We already have a more conservative check in the compiler (if the
format string is not a literal, we warn). Still adding it here for
completeness and since this check is stronger - only triggered if the
format string is tainted.
llvm-svn: 147714
(Stmt*,LocationContext*) pairs to SVals instead of Stmt* to SVals.
This is needed to support basic IPA via inlining. Without this, we cannot tell
if a Stmt* binding is part of the current analysis scope (StackFrameContext) or
part of a parent context.
This change introduces an uglification of the use of getSVal(), and thus takes
two steps forward and one step back. There are also potential performance implications
of enlarging the Environment. Both can be addressed going forward by refactoring the
APIs and optimizing the internal representation of Environment. This patch
mainly introduces the functionality upon when we want to build upon (and clean up).
llvm-svn: 147688
as a result of a call.
Problem:
Global variables, which come in from system libraries should not be
invalidated by all calls. Also, non-system globals should not be
invalidated by system calls.
Solution:
The following solution to invalidation of globals seems flexible enough
for taint (does not invalidate stdin) and should not lead to too
many false positives. We split globals into 3 classes:
* immutable - values are preserved by calls (unless the specific
global is passed in as a parameter):
A : Most system globals and const scalars
* invalidated by functions defined in system headers:
B: errno
* invalidated by all other functions (note, these functions may in
turn contain system calls):
B: errno
C: all other globals (which are not in A nor B)
llvm-svn: 147569
Check if the input parameters are tainted (or point to tainted data) on
a checkPreStmt<CallExpr>. If the output should be tainted, record it in
the state. On post visit (checkPostStmt<CallExpr>), use the state to
make decisions (in addition to the existing logic). Use this logic for
atoi and fscanf.
llvm-svn: 146793
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
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
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
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
Analysis by Ted:
"
if (stateZero && !stateNotZero) {
is checking to see if:
(A) "it is possible for the value to be zero" (stateZero)
AND
(B) "it is not possible for the value to be non-zero" (!stateNotZero)
That said, the only way for both B to be true AND A to be false is if the path is completely infeasible by the time we reach the divide-by-zero check. For the most part (all cases?), such cases should automatically get pruned out at branches (i.e., an infeasible path gets dropped), which is the case in our tests. So the question is whether or not such an infeasible path might not get dropped earlier? I can't envision any right now.
Indeed, the rest of the checker assumes that if the bug condition didn't fire then 'stateNotZero' is non-NULL:
C.addTransition(stateNotZero);
"
llvm-svn: 144114
A step toward making sure that diagnostics report should only
be generated though the CheckerContext and not though BugReporter
or ExprEngine directly.
llvm-svn: 142947
Remove dead members/parameters: ProgramState, respondsToCallback, autoTransition.
Remove addTransition method since it's the same as generateNode. Maybe we should
rename generateNode to genTransition (since a transition is always automatically
generated)?
llvm-svn: 142946
Get rid of the EndOfPathBuilder completely.
Use the generic NodeBuilder to generate nodes.
Enqueue the end of path frontier explicitly.
llvm-svn: 142943
Rafael Espindola