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Merge pull request #14294 from am0o0/amammad-js-CodeInjection_execa
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JS: provide command execution sinks for execa package
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erik-krogh authored May 24, 2024
2 parents 5a7174d + c80f48b commit c743aba
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211 changes: 211 additions & 0 deletions javascript/ql/src/experimental/semmle/javascript/Execa.qll
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/**
* Models the `execa` library in terms of `FileSystemAccess` and `SystemCommandExecution`.
*/

import javascript

/**
* Provide model for [Execa](https://github.com/sindresorhus/execa) package
*/
module Execa {
/**
* The Execa input file read and output file write
*/
class ExecaFileSystemAccess extends FileSystemReadAccess, DataFlow::Node {
API::Node execaArg;
boolean isPipedToFile;

ExecaFileSystemAccess() {
(
execaArg = API::moduleImport("execa").getMember("$").getParameter(0) and
isPipedToFile = false
or
execaArg =
API::moduleImport("execa")
.getMember(["execa", "execaCommand", "execaCommandSync", "execaSync"])
.getParameter([0, 1, 2]) and
isPipedToFile = false
or
execaArg =
API::moduleImport("execa")
.getMember(["execa", "execaCommand", "execaCommandSync", "execaSync"])
.getReturn()
.getMember(["pipeStdout", "pipeAll", "pipeStderr"])
.getParameter(0) and
isPipedToFile = true
) and
this = execaArg.asSink()
}

override DataFlow::Node getADataNode() { none() }

override DataFlow::Node getAPathArgument() {
result = execaArg.getMember("inputFile").asSink() and isPipedToFile = false
or
result = execaArg.asSink() and isPipedToFile = true
}
}

/**
* A call to `execa.execa` or `execa.execaSync`
*/
class ExecaCall extends API::CallNode {
boolean isSync;

ExecaCall() {
this = API::moduleImport("execa").getMember("execa").getACall() and
isSync = false
or
this = API::moduleImport("execa").getMember("execaSync").getACall() and
isSync = true
}
}

/**
* The system command execution nodes for `execa.execa` or `execa.execaSync` functions
*/
class ExecaExec extends SystemCommandExecution, ExecaCall {
ExecaExec() { isSync = [false, true] }

override DataFlow::Node getACommandArgument() { result = this.getArgument(0) }

override predicate isShellInterpreted(DataFlow::Node arg) {
// if shell: true then first and second args are sinks
// options can be third argument
arg = [this.getArgument(0), this.getParameter(1).getUnknownMember().asSink()] and
isExecaShellEnable(this.getParameter(2))
or
// options can be second argument
arg = this.getArgument(0) and
isExecaShellEnable(this.getParameter(1))
}

override DataFlow::Node getArgumentList() {
// execa(cmd, [arg]);
exists(DataFlow::Node arg | arg = this.getArgument(1) |
// if it is a object then it is a option argument not command argument
result = arg and not arg.asExpr() instanceof ObjectExpr
)
}

override predicate isSync() { isSync = true }

override DataFlow::Node getOptionsArg() {
result = this.getLastArgument() and result.asExpr() instanceof ObjectExpr
}
}

/**
* A call to `execa.$` or `execa.$.sync` or `execa.$({})` or `execa.$.sync({})` tag functions
*/
private class ExecaScriptCall extends API::CallNode {
boolean isSync;

ExecaScriptCall() {
exists(API::Node script |
script =
[
API::moduleImport("execa").getMember("$"),
API::moduleImport("execa").getMember("$").getReturn()
]
|
this = script.getACall() and
isSync = false
or
this = script.getMember("sync").getACall() and
isSync = true
)
}
}

/**
* The system command execution nodes for `execa.$` or `execa.$.sync` tag functions
*/
class ExecaScript extends SystemCommandExecution, ExecaScriptCall {
ExecaScript() { isSync = [false, true] }

override DataFlow::Node getACommandArgument() {
result = this.getParameter(1).asSink() and
not isTaggedTemplateFirstChildAnElement(this.getParameter(1).asSink().asExpr().getParent())
}

override predicate isShellInterpreted(DataFlow::Node arg) {
isExecaShellEnable(this.getParameter(0)) and
arg = this.getAParameter().asSink()
}

override DataFlow::Node getArgumentList() {
result = this.getParameter(any(int i | i >= 1)).asSink() and
isTaggedTemplateFirstChildAnElement(this.getParameter(1).asSink().asExpr().getParent())
or
result = this.getParameter(any(int i | i >= 2)).asSink() and
not isTaggedTemplateFirstChildAnElement(this.getParameter(1).asSink().asExpr().getParent())
}

override DataFlow::Node getOptionsArg() { result = this.getParameter(0).asSink() }

override predicate isSync() { isSync = true }
}

/**
* A call to `execa.execaCommandSync` or `execa.execaCommand`
*/
private class ExecaCommandCall extends API::CallNode {
boolean isSync;

