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Swift: Query for escaping parameters of unsafe closures #13706

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1cac879
Initial test for pointer escaping withUnsafeBytes
rdmarsh2 Jul 10, 2023
83a787e
Swift: initial query for unsafe closure arg escape
rdmarsh2 Jul 10, 2023
f27522d
Swift: relocate UnsafePointerEscapesClosure
rdmarsh2 Jul 11, 2023
db18915
Swift: add more funcs to unsafe closure query
rdmarsh2 Jul 12, 2023
8120c8b
Swift: refactor to remove cartesian product
rdmarsh2 Jul 12, 2023
459eea5
Swift: avoid implicit return in tests
rdmarsh2 Jul 12, 2023
f125fa2
Swift: respond to PR comments
rdmarsh2 Jul 13, 2023
5f39a1a
Swift: qhelp for UnsafePointerEscapesClosure
rdmarsh2 Jul 13, 2023
37d69e5
Swift: add change note for unsafe closure query
rdmarsh2 Jul 13, 2023
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121 changes: 121 additions & 0 deletions swift/ql/test/query-tests/Security/CWE-825/test.expected
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WARNING: Unused variable c (test.ql:51,73-74)
edges
| file://:0:0:0:0 | [post] self [field, some:0, some:0, some:0, some:0] | withUnsafeBytes.swift:33:9:33:9 | self[return] |
| file://:0:0:0:0 | [post] self [field, some:0, some:0, some:0, some:0] | withUnsafeBytes.swift:33:9:33:9 | self[return] [field, some:0, some:0, some:0, some:0] |
| file://:0:0:0:0 | [post] self [field, some:0, some:0, some:0] | withUnsafeBytes.swift:33:9:33:9 | self[return] |
| file://:0:0:0:0 | [post] self [field, some:0, some:0, some:0] | withUnsafeBytes.swift:33:9:33:9 | self[return] [field, some:0, some:0, some:0] |
| file://:0:0:0:0 | [post] self [field, some:0, some:0] | withUnsafeBytes.swift:33:9:33:9 | self[return] |
| file://:0:0:0:0 | [post] self [field, some:0, some:0] | withUnsafeBytes.swift:33:9:33:9 | self[return] [field, some:0, some:0] |
| file://:0:0:0:0 | [post] self [field, some:0] | withUnsafeBytes.swift:33:9:33:9 | self[return] |
| file://:0:0:0:0 | [post] self [field, some:0] | withUnsafeBytes.swift:33:9:33:9 | self[return] [field, some:0] |
| file://:0:0:0:0 | [post] self [field] | withUnsafeBytes.swift:33:9:33:9 | self[return] |
| file://:0:0:0:0 | [post] self [field] | withUnsafeBytes.swift:33:9:33:9 | self[return] [field] |
| file://:0:0:0:0 | value | file://:0:0:0:0 | [post] self [field] |
| file://:0:0:0:0 | value [some:0, some:0, some:0, some:0] | file://:0:0:0:0 | [post] self [field, some:0, some:0, some:0, some:0] |
| file://:0:0:0:0 | value [some:0, some:0, some:0] | file://:0:0:0:0 | [post] self [field, some:0, some:0, some:0] |
| file://:0:0:0:0 | value [some:0, some:0] | file://:0:0:0:0 | [post] self [field, some:0, some:0] |
| file://:0:0:0:0 | value [some:0] | file://:0:0:0:0 | [post] self [field, some:0] |
| withUnsafeBytes.swift:9:25:9:25 | $0 | withUnsafeBytes.swift:10:16:10:16 | $0 |
| withUnsafeBytes.swift:13:34:13:37 | p | withUnsafeBytes.swift:13:97:13:97 | p |
| withUnsafeBytes.swift:15:34:15:37 | p | withUnsafeBytes.swift:15:109:15:109 | p |
