diff options
Diffstat (limited to 'library/std/src/sys/sgx')
| -rw-r--r-- | library/std/src/sys/sgx/abi/thread.rs | 8 | ||||
| -rw-r--r-- | library/std/src/sys/sgx/abi/usercalls/alloc.rs | 165 | ||||
| -rw-r--r-- | library/std/src/sys/sgx/abi/usercalls/mod.rs | 8 | ||||
| -rw-r--r-- | library/std/src/sys/sgx/abi/usercalls/raw.rs | 24 | ||||
| -rw-r--r-- | library/std/src/sys/sgx/abi/usercalls/tests.rs | 34 | ||||
| -rw-r--r-- | library/std/src/sys/sgx/mod.rs | 2 | ||||
| -rw-r--r-- | library/std/src/sys/sgx/mutex.rs | 3 |
7 files changed, 207 insertions, 37 deletions
diff --git a/library/std/src/sys/sgx/abi/thread.rs b/library/std/src/sys/sgx/abi/thread.rs index ef55b821a..2b23e368c 100644 --- a/library/std/src/sys/sgx/abi/thread.rs +++ b/library/std/src/sys/sgx/abi/thread.rs @@ -7,7 +7,11 @@ use fortanix_sgx_abi::Tcs; #[unstable(feature = "sgx_platform", issue = "56975")] pub fn current() -> Tcs { extern "C" { - fn get_tcs_addr() -> Tcs; + fn get_tcs_addr() -> *mut u8; + } + let addr = unsafe { get_tcs_addr() }; + match Tcs::new(addr) { + Some(tcs) => tcs, + None => rtabort!("TCS must not be placed at address zero (this is a linker error)"), } - unsafe { get_tcs_addr() } } diff --git a/library/std/src/sys/sgx/abi/usercalls/alloc.rs b/library/std/src/sys/sgx/abi/usercalls/alloc.rs index ea24fedd0..5409bd177 100644 --- a/library/std/src/sys/sgx/abi/usercalls/alloc.rs +++ b/library/std/src/sys/sgx/abi/usercalls/alloc.rs @@ -56,6 +56,8 @@ unsafe impl UserSafeSized for Usercall {} #[unstable(feature = "sgx_platform", issue = "56975")] unsafe impl UserSafeSized for Return {} #[unstable(feature = "sgx_platform", issue = "56975")] +unsafe impl UserSafeSized for Cancel {} +#[unstable(feature = "sgx_platform", issue = "56975")] unsafe impl<T: UserSafeSized> UserSafeSized for [T; 2] {} /// A type that can be represented in memory as one or more `UserSafeSized`s. @@ -115,7 +117,7 @@ pub unsafe trait UserSafe { /// * the pointer is null. /// * the pointed-to range is not in user memory. unsafe fn check_ptr(ptr: *const Self) { - let is_aligned = |p| -> bool { 0 == (p as usize) & (Self::align_of() - 1) }; + let is_aligned = |p: *const u8| -> bool { p.is_aligned_to(Self::align_of()) }; assert!(is_aligned(ptr as *const u8)); assert!(is_user_range(ptr as _, mem::size_of_val(unsafe { &*ptr }))); @@ -305,6 +307,34 @@ where } } +// Split a memory region ptr..ptr + len into three parts: +// +--------+ +// | small0 | Chunk smaller than 8 bytes +// +--------+ +// | big | Chunk 8-byte aligned, and size a multiple of 8 bytes +// +--------+ +// | small1 | Chunk smaller than 8 bytes +// +--------+ +fn region_as_aligned_chunks(ptr: *const u8, len: usize) -> (usize, usize, usize) { + let small0_size = if ptr as usize % 8 == 0 { 0 } else { 8 - ptr as usize % 8 }; + let small1_size = (len - small0_size as usize) % 8; + let big_size = len - small0_size as usize - small1_size as usize; + + (small0_size, big_size, small1_size) +} + +unsafe fn copy_quadwords(src: *const u8, dst: *mut u8, len: usize) { + unsafe { + asm!