Go: Add flow sources for AWS Lambda function handlers #15373
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| this = any(Method m | m.implements(awsLambdaPkg(), "Handler", "Invoke")).getFuncDecl() | ||
| or | ||
| exists(ConversionExpr ce | | ||
| ce.getTypeExpr().getType() instanceof HandlerImpl and | ||
| this = ce.getOperand().(FunctionName).getTarget().getFuncDecl() |
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Note that not requiring these two ways of declaring a handler to be used in a Start* or NewHandler* call to consider their parameters as sources is intended.
Firstly, because there are many ways of passing such a function/struct reference as argument of those calls (a variable, a conversion expression, a struct creation...) and we could have FNs if we tried to model them all, in addition to overcomplicating the models by having to use data flow analysis.
And secondly, because if a function is used in the ways modeled here, even if we don't enforce their use in a Start* or NewHandler* call, chances are that function is indeed going to be used as a lambda handler (and even if it isn't currently, the intention to do it is there, so we should preemptively alert anyway).
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| LambdaInput() { | ||
| exists(Parameter p | p = this.asParameter() | | ||
| p = any(HandlerFunction hf).getAParameter() and | ||
| not p.getType().hasQualifiedName("context", "Context") and |
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For now, I'm not considering any part of the Context as tainted (a more thorough analysis in the future may be worthwhile to make sure).
|
DCA looks uneventful as expected. |
| ]) and | ||
| handlerArgPos = 0 | ||
| or | ||
| this.hasQualifiedName(awsLambdaPkg(), "StartHandlerWithContext") and |
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Good catch, added here.
Co-authored-by: Chris Smowton <smowton@github.com>
Co-authored-by: Chris Smowton <smowton@github.com>
| exists(ConversionExpr ce | | ||
| ce.getTypeExpr().getType() instanceof HandlerImpl and | ||
| this = ce.getOperand().(FunctionName).getTarget().getFuncDecl() |
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| exists(ConversionExpr ce | | |
| ce.getTypeExpr().getType() instanceof HandlerImpl and | |
| this = ce.getOperand().(FunctionName).getTarget().getFuncDecl() | |
| exists(TypeCastNode typeCast | | |
| typeCast.getResultType() instanceof HandlerImpl and | |
| this.(FuncDecl).getFunction().getARead() = typeCast.getOperand() |
Sorry, should have picked this one up at the same time as the above. Also are there any tests for this path at the moment?
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👍
Also are there any tests for this path at the moment?
Yes, the ones using MyHandlerFunc, e.g.
lambda.StartHandler(MyHandlerFunc(Handler9))Co-authored-by: Chris Smowton <smowton@github.com>
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JS/TS support is old; noting for symmetry with advertised support in Python. Golang support is new as of #15373
This PR adds support for flow sources in AWS Lambda function handlers.