| withUnsafeBytes.swift:15:109:15:109 | p | withUnsafeBytes.swift:15:97:15:110 | call to id(pointer:) |
| withUnsafeBytes.swift:15:109:15:109 | p | withUnsafeBytes.swift:28:12:28:21 | pointer |
| withUnsafeBytes.swift:20:28:20:31 | p | withUnsafeBytes.swift:20:68:20:68 | p |
| withUnsafeBytes.swift:20:58:20:68 | ... = ... [field, some:0, some:0, some:0, some:0] | withUnsafeBytes.swift:20:58:20:68 | ... = ... |
| withUnsafeBytes.swift:20:58:20:68 | ... = ... [field, some:0, some:0, some:0] | withUnsafeBytes.swift:20:58:20:68 | ... = ... |
| withUnsafeBytes.swift:20:58:20:68 | ... = ... [field, some:0, some:0] | withUnsafeBytes.swift:20:58:20:68 | ... = ... |
| withUnsafeBytes.swift:20:58:20:68 | ... = ... [field, some:0] | withUnsafeBytes.swift:20:58:20:68 | ... = ... |
| withUnsafeBytes.swift:20:58:20:68 | ... = ... [field] | withUnsafeBytes.swift:20:58:20:68 | ... = ... |
| withUnsafeBytes.swift:20:68:20:68 | p | withUnsafeBytes.swift:20:58:20:68 | ... = ... |
| withUnsafeBytes.swift:20:68:20:68 | p | withUnsafeBytes.swift:20:58:20:68 | ... = ... [field] |
| withUnsafeBytes.swift:20:68:20:68 | p | withUnsafeBytes.swift:20:68:20:68 | p [some:0] |
| withUnsafeBytes.swift:20:68:20:68 | p | withUnsafeBytes.swift:33:9:33:9 | value |
| withUnsafeBytes.swift:20:68:20:68 | p [some:0, some:0, some:0, some:0] | withUnsafeBytes.swift:20:58:20:68 | ... = ... |
| withUnsafeBytes.swift:20:68:20:68 | p [some:0, some:0, some:0, some:0] | withUnsafeBytes.swift:20:58:20:68 | ... = ... [field, some:0, some:0, some:0, some:0] |
| withUnsafeBytes.swift:20:68:20:68 | p [some:0, some:0, some:0, some:0] | withUnsafeBytes.swift:33:9:33:9 | value [some:0, some:0, some:0, some:0] |
| withUnsafeBytes.swift:20:68:20:68 | p [some:0, some:0, some:0] | withUnsafeBytes.swift:20:58:20:68 | ... = ... |
| withUnsafeBytes.swift:20:68:20:68 | p [some:0, some:0, some:0] | withUnsafeBytes.swift:20:58:20:68 | ... = ... [field, some:0, some:0, some:0] |
| withUnsafeBytes.swift:20:68:20:68 | p [some:0, some:0, some:0] | withUnsafeBytes.swift:20:68:20:68 | p [some:0, some:0, some:0, some:0] |
| withUnsafeBytes.swift:20:68:20:68 | p [some:0, some:0, some:0] | withUnsafeBytes.swift:33:9:33:9 | value [some:0, some:0, some:0] |
| withUnsafeBytes.swift:20:68:20:68 | p [some:0, some:0] | withUnsafeBytes.swift:20:58:20:68 | ... = ... |
| withUnsafeBytes.swift:20:68:20:68 | p [some:0, some:0] | withUnsafeBytes.swift:20:58:20:68 | ... = ... [field, some:0, some:0] |
| withUnsafeBytes.swift:20:68:20:68 | p [some:0, some:0] | withUnsafeBytes.swift:20:68:20:68 | p [some:0, some:0, some:0] |
| withUnsafeBytes.swift:20:68:20:68 | p [some:0, some:0] | withUnsafeBytes.swift:33:9:33:9 | value [some:0, some:0] |
| withUnsafeBytes.swift:20:68:20:68 | p [some:0] | withUnsafeBytes.swift:20:58:20:68 | ... = ... |
| withUnsafeBytes.swift:20:68:20:68 | p [some:0] | withUnsafeBytes.swift:20:58:20:68 | ... = ... [field, some:0] |
| withUnsafeBytes.swift:20:68:20:68 | p [some:0] | withUnsafeBytes.swift:20:68:20:68 | p [some:0, some:0] |
