/**

* Provides abstract classes representing generic concepts such as file system

* access or system command execution, for which individual framework libraries

* provide concrete subclasses.

*/

private import python

private import semmle.python.dataflow.new.DataFlow

private import semmle.python.dataflow.new.internal.DataFlowImplSpecific

private import semmle.python.dataflow.new.RemoteFlowSources

private import semmle.python.dataflow.new.TaintTracking

private import semmle.python.Files

private import semmle.python.Frameworks

private import semmle.python.security.internal.EncryptionKeySizes

private import semmle.python.dataflow.new.SensitiveDataSources

private import codeql.threatmodels.ThreatModels

private import codeql.concepts.ConceptsShared

private import semmle.python.ApiGraphs

private import semmle.python.frameworks.data.ModelsAsData

private module ConceptsShared = ConceptsMake<Location, PythonDataFlow>;

/**

* A data flow source, for a specific threat-model.

*

* Extend this class to refine existing API models. If you want to model new APIs,

* extend `ThreatModelSource::Range` instead.

*/

class ThreatModelSource extends DataFlow::Node instanceof ThreatModelSource::Range {

/**

* Gets a string that represents the source kind with respect to threat modeling.

*

* See

* - https://github.com/github/codeql/blob/main/docs/codeql/reusables/threat-model-description.rst

* - https://github.com/github/codeql/blob/main/shared/threat-models/ext/threat-model-grouping.model.yml

*/

string getThreatModel() { result = super.getThreatModel() }

/** Gets a string that describes the type of this threat-model source. */

string getSourceType() { result = super.getSourceType() }

}

/** Provides a class for modeling new sources for specific threat-models. */

module ThreatModelSource {

/**

* A data flow source, for a specific threat-model.

*

* Extend this class to model new APIs. If you want to refine existing API models,

* extend `ThreatModelSource` instead.

*/

abstract class Range extends DataFlow::Node {

/**

* Gets a string that represents the source kind with respect to threat modeling.

*

* See

* - https://github.com/github/codeql/blob/main/docs/codeql/reusables/threat-model-description.rst

* - https://github.com/github/codeql/blob/main/shared/threat-models/ext/threat-model-grouping.model.yml

*/

abstract string getThreatModel();

/** Gets a string that describes the type of this threat-model source. */

abstract string getSourceType();

}

}

/**

* A data flow source that is enabled in the current threat model configuration.

*/

class ActiveThreatModelSource extends ThreatModelSource {

ActiveThreatModelSource() {

exists(string kind |

currentThreatModel(kind) and

this.getThreatModel() = kind

)

}

}

/**

* A data-flow node that executes an operating system command,

* for instance by spawning a new process.

*

* Extend this class to refine existing API models. If you want to model new APIs,

* extend `SystemCommandExecution::Range` instead.

*/

class SystemCommandExecution extends DataFlow::Node instanceof SystemCommandExecution::Range {

/** Holds if a shell interprets `arg`. */

predicate isShellInterpreted(DataFlow::Node arg) { super.isShellInterpreted(arg) }

/** Gets the argument that specifies the command to be executed. */

DataFlow::Node getCommand() { result = super.getCommand() }

}

/** Provides a class for modeling new system-command execution APIs. */

module SystemCommandExecution {

/**

* A data-flow node that executes an operating system command,

* for instance by spawning a new process.

*

* Extend this class to model new APIs. If you want to refine existing API models,

* extend `SystemCommandExecution` instead.

*/

abstract class Range extends DataFlow::Node {

/** Gets the argument that specifies the command to be executed. */

abstract DataFlow::Node getCommand();

/** Holds if a shell interprets `arg`. */

predicate isShellInterpreted(DataFlow::Node arg) { none() }

}

}

/**

* A data flow node that performs a file system access, including reading and writing data,

* creating and deleting files and folders, checking and updating permissions, and so on.

