QL1.21: Finalize change notes for C/C++ #1413

felicitymay · 2019-06-06T17:00:13Z

This PR tidies up the C/C++ change notes ready for the release of 1.21.

There are three commits:

Updates the text for consistency.
Sorts the table rows alphabetically.
Merges two rows with information for the same query.

Note that the names of some queries seemed to be wrong. I've updated the ones that I noticed based on what I see on LGTM.com. Also, the first two queries mentioned in the New queries section appeared to be the same query. Please check the first commit carefully.

@Semmle/cpp

jbj · 2019-06-07T03:52:12Z

change-notes/1.21/analysis-cpp.md

 | **Query**                   | **Tags**  | **Purpose**                                                        |
 |-----------------------------|-----------|--------------------------------------------------------------------|
-| `()`-declared function called with too few arguments (`cpp/too-few-arguments`) | Correctness | Find all cases where the number of arguments is less than the number of parameters of the function, provided the function is also properly declared/defined elsewhere. |
-| `()`-declared function called with mismatched arguments (`cpp/mismatched-function-arguments`) | Correctness | Find all cases where the types of arguments do not match the types of parameters of the function, provided the function is also properly declared/defined elsewhere. |


Where did the changelog entry for cpp/mismatched-function-arguments go? The query has tags correctness, maintainability.

My apologies - I got confused and thought these were the same query. There were problems with the @names which didn't help. I'll put it back and find the right @name for it.

I can't find a query with that identifier at all. Maybe I'm looking in the wrong place.

It looks as if it should be cpp/misttyped-function-arguments which was added in: #1136. I'll return the table row and amend accordingly. Please check that I've done the right thing.

s/misttyped/mistyped/.

Good point. Fortunately it's correct in the file, just not my comment!

jbj · 2019-06-07T03:54:54Z

change-notes/1.21/analysis-cpp.md

-| `()`-declared function called with mismatched arguments (`cpp/mismatched-function-arguments`) | Correctness | Find all cases where the types of arguments do not match the types of parameters of the function, provided the function is also properly declared/defined elsewhere. |
-| Call to alloca in a loop (`cpp/alloca-in-loop`) | reliability, correctness, external/cwe/cwe-770 | Finds calls to `alloca` in loops, which can lead to stack overflow if the number of iterations is large.  Newly displayed on LGTM. |
-| Use of dangerous function (`dangerous-function-overflow`) | reliability, security, external/cwe/cwe-242 | Finds calls to `gets`, which does not guard against buffer overflow.  These results were previously detected by the `cpp/potentially-dangerous-function` query. |
+| Call to alloca in a loop (`cpp/alloca-in-loop`) | reliability, correctness, external/cwe/cwe-770 | Finds calls to `alloca` in loops, which can lead to stack overflow if the number of iterations is large.  Newly displayed on [LGTM](https://lgtm.com/rules/1508831665988/). |


I'd write [on LGTM] instead of on [LGTM] since otherwise readers might expect the link to just point to lgtm.com.

The link will only point to LGTM.com. It's not currently possible to add a link that would work in an enterprise system. The benefit of including a link to LGTM.com is that people can see the type of results that the query generates.

He means they would expect it to point to https://lgtm.com/ rather than https://lgtm.com/rules/1508831665988/.

Yes, that's what I meant.

Thanks for clarifying.

jbj · 2019-06-07T03:58:34Z

change-notes/1.21/analysis-cpp.md

-| Call to alloca in a loop (`cpp/alloca-in-loop`) | reliability, correctness, external/cwe/cwe-770 | Finds calls to `alloca` in loops, which can lead to stack overflow if the number of iterations is large.  Newly displayed on LGTM. |
-| Use of dangerous function (`dangerous-function-overflow`) | reliability, security, external/cwe/cwe-242 | Finds calls to `gets`, which does not guard against buffer overflow.  These results were previously detected by the `cpp/potentially-dangerous-function` query. |
+| Call to alloca in a loop (`cpp/alloca-in-loop`) | reliability, correctness, external/cwe/cwe-770 | Finds calls to `alloca` in loops, which can lead to stack overflow if the number of iterations is large.  Newly displayed on [LGTM](https://lgtm.com/rules/1508831665988/). |
+| Call to function with fewer arguments than declared parameters (`cpp/too-few-arguments`) | Correctness | Find all cases where the number of arguments is fewer than the number of parameters of the function, provided the function is also properly declared/defined elsewhere. Results are displayed by default on [LGTM](https://lgtm.com/rules/1508860726279/). |


The tags for this query are, in lower case: correctness, maintainability, security.

jbj · 2019-06-07T04:02:50Z

change-notes/1.21/analysis-cpp.md

-| `()`-declared function called with too many arguments (`cpp/futile-params`) | Improved coverage | Query has been generalized to find all cases where the number of arguments exceedes the number of parameters of the function, provided the function is also properly declared/defined elsewhere. |
-| Use of potentially dangerous function (`cpp/potentially-dangerous-function`) | Fewer results | Results relating to the standard library `gets` function have been moved into a new query (`dangerous-function-overflow`). |
-| Constructor with default arguments will be used as a copy constructor (`cpp/constructor-used-as-copy-constructor`) | Lowered severity and precision | The severity and precision of this query have been reduced to "warning" and "low", respectively, due to this coding pattern being used intentionally and safely in a number of real-world projects. |
+| Wrong type of arguments to formatting function (`cpp/wrong-type-format-argument`) | More correct results and fewer false positive results | This query now understands non-standard uses of `%L`. In addition, it more accurately identifies wide and non-wide string/character format arguments on different platforms.  Platform detection has also been made more accurate for this query. |


The last sentence, about platform detection, seems redundant. What do you think, @geoffw0?

