CVE-2021-47383

In the Linux kernel, the following vulnerability has been resolved: tty: Fix out-of-bound vmalloc access in imageblit This issue happens when a userspace program does an ioctl FBIOPUT_VSCREENINFO passing the fb_var_screeninfo struct containing only the fields xres, yres, and bits_per_pixel with values. If this struct is the same as the previous ioctl, the vc_resize() detects it and doesn't call the resize_screen(), leaving the fb_var_screeninfo incomplete. And this leads to the updatescrollmode() calculates a wrong value to fbcon_display->vrows, which makes the real_y() return a wrong value of y, and that value, eventually, causes the imageblit to access an out-of-bound address value. To solve this issue I made the resize_screen() be called even if the screen does not need any resizing, so it will "fix and fill" the fb_var_screeninfo independently.

• linux linux kernel (< 4.4.286) • linux linux kernel (>= 4.5 < 4.9.285) • linux linux kernel (>= 4.10 < 4.14.249) • linux linux kernel (>= 4.15 < 4.19.209) • linux linux kernel (>= 4.20 < 5.4.151) • linux linux kernel (>= 5.5 < 5.10.71) • linux linux kernel (>= 5.11 < 5.14.10)