Bogus C-cast and illegal assumptions of Object-layout causes segfault in convhull.cpp #26952
Description
System Information
OpenCV version: 7a2b048 (Current HEAD)
Platform: OpenSUSE Tumbleweed (20250216) linux-6.13.2-1-default x86_64
GCC: gcc (SUSE Linux) 14.2.1 20241007 [revision 4af44f2cf7d281f3e4f3957efce10e8b2ccb2ad3]
Detailed description
At
opencv/modules/imgproc/src/convhull.cpp
Line 157 in 7a2b048
The code assumes that a C-Cast will:
- Correctly convert between int and float
- The size of int and float
And additionally it makes illegal assumption of the memory layout of objects:
opencv/modules/imgproc/src/convhull.cpp
Line 158 in 7a2b048
Which spuriously leads to a segfault at
opencv/modules/imgproc/src/convhull.cpp
Line 182 in 7a2b048
The pointer handling is none-optimal in other respects aswell. e.g. not using memcpy when possible and the general use of a pointer-of-pointer indirection while not necessary.
Steps to reproduce
https://docs.opencv.org/3.4/d7/d1d/tutorial_hull.html
Issue submission checklist
- I report the issue, it's not a question
- I checked the problem with documentation, FAQ, open issues, forum.opencv.org, Stack Overflow, etc and have not found any solution
- I updated to the latest OpenCV version and the issue is still there
- There is reproducer code and related data files (videos, images, onnx, etc)