Yeah, I was talking about two slightly different changes, but to a user they are the same. Happy for the last sentence to be deleted.

felicitymay · 2019-06-07T09:53:56Z

Thanks for the review @jbj. I've returned the incorrectly deleted new query with what I hope is the correct name and identifier.

geoffw0 · 2019-06-07T11:25:54Z

LGTM.

jbj

Otherwise LGTM

jbj · 2019-06-07T14:13:17Z

change-notes/1.21/analysis-cpp.md

-| `()`-declared function called with mismatched arguments (`cpp/mismatched-function-arguments`) | Correctness | Find all cases where the types of arguments do not match the types of parameters of the function, provided the function is also properly declared/defined elsewhere. |
-| Call to alloca in a loop (`cpp/alloca-in-loop`) | reliability, correctness, external/cwe/cwe-770 | Finds calls to `alloca` in loops, which can lead to stack overflow if the number of iterations is large.  Newly displayed on LGTM. |
-| Use of dangerous function (`dangerous-function-overflow`) | reliability, security, external/cwe/cwe-242 | Finds calls to `gets`, which does not guard against buffer overflow.  These results were previously detected by the `cpp/potentially-dangerous-function` query. |
+| Call to alloca in a loop (`cpp/alloca-in-loop`) | reliability, correctness, external/cwe/cwe-770 | Finds calls to `alloca` in loops, which can lead to stack overflow if the number of iterations is large.  Newly displayed on [LGTM](https://lgtm.com/rules/1508831665988/). |


Yes, that's what I meant.

jbj · 2019-06-07T14:15:44Z

change-notes/1.21/analysis-cpp.md

-| Use of dangerous function (`dangerous-function-overflow`) | reliability, security, external/cwe/cwe-242 | Finds calls to `gets`, which does not guard against buffer overflow.  These results were previously detected by the `cpp/potentially-dangerous-function` query. |
+| Call to alloca in a loop (`cpp/alloca-in-loop`) | reliability, correctness, external/cwe/cwe-770 | Finds calls to `alloca` in loops, which can lead to stack overflow if the number of iterations is large.  Newly displayed on [LGTM](https://lgtm.com/rules/1508831665988/). |
+| Call to function with fewer arguments than declared parameters (`cpp/too-few-arguments`) | correctness, maintainability, security | Finds all cases where the number of arguments is fewer than the number of parameters of the function, provided the function is also properly declared/defined elsewhere. Results are displayed by default on [LGTM](https://lgtm.com/rules/1508860726279/). |
+| Call to a function with one or more incompatible arguments (`cpp/mismatched-function-arguments`) | correctness, maintainability | Finds all cases where the types of arguments do not match the types of parameters of the function, provided the function is also properly declared/defined elsewhere. Results are not displayed by default on [LGTM](https://lgtm.com/rules/1508849286093/). |


AFAICT, the id of this query is cpp/mistyped-function-arguments (mistyped instead of mismatched).

Odd. I could have sworn that I made that change (once I found the right query).

I also misremember it being called cpp/mismatched-function-arguments for some reason...

felicitymay · 2019-06-07T14:23:29Z

Thanks for the further comments. I think this now addresses all feedback.

Felicity Chapman added 3 commits June 6, 2019 17:45

Update text for consistency

36a6d9e

Sort table rows alphabetically

2f97aac

Merge two rows for one query

463371a

felicitymay added C++ documentation labels Jun 6, 2019

felicitymay added this to the 1.21.0 milestone Jun 6, 2019

felicitymay assigned jonas-semmle Jun 6, 2019

felicitymay changed the base branch from master to rc/1.21 June 6, 2019 17:00

felicitymay changed the title ~~LGTM 1.21: Finalize change notes for C/C++~~ QL1.21: Finalize change notes for C/C++ Jun 6, 2019

jbj assigned jbj and unassigned jonas-semmle Jun 7, 2019

jbj reviewed Jun 7, 2019

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jbj mentioned this pull request Jun 7, 2019

C++: Suspicious pointer scaling: @precision medium #1400

Merged

Update for feedback

53ea76b

Remove redundant sentence

da9b9ed

jbj reviewed Jun 7, 2019

View reviewed changes

Further corrections

1a97936

jbj approved these changes Jun 7, 2019

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jbj merged commit de4c20e into github:rc/1.21 Jun 7, 2019

felicitymay deleted the 1.21/cpp-change-notes branch September 23, 2019 16:32

kamarcum unassigned jbj Apr 28, 2020

QL1.21: Finalize change notes for C/C++ #1413

QL1.21: Finalize change notes for C/C++ #1413

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felicitymay commented Jun 7, 2019

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