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Merge pull request #681 from Aaron1011/fix/more-iter-offset 

Fix some out-of-bounds `offset` calls
This commit is contained in:
Sébastien Crozet 2019-11-22 08:08:57 +01:00
parent e0db624031 6bb355f4d0
commit c17b08190a
1 changed files with 13 additions and 3 deletions
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16
src/base/iter.rs
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@ -74,7 +74,12 @@ macro_rules! iterator {
// Jump to the next outer dimension if needed. // Jump to the next outer dimension if needed.
if self.ptr == self.inner_end { if self.ptr == self.inner_end {
let stride = self.strides.1.value() as isize; let stride = self.strides.1.value() as isize;
self.inner_end = self.ptr.offset(stride); // This might go past the end of the allocation,
// depending on the value of 'size'. We use
// `wrapping_offset` to avoid UB
self.inner_end = self.ptr.wrapping_offset(stride);
// This will always be in bounds, since
// we're going to dereference it
self.ptr = self.inner_ptr.offset(stride); self.ptr = self.inner_ptr.offset(stride);
self.inner_ptr = self.ptr; self.inner_ptr = self.ptr;
} }
@ -83,8 +88,13 @@ macro_rules! iterator {
let old = self.ptr; let old = self.ptr;
let stride = self.strides.0.value() as isize; let stride = self.strides.0.value() as isize;
self.ptr = self.ptr.offset(stride); // Don't offset `self.ptr` for the last element,
// as this will be out of bounds. Iteration is done
// at this point (the next call to `next` will return `None`)
// so this is not observable.
if self.size != 0 {
self.ptr = self.ptr.offset(stride);
}
Some(mem::transmute(old)) Some(mem::transmute(old))
} }
} }