| withUnsafeBytes.swift:20:68:20:68 | p [some:0] | withUnsafeBytes.swift:33:9:33:9 | value [some:0] |
| withUnsafeBytes.swift:28:12:28:21 | pointer | withUnsafeBytes.swift:29:12:29:12 | pointer |
| withUnsafeBytes.swift:28:12:28:21 | pointer | withUnsafeBytes.swift:29:12:29:12 | pointer |
| withUnsafeBytes.swift:33:9:33:9 | value | file://:0:0:0:0 | value |
| withUnsafeBytes.swift:33:9:33:9 | value [some:0, some:0, some:0, some:0] | file://:0:0:0:0 | value [some:0, some:0, some:0, some:0] |
| withUnsafeBytes.swift:33:9:33:9 | value [some:0, some:0, some:0] | file://:0:0:0:0 | value [some:0, some:0, some:0] |
| withUnsafeBytes.swift:33:9:33:9 | value [some:0, some:0] | file://:0:0:0:0 | value [some:0, some:0] |
| withUnsafeBytes.swift:33:9:33:9 | value [some:0] | file://:0:0:0:0 | value [some:0] |
nodes
| file://:0:0:0:0 | [post] self [field, some:0, some:0, some:0, some:0] | semmle.label | [post] self [field, some:0, some:0, some:0, some:0] |
| file://:0:0:0:0 | [post] self [field, some:0, some:0, some:0] | semmle.label | [post] self [field, some:0, some:0, some:0] |
| file://:0:0:0:0 | [post] self [field, some:0, some:0] | semmle.label | [post] self [field, some:0, some:0] |
| file://:0:0:0:0 | [post] self [field, some:0] | semmle.label | [post] self [field, some:0] |
| file://:0:0:0:0 | [post] self [field] | semmle.label | [post] self [field] |
| file://:0:0:0:0 | value | semmle.label | value |
| file://:0:0:0:0 | value [some:0, some:0, some:0, some:0] | semmle.label | value [some:0, some:0, some:0, some:0] |
| file://:0:0:0:0 | value [some:0, some:0, some:0] | semmle.label | value [some:0, some:0, some:0] |
| file://:0:0:0:0 | value [some:0, some:0] | semmle.label | value [some:0, some:0] |
| file://:0:0:0:0 | value [some:0] | semmle.label | value [some:0] |
| withUnsafeBytes.swift:9:25:9:25 | $0 | semmle.label | $0 |
| withUnsafeBytes.swift:10:16:10:16 | $0 | semmle.label | $0 |
| withUnsafeBytes.swift:13:34:13:37 | p | semmle.label | p |
| withUnsafeBytes.swift:13:97:13:97 | p | semmle.label | p |
| withUnsafeBytes.swift:15:34:15:37 | p | semmle.label | p |
| withUnsafeBytes.swift:15:97:15:110 | call to id(pointer:) | semmle.label | call to id(pointer:) |
| withUnsafeBytes.swift:15:109:15:109 | p | semmle.label | p |
| withUnsafeBytes.swift:20:28:20:31 | p | semmle.label | p |
| withUnsafeBytes.swift:20:58:20:68 | ... = ... | semmle.label | ... = ... |
| withUnsafeBytes.swift:20:58:20:68 | ... = ... [field, some:0, some:0, some:0, some:0] | semmle.label | ... = ... [field, some:0, some:0, some:0, some:0] |
| withUnsafeBytes.swift:20:58:20:68 | ... = ... [field, some:0, some:0, some:0] | semmle.label | ... = ... [field, some:0, some:0, some:0] |
| withUnsafeBytes.swift:20:58:20:68 | ... = ... [field, some:0, some:0] | semmle.label | ... = ... [field, some:0, some:0] |
| withUnsafeBytes.swift:20:58:20:68 | ... = ... [field, some:0] | semmle.label | ... = ... [field, some:0] |
| withUnsafeBytes.swift:20:58:20:68 | ... = ... [field] | semmle.label | ... = ... [field] |
| withUnsafeBytes.swift:20:68:20:68 | p | semmle.label | p |
