The gets function has no SrcArgs. Because the default value for isTainted was
false, it didn't mark its DstArgs as tainted.
Patch by Gábor Borsik!
Differential Revision: https://reviews.llvm.org/D58828
llvm-svn: 355396
When a function takes the address of a field the analyzer will no longer
assume that the function will change other fields of the enclosing structs.
Differential Revision: https://reviews.llvm.org/D57230
llvm-svn: 352473
Summary:
GenericTaintChecker can't recognize stdin in some cases. The reason is that `if (PtrTy->getPointeeType() == C.getASTContext().getFILEType()` does not hold when stdin is encountered.
My platform is ubuntu16.04 64bit, gcc 5.4.0, glibc 2.23. The definition of stdin is as follows:
```
__BEGIN_NAMESPACE_STD
/* The opaque type of streams. This is the definition used elsewhere. */
typedef struct _IO_FILE FILE;
___END_NAMESPACE_STD
...
/* The opaque type of streams. This is the definition used elsewhere. */
typedef struct _IO_FILE __FILE;
...
/* Standard streams. */
extern struct _IO_FILE *stdin; /* Standard input stream. */
extern struct _IO_FILE *stdout; /* Standard output stream. */
extern struct _IO_FILE *stderr; /* Standard error output stream. */
```
The type of stdin is as follows AST:
```
ElaboratedType 0xc911170'struct _IO_FILE'sugar
`-RecordType 0xc911150'struct _IO_FILE'
`-CXXRecord 0xc923ff0'_IO_FILE'
```
`C.getASTContext().GetFILEType()` is as follows AST:
```
TypedefType 0xc932710 'FILE' sugar
|-Typedef 0xc9111c0 'FILE'
`-ElaboratedType 0xc911170 'struct _IO_FILE' sugar
`-RecordType 0xc911150 'struct _IO_FILE'
`-CXXRecord 0xc923ff0 '_IO_FILE'
```
So I think it's better to use `getCanonicalType()`.
Reviewers: zaks.anna, NoQ, george.karpenkov, a.sidorin
Reviewed By: zaks.anna, a.sidorin
Subscribers: a.sidorin, cfe-commits, xazax.hun, szepet, MTC
Differential Revision: https://reviews.llvm.org/D39159
llvm-svn: 326709
The analyzer's taint analysis can now reason about structures or arrays
originating from taint sources in which only certain sections are tainted.
In particular, it also benefits modeling functions like read(), which may
read tainted data into a section of a structure, but RegionStore is incapable of
expressing the fact that the rest of the structure remains intact, even if we
try to model read() directly.
Patch by Vlad Tsyrklevich!
Differential revision: https://reviews.llvm.org/D28445
llvm-svn: 304162
These aren't generated by default, but they are needed when either side of
the comparison is tainted.
Should fix our internal buildbot.
llvm-svn: 177846
The resulting type info is stored in the SymSymExpr, so no reason not to
support construction of expression with different subexpression types.
llvm-svn: 156051
Also, slightly modify the diagnostic message in ArrayBound and DivZero (still use 'taint', which might not mean much to the user, but plan on changing it later).
llvm-svn: 148626
size (Ex: in malloc, memcpy, strncpy..)
(Maybe some of this could migrate to the CString checker. One issue
with that is that we might want to separate security issues from
regular API misuse.)
llvm-svn: 148371
To simplify the process:
Refactor taint generation checker to simplify passing the
information on which arguments need to be tainted from pre to post
visit.
Todo: We need to factor out the code that sema is using to identify the
string and memcpy functions and use it here and in the CString checker.
llvm-svn: 148010
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
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
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
Artem Dergachev