ExecaCommandCall() {
this = API::moduleImport("execa").getMember("execaCommandSync").getACall() and
isSync = true
or
this = API::moduleImport("execa").getMember("execaCommand").getACall() and
isSync = false
}
}

/**
* The system command execution nodes for `execa.execaCommand` or `execa.execaCommandSync` functions
*/
class ExecaCommandExec extends SystemCommandExecution, ExecaCommandCall {
ExecaCommandExec() { isSync = [false, true] }

override DataFlow::Node getACommandArgument() {
result = this.(DataFlow::CallNode).getArgument(0)
}

override DataFlow::Node getArgumentList() {
// execaCommand(`${cmd} ${arg}`);
result.asExpr() = this.getParameter(0).asSink().asExpr().getAChildExpr() and
not result.asExpr() = this.getArgument(0).asExpr().getChildExpr(0)
}

override predicate isShellInterpreted(DataFlow::Node arg) {
// execaCommandSync(`${cmd} ${arg}`, {shell: true})
arg.asExpr() = this.getArgument(0).asExpr().getAChildExpr+() and
isExecaShellEnable(this.getParameter(1))
or
// there is only one argument that is constructed in previous nodes,
// it makes sanitizing really hard to select whether it is vulnerable to argument injection or not
arg = this.getParameter(0).asSink() and
not exists(this.getArgument(0).asExpr().getChildExpr(1))
}

override predicate isSync() { isSync = true }

override DataFlow::Node getOptionsArg() {
result = this.getLastArgument() and result.asExpr() instanceof ObjectExpr
}
}

/** Gets a TemplateLiteral and check if first child is a template element */
private predicate isTaggedTemplateFirstChildAnElement(TemplateLiteral templateLit) {
exists(templateLit.getChildExpr(0).(TemplateElement))
}

/**
* Holds whether Execa has shell enabled options or not, get Parameter responsible for options
*/
pragma[inline]
private predicate isExecaShellEnable(API::Node n) {
n.getMember("shell").asSink().asExpr().(BooleanLiteral).getValue() = "true"
}
}
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passingPositiveTests
| PASSED | CommandInjection | tests.js:11:46:11:70 | // test ... jection |
| PASSED | CommandInjection | tests.js:12:43:12:67 | // test ... jection |
| PASSED | CommandInjection | tests.js:13:63:13:87 | // test ... jection |
| PASSED | CommandInjection | tests.js:14:62:14:86 | // test ... jection |
| PASSED | CommandInjection | tests.js:15:60:15:84 | // test ... jection |
| PASSED | CommandInjection | tests.js:17:45:17:69 | // test ... jection |
| PASSED | CommandInjection | tests.js:18:42:18:66 | // test ... jection |
| PASSED | CommandInjection | tests.js:19:62:19:86 | // test ... jection |
| PASSED | CommandInjection | tests.js:20:63:20:87 | // test ... jection |
| PASSED | CommandInjection | tests.js:21:60:21:84 | // test ... jection |
| PASSED | CommandInjection | tests.js:23:43:23:67 | // test ... jection |
| PASSED | CommandInjection | tests.js:24:40:24:64 | // test ... jection |
| PASSED | CommandInjection | tests.js:25:40:25:64 | // test ... jection |
| PASSED | CommandInjection | tests.js:26:60:26:84 | // test ... jection |
| PASSED | CommandInjection | tests.js:28:41:28:65 | // test ... jection |
| PASSED | CommandInjection | tests.js:29:58:29:82 | // test ... jection |
| PASSED | CommandInjection | tests.js:31:51:31:75 | // test ... jection |
| PASSED | CommandInjection | tests.js:32:68:32:92 | // test ... jection |
| PASSED | CommandInjection | tests.js:34:49:34:73 | // test ... jection |
| PASSED | CommandInjection | tests.js:35:66:35:90 | // test ... jection |
failingPositiveTests
36 changes: 36 additions & 0 deletions javascript/ql/test/experimental/Execa/CommandInjection/tests.js
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import { execa, execaSync, execaCommand, execaCommandSync, $ } from 'execa';
import http from 'node:http'
import url from 'url'

http.createServer(async function (req, res) {
let cmd = url.parse(req.url, true).query["cmd"][0];
let arg1 = url.parse(req.url, true).query["arg1"];
let arg2 = url.parse(req.url, true).query["arg2"];
let arg3 = url.parse(req.url, true).query["arg3"];

await $`${cmd} ${arg1} ${arg2} ${arg3}`; // test: CommandInjection
await $`ssh ${arg1} ${arg2} ${arg3}`; // test: CommandInjection
$({ shell: false }).sync`${cmd} ${arg1} ${arg2} ${arg3}`; // test: CommandInjection
$({ shell: true }).sync`${cmd} ${arg1} ${arg2} ${arg3}`; // test: CommandInjection
$({ shell: false }).sync`ssh ${arg1} ${arg2} ${arg3}`; // test: CommandInjection

