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C++: Add type check to prevent field conflation

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This commit is contained in:
Jonas Jensen
2020-05-13 09:13:13 +02:00
parent 250e12a323
commit 038bea2f52
3 changed files with 9 additions and 8 deletions
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11
cpp/ql/src/semmle/code/cpp/ir/dataflow/internal/DataFlowUtil.qll
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@@ -492,8 +492,15 @@ private predicate simpleInstructionLocalFlowStep(Instruction iFrom, Instruction
// `LoadInstruction` together directly, this rule will break if there's any
// reassignment of the parameter indirection, including a conditional one that
// leads to a phi node.
iTo.(LoadInstruction).getSourceValueOperand().getAnyDef() =
iFrom.(InitializeIndirectionInstruction)
exists(InitializeIndirectionInstruction init |
iFrom = init and
iTo.(LoadInstruction).getSourceValueOperand().getAnyDef() = init and
// Check that the types match. Otherwise we can get flow from an object to
// its fields, which leads to field conflation when there's flow from other
// fields to the object elsewhere.
init.getParameter().getType().getUnspecifiedType().(DerivedType).getBaseType() =
iTo.getResultType().getUnspecifiedType()
)
or
// Treat all conversions as flow, even conversions between different numeric types.
iTo.(ConvertInstruction).getUnary() = iFrom

3
cpp/ql/test/library-tests/dataflow/DefaultTaintTracking/tainted.expected
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@@ -115,15 +115,12 @@
| defaulttainttracking.cpp:113:9:113:14 | call to getenv | defaulttainttracking.cpp:113:9:113:24 | access to array |
| defaulttainttracking.cpp:113:9:113:14 | call to getenv | defaulttainttracking.cpp:114:10:114:10 | x |
| defaulttainttracking.cpp:113:9:113:14 | call to getenv | test_diff.cpp:2:11:2:13 | p#0 |
| defaulttainttracking.cpp:120:11:120:16 | call to getenv | defaulttainttracking.cpp:10:11:10:13 | p#0 |
| defaulttainttracking.cpp:120:11:120:16 | call to getenv | defaulttainttracking.cpp:120:11:120:16 | call to getenv |
| defaulttainttracking.cpp:120:11:120:16 | call to getenv | defaulttainttracking.cpp:120:11:120:26 | (int)... |
| defaulttainttracking.cpp:120:11:120:16 | call to getenv | defaulttainttracking.cpp:120:11:120:26 | access to array |
| defaulttainttracking.cpp:120:11:120:16 | call to getenv | defaulttainttracking.cpp:123:23:123:24 | pp |
| defaulttainttracking.cpp:120:11:120:16 | call to getenv | defaulttainttracking.cpp:124:8:124:9 | pp |
| defaulttainttracking.cpp:120:11:120:16 | call to getenv | defaulttainttracking.cpp:124:12:124:12 | y |
| defaulttainttracking.cpp:120:11:120:16 | call to getenv | defaulttainttracking.cpp:130:13:130:14 | & ... |
| defaulttainttracking.cpp:120:11:120:16 | call to getenv | test_diff.cpp:2:11:2:13 | p#0 |
| globals.cpp:5:20:5:25 | call to getenv | globals.cpp:2:17:2:25 | sinkParam |
| globals.cpp:5:20:5:25 | call to getenv | globals.cpp:5:12:5:16 | local |
| globals.cpp:5:20:5:25 | call to getenv | globals.cpp:5:20:5:25 | call to getenv |

3
cpp/ql/test/library-tests/dataflow/DefaultTaintTracking/test_diff.expected
View File

@@ -27,13 +27,10 @@
| defaulttainttracking.cpp:113:9:113:14 | call to getenv | defaulttainttracking.cpp:113:5:113:5 | x | AST only |
| defaulttainttracking.cpp:113:9:113:14 | call to getenv | defaulttainttracking.cpp:114:10:114:10 | x | IR only |
| defaulttainttracking.cpp:113:9:113:14 | call to getenv | test_diff.cpp:2:11:2:13 | p#0 | IR only |
| defaulttainttracking.cpp:120:11:120:16 | call to getenv | defaulttainttracking.cpp:10:11:10:13 | p#0 | IR only |
| defaulttainttracking.cpp:120:11:120:16 | call to getenv | defaulttainttracking.cpp:120:7:120:7 | x | AST only |
| defaulttainttracking.cpp:120:11:120:16 | call to getenv | defaulttainttracking.cpp:123:23:123:24 | pp | IR only |
| defaulttainttracking.cpp:120:11:120:16 | call to getenv | defaulttainttracking.cpp:124:8:124:9 | pp | IR only |
| defaulttainttracking.cpp:120:11:120:16 | call to getenv | defaulttainttracking.cpp:124:12:124:12 | y | IR only |
| defaulttainttracking.cpp:120:11:120:16 | call to getenv | defaulttainttracking.cpp:130:13:130:14 | & ... | IR only |
| defaulttainttracking.cpp:120:11:120:16 | call to getenv | test_diff.cpp:2:11:2:13 | p#0 | IR only |
| globals.cpp:13:15:13:20 | call to getenv | globals.cpp:13:5:13:11 | global1 | AST only |
| globals.cpp:23:15:23:20 | call to getenv | globals.cpp:23:5:23:11 | global2 | AST only |
| test_diff.cpp:104:12:104:15 | argv | test_diff.cpp:104:11:104:20 | (...) | IR only |