Example #1
0
func LinuxInterrupt(u models.Usercorn, intno uint32) {
	if intno == 2 {
		// TODO: thumb? issue #121
		pc, _ := u.RegRead(uc.ARM_REG_PC)
		var tmp [4]byte
		if err := u.MemReadInto(tmp[:], pc-4); err != nil {
			panic(err)
		}
		n := u.UnpackAddr(tmp[:]) & 0xffff
		if n > 0 {
			LinuxSyscall(u, int(n))
			return
		}

		// TODO: handle errors or something
		num, _ := u.RegRead(uc.ARM_REG_R7)
		LinuxSyscall(u, int(num))
		return
	}
	panic(fmt.Sprintf("unhandled ARM interrupt: %d", intno))
}
Example #2
0
func setupTraps(u models.Usercorn, kernel *ArmLinuxKernel) error {
	// handle arm kernel traps
	// https://www.kernel.org/doc/Documentation/arm/kernel_user_helpers.txt
	if err := u.MemMap(0xffff0000, 0x10000); err != nil {
		return err
	}
	for addr := 0; addr < 0x10000; addr += 4 {
		// write "bx lr" to all kernel trap addresses so they will return
		bxlr := []byte{0x1e, 0xff, 0x2f, 0xe1}
		if err := u.MemWrite(0xffff0000+uint64(addr), bxlr); err != nil {
			return err
		}
	}
	_, err := u.HookAdd(uc.HOOK_CODE, func(_ uc.Unicorn, addr uint64, size uint32) {
		switch addr {
		case 0xffff0fa0:
			// __kuser_memory_barrier
			// *shrug*
		case 0xffff0f60:
			// __kuser_cmpxchg64
			// TODO: DRY possible here?
			oldval, _ := u.RegRead(uc.ARM_REG_R0)
			newval, _ := u.RegRead(uc.ARM_REG_R1)
			ptr, _ := u.RegRead(uc.ARM_REG_R2)
			var tmp [8]byte
			var status uint64
			if err := u.MemReadInto(tmp[:], ptr); err != nil {
				// error
			} else if u.ByteOrder().Uint64(tmp[:]) == oldval {
				u.ByteOrder().PutUint64(tmp[:], newval)
				u.MemWrite(ptr, tmp[:])
				status = 1
			}
			u.RegWrite(uc.ARM_REG_R0, status)
		case 0xffff0fc0:
			// __kuser_cmpxchg
			// TODO: would this throw a segfault?
			// TODO: flags are not set
			oldval, _ := u.RegRead(uc.ARM_REG_R0)
			newval, _ := u.RegRead(uc.ARM_REG_R1)
			ptr, _ := u.RegRead(uc.ARM_REG_R2)
			var tmp [4]byte
			var status uint64
			if err := u.MemReadInto(tmp[:], ptr); err != nil {
				// error
			} else if u.UnpackAddr(tmp[:]) == oldval {
				u.PackAddr(tmp[:], newval)
				u.MemWrite(ptr, tmp[:])
				status = 1
			}
			u.RegWrite(uc.ARM_REG_R0, status)
		case 0xffff0fe0:
			// __kuser_get_tls
			u.RegWrite(uc.ARM_REG_R0, kernel.tls)
		case 0xffff0ffc:
			// __kuser_helper_version
			u.RegWrite(uc.ARM_REG_R0, 2)
		default:
			panic(fmt.Sprintf("unsupported kernel trap: 0x%x\n", addr))
		}
	}, 0xffff0000, 0xffffffff)
	if err != nil {
		return err
	}
	return nil
}