*

* Extend this class to refine existing API models. If you want to model new APIs,

* extend `FileSystemAccess::Range` instead.

*/

class FileSystemAccess extends DataFlow::Node instanceof FileSystemAccess::Range {

/** Gets an argument to this file system access that is interpreted as a path. */

DataFlow::Node getAPathArgument() { result = super.getAPathArgument() }

/**

* Gets an argument to this file system access that is interpreted as a path

* which is vulnerable to path injection.

*

* By default all path arguments are considered vulnerable, but this can be overridden to

* exclude certain arguments that are known to be safe, for example because they are

* restricted to a specific directory.

*/

DataFlow::Node getAVulnerablePathArgument() { result = super.getAVulnerablePathArgument() }

}

/** Provides a class for modeling new file system access APIs. */

module FileSystemAccess {

/**

* A data-flow node that performs a file system access, including reading and writing data,

* creating and deleting files and folders, checking and updating permissions, and so on.

*

* Extend this class to model new APIs. If you want to refine existing API models,

* extend `FileSystemAccess` instead.

*/

abstract class Range 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 path

* which is vulnerable to path injection.

*

* By default all path arguments are considered vulnerable, but this can be overridden to

* exclude certain arguments that are known to be safe, for example because they are

* restricted to a specific directory.

*/

DataFlow::Node getAVulnerablePathArgument() { result = this.getAPathArgument() }

}

}

/**

* A data flow node that writes data to the file system access.

*

* Extend this class to refine existing API models. If you want to model new APIs,

* extend `FileSystemWriteAccess::Range` instead.

*/

class FileSystemWriteAccess extends FileSystemAccess instanceof FileSystemWriteAccess::Range {

/**

* Gets a node that represents data to be written to the file system (possibly with

* some transformation happening before it is written, like JSON encoding).

*/

DataFlow::Node getADataNode() { result = super.getADataNode() }

}

/** Provides a class for modeling new file system writes. */

module FileSystemWriteAccess {

/**

* A data flow node that writes data to the file system access.

*

* Extend this class to model new APIs. If you want to refine existing API models,

* extend `FileSystemWriteAccess` instead.

*/

abstract class Range extends FileSystemAccess::Range {

/**

* Gets a node that represents data to be written to the file system (possibly with

* some transformation happening before it is written, like JSON encoding).

*/

abstract DataFlow::Node getADataNode();

}

}

/** Provides classes for modeling path-related APIs. */

module Path {

/**

* A data-flow node that performs path normalization. This is often needed in order

* to safely access paths.

*/

class PathNormalization extends DataFlow::Node instanceof PathNormalization::Range {

/** Gets an argument to this path normalization that is interpreted as a path. */

DataFlow::Node getPathArg() { result = super.getPathArg() }

}

/** Provides a class for modeling new path normalization APIs. */

module PathNormalization {

/**

* A data-flow node that performs path normalization. This is often needed in order

* to safely access paths.

*/

abstract class Range extends DataFlow::Node {

/** Gets an argument to this path normalization that is interpreted as a path. */

abstract DataFlow::Node getPathArg();

}

}

/** A data-flow node that checks that a path is safe to access in some way, for example by having a controlled prefix. */

class SafeAccessCheck extends DataFlow::ExprNode {

SafeAccessCheck() { this = DataFlow::BarrierGuard<safeAccessCheck/3>::getABarrierNode() }

}

private predicate safeAccessCheck(DataFlow::GuardNode g, ControlFlowNode node, boolean branch) {

g.(SafeAccessCheck::Range).checks(node, branch)

}

/** Provides a class for modeling new path safety checks. */

module SafeAccessCheck {

/** A data-flow node that checks that a path is safe to access in some way, for example by having a controlled prefix. */

abstract class Range extends DataFlow::GuardNode {

/** Holds if this guard validates `node` upon evaluating to `branch`. */

abstract predicate checks(ControlFlowNode node, boolean branch);

}

}

}

/**

* A data-flow node that decodes data from a binary or textual format. This

* is intended to include deserialization, unmarshalling, decoding, unpickling,

* decompressing, decrypting, parsing etc.