| withUnsafeBytes.swift:20:68:20:68 | p [some:0, some:0, some:0, some:0] | semmle.label | p [some:0, some:0, some:0, some:0] |
| withUnsafeBytes.swift:20:68:20:68 | p [some:0, some:0, some:0] | semmle.label | p [some:0, some:0, some:0] |
| withUnsafeBytes.swift:20:68:20:68 | p [some:0, some:0] | semmle.label | p [some:0, some:0] |
| withUnsafeBytes.swift:20:68:20:68 | p [some:0] | semmle.label | p [some:0] |
| withUnsafeBytes.swift:28:12:28:21 | pointer | semmle.label | pointer |
| withUnsafeBytes.swift:28:12:28:21 | pointer | semmle.label | pointer |
| withUnsafeBytes.swift:29:12:29:12 | pointer | semmle.label | pointer |
| withUnsafeBytes.swift:29:12:29:12 | pointer | semmle.label | pointer |
| withUnsafeBytes.swift:33:9:33:9 | self[return] | semmle.label | self[return] |
| withUnsafeBytes.swift:33:9:33:9 | self[return] | semmle.label | self[return] |
| withUnsafeBytes.swift:33:9:33:9 | self[return] | semmle.label | self[return] |
| withUnsafeBytes.swift:33:9:33:9 | self[return] | semmle.label | self[return] |
| withUnsafeBytes.swift:33:9:33:9 | self[return] | semmle.label | self[return] |
| withUnsafeBytes.swift:33:9:33:9 | self[return] [field, some:0, some:0, some:0, some:0] | semmle.label | self[return] [field, some:0, some:0, some:0, some:0] |
| withUnsafeBytes.swift:33:9:33:9 | self[return] [field, some:0, some:0, some:0] | semmle.label | self[return] [field, some:0, some:0, some:0] |
| withUnsafeBytes.swift:33:9:33:9 | self[return] [field, some:0, some:0] | semmle.label | self[return] [field, some:0, some:0] |
| withUnsafeBytes.swift:33:9:33:9 | self[return] [field, some:0] | semmle.label | self[return] [field, some:0] |
| withUnsafeBytes.swift:33:9:33:9 | self[return] [field] | semmle.label | self[return] [field] |
| withUnsafeBytes.swift:33:9:33:9 | value | semmle.label | value |
| withUnsafeBytes.swift:33:9:33:9 | value [some:0, some:0, some:0, some:0] | semmle.label | value [some:0, some:0, some:0, some:0] |
| withUnsafeBytes.swift:33:9:33:9 | value [some:0, some:0, some:0] | semmle.label | value [some:0, some:0, some:0] |
| withUnsafeBytes.swift:33:9:33:9 | value [some:0, some:0] | semmle.label | value [some:0, some:0] |
| withUnsafeBytes.swift:33:9:33:9 | value [some:0] | semmle.label | value [some:0] |
subpaths
| withUnsafeBytes.swift:15:109:15:109 | p | withUnsafeBytes.swift:28:12:28:21 | pointer | withUnsafeBytes.swift:29:12:29:12 | pointer | withUnsafeBytes.swift:15:97:15:110 | call to id(pointer:) |
| withUnsafeBytes.swift:20:68:20:68 | p | withUnsafeBytes.swift:33:9:33:9 | value | withUnsafeBytes.swift:33:9:33:9 | self[return] | withUnsafeBytes.swift:20:58:20:68 | ... = ... |
| withUnsafeBytes.swift:20:68:20:68 | p | withUnsafeBytes.swift:33:9:33:9 | value | withUnsafeBytes.swift:33:9:33:9 | self[return] [field] | withUnsafeBytes.swift:20:58:20:68 | ... = ... [field] |
| withUnsafeBytes.swift:20:68:20:68 | p [some:0, some:0, some:0, some:0] | withUnsafeBytes.swift:33:9:33:9 | value [some:0, some:0, some:0, some:0] | withUnsafeBytes.swift:33:9:33:9 | self[return] | withUnsafeBytes.swift:20:58:20:68 | ... = ... |