( + "rep movsq (%rsi), (%rdi)", + inout("rcx") len / 8 => _, + inout("rdi") dst => _, + inout("rsi") src => _, + options(att_syntax, nostack, preserves_flags) + ); + } +} + /// Copies `len` bytes of data from enclave pointer `src` to userspace `dst` /// /// This function mitigates stale data vulnerabilities by ensuring all writes to untrusted memory are either: @@ -343,17 +373,6 @@ pub(crate) unsafe fn copy_to_userspace(src: *const u8, dst: *mut u8, len: usize) } } - unsafe fn copy_aligned_quadwords_to_userspace(src: *const u8, dst: *mut u8, len: usize) { - unsafe { - asm!( - "rep movsq (%rsi), (%rdi)", - inout("rcx") len / 8 => _, - inout("rdi") dst => _, - inout("rsi") src => _, - options(att_syntax, nostack, preserves_flags) - ); - } - } assert!(!src.is_null()); assert!(!dst.is_null()); assert!(is_enclave_range(src, len)); @@ -367,10 +386,10 @@ pub(crate) unsafe fn copy_to_userspace(src: *const u8, dst: *mut u8, len: usize) unsafe { copy_bytewise_to_userspace(src, dst, len); } - } else if len % 8 == 0 && dst as usize % 8 == 0 { + } else if len % 8 == 0 && dst.is_aligned_to(8) { // Copying 8-byte aligned quadwords: copy quad word per quad word unsafe { - copy_aligned_quadwords_to_userspace(src, dst, len); + copy_quadwords(src, dst, len); } } else { // Split copies into three parts: @@ -381,20 +400,16 @@ pub(crate) unsafe fn copy_to_userspace(src: *const u8, dst: *mut u8, len: usize) // +--------+ // | small1 | Chunk smaller than 8 bytes // +--------+ + let (small0_size, big_size, small1_size) = region_as_aligned_chunks(dst, len); unsafe { // Copy small0 - let small0_size = (8 - dst as usize % 8) as u8; - let small0_src = src; - let small0_dst = dst; - copy_bytewise_to_userspace(small0_src as _, small0_dst, small0_size as _); + copy_bytewise_to_userspace(src, dst, small0_size as _); // Copy big - let small1_size = ((len - small0_size as usize) % 8) as u8; - let big_size = len - small0_size as usize - small1_size as usize; let big_src = src.offset(small0_size as _); let big_dst = dst.offset(small0_size as _); - copy_aligned_quadwords_to_userspace(big_src as _, big_dst, big_size); + copy_quadwords(big_src as _, big_dst, big_size); // Copy small1 let small1_src = src.offset(big_size as isize + small0_size as isize); @@ -404,6 +419,106 @@ pub(crate) unsafe fn copy_to_userspace(src: *const u8, dst: *mut u8, len: usize) } } +/// Copies `len` bytes of data from userspace pointer `src` to enclave pointer `dst` +/// +/// This function mitigates AEPIC leak vulnerabilities by ensuring all reads from untrusted memory are 8-byte aligned +/// +/// # Panics +/// This function panics if: +/// +/// * The `src` pointer is null +/// * The `dst` pointer is null +/// * The `src` memory range is not in user memory +/// * The `dst` memory range is not in enclave memory +/// +/// # References +/// - https://www.intel.com/content/www/us/en/security-center/advisory/intel-sa-00657.html +/// - https://www.intel.com/content/www/us/en/developer/articles/technical/software-security-guidance/advisory-guidance/stale-data-read-from-xapic.html +pub(crate) unsafe fn copy_from_userspace(src: *const u8, dst: *mut u8, len: usize) { + // Copies memory region `src..src + len` to the enclave at `dst`. The source memory region + // is: + // - strictly less than 8 bytes in size and may be + // - located at a misaligned memory location + fn copy_misaligned_chunk_to_enclave(src: *const u8, dst: *mut u8, len: usize) { + let mut tmp_buff = [0u8; 16]; + + unsafe { + // Compute an aligned memory region to read from + // +--------+ <-- aligned_src + aligned_len (8B-aligned) + // | pad1 | + // +--------+ <-- src + len (misaligned) + // | | + // | | + // | | + // +--------+ <-- src (misaligned) + // | pad0 | + // +--------+ <-- aligned_src (8B-aligned) + let pad0_size = src as usize % 8; + let aligned_src = src.sub(pad0_size); + + let pad1_size = 8 - (src.add(len) as usize % 8); + let aligned_len = pad0_size + len + pad1_size; + + debug_assert!