Some of the test cases do not currently work because the analyzer core
does not seem to call checkers for pre/post DeclRefExpr visits.
(Opened radar://10573500. To be fixed later on.)
llvm-svn: 146536
We are now often generating expressions even if the solver is not known to be able to simplify it. This is another cleanup of the existing code, where the rest of the analyzer and checkers should not base their logic on knowing ahead of the time what the solver can reason about.
In this case, CStringChecker is performing a check for overflow of 'left+right' operation. The overflow can be checked with either 'maxVal-left' or 'maxVal-right'. Previously, the decision was based on whether the expresion evaluated to undef or not. With this patch, we check if one of the arguments is a constant, in which case we know that 'maxVal-const' is easily simplified. (Another option is to use canReasonAbout() method of the solver here, however, it's currently is protected.)
This patch also contains 2 small bug fixes:
- swap the order of operators inside SValBuilder::makeGenericVal.
- handle a case when AddeVal is unknown in GenericTaintChecker::getPointedToSymbol.
llvm-svn: 146343
Fix a bug in SimpleSValBuilder, where we should swap lhs and rhs when calling generateUnknownVal(), - the function which creates symbolic expressions when data is tainted. The issue is not visible when we only create the expressions for taint since all expressions are commutative from taint perspective.
Refactor SymExpr::symbol_iterator::expand() to use a switch instead of a chain of ifs.
llvm-svn: 146336
types are equivalent.
+ A taint test which tests bitwise operations and which was
triggering an assertion due to presence of the integer to integer cast.
llvm-svn: 146240
between the casted type of the return value of a malloc/calloc/realloc
call and the operand of any sizeof expressions contained within
its argument(s).
llvm-svn: 146144
- Created a new SymExpr type - SymbolCast.
- SymbolCast is created when we don't know how to simplify a NonLoc to
NonLoc casts.
- A bit of code refactoring: introduced dispatchCast to have better
code reuse, remove a goto.
- Updated the test case to showcase the new taint flow.
llvm-svn: 145985
class.
We are going into the direction of handling SymbolData and other SymExpr
uniformly, so it makes less sense to keep two different SVal classes.
For example, the checkers would have to take an extra step to reason
about each type separately.
The classes have the same members, we were just using the SVal kind
field for easy differentiation in 3 switch statements. The switch
statements look more ugly now, but we can make the code more readable in
other ways, for example, moving some code into separate functions.
llvm-svn: 145833
ExprEngine.
Teach SimpleConstraintManager::assumeSymRel() to propagate constraints
to symbolic expressions.
+ One extra warning (real bug) is now generated due to enhanced
assumeSymRel().
llvm-svn: 145832
ConstraintManager::canReasonAbout() from the ExprEngine.
ExprEngine should not care if the constraint solver can reason about
something or not. The solver should be able to handle all the SymExprs.
To do this, the solver should be able to keep track of not only the
SymbolData but of all SymExprs. This is why we change SymbolRef to be an
alias of SymExpr*. When encountering an expression it cannot simplify,
the solver should just add the constraints to it.
llvm-svn: 145831
We trigger an error if free is called after a possibly failed allocation. Do not trigger the error if we know that the buffer is not null.
llvm-svn: 145584
We are getting name of the called function or it's declaration in a few checkers. Refactor them to use the helper function in the CheckerContext.
llvm-svn: 145576
explicit template specializations (which represent actual functions somebody wrote).
Along the way, refactor some other code which similarly cares about whether or
not they are looking at a template instantiation.
llvm-svn: 145547
When the solver and SValBuilder cannot reason about symbolic expressions (ex: (x+1)*y ), the analyzer conjures a new symbol with no ties to the past. This helps it to recover some path-sensitivity. However, this breaks the taint propagation.
With this commit, we are going to construct the expression even if we cannot reason about it later on if an operand is tainted.
Also added some comments and asserts.
llvm-svn: 144932
Change the ArrayBoundCheckerV2 to be more aggressive in reporting buffer overflows
when the offset is tainted. Previously, we did not report bugs when the state was
underconstrained (not enough information about the bound to determine if there is
an overflow) to avoid false positives. However, if we know that the buffer
offset is tainted - comes in from the user space and can be anything, we should
report it as a bug.
+ The very first example of us catching a taint related bug.
This is the only example we can currently handle. More to come...
llvm-svn: 144826
TaintTag.h will contain definitions of different taint kinds and their properties.
TaintManager will be responsible for implementing taint specific operations, storing taint.
ProgramState will provide API to add/remove taint.
llvm-svn: 144824
Anna Zaks