"value":"In the Linux kernel, the following vulnerability has been resolved:\n\nfbcon: Fix a NULL pointer dereference issue in fbcon_putcs\n\nsyzbot has found a NULL pointer dereference bug in fbcon.\nHere is the simplified C reproducer:\n\nstruct param {\n\tuint8_t type;\n\tstruct tiocl_selection ts;\n};\n\nint main()\n{\n\tstruct fb_con2fbmap con2fb;\n\tstruct param param;\n\n\tint fd = open(\"/dev/fb1\", 0, 0);\n\n\tcon2fb.console = 0x19;\n\tcon2fb.framebuffer = 0;\n\tioctl(fd, FBIOPUT_CON2FBMAP, &con2fb);\n\n\tparam.type = 2;\n\tparam.ts.xs = 0; param.ts.ys = 0;\n\tparam.ts.xe = 0; param.ts.ye = 0;\n\tparam.ts.sel_mode = 0;\n\n\tint fd1 = open(\"/dev/tty1\", O_RDWR, 0);\n\tioctl(fd1, TIOCLINUX, ¶m);\n\n\tcon2fb.console = 1;\n\tcon2fb.framebuffer = 0;\n\tioctl(fd, FBIOPUT_CON2FBMAP, &con2fb);\n\n\treturn 0;\n}\n\nAfter calling ioctl(fd1, TIOCLINUX, ¶m), the subsequent ioctl(fd, FBIOPUT_CON2FBMAP, &con2fb)\ncauses the kernel to follow a different execution path:\n\n set_con2fb_map\n -> con2fb_init_display\n -> fbcon_set_disp\n -> redraw_screen\n -> hide_cursor\n -> clear_selection\n -> highlight\n -> invert_screen\n -> do_update_region\n -> fbcon_putcs\n -> ops->putcs\n\nSince ops->putcs is a NULL pointer, this leads to a kernel panic.\nTo prevent this, we need to call set_blitting_type() within set_con2fb_map()\nto properly initialize ops->putcs."
"value":"En el kernel de Linux, se ha resuelto la siguiente vulnerabilidad: fbcon: soluciona un problema de desreferencia de puntero NULL en fbcon_putcs syzbot ha encontrado un error de desreferencia de puntero NULL en fbcon. Aqu\u00ed est\u00e1 el reproductor C simplificado: 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); devolver 0; } Despu\u00e9s de llamar a ioctl(fd1, TIOCLINUX, &param), el ioctl(fd, FBIOPUT_CON2FBMAP, &con2fb) subsiguiente hace que el n\u00facleo siga una ruta de ejecuci\u00f3n diferente: 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 Dado que ops->putcs es un puntero NULL, esto lleva a un p\u00e1nico del n\u00facleo. Para evitar esto, necesitamos llamar a set_blitting_type() dentro de set_con2fb_map() para inicializar correctamente ops->putcs."