*

* A decoding (automatically) preserves taint from input to output. However, it can

* also be a problem in itself, for example if it allows code execution or could result

* in denial-of-service.

*

* Extend this class to refine existing API models. If you want to model new APIs,

* extend `Decoding::Range` instead.

*/

class Decoding extends DataFlow::Node instanceof Decoding::Range {

/** Holds if this call may execute code embedded in its input. */

predicate mayExecuteInput() { super.mayExecuteInput() }

/** Gets an input that is decoded by this function. */

DataFlow::Node getAnInput() { result = super.getAnInput() }

/** Gets the output that contains the decoded data produced by this function. */

DataFlow::Node getOutput() { result = super.getOutput() }

/** Gets an identifier for the format this function decodes from, such as "JSON". */

string getFormat() { result = super.getFormat() }

}

/** Provides a class for modeling new decoding mechanisms. */

module Decoding {

/**

* A data-flow node that decodes data from a binary or textual format. This

* is intended to include deserialization, unmarshalling, decoding, unpickling,

* decompressing, decrypting, parsing etc.

*

* A decoding (automatically) preserves taint from input to output. However, it can

* also be a problem in itself, for example if it allows code execution or could result

* in denial-of-service.

*

* Extend this class to model new APIs. If you want to refine existing API models,

* extend `Decoding` instead.

*/

abstract class Range extends DataFlow::Node {

/** Holds if this call may execute code embedded in its input. */

abstract predicate mayExecuteInput();

/** Gets an input that is decoded by this function. */

abstract DataFlow::Node getAnInput();

/** Gets the output that contains the decoded data produced by this function. */

abstract DataFlow::Node getOutput();

/** Gets an identifier for the format this function decodes from, such as "JSON". */

abstract string getFormat();

}

}

private class DecodingAdditionalTaintStep extends TaintTracking::AdditionalTaintStep {

override predicate step(DataFlow::Node nodeFrom, DataFlow::Node nodeTo, string model) {

exists(Decoding decoding |

nodeFrom = decoding.getAnInput() and

nodeTo = decoding.getOutput() and

model = "Decoding-" + decoding.getFormat()

)

}

}

/**

* A data-flow node that encodes data to a binary or textual format. This

* is intended to include serialization, marshalling, encoding, pickling,

* compressing, encrypting, etc.

*

* An encoding (automatically) preserves taint from input to output.

*

* Extend this class to refine existing API models. If you want to model new APIs,

* extend `Encoding::Range` instead.

*/

class Encoding extends DataFlow::Node instanceof Encoding::Range {

/** Gets an input that is encoded by this function. */

DataFlow::Node getAnInput() { result = super.getAnInput() }

/** Gets the output that contains the encoded data produced by this function. */

DataFlow::Node getOutput() { result = super.getOutput() }

/** Gets an identifier for the format this function decodes from, such as "JSON". */

string getFormat() { result = super.getFormat() }

}

/** Provides a class for modeling new encoding mechanisms. */

module Encoding {

/**

* A data-flow node that encodes data to a binary or textual format. This

* is intended to include serialization, marshalling, encoding, pickling,

* compressing, encrypting, etc.

*

* An encoding (automatically) preserves taint from input to output.

*

* Extend this class to model new APIs. If you want to refine existing API models,

* extend `Encoding` instead.

*/

abstract class Range extends DataFlow::Node {

/** Gets an input that is encoded by this function. */

abstract DataFlow::Node getAnInput();

/** Gets the output that contains the encoded data produced by this function. */

abstract DataFlow::Node getOutput();

/** Gets an identifier for the format this function decodes from, such as "JSON". */

abstract string getFormat();

}

}

private class EncodingAdditionalTaintStep extends TaintTracking::AdditionalTaintStep {

override predicate step(DataFlow::Node nodeFrom, DataFlow::Node nodeTo) {

exists(Encoding encoding |

nodeFrom = encoding.getAnInput() and

nodeTo = encoding.getOutput()

)

}

}

/**

* A data-flow node that logs data.

