Fix undefined behavior in dsortf comparison function #500
Add this suggestion to a batch that can be applied as a single commit.
This suggestion is invalid because no changes were made to the code.
Suggestions cannot be applied while the pull request is closed.
Suggestions cannot be applied while viewing a subset of changes.
Only one suggestion per line can be applied in a batch.
Add this suggestion to a batch that can be applied as a single commit.
Applying suggestions on deleted lines is not supported.
You must change the existing code in this line in order to create a valid suggestion.
Outdated suggestions cannot be applied.
This suggestion has been applied or marked resolved.
Suggestions cannot be applied from pending reviews.
Suggestions cannot be applied on multi-line comments.
Suggestions cannot be applied while the pull request is queued to merge.
Suggestion cannot be applied right now. Please check back later.
In the dsortf function, when both (*e1)->name[0] == '/' and (*e2)->name[0] == '/', a situation occurs where a < b but b < a, violating the transitivity requirement for comparison functions used by qsort as specified by the C standard. This leads to undefined behavior, which can cause incorrect sorting and memory corruption in glibc's qsort implementation, creating a potential security issue [1].
Fix the issue by returning 0 when both entries begin with '/', preventing the undefined behavior.
[1] https://www.qualys.com/2024/01/30/qsort.txt