(len < 8); + debug_assert_eq!(aligned_src as usize % 8, 0); + debug_assert_eq!(aligned_len % 8, 0); + debug_assert!(aligned_len <= 16); + + // Copy the aligned buffer to a temporary buffer + // Note: copying from a slightly different memory location is a bit odd. In this case it + // can't lead to page faults or inadvertent copying from the enclave as we only ensured + // that the `src` pointer is aligned at an 8 byte boundary. As pages are 4096 bytes + // aligned, `aligned_src` must be on the same page as `src`. A similar argument can be made + // for `src + len` + copy_quadwords(aligned_src as _, tmp_buff.as_mut_ptr(), aligned_len); + + // Copy the correct parts of the temporary buffer to the destination + ptr::copy(tmp_buff.as_ptr().add(pad0_size), dst, len); + } + } + + assert!(!src.is_null()); + assert!(!dst.is_null()); + assert!(is_user_range(src, len)); + assert!(is_enclave_range(dst, len)); + assert!(!(src as usize).overflowing_add(len + 8).1); + assert!(!(dst as usize).overflowing_add(len + 8).1); + + if len < 8 { + copy_misaligned_chunk_to_enclave(src, dst, len); + } else if len % 8 == 0 && src as usize % 8 == 0 { + // Copying 8-byte aligned quadwords: copy quad word per quad word + unsafe { + copy_quadwords(src, dst, len); + } + } else { + // Split copies into three parts: + // +--------+ + // | small0 | Chunk smaller than 8 bytes + // +--------+ + // | big | Chunk 8-byte aligned, and size a multiple of 8 bytes + // +--------+ + // | small1 | Chunk smaller than 8 bytes + // +--------+ + let (small0_size, big_size, small1_size) = region_as_aligned_chunks(dst, len); + + unsafe { + // Copy small0 + copy_misaligned_chunk_to_enclave(src, dst, small0_size); + + // Copy big + let big_src = src.add(small0_size); + let big_dst = dst.add(small0_size); + copy_quadwords(big_src, big_dst, big_size); + + // Copy small1 + let small1_src = src.add(big_size + small0_size); + let small1_dst = dst.add(big_size + small0_size); + copy_misaligned_chunk_to_enclave(small1_src, small1_dst, small1_size); + } + } +} + #[unstable(feature = "sgx_platform", issue = "56975")] impl<T: ?Sized> UserRef<T> where @@ -468,7 +583,7 @@ where pub fn copy_to_enclave(&self, dest: &mut T) { unsafe { assert_eq!(mem::size_of_val(dest), mem::size_of_val(&*self.0.get())); - ptr::copy( + copy_from_userspace( self.0.get() as *const T as *const u8, dest as *mut T as *mut u8, mem::size_of_val(dest), @@ -494,7 +609,11 @@ where { /// Copies the value from user memory into enclave memory. pub fn to_enclave(&self) -> T { - unsafe { ptr::read(self.0.get()) } + unsafe { + let mut data: T = mem::MaybeUninit::uninit().assume_init(); + copy_from_userspace(self.0.get() as _, &mut data as *mut T as _, mem::size_of::<T>()); + data + } } } diff --git a/library/std/src/sys/sgx/abi/usercalls/mod.rs b/library/std/src/sys/sgx/abi/usercalls/mod.rs index 79d1db5e1..e19e84326 100644 --- a/library/std/src/sys/sgx/abi/usercalls/mod.rs +++ b/library/std/src/sys/sgx/abi/usercalls/mod.rs @@ -292,12 +292,17 @@ fn check_os_error(err: Result) -> i32 { } } -trait FromSgxResult { +/// Translate the raw result of an SGX usercall. +#[unstable(feature = "sgx_platform", issue = "56975")] +pub trait FromSgxResult { + /// Return type type Return; + /// Translate the raw result of an SGX usercall. fn from_sgx_result(self) -> IoResult<Self::Return>; } +#[unstable(feature = "sgx_platform", issue = "56975")] impl<T> FromSgxResult for (Result, T) { type Return = T; @@ -310,6 +315,7 @@ impl<T> FromSgxResult for (Result, T) { } } +#[unstable(feature = "sgx_platform", issue = "56975")] impl FromSgxResult for Result { type Return = (); diff --git a/library/std/src/sys/sgx/abi/usercalls/raw.rs b/library/std/src/sys/sgx/abi/usercalls/raw.rs index 4267b96cc..10c1456d4 100644 --- a/library/std/src/sys/sgx/abi/usercalls/raw.rs +++ b/library/std/src/sys/sgx/abi/usercalls/raw.rs @@ -37,14 +37,23 @@ pub unsafe fn do_usercall( (a, b) } -type Register = u64; +/// A value passed or returned in a CPU register. +#[unstable(feature = "sgx_platform", issue = "56975")] +pub type Register = u64; -trait RegisterArgument { +/// Translate a type from/to Register to be used as an argument. +#[unstable(feature = "sgx_platform", issue = "56975")] +pub trait RegisterArgument { + /// Translate a Register to Self. fn from_register(_: Register) -> Self; + /// Translate self to a Register. fn into_register(self) -> Register; } -trait ReturnValue { +/// Translate a pair of Registers to the raw usercall return value. +#[unstable(feature = "sgx_platform", issue = "56975")] +pub trait ReturnValue { + /// Translate a pair of Registers to the raw usercall return value. fn from_registers(call: &'static str, regs: (Register, Register)) -> Self; } @@ -68,6 +77,7 @@ macro_rules! define_usercalls { macro_rules! define_ra { (< $i:ident > $t:ty) => { + #[unstable(feature = "sgx_platform", issue = "56975")] impl<$i> RegisterArgument for $t { fn from_register(a: Register) -> Self { a as _ @@ -78,6 +88,7 @@ macro_rules! define_ra { } }; ($i:ty as $t:ty) => { + #[unstable(feature = "sgx_platform", issue = "56975")] impl RegisterArgument for $t { fn from_register(a: Register) -> Self { a as $i as _ @@ -88,6 +99,7 @@ macro_rules! define_ra { } }; ($t:ty) => { + #[unstable(feature = "sgx_platform", issue = "56975")] impl RegisterArgument for $t { fn from_register(a: Register) -> Self { a as _ @@ -112,6 +124,7 @@ define_ra!(usize as isize); define_ra!(<T> *const T); define_ra!(<T> *mut T); +#[unstable(feature = "sgx_platform", issue = "56975")] impl RegisterArgument for bool { fn from_register(a: Register) -> bool { if a != 0 { true } else { false } @@ -121,6 +134,7 @@ impl RegisterArgument for bool { } } +#[unstable(feature = "sgx_platform", issue = "56975")] impl<T: RegisterArgument> RegisterArgument for Option<NonNull<T>> { fn from_register(a: Register) -> Option<NonNull<T>> { NonNull::new(a as _) @@ -130,12 +144,14 @@ impl<T: RegisterArgument> RegisterArgument for Option<NonNull<T>> { } } +#[unstable(feature = "sgx_platform", issue = "56975")] impl ReturnValue for ! { fn from_registers(call: &'static str, _regs: (Register, Register)) -> Self { rtabort!