C++: Remove pointer/pointee conflation from models of "pure" functions #18556
Conversation
This file contains 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
There was a problem hiding this comment.
Copilot encountered an error and was unable to review this pull request. You can try again, by re-requesting a review.
github-actions
bot
added
C++
and removed
no-change-note-required
paldepind
requested changes
Jan 23, 2025
| @@ -26,22 +27,43 @@ private class PureStrFunction extends AliasFunction, ArrayFunction, TaintFunctio | |||
| } | |||
|
|
|||
There was a problem hiding this comment.
We could add a helper predicate for the locale argument check?
Suggested change
| /** Holds if `i` is a locale parameter that does not carry taint. */ | |
| private predicate isLocaleParameter(ParameterIndex i) { | |
| this.getName().matches("%\\_l") and i + 1 = this.getNumberOfParameters() | |
| } | |
There was a problem hiding this comment.
Good idea! Fixed in 7792839
| // indirection of the parameter. Otherwise, there is taint from the | ||
| // parameter. | ||
| // 2. If the return value is of a pointer type then there is taint to the | ||
| // indirection of the return. Otherwise, there is taint to the return. |
There was a problem hiding this comment.
Does it make sense to move this comment up before the exists given that it concerns both the stuff inside the exists and also the conjunct after it?
There was a problem hiding this comment.
Sure. Fixed in 67e3b69
Co-authored-by: Simon Friis Vindum <[email protected]>
Co-authored-by: Simon Friis Vindum <[email protected]>
|
Thanks for the review, @paldepind! I believe I've resolved all your comments now. |
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
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Outdated suggestions cannot be applied.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.
This PR cleans up the taint-flow model for the
PureStrFunctionclass. Previously, this was conflating pointers and their indirections which caused false flow in some cases. See the first commit for an example of this.Additionally, I added a dataflow model for the cases where the pointer is actually preserved.
DCA shows 3 lost results, and they appear to be FPs that are now correctly removed.