fbcon：修复 fbcon_putcs 中的空指针取消引用问题（CVE-2024-50048）
CVE编号
CVE-2024-50048利用情况
暂无补丁情况
N/A披露时间
2024-10-22漏洞描述
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, ¶m); con2fb.console = 1; con2fb.framebuffer = 0; ioctl(fd, FBIOPUT_CON2FBMAP, &con2fb); return 0; } After calling ioctl(fd1, TIOCLINUX, ¶m), 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.解决建议
建议您更新当前系统或软件至最新版，完成漏洞的修复。受影响软件情况
| # | 类型 | 厂商 | 产品 | 版本 | 影响面 | ||||
| 1 | |||||||||
|---|---|---|---|---|---|---|---|---|---|
| 运行在以下环境 | |||||||||
| 系统 | linux | linux_kernel | * | Up to (excluding) 6.1.113 | |||||
| 运行在以下环境 | |||||||||
| 系统 | linux | linux_kernel | * | From (including) 6.2 | Up to (excluding) 6.6.57 | ||||
| 运行在以下环境 | |||||||||
| 系统 | linux | linux_kernel | * | From (including) 6.7 | Up to (excluding) 6.11.4 | ||||
- 攻击路径 本地
- 攻击复杂度 低
- 权限要求 低
- 影响范围 未更改
- 用户交互 无
- 可用性 高
- 保密性 无
- 完整性 无
| CWE-ID | 漏洞类型 |
| CWE-476 | 空指针解引用 |
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