("Usercall {call}: did not expect to be re-entered"); } } +#[unstable(feature = "sgx_platform", issue = "56975")] impl ReturnValue for () { fn from_registers(call: &'static str, usercall_retval: (Register, Register)) -> Self { rtassert!(usercall_retval.0 == 0); @@ -144,6 +160,7 @@ impl ReturnValue for () { } } +#[unstable(feature = "sgx_platform", issue = "56975")] impl<T: RegisterArgument> ReturnValue for T { fn from_registers(call: &'static str, usercall_retval: (Register, Register)) -> Self { rtassert!(usercall_retval.1 == 0); @@ -151,6 +168,7 @@ impl<T: RegisterArgument> ReturnValue for T { } } +#[unstable(feature = "sgx_platform", issue = "56975")] impl<T: RegisterArgument, U: RegisterArgument> ReturnValue for (T, U) { fn from_registers(_call: &'static str, regs: (Register, Register)) -> Self { (T::from_register(regs.0), U::from_register(regs.1)) diff --git a/library/std/src/sys/sgx/abi/usercalls/tests.rs b/library/std/src/sys/sgx/abi/usercalls/tests.rs index cbf7d7d54..58b8eb215 100644 --- a/library/std/src/sys/sgx/abi/usercalls/tests.rs +++ b/library/std/src/sys/sgx/abi/usercalls/tests.rs @@ -1,8 +1,8 @@ -use super::alloc::copy_to_userspace; use super::alloc::User; +use super::alloc::{copy_from_userspace, copy_to_userspace}; #[test] -fn test_copy_function() { +fn test_copy_to_userspace_function() { let mut src = [0u8; 100]; let mut dst = User::<[u8]>::uninitialized(100); @@ -17,12 +17,38 @@ fn test_copy_function() { dst.copy_from_enclave(&[0u8; 100]); // Copy src[0..size] to dst + offset - unsafe { copy_to_userspace(src.as_ptr(), dst.as_mut_ptr().offset(offset), size) }; + unsafe { copy_to_userspace(src.as_ptr(), dst.as_mut_ptr().add(offset), size) }; // Verify copy for byte in 0..size { unsafe { - assert_eq!(*dst.as_ptr().offset(offset + byte as isize), src[byte as usize]); + assert_eq!(*dst.as_ptr().add(offset + byte), src[byte as usize]); + } + } + } + } +} + +#[test] +fn test_copy_from_userspace_function() { + let mut dst = [0u8; 100]; + let mut src = User::<[u8]>::uninitialized(100); + + src.copy_from_enclave(&[0u8; 100]); + + for size in 0..48 { + // For all possible alignment + for offset in 0..8 { + // overwrite complete dst + dst = [0u8; 100]; + + // Copy src[0..size] to dst + offset + unsafe { copy_from_userspace(src.as_ptr().offset(offset), dst.as_mut_ptr(), size) }; + + // Verify copy + for byte in 0..size { + unsafe { + assert_eq!(dst[byte as usize], *src.as_ptr().offset(offset + byte as isize)); } } } diff --git a/library/std/src/sys/sgx/mod.rs b/library/std/src/sys/sgx/mod.rs index 696400670..b1d32929e 100644 --- a/library/std/src/sys/sgx/mod.rs +++ b/library/std/src/sys/sgx/mod.rs @@ -47,7 +47,7 @@ pub mod locks { // SAFETY: must be called only once during runtime initialization. // NOTE: this is not guaranteed to run, for example when Rust code is called externally. -pub unsafe fn init(argc: isize, argv: *const *const u8) { +pub unsafe fn init(argc: isize, argv: *const *const u8, _sigpipe: u8) { unsafe { args::init(argc, argv); } diff --git a/library/std/src/sys/sgx/mutex.rs b/library/std/src/sys/sgx/mutex.rs index 513cd77fd..aa747d56b 100644 --- a/library/std/src/sys/sgx/mutex.rs +++ b/library/std/src/sys/sgx/mutex.rs @@ -21,9 +21,6 @@ impl Mutex { } #[inline] - pub unsafe fn init(&mut self) {} - - #[inline] pub unsafe fn lock(&self) { let mut guard = self.inner.lock(); if *guard.lock_var() { |