CVE-2022-50222

About vulnerability

In the Linux kernel, the following vulnerability has been resolved:

tty: vt: initialize unicode screen buffer

syzbot reports kernel infoleak at vcs_read() [1], for buffer can be read immediately after resize operation. Initialize buffer using kzalloc().

#include <fcntl.h> #include <unistd.h> #include <sys/ioctl.h> #include <linux/fb.h>

int main(int argc, char *argv[]) { struct fb_var_screeninfo var = { }; const int fb_fd = open("/dev/fb0", 3); ioctl(fb_fd, FBIOGET_VSCREENINFO, &var); var.yres = 0x21; ioctl(fb_fd, FBIOPUT_VSCREENINFO, &var); return read(open("/dev/vcsu", O_RDONLY), &var, sizeof(var)) == -1; }

Affected product:

AlmaLinux 9.2 ESU , Oracle Linux 7 ELS , TuxCare 9.6 ESU , Ubuntu 20.04 ELS

Affected packages:

linux @ 5.4.0 (+3 more)

In the Linux kernel, the following vulnerability has been resolved:

tty: vt: initialize unicode screen buffer

syzbot reports kernel infoleak at vcs_read() [1], for buffer can be read immediately after resize operation. Initialize buffer using kzalloc().

#include <fcntl.h> #include <unistd.h> #include <sys/ioctl.h> #include <linux/fb.h>

int main(int argc, char *argv[]) { struct fb_var_screeninfo var = { }; const int fb_fd = open("/dev/fb0", 3); ioctl(fb_fd, FBIOGET_VSCREENINFO, &var); var.yres = 0x21; ioctl(fb_fd, FBIOPUT_VSCREENINFO, &var); return read(open("/dev/vcsu", O_RDONLY), &var, sizeof(var)) == -1; }