| withUnsafeBytes.swift:20:68:20:68 | p [some:0, some:0, some:0, some:0] | withUnsafeBytes.swift:33:9:33:9 | value [some:0, some:0, some:0, some:0] | withUnsafeBytes.swift:33:9:33:9 | self[return] [field, some:0, some:0, some:0, some:0] | withUnsafeBytes.swift:20:58:20:68 | ... = ... [field, some:0, some:0, some:0, some:0] |
| withUnsafeBytes.swift:20:68:20:68 | p [some:0, some:0, some:0] | withUnsafeBytes.swift:33:9:33:9 | value [some:0, some:0, some:0] | withUnsafeBytes.swift:33:9:33:9 | self[return] | withUnsafeBytes.swift:20:58:20:68 | ... = ... |
| withUnsafeBytes.swift:20:68:20:68 | p [some:0, some:0, some:0] | withUnsafeBytes.swift:33:9:33:9 | value [some:0, some:0, some:0] | withUnsafeBytes.swift:33:9:33:9 | self[return] [field, some:0, some:0, some:0] | withUnsafeBytes.swift:20:58:20:68 | ... = ... [field, some:0, some:0, some:0] |
| withUnsafeBytes.swift:20:68:20:68 | p [some:0, some:0] | withUnsafeBytes.swift:33:9:33:9 | value [some:0, some:0] | withUnsafeBytes.swift:33:9:33:9 | self[return] | withUnsafeBytes.swift:20:58:20:68 | ... = ... |
| withUnsafeBytes.swift:20:68:20:68 | p [some:0, some:0] | withUnsafeBytes.swift:33:9:33:9 | value [some:0, some:0] | withUnsafeBytes.swift:33:9:33:9 | self[return] [field, some:0, some:0] | withUnsafeBytes.swift:20:58:20:68 | ... = ... [field, some:0, some:0] |
| withUnsafeBytes.swift:20:68:20:68 | p [some:0] | withUnsafeBytes.swift:33:9:33:9 | value [some:0] | withUnsafeBytes.swift:33:9:33:9 | self[return] | withUnsafeBytes.swift:20:58:20:68 | ... = ... |
| withUnsafeBytes.swift:20:68:20:68 | p [some:0] | withUnsafeBytes.swift:33:9:33:9 | value [some:0] | withUnsafeBytes.swift:33:9:33:9 | self[return] [field, some:0] | withUnsafeBytes.swift:20:58:20:68 | ... = ... [field, some:0] |
#select
| withUnsafeBytes.swift:10:16:10:16 | $0 | withUnsafeBytes.swift:9:25:9:25 | $0 | withUnsafeBytes.swift:10:16:10:16 | $0 | This unsafe parameter may escape its invocation |
| withUnsafeBytes.swift:13:97:13:97 | p | withUnsafeBytes.swift:13:34:13:37 | p | withUnsafeBytes.swift:13:97:13:97 | p | This unsafe parameter may escape its invocation |
| withUnsafeBytes.swift:15:97:15:110 | call to id(pointer:) | withUnsafeBytes.swift:15:34:15:37 | p | withUnsafeBytes.swift:15:97:15:110 | call to id(pointer:) | This unsafe parameter may escape its invocation |
| withUnsafeBytes.swift:20:58:20:68 | ... = ... | withUnsafeBytes.swift:20:28:20:31 | p | withUnsafeBytes.swift:20:58:20:68 | ... = ... | This unsafe parameter may escape its invocation |
| withUnsafeBytes.swift:29:12:29:12 | pointer | withUnsafeBytes.swift:28:12:28:21 | pointer | withUnsafeBytes.swift:29:12:29:12 | pointer | This unsafe parameter may escape its invocation |
61 changes: 61 additions & 0 deletions swift/ql/test/query-tests/Security/CWE-825/test.ql
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Original file line number Diff line number Diff line change
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import swift
import codeql.swift.dataflow.DataFlow
import Flow::PathGraph

