Function 'fileno' fails only if invalid pointer is passed, this is a
case that is often ignored in source code. The failure case leads to
many "false positive" reports when `fileno` returns -1 and this is not
checked in the program. Because this, the function is now assumed
to not fail (this is assumption that the passed file pointer is correct).
The change affects `StdCLibraryFunctionsChecker` and
`StreamChecker`.
Some stream functions were recently added to `StreamChecker` that were
not modeled by `StdCLibraryFunctionsChecker`. To ensure consistency
these functions are added to the other checker too.
Some of the related tests are re-organized.
Cleanup most of the lazy-init `BugType` legacy.
Some will be preserved, as those are slightly more complicated to
refactor.
Notice, that the default category for `BugType` is `LogicError`. I
omitted setting this explicitly where I could.
Please, actually have a look at the diff. I did this manually, and we
rarely check the bug type descriptions and stuff in tests, so the
testing might be shallow on this one.
This patch fixes:
clang/lib/StaticAnalyzer/Checkers/StdLibraryFunctionsChecker.cpp:609:23:
error: 'describe' overrides a member function but is not marked
'override' [-Werror,-Winconsistent-missing-override]
clang/lib/StaticAnalyzer/Checkers/StdLibraryFunctionsChecker.cpp:627:23:
error: 'describe' overrides a member function but is not marked
'override' [-Werror,-Winconsistent-missing-override]
The checker now displays one combined note tag for errno-related and
"case"-related notes. Previous functions in the errno-modeling part that
were used for construction of note tags are removed. The note tag added
by StdLibraryFunctionsChecker contains the code to display the note tag
for 'errno' (this was done previously by these removed functions).
Recent changes in StdLibraryFunctionsChecker introduced a situation
where the checker sequentially performed two state transitions to add
two separate note tags.
In the unlikely case when the updated state (the variable `NewState`)
was posteriorly overconstrained, the engine marked the node after the
first state transition as a sink to stop the "natural" graph exploration
after that point.
However, in this particular case the checker tried to directly add a
second node, and this triggered an assertion in the `addPredecessor()`
method of `ExplodedNode`.
This commit introduces an explicit `isSink()` check to avoid this crash.
To avoid similar bugs in the future, perhaps it would be possible to
tweak `addTransition()` and ensure that it returns `nullptr` when it
would return a sink node (to unify the two possible error conditions).
This crash was observed in an analysis of the curl project (in a very
long and complex function), and there I validated that this is the root
cause, but I don't have a self-contained testcase that can trigger the
creation of a PosteriorlyOverconstrained node in this situation.
The modeling of send, recv, sendmsg, recvmsg, sendto, recvfrom is changed:
These functions do not return 0, except if the message length is 0.
(In sendmsg, recvmsg the length is not checkable but it is more likely
that a message with 0 length is invalid for these functions.)
Reviewed By: donat.nagy
Differential Revision: https://reviews.llvm.org/D155715
Success or failure messages are now shown at all checked functions, if the call
(return value) is interesting.
Additionally new functions are added: open, openat, socket, shutdown
Reviewed By: donat.nagy
Differential Revision: https://reviews.llvm.org/D154423
The note tag that was previously added in all cases when a standard function call
is found is displayed now only if the function call (return value) is "interesting".
This results in less unneeded notes but some of the previously good notes disappear
too. This is because interestingness is not always set as it should be.
Reviewed By: donat.nagy
Differential Revision: https://reviews.llvm.org/D153776
Change 1: ErrnoChecker notes show only messages related to errno,
not to assumption of success or failure of functions.
Change 2: StdLibraryFunctionsChecker adds its own note about success
or failure of functions, and the errno related note, independently.
Change 3: Every modeled function in StdLibraryFunctionsChecker
should have a note tag message in all "cases". This is not implemented yet,
only for file (stream) related functions.
Reviewed By: donat.nagy
Differential Revision: https://reviews.llvm.org/D153612
I'm involved with the Static Analyzer for the most part.
I think we should embrace newer language standard features and gradually
move forward.
Differential Revision: https://reviews.llvm.org/D154325
Main reason for this change is that these checkers were implemented in the same class
but had different dependency ordering. (NonNullParamChecker should run before StdCLibraryFunctionArgs
to get more special warning about null arguments, but the apiModeling.StdCLibraryFunctions was a modeling
checker that should run before other non-modeling checkers. The modeling checker changes state in a way
that makes it impossible to detect a null argument by NonNullParamChecker.)
To make it more simple, the modeling part is removed as separate checker and can be only used if
checker StdCLibraryFunctions is turned on, that produces the warnings too. Modeling the functions
without bug detection (for invalid argument) is not possible. The modeling of standard functions
does not happen by default from this change on.
Reviewed By: Szelethus
Differential Revision: https://reviews.llvm.org/D151225
If a wrong (too small) buffer argument is found, the dynamic buffer size and
values of connected arguments are displayed in the warning message, if
these are simple known integer values.
Reviewed By: Szelethus
Differential Revision: https://reviews.llvm.org/D149321
Some file and directory related functions have an integer file descriptor argument
that can be a valid file descriptor or a special value AT_FDCWD. This value is
relatively often used in open source projects and is usually defined as a negative
number, and the checker reports false warnings (a valid file descriptor is not
negative) if this fix is not included.
Reviewed By: steakhal
Differential Revision: https://reviews.llvm.org/D149160
Add an additional explanation of what is wrong if a constraint is
not satisfied, in some cases.
Additionally the bug report generation is changed to use raw_ostream.