*

* Extend this class to refine existing API models. If you want to model new APIs,

* extend `Logging::Range` instead.

*/

class Logging extends DataFlow::Node instanceof Logging::Range {

/** Gets an input that is logged. */

DataFlow::Node getAnInput() { result = super.getAnInput() }

}

/** Provides a class for modeling new logging mechanisms. */

module Logging {

/**

* A data-flow node that logs data.

*

* Extend this class to model new APIs. If you want to refine existing API models,

* extend `Logging` instead.

*/

abstract class Range extends DataFlow::Node {

/** Gets an input that is logged. */

abstract DataFlow::Node getAnInput();

}

}

/**

* A data-flow node that dynamically executes Python code.

*

* Extend this class to refine existing API models. If you want to model new APIs,

* extend `CodeExecution::Range` instead.

*/

class CodeExecution extends DataFlow::Node instanceof CodeExecution::Range {

/** Gets the argument that specifies the code to be executed. */

DataFlow::Node getCode() { result = super.getCode() }

}

/** Provides a class for modeling new dynamic code execution APIs. */

module CodeExecution {

/**

* A data-flow node that dynamically executes Python code.

*

* Extend this class to model new APIs. If you want to refine existing API models,

* extend `CodeExecution` instead.

*/

abstract class Range extends DataFlow::Node {

/** Gets the argument that specifies the code to be executed. */

abstract DataFlow::Node getCode();

}

}

/**

* A data-flow node that constructs an SQL statement.

*

* Often, it is worthy of an alert if an SQL statement is constructed such that

* executing it would be a security risk.

*

* If it is important that the SQL statement is indeed executed, then use `SqlExecution`.

*

* Extend this class to refine existing API models. If you want to model new APIs,

* extend `SqlConstruction::Range` instead.

*/

class SqlConstruction extends DataFlow::Node instanceof SqlConstruction::Range {

/** Gets the argument that specifies the SQL statements to be constructed. */

DataFlow::Node getSql() { result = super.getSql() }

}

/** Provides a class for modeling new SQL execution APIs. */

module SqlConstruction {

/**

* A data-flow node that constructs an SQL statement.

*

* Often, it is worthy of an alert if an SQL statement is constructed such that

* executing it would be a security risk.

*

* If it is important that the SQL statement is indeed executed, then use `SqlExecution`.

*

* Extend this class to model new APIs. If you want to refine existing API models,

* extend `SqlConstruction` instead.

*/

abstract class Range extends DataFlow::Node {

/** Gets the argument that specifies the SQL statements to be constructed. */

abstract DataFlow::Node getSql();

}

}

/**

* A data-flow node that executes SQL statements.

*

* If the context of interest is such that merely constructing an SQL statement

* would be valuable to report, then consider using `SqlConstruction`.

*

* Extend this class to refine existing API models. If you want to model new APIs,

* extend `SqlExecution::Range` instead.

*/

class SqlExecution extends DataFlow::Node instanceof SqlExecution::Range {

/** Gets the argument that specifies the SQL statements to be executed. */

DataFlow::Node getSql() { result = super.getSql() }

}

/** Provides a class for modeling new SQL execution APIs. */

module SqlExecution {

/**

* A data-flow node that executes SQL statements.

*

* If the context of interest is such that merely constructing an SQL statement

* would be valuable to report, then consider using `SqlConstruction`.

*

* Extend this class to model new APIs. If you want to refine existing API models,

* extend `SqlExecution` instead.

*/

abstract class Range extends DataFlow::Node {

/** Gets the argument that specifies the SQL statements to be executed. */

abstract DataFlow::Node getSql();

}

}

/** Provides a class for modeling NoSQL execution APIs. */

module NoSqlExecution {

/**

* A data-flow node that executes NoSQL queries.

