1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107
/* MIT License Copyright (c) 2021 Philipp Schuster Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions: The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software. THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. */ //! Small `no_std`-lib that checks if the binary is running inside a QEMU virtual machine. //! Only works on x86/x86_64 platform. There are no heap allocation required. //! //! Under the hood, this is a wrapper around the awesome crate https://crates.io/crates/raw-cpuid. #![no_std] #[cfg(any(target_arch = "x86", target_arch = "x86_64"))] use raw_cpuid::{CpuId, Hypervisor}; use raw_cpuid::{ExtendedFunctionInfo, HypervisorInfo}; /// Returns if the code is running inside a QEMU virtual machine. /// Only works on x86/x86_64 platform. /// /// ## Example Usage /// /// ```rust /// use runs_inside_qemu::runs_inside_qemu; /// /// fn main() { /// // If we are in QEMU, we use the nice "debugcon"-feature which maps /// // the x86 I/O-port `0xe9` to stdout or a file. /// if runs_inside_qemu() { /// unsafe { /// x86::io::outb(0xe9, b'H'); /// x86::io::outb(0xe9, b'e'); /// x86::io::outb(0xe9, b'l'); /// x86::io::outb(0xe9, b'l'); /// x86::io::outb(0xe9, b'o'); /// x86::io::outb(0xe9, b'\n'); /// } /// } /// } /// ``` pub fn runs_inside_qemu() -> bool { #[cfg(not(any(target_arch = "x86", target_arch = "x86_64")))] compile_error!("This crate only works on the x86/x86_64-platform."); let id = CpuId::new(); let hypervisor_info = id.get_hypervisor_info(); if hypervisor_info.is_none() { // QEMU is a hypervisor and no real machine => exit return false; } let hypervisor_info = hypervisor_info.unwrap(); // if this returns false, because the hypervisor ID can be "KVM", // we still could be executed by QEMU -> further checks needed if hypervisor_has_qemu_id(&hypervisor_info) { return true; } // now check the extended CPU id, which is provided by QEMU let extended_info = id.get_extended_function_info(); if extended_info.is_none() { return false; } let extended_info = extended_info.unwrap(); extended_brand_string_contains_qemu(&extended_info) } /// Checks if the Hypervisor-ID is the well-known value of QEMU. /// If this fails, we still could be in a QEMU environment, because /// if QEMU is accelerated by KVM, the Hypervisor-ID is the one from KVM. fn hypervisor_has_qemu_id(info: &HypervisorInfo) -> bool { match info.identify() { // `TCGTCGTCGTCG` is the magic value of the CPU signature of QEMU, // see https://github.com/qemu/qemu/blob/6512fa497c2fa9751b9d774ab32d87a9764d1958/target/i386/cpu.c Hypervisor::Unknown(0x5447_4354, 0x4354_4743, 0x4743_5447) => { // definitely QEMU true } _ => false, } } /// Consumes the extended function info from CPU-ID. In a QEMU environment, /// this contains a string such as *QEMU Virtual CPU version 2.5+*. /// If this returns true, we are in QEMU. If not, we are not. fn extended_brand_string_contains_qemu(info: &ExtendedFunctionInfo) -> bool { info.processor_brand_string() .filter(|s| s.contains("QEMU")) .map_or(false, |_| true) }