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C#: Fix an incorrect merge conflict resolution. #312

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Merged
dilanbhalla merged 3 commits into from
Dec 18, 2025
Merged

C#: Fix an incorrect merge conflict resolution. #312

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9d04abb
C#: Fix an incorrect merge conflict resolution.
MathiasVP Dec 18, 2025
fa9f02a
C#: Drive-by fix. The 'GOOD' test was not actually
MathiasVP Dec 18, 2025
f9e1165
Merge branch 'main' into fix-merge-conflict-inTaintedPathQuery-2
MathiasVP Dec 18, 2025
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38 changes: 2 additions & 36 deletions csharp/ql/lib/semmle/code/csharp/security/dataflow/TaintedPathQuery.qll
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Original file line number Diff line number Diff line change
Expand Up @@ -52,40 +52,6 @@ private class GetFullPathStep extends PathNormalizationStep {
}
}

/** Holds if `e` may evaluate to an absolute path. */
bindingset[e]
pragma[inline_late]
private predicate isAbsolute(Expr e) {
exists(Expr absolute | DataFlow::localExprFlow(absolute, e) |
exists(Call call | absolute = call |
call.getARuntimeTarget()
.hasFullyQualifiedName(["System.Web.HttpServerUtilityBase", "System.Web.HttpRequest"],
"MapPath")
or
call.getARuntimeTarget().hasFullyQualifiedName("System.IO.Path", "GetFullPath")
or
call.getARuntimeTarget().hasFullyQualifiedName("System.IO.Directory", "GetCurrentDirectory")
)
or
exists(PropertyRead read | absolute = read |
read.getTarget().hasFullyQualifiedName("System", "Environment", "CurrentDirectory")
)
)
}

private class PathCombineStep extends PathNormalizationStep {
override predicate isAdditionalFlowStep(DataFlow::Node n1, DataFlow::Node n2) {
exists(Call call |
// The result of `Path.Combine(x, y)` is an absolute path when `x` is an
// absolute path.
call.getARuntimeTarget().hasFullyQualifiedName("System.IO.Path", "Combine") and
isAbsolute(call.getArgument(0)) and
n1.asExpr() = call.getArgument(1) and
n2.asExpr() = call
)
}
}

/**
* A taint-tracking configuration for uncontrolled data in path expression vulnerabilities.
*/
Expand All @@ -108,12 +74,12 @@ private module TaintedPathConfig implements DataFlow::StateConfigSig {
s2 = Normalized()
}

predicate isBarrier(DataFlow::Node node, FlowState state) { node.(Sanitizer).isBarrier(state) }

predicate isBarrierOut(DataFlow::Node node, FlowState state) {
isAdditionalFlowStep(_, state, node, _)
}

predicate isBarrier(DataFlow::Node node) { node instanceof Sanitizer }

predicate observeDiffInformedIncrementalMode() { any() }
}

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7 changes: 6 additions & 1 deletion csharp/ql/test/query-tests/Security Features/CWE-022/TaintedPath/TaintedPath.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -68,7 +68,12 @@ public void ProcessRequest(HttpContext ctx)
string absolutePath = ctx.Request.MapPath("~MyTempFile");
string fullPath2 = Path.Combine(absolutePath, path);
if (fullPath2.StartsWith(absolutePath + Path.DirectorySeparatorChar)) {
File.ReadAllText(fullPath2); // GOOD
File.ReadAllText(fullPath2); // BAD
}

string normalizedFullPath2 = Path.GetFullPath(fullPath2);
if (normalizedFullPath2.StartsWith(absolutePath + Path.DirectorySeparatorChar)) {
File.ReadAllText(normalizedFullPath2); // GOOD
}
}