*

* Extend this class to model new APIs. If you want to refine existing API models,

* extend `NoSqlExecution` instead.

*/

abstract class Range extends DataFlow::Node {

/** Gets the argument that specifies the NoSQL query to be executed. */

abstract DataFlow::Node getQuery();

/** Holds if this query will unpack/interpret a dictionary */

abstract predicate interpretsDict();

/** Holds if this query can be dangerous when run on a user-controlled string */

abstract predicate vulnerableToStrings();

}

}

/**

* A data-flow node that executes NoSQL queries.

*

* Extend this class to refine existing API models. If you want to model new APIs,

* extend `NoSqlExecution::Range` instead.

*/

class NoSqlExecution extends DataFlow::Node instanceof NoSqlExecution::Range {

/** Gets the argument that specifies the NoSQL query to be executed. */

DataFlow::Node getQuery() { result = super.getQuery() }

/** Holds if this query will unpack/interpret a dictionary */

predicate interpretsDict() { super.interpretsDict() }

/** Holds if this query can be dangerous when run on a user-controlled string */

predicate vulnerableToStrings() { super.vulnerableToStrings() }

}

/** Provides classes for modeling NoSql sanitization-related APIs. */

module NoSqlSanitizer {

/**

* A data-flow node that collects functions sanitizing NoSQL queries.

*

* Extend this class to model new APIs. If you want to refine existing API models,

* extend `NoSQLSanitizer` instead.

*/

abstract class Range extends DataFlow::Node {

/** Gets the argument that specifies the NoSql query to be sanitized. */

abstract DataFlow::Node getAnInput();

}

}

/**

* A data-flow node that collects functions sanitizing NoSQL queries.

*

* Extend this class to model new APIs. If you want to refine existing API models,

* extend `NoSQLSanitizer::Range` instead.

*/

class NoSqlSanitizer extends DataFlow::Node instanceof NoSqlSanitizer::Range {

/** Gets the argument that specifies the NoSql query to be sanitized. */

DataFlow::Node getAnInput() { result = super.getAnInput() }

}

/**

* A data-flow node that executes a regular expression.

*

* Extend this class to refine existing API models. If you want to model new APIs,

* extend `RegexExecution::Range` instead.

*/

class RegexExecution extends DataFlow::Node instanceof RegexExecution::Range {

/** Gets the data flow node for the regex being executed by this node. */

DataFlow::Node getRegex() { result = super.getRegex() }

/** Gets a dataflow node for the string to be searched or matched against. */

DataFlow::Node getString() { result = super.getString() }

/**

* Gets the name of this regex execution, typically the name of an executing method.

* This is used for nice alert messages and should include the module if possible.

*/

string getName() { result = super.getName() }

}

/** Provides classes for modeling new regular-expression execution APIs. */

module RegexExecution {

/**

* A data-flow node that executes a regular expression.

*

* Extend this class to model new APIs. If you want to refine existing API models,

* extend `RegexExecution` instead.

*/

abstract class Range extends DataFlow::Node {

/** Gets the data flow node for the regex being executed by this node. */

abstract DataFlow::Node getRegex();

/** Gets a dataflow node for the string to be searched or matched against. */

abstract DataFlow::Node getString();

/**

* Gets the name of this regex execution, typically the name of an executing method.

* This is used for nice alert messages and should include the module if possible.

*/

abstract string getName();

}

}

/**

* A node where a string is interpreted as a regular expression,

* for instance an argument to `re.compile`.

*

* Extend this class to refine existing API models. If you want to model new APIs,

* extend `RegExpInterpretation::Range` instead.

*/

class RegExpInterpretation extends DataFlow::Node instanceof RegExpInterpretation::Range { }

/** Provides a class for modeling regular expression interpretations. */

module RegExpInterpretation {

/**

* A node where a string is interpreted as a regular expression,

* for instance an argument to `re.compile`.

