From fe9cd1c98d5ca861986eaf2bc0aaf953a375ca5c Mon Sep 17 00:00:00 2001
From: Ralf Jung <post@ralfj.de>
Date: Thu, 30 Aug 2018 10:50:13 +0200
Subject: [PATCH 1/3] strictly enforce pointer validity even for zero-sized
accesses
---
src/intrinsic.rs | 34 +++++++++++++---------------------
1 file changed, 13 insertions(+), 21 deletions(-)
diff --git a/src/intrinsic.rs b/src/intrinsic.rs
index 6847d8e546..f562aec323 100644
--- a/src/intrinsic.rs
+++ b/src/intrinsic.rs
@@ -179,21 +179,17 @@ impl<'a, 'mir, 'tcx> EvalContextExt<'tcx> for EvalContext<'a, 'mir, 'tcx, super:
let elem_layout = self.layout_of(elem_ty)?;
let elem_size = elem_layout.size.bytes();
let count = self.read_scalar(args[2])?.to_usize(&self)?;
- if count * elem_size != 0 {
- // TODO: We do not even validate alignment for the 0-bytes case. libstd relies on this in vec::IntoIter::next.
- // Also see the write_bytes intrinsic.
- let elem_align = elem_layout.align;
- let src = self.read_scalar(args[0])?.not_undef()?;
- let dest = self.read_scalar(args[1])?.not_undef()?;
- self.memory.copy(
- src,
- elem_align,
- dest,
- elem_align,
- Size::from_bytes(count * elem_size),
- intrinsic_name.ends_with("_nonoverlapping"),
- )?;
- }
+ let elem_align = elem_layout.align;
+ let src = self.read_scalar(args[0])?.not_undef()?;
+ let dest = self.read_scalar(args[1])?.not_undef()?;
+ self.memory.copy(
+ src,
+ elem_align,
+ dest,
+ elem_align,
+ Size::from_bytes(count * elem_size),
+ intrinsic_name.ends_with("_nonoverlapping"),
+ )?;
}
"discriminant_value" => {
@@ -563,12 +559,8 @@ impl<'a, 'mir, 'tcx> EvalContextExt<'tcx> for EvalContext<'a, 'mir, 'tcx, super:
let val_byte = self.read_scalar(args[1])?.to_u8()?;
let ptr = self.read_scalar(args[0])?.not_undef()?;
let count = self.read_scalar(args[2])?.to_usize(&self)?;
- if count > 0 {
- // HashMap relies on write_bytes on a NULL ptr with count == 0 to work
- // TODO: Should we, at least, validate the alignment? (Also see the copy intrinsic)
- self.memory.check_align(ptr, ty_layout.align)?;
- self.memory.write_repeat(ptr, val_byte, ty_layout.size * count)?;
- }
+ self.memory.check_align(ptr, ty_layout.align)?;
+ self.memory.write_repeat(ptr, val_byte, ty_layout.size * count)?;
}
name => return err!(Unimplemented(format!("unimplemented intrinsic: {}", name))),
From 95eb77c18e8532d490efbedff6424d369b7e83df Mon Sep 17 00:00:00 2001
From: Ralf Jung <post@ralfj.de>
Date: Sun, 16 Sep 2018 16:47:37 +0200
Subject: [PATCH 2/3] add some compile-fail tests
---
tests/compile-fail/copy_null.rs | 18 ++++++++++++++++++
tests/compile-fail/copy_unaligned.rs | 18 ++++++++++++++++++
2 files changed, 36 insertions(+)
create mode 100644 tests/compile-fail/copy_null.rs
create mode 100644 tests/compile-fail/copy_unaligned.rs
diff --git a/tests/compile-fail/copy_null.rs b/tests/compile-fail/copy_null.rs
new file mode 100644
index 0000000000..e46e327e61
--- /dev/null
+++ b/tests/compile-fail/copy_null.rs
@@ -0,0 +1,18 @@
+// Copyright 2015 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+//error-pattern: invalid use of NULL pointer
+
+fn main() {
+ let mut data = [0u16; 4];
+ let ptr = &mut data[0] as *mut u16;
+ // Even copying 0 elements from NULL should error
+ unsafe { ptr.copy_from(std::ptr::null(), 0); }
+}
diff --git a/tests/compile-fail/copy_unaligned.rs b/tests/compile-fail/copy_unaligned.rs
new file mode 100644
index 0000000000..0f04dc68db
--- /dev/null
+++ b/tests/compile-fail/copy_unaligned.rs
@@ -0,0 +1,18 @@
+// Copyright 2015 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+//error-pattern: tried to access memory with alignment 1, but alignment 2 is required
+
+fn main() {
+ let mut data = [0u16; 8];
+ let ptr = (&mut data[0] as *mut u16 as *mut u8).wrapping_add(1) as *mut u16;
+ // Even copying 0 elements to something unaligned should error
+ unsafe { ptr.copy_from(&data[5], 0); }
+}
From c096d3405389089bab4379161a1546094b1db479 Mon Sep 17 00:00:00 2001
From: Ralf Jung <post@ralfj.de>
Date: Mon, 17 Sep 2018 08:40:17 +0200
Subject: [PATCH 3/3] bump toolchain
---
rust-toolchain | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/rust-toolchain b/rust-toolchain
index 125ee2d988..60c47a9305 100644
--- a/rust-toolchain
+++ b/rust-toolchain
@@ -1 +1 @@
-nightly-2018-09-15
+nightly-2018-09-17