module Conf implements DataFlow::StateConfigSig {
class FlowState = Callable;

predicate isSource(DataFlow::Node node, FlowState state) {
// parameter of closure or function passed to withUnsafeBytes
exists(
CallExpr call |
call.getStaticTarget().hasName("withUnsafeBytes(_:)") and
state = node.(DataFlow::ParameterNode).getDeclaringFunction().getUnderlyingCallable() and
(
// if the declaring callable is a closure expr
state = call.getArgument(0).getExpr()
or
state.(Function).getAnAccess() = call.getArgument(0).getExpr()
)
)
}

predicate isSink(DataFlow::Node node, FlowState state) {
node.(DataFlow::InoutReturnNode).getParameter().getDeclaringFunction() = state
or
exists(ReturnStmt stmt |
node.asExpr() = stmt.getResult() and
stmt.getEnclosingCallable() = state
)
}

predicate isBarrier(DataFlow::Node node) {
none()
}
predicate isBarrierIn(DataFlow::Node node) {
none()
}
predicate isBarrierOut(DataFlow::Node node) {
none()
}
predicate isBarrier(DataFlow::Node node, FlowState state) {
none()
}
predicate isAdditionalFlowStep(DataFlow::Node node1, DataFlow::Node node2) { none() }
predicate isAdditionalFlowStep(DataFlow::Node node1, FlowState state1, DataFlow::Node node2, FlowState state2) {
none()
}

int fieldFlowBranchLimit() { result = 2 }

predicate allowImplicitRead(DataFlow::Node node, DataFlow::ContentSet c) {
isSink(node, _) and
c = any(DataFlow::ContentSet set)
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This looks like a cartesian product - might be a performance issue.

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Yes, it is (and I hit the performance issue on a real database). I've shrunk it by narrowing the sinks.

}
}

module Flow = DataFlow::GlobalWithState<Conf>;

from Flow::PathNode source, Flow::PathNode sink
where Flow::flowPath(source, sink)
select sink, source, sink, "This unsafe parameter may escape its invocation"
38 changes: 38 additions & 0 deletions swift/ql/test/query-tests/Security/CWE-825/withUnsafeBytes.swift
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// stubs



// tests

func arrayTest() {
let ints = [1,2,3]
ints.withUnsafeBytes{ // BAD
return $0
}

print(ints.withUnsafeBytes({(p: UnsafeRawBufferPointer) -> UnsafeRawBufferPointer in return p})) // BAD

print(ints.withUnsafeBytes({(p: UnsafeRawBufferPointer) -> UnsafeRawBufferPointer in return id(pointer: p)})) // BAD

ints.withUnsafeBytes({(p: UnsafeRawBufferPointer) in print(p)}) // GOOD

var v = PointerHolder()
ints.withUnsafeBytes({(p: UnsafeRawBufferPointer) in v.field = p}) // BAD
print(v.field)

ints.withUnsafeBytes(myPrint) // GOOD
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Another variant here would be calling a member function that stores the pointer argument in the object it's called on for later use. The effect is similar to the v.field = p case.


myPrint(p: ints.withUnsafeBytes(id)) // BAD
}

func id<T>(pointer: T) -> T {
return pointer
}

struct PointerHolder {
var field: UnsafeRawBufferPointer?
}

func myPrint(p: UnsafeRawBufferPointer) {
print(p)
}