*/

abstract class Range extends DataFlow::Node { }

}

/** Provides classes for modeling XML-related APIs. */

module XML {

/**

* A data-flow node that constructs an XPath expression.

*

* Often, it is worthy of an alert if an XPath expression is constructed such that

* executing it would be a security risk.

*

* If it is important that the XPath expression is indeed executed, then use `XPathExecution`.

*

* Extend this class to refine existing API models. If you want to model new APIs,

* extend `XPathConstruction::Range` instead.

*/

class XPathConstruction extends DataFlow::Node instanceof XPathConstruction::Range {

/** Gets the argument that specifies the XPath expressions to be constructed. */

DataFlow::Node getXPath() { result = super.getXPath() }

/**

* Gets the name of this XPath expression construction, typically the name of an executing method.

* This is used for nice alert messages and should include the module if possible.

*/

string getName() { result = super.getName() }

}

/** Provides a class for modeling new XPath construction APIs. */

module XPathConstruction {

/**

* A data-flow node that constructs an XPath expression.

*

* Often, it is worthy of an alert if an XPath expression is constructed such that

* executing it would be a security risk.

*

* Extend this class to model new APIs. If you want to refine existing API models,

* extend `XPathConstruction` instead.

*/

abstract class Range extends DataFlow::Node {

/** Gets the argument that specifies the XPath expressions to be constructed. */

abstract DataFlow::Node getXPath();

/**

* Gets the name of this XPath expression construction, typically the name of an executing method.

* This is used for nice alert messages and should include the module if possible.

*/

abstract string getName();

}

}

/**

* A data-flow node that executes a xpath expression.

*

* If the context of interest is such that merely constructing an XPath expression

* would be valuable to report, then consider using `XPathConstruction`.

*

* Extend this class to refine existing API models. If you want to model new APIs,

* extend `XPathExecution::Range` instead.

*/

class XPathExecution extends DataFlow::Node instanceof XPathExecution::Range {

/** Gets the data flow node for the XPath expression being executed by this node. */

DataFlow::Node getXPath() { result = super.getXPath() }

/**

* Gets the name of this XPath expression execution, typically the name of an executing method.

* This is used for nice alert messages and should include the module if possible.

*/

string getName() { result = super.getName() }

}

/** Provides classes for modeling new regular-expression execution APIs. */

module XPathExecution {

/**

* A data-flow node that executes a XPath expression.

*

* If the context of interest is such that merely constructing an XPath expression

* would be valuable to report, then consider using `XPathConstruction`.

*

* Extend this class to model new APIs. If you want to refine existing API models,

* extend `XPathExecution` instead.

*/

abstract class Range extends DataFlow::Node {

/** Gets the data flow node for the XPath expression being executed by this node. */

abstract DataFlow::Node getXPath();

/**

* Gets the name of this xpath expression execution, typically the name of an executing method.

* This is used for nice alert messages and should include the module if possible.

*/

abstract string getName();

}

}

/**

* A kind of XML vulnerability.

*

* See overview of kinds at https://pypi.org/project/defusedxml/#python-xml-libraries

*

* See PoC at `python/PoCs/XmlParsing/PoC.py` for some tests of vulnerable XML parsing.

*/

class XmlParsingVulnerabilityKind extends string {

XmlParsingVulnerabilityKind() { this in ["XML bomb", "XXE", "DTD retrieval"] }

/**

* Holds for XML bomb vulnerability kind, such as 'Billion Laughs' and 'Quadratic

* Blowup'.

*

* While a parser could technically be vulnerable to one and not the other, from our

* point of view the interesting part is that it IS vulnerable to these types of

* attacks, and not so much which one specifically works. In practice I haven't seen

* a parser that is vulnerable to one and not the other.

