NVIDIA / NVIDIA/cccl

[BUG]: `thrust::zip_iterator` allows out-of-bounds access if first iterator is longer than the others

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#1,155 1 comment 0 reactions 1 assignee Claimed by @griwes View on GitHub
needs triage
Dominant language
C++
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Description

### Is this a duplicate?

- [X] I confirmed there appear to be no [duplicate issues](https://github.com/NVIDIA/cccl/issues) for this bug and that I agree to the [Code of Conduct](CODE_OF_CONDUCT.md)

### Type of Bug

Runtime Error

### Component

Thrust

### Describe the bug

Out of bounds access when the first iterator in a `zip_iterator` is longer than the others

### How to Reproduce

```c++
// clang++ -I/path/to/thrust thrust_bug.cpp -o thrust_bug && ./thrust_bug
#include
#include

#include
#include

int main()
{
std::vector v(4, 0); // change me to 5!
std::vector y(4, 1);

auto zip_begin = thrust::make_zip_iterator(thrust::make_tuple(v.begin(), y.begin()));
auto zip_end = thrust::make_zip_iterator(thrust::make_tuple(v.end(), y.end()));

for (auto it = zip_begin; it != zip_end; ++it) {
// BOOM out of bounds
std::cout << "[" << thrust::get<0>(*it) << ", " << thrust::get<1>(*it) << "]" << std::endl;
}
}
```
Note the size of `v` and `y` are equal. If, however, you change `v` to be size 5
```diff
- std::vector v(4, 0);
+ std::vector v(5, 0);
```
You will find that the iterator runs out of bounds.

### Expected behavior

No out of bounds

### Reproduction link

_No response_

### Operating System

_No response_

### nvidia-smi output

_No response_

### NVCC version

_No response_

Contributor guide

Open the contributing guide

Assessment

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