Rust: Value flow and taint flow through formatting strings #18394
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hvitved
requested changes
Jan 6, 2025
| @@ -522,6 +522,7 @@ private ExprCfgNode getALastEvalNode(ExprCfgNode e) { | |||
| result = e.(BreakExprCfgNode).getExpr() or | |||
| result = e.(BlockExprCfgNode).getTailExpr() or | |||
| result = e.(MatchExprCfgNode).getArmExpr(_) or | |||
| result = e.(MacroExprCfgNode).getMacroCall().(MacroCallCfgNode).getExpandedNode() or | |||
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Should this rather be
result = e.(MacroExprCfgNode).getMacroCall() or
result = e.(MacroCallCfgNode).getExpandedNode() or?
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Conceptually yes, but MacroCall is not an expression and doesn't have a node in the data-flow graph, so it won't work. To do that I think we'd have to change the type of getALastEvalNode and add a new kind of data-flow node for MacroCall.
ThaSo just adding a step over the MacroCall seems simpler and is also what we do for the other kind of nodes that have their expression nested further down.
We could add a method on MacroExprCfgNode to get the expanded node directly?
| @@ -0,0 +1,2 @@ | |||
| edges | |||
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This file should be removed again.
| @@ -0,0 +1,122 @@ | |||
| localStep | |||
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Is the corresponding .ql test missing?
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This PR adds:
format_args!to theformat_args!expression itself.format!.The original goal was to get taint through the
format!macro. But since its definition uses aletstatement, the issue in #18330 prevents that from working. Once that is fixed, the changes here should give flow throughfomat!.MacroCallAST nodes are now included in the CFG in post-order. Previously they where skipped over and not included in the CFG, but this caused thegetMacroCallpredicate onMacroExprCfgNodeto never have any results. Including them in the CFG fixes that, and I don't think there's any reason to exclude them.