ffffc90005000000 [ 583.339049] #PF: supervisor write access in kernel mode [ 583.339052] #PF: error_code(0x0002) - not-present page [ 583.339074] RIP: 0010:memset_orig+0x33/0xb0 [ 583.339110] Call Trace: [ 583.339118] vt8623fb_set_par+0x11cd/0x21e0 [ 583.339146] fb_set_var+0x604/0xeb0 [ 583.339181] do_fb_ioctl+0x234/0x670 [ 583.339209] fb_ioctl+0xdd/0x130 Fix the this by checking the value of 'screen_size' before memset_io().

References

• https://git.kernel.org/stable/c/73280a184aa2e1a625ce54ce761042955cc79cd0
• https://git.kernel.org/stable/c/52ad9bfeb8a0e62de30de6d39e8a49a72dd78150
• https://git.kernel.org/stable/c/d71528ccdc7ae8d7500d414091d27805c51407a2
• https://git.kernel.org/stable/c/bd8269e57621e5b38cc0b4bd2fa02e85c9f2a441
• https://git.kernel.org/stable/c/4a3cef1eaced13ba9b55381d46bfad937a3dac2c
• https://git.kernel.org/stable/c/b17caec5127bba6f90af92bcc85871df54548ac0
• https://git.kernel.org/stable/c/c7a3f41e4b133d4dd25bc996b69039b19a34d69d
• https://git.kernel.org/stable/c/ec0754c60217248fa77cc9005d66b2b55200ac06