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Merge pull request #691 from asger-semmle/sendfile-root

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JS: Recognize 'root' option in Express res.sendFile
This commit is contained in:
Esben Sparre Andreasen
2018-12-19 16:06:15 +01:00
committed by GitHub
parent 495a1fcf3b f9da1dc03e
commit c57f8a6d6e
6 changed files with 29 additions and 2 deletions
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10
javascript/ql/src/semmle/javascript/Concepts.qll
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@@ -28,7 +28,15 @@ abstract class FileSystemAccess extends DataFlow::Node {
/** Gets an argument to this file system access that is interpreted as a path. */
abstract DataFlow::Node getAPathArgument();
/**
* Gets an argument to this file system access that is interpreted as a root folder
* in which the path arguments are constrained.
*
* In other words, if a root argument is provided, the underlying file access does its own
* sanitization to prevent the path arguments from traversing outside the root folder.
*/
DataFlow::Node getRootPathArgument() { none() }
}
/**

4
javascript/ql/src/semmle/javascript/frameworks/Express.qll
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@@ -866,6 +866,10 @@ module Express {
override DataFlow::Node getAPathArgument() {
result = DataFlow::valueNode(astNode.getArgument(0))
}
override DataFlow::Node getRootPathArgument() {
result = this.(DataFlow::CallNode).getOptionArgument(1, "root")
}
}
/**

6
javascript/ql/src/semmle/javascript/security/dataflow/TaintedPath.qll
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@@ -71,7 +71,11 @@ module TaintedPath {
*/
class FsPathSink extends Sink, DataFlow::ValueNode {
FsPathSink() {
this = any(FileSystemAccess fs).getAPathArgument()
exists (FileSystemAccess fs |
this = fs.getAPathArgument() and
not exists(fs.getRootPathArgument())
or
this = fs.getRootPathArgument())
}
}

2
javascript/ql/test/query-tests/Security/CWE-022/TaintedPath.expected
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@@ -87,6 +87,7 @@ nodes
| tainted-require.js:7:19:7:37 | req.param("module") |
| tainted-sendFile.js:7:16:7:33 | req.param("gimme") |
| tainted-sendFile.js:9:16:9:33 | req.param("gimme") |
| tainted-sendFile.js:17:43:17:58 | req.param("dir") |
| views.js:1:43:1:55 | req.params[0] |
edges
| TaintedPath-es6.js:7:7:7:44 | path | TaintedPath-es6.js:10:41:10:44 | path |
@@ -194,4 +195,5 @@ edges
| tainted-require.js:7:19:7:37 | req.param("module") | tainted-require.js:7:19:7:37 | req.param("module") | tainted-require.js:7:19:7:37 | req.param("module") | This path depends on $@. | tainted-require.js:7:19:7:37 | req.param("module") | a user-provided value |
| tainted-sendFile.js:7:16:7:33 | req.param("gimme") | tainted-sendFile.js:7:16:7:33 | req.param("gimme") | tainted-sendFile.js:7:16:7:33 | req.param("gimme") | This path depends on $@. | tainted-sendFile.js:7:16:7:33 | req.param("gimme") | a user-provided value |
| tainted-sendFile.js:9:16:9:33 | req.param("gimme") | tainted-sendFile.js:9:16:9:33 | req.param("gimme") | tainted-sendFile.js:9:16:9:33 | req.param("gimme") | This path depends on $@. | tainted-sendFile.js:9:16:9:33 | req.param("gimme") | a user-provided value |
| tainted-sendFile.js:17:43:17:58 | req.param("dir") | tainted-sendFile.js:17:43:17:58 | req.param("dir") | tainted-sendFile.js:17:43:17:58 | req.param("dir") | This path depends on $@. | tainted-sendFile.js:17:43:17:58 | req.param("dir") | a user-provided value |
| views.js:1:43:1:55 | req.params[0] | views.js:1:43:1:55 | req.params[0] | views.js:1:43:1:55 | req.params[0] | This path depends on $@. | views.js:1:43:1:55 | req.params[0] | a user-provided value |

8
javascript/ql/test/query-tests/Security/CWE-022/tainted-sendFile.js
View File

@@ -7,4 +7,12 @@ app.get('/some/path', function(req, res) {
res.sendFile(req.param("gimme"));
// BAD: same as above
res.sendfile(req.param("gimme"));
// GOOD: ensures files cannot be accessed outside of root folder
res.sendFile(req.param("gimme"), { root: process.cwd() });
// GOOD: ensures files cannot be accessed outside of root folder
res.sendfile(req.param("gimme"), { root: process.cwd() });
// BAD: doesn't help if user controls root
res.sendFile(req.param("file"), { root: req.param("dir") });
});