Reviewed By: Szelethus, NoQ
Differential Revision: https://reviews.llvm.org/D144003
The code was difficult to maintain (big internal class definitions
with long inline functions, other functions of the same class at
different location far away, irregular ordering of classes and
function definitions). It is now improved to some extent.
New functions are added to RangeConstraint to remove code repetition,
these are useful for planned new features too.
Comments are improved.
Reviewed By: Szelethus
Differential Revision: https://reviews.llvm.org/D143751
Warnings and notes of checker alpha.unix.StdLibraryFunctionArgs are
improved. Previously one warning and one note was emitted for every
finding, now one warning is emitted only that contains a detailed
description of the found issue.
Reviewed By: Szelethus
Differential Revision: https://reviews.llvm.org/D143194
Additional stream handling functions are added.
These are partially evaluated by StreamChecker, result of the addition is
check for more preconditions and construction of success and failure branches
with specific errno handling.
Reviewed By: Szelethus
Differential Revision: https://reviews.llvm.org/D140387
The checker applies constraints in a sequence and adds new nodes for these states.
If a constraint violation is found this sequence should be stopped with a sink
(error) node. Instead the `generateErrorNode` did add a new error node as a new
branch that is parallel to the other node sequence, the other branch was not
stopped and analysis was continuing on that invalid branch.
To add an error node after any previous node a new version of `generateErrorNode`
is needed, this function is added here and used by `StdLibraryFunctionsChecker`.
The added test executes a situation where the checker adds a number of
constraints before it finds a constraint violation.
Reviewed By: NoQ
Differential Revision: https://reviews.llvm.org/D137722
This patch mechanically replaces None with std::nullopt where the
compiler would warn if None were deprecated. The intent is to reduce
the amount of manual work required in migrating from Optional to
std::optional.
This is part of an effort to migrate from llvm::Optional to
std::optional:
https://discourse.llvm.org/t/deprecating-llvm-optional-x-hasvalue-getvalue-getvalueor/63716
constraints
In this patch I add a new NoteTag for each applied argument constraint.
This way, any other checker that reports a bug - where the applied
constraint is relevant - will display the corresponding note. With this
change we provide more information for the users to understand some
bug reports easier.
Differential Revision: https://reviews.llvm.org/D101526
Reviewed By: NoQ
Some of the code used in StdLibraryFunctionsChecker is applicable to
other checkers, this is put into common functions. Errno related
parts of the checker are simplified and renamed. Documentations in
errno_modeling functions are updated.
This change makes it available to have more checkers that perform
modeling of some standard functions. These can set the errno state
with common functions and the bug report messages (note tags) can
look similar.
Reviewed By: steakhal, martong
Differential Revision: https://reviews.llvm.org/D131879
The functions 'mkdir', 'mknod', 'mkdirat', 'mknodat' return 0 on success
and -1 on failure. The checker modeled these functions with a >= 0
return value on success which is changed to 0 only. This fix makes
ErrnoChecker work better for these functions.
Reviewed By: steakhal
Differential Revision: https://reviews.llvm.org/D127277
This updates StdLibraryFunctionsChecker to set the state of 'errno'
by using the new errno_modeling functionality.
The errno value is set in the PostCall callback. Setting it in call::Eval
did not work for some reason and then every function should be
EvalCallAsPure which may be bad to do. Now the errno value and state
is not allowed to be checked in any PostCall checker callback because
it is unspecified if the errno was set already or will be set later
by this checker.
Reviewed By: martong, steakhal
Differential Revision: https://reviews.llvm.org/D125400
The patch is straightforward except the tiny fix in BugReporterVisitors.cpp
that suppresses a default note for "Assuming pointer value is null" when
a note tag from the checker is present. This is probably the right thing to do
but also definitely not a complete solution to the problem of different sources
of path notes being unaware of each other, which is a large and annoying issue
that we have to deal with. Note tags really help there because they're nicely
introspectable. The problem is demonstrated by the newly added getenv() test.
Differential Revision: https://reviews.llvm.org/D122285
A recent review emphasized the preference to use DefaultBool instead of
bool for checker options. This change is a NFC and cleans up some of the
instances where bool was used, and could be changed to DefaultBool.
Reviewed By: steakhal
Differential Revision: https://reviews.llvm.org/D123464
If the `assume-controlled-environment` is `true`, we should expect `getenv()`
to succeed, and the result should not be considered tainted.
By default, the option will be `false`.
Reviewed By: NoQ, martong
Differential Revision: https://reviews.llvm.org/D111296
The `getenv()` function might return `NULL` just like any other function.
However, in case of `getenv()` a state-split seems justified since the
programmer should expect the failure of this function.
`secure_getenv(const char *name)` behaves the same way but is not handled
right now.
Note that `std::getenv()` is also not handled.
Reviewed By: martong
Differential Revision: https://reviews.llvm.org/D111245
When we report an argument constraint violation, we should track those
other arguments that participate in the evaluation of the violation. By
default, we depend only on the argument that is constrained, however,
there are some special cases like the buffer size constraint that might
be encoded in another argument(s).
Differential Revision: https://reviews.llvm.org/D101358
In this patch, I provide a detailed explanation for each argument
constraint. This explanation is added in an extra 'note' tag, which is
displayed alongside the warning.
Since these new notes describe clearly the constraint, there is no need
to provide the number of the argument (e.g. 'Arg3') within the warning.
However, I decided to keep the name of the constraint in the warning (but
this could be a subject of discussion) in order to be able to identify
the different kind of constraint violations easily in a bug database
(e.g. CodeChecker).
Differential Revision: https://reviews.llvm.org/D101060
