From 9349fcef2bc92a2d7d9fc81775ab038f32d0ba23 Mon Sep 17 00:00:00 2001 From: Ralf Jung Date: Wed, 11 Sep 2024 16:39:07 +0200 Subject: [PATCH] miri: fix overflow detection for unsigned pointer offset --- .../intrinsics/ptr_offset_unsigned_overflow.rs | 7 +++++++ .../ptr_offset_unsigned_overflow.stderr | 15 +++++++++++++++ 2 files changed, 22 insertions(+) create mode 100644 tests/fail/intrinsics/ptr_offset_unsigned_overflow.rs create mode 100644 tests/fail/intrinsics/ptr_offset_unsigned_overflow.stderr diff --git a/tests/fail/intrinsics/ptr_offset_unsigned_overflow.rs b/tests/fail/intrinsics/ptr_offset_unsigned_overflow.rs new file mode 100644 index 0000000000..a2739842bc --- /dev/null +++ b/tests/fail/intrinsics/ptr_offset_unsigned_overflow.rs @@ -0,0 +1,7 @@ +fn main() { + let x = &[0i32; 2]; + let x = x.as_ptr().wrapping_add(1); + // If the `!0` is interpreted as `isize`, it is just `-1` and hence harmless. + // However, this is unsigned arithmetic, so really this is `usize::MAX` and hence UB. + unsafe { x.byte_add(!0).read() }; //~ERROR: does not fit in an `isize` +} diff --git a/tests/fail/intrinsics/ptr_offset_unsigned_overflow.stderr b/tests/fail/intrinsics/ptr_offset_unsigned_overflow.stderr new file mode 100644 index 0000000000..43cd80a6d3 --- /dev/null +++ b/tests/fail/intrinsics/ptr_offset_unsigned_overflow.stderr @@ -0,0 +1,15 @@ +error: Undefined Behavior: overflowing pointer arithmetic: the total offset in bytes does not fit in an `isize` + --> $DIR/ptr_offset_unsigned_overflow.rs:LL:CC + | +LL | unsafe { x.byte_add(!0).read() }; + | ^^^^^^^^^^^^^^ overflowing pointer arithmetic: the total offset in bytes does not fit in an `isize` + | + = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior + = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information + = note: BACKTRACE: + = note: inside `main` at $DIR/ptr_offset_unsigned_overflow.rs:LL:CC + +note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace + +error: aborting due to 1 previous error +