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Python: Propagate taint through parse_qs

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This commit is contained in:
Rasmus Wriedt Larsen
2020-04-22 08:51:27 +02:00
parent 243dea706e
commit 30e2592701
4 changed files with 45 additions and 12 deletions
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28
python/ql/src/semmle/python/security/strings/External.qll
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@@ -22,6 +22,8 @@ abstract class ExternalStringKind extends StringKind {
urlsplit(fromnode, tonode) and result.(ExternalUrlSplitResult).getItem() = this
or
urlparse(fromnode, tonode) and result.(ExternalUrlParseResult).getItem() = this
or
parse_qs(fromnode, tonode) and result.(ExternalStringDictKind).getValue() = this
}
}
@@ -181,6 +183,32 @@ private predicate urlparse(ControlFlowNode fromnode, CallNode tonode) {
)
}
private predicate parse_qs(ControlFlowNode fromnode, CallNode tonode) {
// This could be implemented as `exists(FunctionValue` without the explicit six part,
// but then our tests will need to import +100 modules, so for now this slightly
// altered version gets to live on.
exists(Value parse_qs |
(
parse_qs = Value::named("six.moves.urllib.parse.parse_qs")
or
// Python 2
parse_qs = Value::named("urlparse.parse_qs")
or
// Python 2 deprecated version of `urlparse.parse_qs`
parse_qs = Value::named("cgi.parse_qs")
or
// Python 3
parse_qs = Value::named("urllib.parse.parse_qs")
) and
tonode = parse_qs.getACall() and
(
tonode.getArg(0) = fromnode
or
tonode.getArgByName("qs") = fromnode
)
)
}
/** A kind of "taint", representing an open file-like object from an external source. */
class ExternalFileObject extends TaintKind {
ExternalFileObject() { this = "file[" + any(ExternalStringKind key) + "]" }