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10 changes: 10 additions & 0 deletions csharp/ql/test/query-tests/Security Features/CWE-022/TaintedPath/TaintedPath.expected
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Original file line number Diff line number Diff line change
Expand Up @@ -7,6 +7,7 @@
| TaintedPath.cs:38:49:38:55 | access to local variable badPath | TaintedPath.cs:10:23:10:45 | access to property QueryString : NameValueCollection | TaintedPath.cs:38:49:38:55 | access to local variable badPath | This path depends on a $@. | TaintedPath.cs:10:23:10:45 | access to property QueryString | user-provided value |
| TaintedPath.cs:51:26:51:29 | access to local variable path | TaintedPath.cs:10:23:10:45 | access to property QueryString : NameValueCollection | TaintedPath.cs:51:26:51:29 | access to local variable path | This path depends on a $@. | TaintedPath.cs:10:23:10:45 | access to property QueryString | user-provided value |
| TaintedPath.cs:66:45:66:48 | access to local variable path | TaintedPath.cs:10:23:10:45 | access to property QueryString : NameValueCollection | TaintedPath.cs:66:45:66:48 | access to local variable path | This path depends on a $@. | TaintedPath.cs:10:23:10:45 | access to property QueryString | user-provided value |
| TaintedPath.cs:71:30:71:38 | access to local variable fullPath2 | TaintedPath.cs:10:23:10:45 | access to property QueryString : NameValueCollection | TaintedPath.cs:71:30:71:38 | access to local variable fullPath2 | This path depends on a $@. | TaintedPath.cs:10:23:10:45 | access to property QueryString | user-provided value |
edges
| TaintedPath.cs:10:16:10:19 | access to local variable path : String | TaintedPath.cs:12:50:12:53 | access to local variable path | provenance | |
| TaintedPath.cs:10:16:10:19 | access to local variable path : String | TaintedPath.cs:17:51:17:54 | access to local variable path | provenance | |
Expand All @@ -21,8 +22,13 @@ edges
| TaintedPath.cs:35:16:35:22 | access to local variable badPath : String | TaintedPath.cs:36:25:36:31 | access to local variable badPath | provenance | |
| TaintedPath.cs:35:16:35:22 | access to local variable badPath : String | TaintedPath.cs:38:49:38:55 | access to local variable badPath | provenance | |
| TaintedPath.cs:59:44:59:47 | access to local variable path : String | TaintedPath.cs:66:45:66:48 | access to local variable path | provenance | |
| TaintedPath.cs:59:44:59:47 | access to local variable path : String | TaintedPath.cs:69:55:69:58 | access to local variable path : String | provenance | |
| TaintedPath.cs:69:16:69:24 | access to local variable fullPath2 : String | TaintedPath.cs:71:30:71:38 | access to local variable fullPath2 | provenance | |
| TaintedPath.cs:69:28:69:59 | call to method Combine : String | TaintedPath.cs:69:16:69:24 | access to local variable fullPath2 : String | provenance | |
| TaintedPath.cs:69:55:69:58 | access to local variable path : String | TaintedPath.cs:69:28:69:59 | call to method Combine : String | provenance | MaD:2 |
models
| 1 | Summary: System.Collections.Specialized; NameValueCollection; false; get_Item; (System.String); ; Argument[this]; ReturnValue; taint; df-generated |
| 2 | Summary: System.IO; Path; false; Combine; (System.String,System.String); ; Argument[1]; ReturnValue; taint; manual |
nodes
| TaintedPath.cs:10:16:10:19 | access to local variable path : String | semmle.label | access to local variable path : String |
| TaintedPath.cs:10:23:10:45 | access to property QueryString : NameValueCollection | semmle.label | access to property QueryString : NameValueCollection |
Expand All @@ -37,4 +43,8 @@ nodes
| TaintedPath.cs:51:26:51:29 | access to local variable path | semmle.label | access to local variable path |
| TaintedPath.cs:59:44:59:47 | access to local variable path : String | semmle.label | access to local variable path : String |
| TaintedPath.cs:66:45:66:48 | access to local variable path | semmle.label | access to local variable path |
| TaintedPath.cs:69:16:69:24 | access to local variable fullPath2 : String | semmle.label | access to local variable fullPath2 : String |
| TaintedPath.cs:69:28:69:59 | call to method Combine : String | semmle.label | call to method Combine : String |
| TaintedPath.cs:69:55:69:58 | access to local variable path : String | semmle.label | access to local variable path : String |
| TaintedPath.cs:71:30:71:38 | access to local variable fullPath2 | semmle.label | access to local variable fullPath2 |
subpaths