NULL Pointer Dereference Affecting kernel-uki-virt-addons package, versions *


Severity

Recommended
0.0
medium
0
10

Based on Red Hat Enterprise Linux security rating.

Threat Intelligence

EPSS
0.04% (6th percentile)

Do your applications use this vulnerable package?

In a few clicks we can analyze your entire application and see what components are vulnerable in your application, and suggest you quick fixes.

Test your applications

Snyk Learn

Learn about NULL Pointer Dereference vulnerabilities in an interactive lesson.

Start learning
  • Snyk IDSNYK-RHEL9-KERNELUKIVIRTADDONS-8423702
  • published27 Nov 2024
  • disclosed21 Oct 2024

Introduced: 21 Oct 2024

CVE-2024-50048  (opens in a new tab)
CWE-476  (opens in a new tab)

How to fix?

There is no fixed version for RHEL:9 kernel-uki-virt-addons.

NVD Description

Note: Versions mentioned in the description apply only to the upstream kernel-uki-virt-addons package and not the kernel-uki-virt-addons package as distributed by RHEL. See How to fix? for RHEL:9 relevant fixed versions and status.

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

fbcon: Fix a NULL pointer dereference issue in fbcon_putcs

syzbot has found a NULL pointer dereference bug in fbcon. Here is the simplified C reproducer:

struct param { uint8_t type; struct tiocl_selection ts; };

int main() { struct fb_con2fbmap con2fb; struct param param;

int fd = open("/dev/fb1", 0, 0);

con2fb.console = 0x19; con2fb.framebuffer = 0; ioctl(fd, FBIOPUT_CON2FBMAP, &con2fb);

param.type = 2; param.ts.xs = 0; param.ts.ys = 0; param.ts.xe = 0; param.ts.ye = 0; param.ts.sel_mode = 0;

int fd1 = open("/dev/tty1", O_RDWR, 0); ioctl(fd1, TIOCLINUX, &param);

con2fb.console = 1; con2fb.framebuffer = 0; ioctl(fd, FBIOPUT_CON2FBMAP, &con2fb);

return 0;

}

After calling ioctl(fd1, TIOCLINUX, &param), the subsequent ioctl(fd, FBIOPUT_CON2FBMAP, &con2fb) causes the kernel to follow a different execution path:

set_con2fb_map -> con2fb_init_display -> fbcon_set_disp -> redraw_screen -> hide_cursor -> clear_selection -> highlight -> invert_screen -> do_update_region -> fbcon_putcs -> ops->putcs

Since ops->putcs is a NULL pointer, this leads to a kernel panic. To prevent this, we need to call set_blitting_type() within set_con2fb_map() to properly initialize ops->putcs.

CVSS Scores

version 3.1