$.sync`${cmd} ${arg1} ${arg2} ${arg3}`; // test: CommandInjection
$.sync`ssh ${arg1} ${arg2} ${arg3}`; // test: CommandInjection
await $({ shell: true })`${cmd} ${arg1} ${arg2} ${arg3}` // test: CommandInjection
await $({ shell: false })`${cmd} ${arg1} ${arg2} ${arg3}` // test: CommandInjection
await $({ shell: false })`ssh ${arg1} ${arg2} ${arg3}` // test: CommandInjection

await execa(cmd, [arg1, arg2, arg3]); // test: CommandInjection
await execa(cmd, { shell: true }); // test: CommandInjection
await execa(cmd, { shell: true }); // test: CommandInjection
await execa(cmd, [arg1, arg2, arg3], { shell: true }); // test: CommandInjection

execaSync(cmd, [arg1, arg2, arg3]); // test: CommandInjection
execaSync(cmd, [arg1, arg2, arg3], { shell: true }); // test: CommandInjection

await execaCommand(cmd + arg1 + arg2 + arg3); // test: CommandInjection
await execaCommand(cmd + arg1 + arg2 + arg3, { shell: true }); // test: CommandInjection

execaCommandSync(cmd + arg1 + arg2 + arg3); // test: CommandInjection
execaCommandSync(cmd + arg1 + arg2 + arg3, { shell: true }); // test: CommandInjection
});
38 changes: 38 additions & 0 deletions javascript/ql/test/experimental/Execa/CommandInjection/tests.ql
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import javascript

class InlineTest extends LineComment {
string tests;

InlineTest() { tests = this.getText().regexpCapture("\\s*test:(.*)", 1) }

string getPositiveTest() {
result = tests.trim().splitAt(",").trim() and not result.matches("!%")
}

predicate hasPositiveTest(string test) { test = this.getPositiveTest() }

predicate inNode(DataFlow::Node n) {
this.getLocation().getFile() = n.getFile() and
this.getLocation().getStartLine() = n.getStartLine()
}
}

import experimental.semmle.javascript.Execa

query predicate passingPositiveTests(string res, string expectation, InlineTest t) {
res = "PASSED" and
t.hasPositiveTest(expectation) and
expectation = "CommandInjection" and
exists(SystemCommandExecution n |
t.inNode(n.getArgumentList()) or t.inNode(n.getACommandArgument())
)
}

query predicate failingPositiveTests(string res, string expectation, InlineTest t) {
res = "FAILED" and
t.hasPositiveTest(expectation) and
expectation = "CommandInjection" and
not exists(SystemCommandExecution n |
t.inNode(n.getArgumentList()) or t.inNode(n.getACommandArgument())
)
}
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passingPositiveTests
| PASSED | PathInjection | tests.js:9:43:9:64 | // test ... jection |
| PASSED | PathInjection | tests.js:12:50:12:71 | // test ... jection |
| PASSED | PathInjection | tests.js:15:61:15:82 | // test ... jection |
| PASSED | PathInjection | tests.js:18:73:18:94 | // test ... jection |
failingPositiveTests
19 changes: 19 additions & 0 deletions javascript/ql/test/experimental/Execa/PathInjection/tests.js
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import { execa, $ } from 'execa';
import http from 'node:http'
import url from 'url'

http.createServer(async function (req, res) {
let filePath = url.parse(req.url, true).query["filePath"][0];

// Piping to stdin from a file
await $({ inputFile: filePath })`cat` // test: PathInjection

// Piping to stdin from a file
await execa('cat', { inputFile: filePath }); // test: PathInjection

// Piping Stdout to file
await execa('echo', ['example3']).pipeStdout(filePath); // test: PathInjection

// Piping all of command output to file
await execa('echo', ['example4'], { all: true }).pipeAll(filePath); // test: PathInjection
});
34 changes: 34 additions & 0 deletions javascript/ql/test/experimental/Execa/PathInjection/tests.ql
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import javascript

class InlineTest extends LineComment {
string tests;

InlineTest() { tests = this.getText().regexpCapture("\\s*test:(.*)", 1) }

string getPositiveTest() {
result = tests.trim().splitAt(",").trim() and not result.matches("!%")
}

predicate hasPositiveTest(string test) { test = this.getPositiveTest() }

predicate inNode(DataFlow::Node n) {
this.getLocation().getFile() = n.getFile() and
this.getLocation().getStartLine() = n.getStartLine()
}
}

import experimental.semmle.javascript.Execa

query predicate passingPositiveTests(string res, string expectation, InlineTest t) {
res = "PASSED" and
t.hasPositiveTest(expectation) and
expectation = "PathInjection" and
exists(FileSystemReadAccess n | t.inNode(n.getAPathArgument()))
}

query predicate failingPositiveTests(string res, string expectation, InlineTest t) {
res = "FAILED" and
t.hasPositiveTest(expectation) and
expectation = "PathInjection" and
not exists(FileSystemReadAccess n | t.inNode(n.getAPathArgument()))
}

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