lib: avoid overflow in computation of s_seq_expect #438
+4
−1
Conversation
This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
On some systems, the clock is reset, or is lost, so the value returned by the time function can be a very small value. In that case, the _badrandom_from_time functions returns a large value close to the maximum unsigned int value for s_seq_expect. This can lead to the value wrapping around fairly quickly. When compiling the library with the unsigned-integer-overflow sanitizer enabled, this causes an abort. Detect this potential wrap around condition and avoid it.
Owner
|
Unsigned overflow is explicitly supported and fine in C. And obviously, the overflow here is not an accident or unintentional. It seems to me that this sanitizer is a bit too strict. Can you even enable it on a non-trivial code base? Isn't unsigned overflow a common thing (that often enough happens intentionally)? Anyway. Will merge. Thank you. |
thom311
pushed a commit
that referenced
this pull request
Jul 31, 2025
On some systems, the clock is reset, or is lost, so the value returned by the time function can be a very small value. In that case, the _badrandom_from_time functions returns a large value close to the maximum unsigned int value for s_seq_expect. This can lead to the value wrapping around fairly quickly. When compiling the library with the unsigned-integer-overflow sanitizer enabled, this causes an abort. Detect this potential wrap around condition and avoid it. #438
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
2 participants
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Outdated suggestions cannot be applied.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.
On some systems, the clock is reset, or is lost, so the value returned by the time function can be a very small value. In that case, the _badrandom_from_time functions returns a large value close to the maximum unsigned int value for s_seq_expect. This can lead to the value wrapping around fairly quickly.
When compiling the library with the unsigned-integer-overflow sanitizer enabled, this causes an abort.
Detect this potential wrap around condition and avoid it.