Summary:
I wanted to extend the diagnostics of the CStringChecker with taintedness.
This requires the CStringChecker to be refactored to support a more flexible
reporting mechanism.
This patch does only refactorings, such:
- eliminates always false parameters (like WarnAboutSize)
- reduces the number of parameters
- makes strong types differentiating *source* and *destination* buffers
(same with size expressions)
- binds the argument expression and the index, making diagnostics accurate
and easy to emit
- removes a bunch of default parameters to make it more readable
- remove random const char* warning message parameters, making clear where
and what is going to be emitted
Note that:
- CheckBufferAccess now checks *only* one buffer, this removed about 100 LOC
code duplication
- not every function was refactored to use the /new/ strongly typed API, since
the CString related functions are really closely coupled monolithic beasts,
I will refactor them separately
- all tests are preserved and passing; only the message changed at some places.
In my opinion, these messages are holding the same information.
I would also highlight that this refactoring caught a bug in
clang/test/Analysis/string.c:454 where the diagnostic did not reflect reality.
This catch backs my effort on simplifying this monolithic CStringChecker.
Reviewers: NoQ, baloghadamsoftware, Szelethus, rengolin, Charusso
Reviewed By: NoQ
Subscribers: whisperity, xazax.hun, szepet, rnkovacs, a.sidorin,
mikhail.ramalho, donat.nagy, dkrupp, Charusso, martong, cfe-commits
Tags: #clang
Differential Revision: https://reviews.llvm.org/D74806
Converting a pointer to an integer whose result cannot represented in the
integer type is undefined behavior is C and prohibited in C++. C++ already
has a diagnostic when casting. This adds a diagnostic for C.
Since this diagnostic uses the range of the conversion it also modifies
int-to-pointer-cast diagnostic to use a range.
Fixes PR8718: No warning on casting between pointer and non-pointer-sized int
Differential Revision: https://reviews.llvm.org/D72231
While analyzing code `memcmp(a, NULL, n);', where `a' has an unconstrained
symbolic value, the analyzer was emitting a warning about the *first* argument
being a null pointer, even though we'd rather have it warn about the *second*
argument.
This happens because CStringChecker first checks whether the two argument
buffers are in fact the same buffer, in order to take the fast path.
This boils down to assuming `a == NULL' to true. Then the subsequent check
for null pointer argument "discovers" that `a' is null.
Don't take the fast path unless we are *sure* that the buffers are the same.
Otherwise proceed as normal.
Differential Revision: https://reviews.llvm.org/D71322
These diagnose overflowing calls to subset of fortifiable functions. Some
functions, like sprintf or strcpy aren't supported right not, but we should
probably support these in the future. We previously supported this kind of
functionality with -Wbuiltin-memcpy-chk-size, but that diagnostic doesn't work
with _FORTIFY implementations that use wrapper functions. Also unlike that
diagnostic, we emit these warnings regardless of whether _FORTIFY_SOURCE is
actually enabled, which is nice for programs that don't enable the runtime
checks.
Why not just use diagnose_if, like Bionic does? We can get better diagnostics in
the compiler (i.e. mention the sizes), and we have the potential to diagnose
sprintf and strcpy which is impossible with diagnose_if (at least, in languages
that don't support C++14 constexpr). This approach also saves standard libraries
from having to add diagnose_if.
rdar://48006655
Differential revision: https://reviews.llvm.org/D58797
llvm-svn: 356397
Summary:
This makes it consistent with `memcmp` and `__builtin_bcmp`.
Also see the discussion in https://reviews.llvm.org/D56593.
Reviewers: jyknight
Subscribers: kristina, cfe-commits
Tags: #clang
Differential Revision: https://reviews.llvm.org/D58120
llvm-svn: 354023
The return value of mempcpy is only correct when the destination type is
one byte in size. This patch casts the argument to a char* so the
calculation is also correct for structs, ints etc.
A patch by Daniel Fahlgren!
llvm-svn: 219024
specifically checks for equality to null.
Enforcing this general practice, which keeps the analyzer less
noisy, in the CString Checker. This change suppresses "Assigned value is
garbage or undefined" warning in the added test case.
llvm-svn: 156085
Models mempcpy() so that if length is NULL the destination pointer is returned. Otherwise, the source and destination are confirmed not to be NULL and not overlapping. Finally the copy is validated to not cause a buffer overrun and the return value is bound to the address of the byte after the last byte copied.
llvm-svn: 128677
They cooperate in that NSErrorChecker listens for ImplicitNullDerefEvent events that
DereferenceChecker can dispatch.
ImplicitNullDerefEvent is when we dereferenced a location that may be null.
llvm-svn: 126659
CStringChecker
ChrootChecker
MallocChecker
PthreadLockChecker
StreamChecker
UnreachableCodeChecker
MallocChecker creates implicit dependencies between checkers and needs to be handled differently.
llvm-svn: 125598
- Fix memcpy() and friends to actually invalidate the destination buffer.
- Emit a different message for out-of-bounds buffer accesses if the buffer is being written to.
- When conjuring symbols, let ValueManager figure out the type.
llvm-svn: 111120
- Allowed reporting of dead macros
- Added path walking function to search for false positives in conditional statements
- Updated some affected tests
- Added some false positive test cases
llvm-svn: 109561
- Created a new class to do post-analysis
- Updated several test cases with unreachable code to expect a warning
- Added some general tests
llvm-svn: 109286
Balazs Benics