*/

predicate isXmlBomb() { this = "XML bomb" }

/** Holds for XXE vulnerability kind. */

predicate isXxe() { this = "XXE" }

/** Holds for DTD retrieval vulnerability kind. */

predicate isDtdRetrieval() { this = "DTD retrieval" }

}

/**

* A data-flow node that parses XML.

*

* Extend this class to model new APIs. If you want to refine existing API models,

* extend `XmlParsing` instead.

*/

class XmlParsing extends Decoding instanceof XmlParsing::Range {

/**

* Holds if this XML parsing is vulnerable to `kind`.

*/

predicate vulnerableTo(XmlParsingVulnerabilityKind kind) { super.vulnerableTo(kind) }

}

/** Provides classes for modeling XML parsing APIs. */

module XmlParsing {

/**

* A data-flow node that parses XML.

*

* Extend this class to model new APIs. If you want to refine existing API models,

* extend `XmlParsing` instead.

*/

abstract class Range extends Decoding::Range {

/**

* Holds if this XML parsing is vulnerable to `kind`.

*/

abstract predicate vulnerableTo(XmlParsingVulnerabilityKind kind);

override string getFormat() { result = "XML" }

}

}

}

/** Provides classes for modeling LDAP-related APIs. */

module Ldap {

/**

* A data-flow node that executes an LDAP query.

*

* Extend this class to refine existing API models. If you want to model new APIs,

* extend `LDAPQuery::Range` instead.

*/

class LdapExecution extends DataFlow::Node instanceof LdapExecution::Range {

/** Gets the argument containing the filter string. */

DataFlow::Node getFilter() { result = super.getFilter() }

/** Gets the argument containing the base DN. */

DataFlow::Node getBaseDn() { result = super.getBaseDn() }

}

/** Provides classes for modeling new LDAP query execution-related APIs. */

module LdapExecution {

/**

* A data-flow node that executes an LDAP query.

*

* Extend this class to model new APIs. If you want to refine existing API models,

* extend `LDAPQuery` instead.

*/

abstract class Range extends DataFlow::Node {

/** Gets the argument containing the filter string. */

abstract DataFlow::Node getFilter();

/** Gets the argument containing the base DN. */

abstract DataFlow::Node getBaseDn();

}

}

}

/**

* A data-flow node that escapes meta-characters, which could be used to prevent

* injection attacks.

*

* Extend this class to refine existing API models. If you want to model new APIs,

* extend `Escaping::Range` instead.

*/

class Escaping extends DataFlow::Node instanceof Escaping::Range {

Escaping() {

// escapes that don't have _both_ input/output defined are not valid

exists(super.getAnInput()) and

exists(super.getOutput())

}

/** Gets an input that will be escaped. */

DataFlow::Node getAnInput() { result = super.getAnInput() }

/** Gets the output that contains the escaped data. */

DataFlow::Node getOutput() { result = super.getOutput() }

/**

* Gets the context that this function escapes for, such as `html`, or `url`.

*/

string getKind() { result = super.getKind() }

}

/** Provides a class for modeling new escaping APIs. */

module Escaping {

/**

* A data-flow node that escapes meta-characters, which could be used to prevent

* injection attacks.

*

* Extend this class to model new APIs. If you want to refine existing API models,

* extend `Escaping` instead.

*/

abstract class Range extends DataFlow::Node {

/** Gets an input that will be escaped. */

abstract DataFlow::Node getAnInput();

/** Gets the output that contains the escaped data. */

abstract DataFlow::Node getOutput();

/**

* Gets the context that this function escapes for.

*

* While kinds are represented as strings, this should not be relied upon. Use the

* predicates in the `Escaping` module, such as `getHtmlKind`.

*/

abstract string getKind();

}

/** Gets the escape-kind for escaping a string so it can safely be included in HTML. */

string getHtmlKind() { result = "html" }

/** Gets the escape-kind for escaping a string so it can safely be included in XML. */

string getXmlKind() { result = "xml" }

/** Gets the escape-kind for escaping a string so it can safely be included in a regular expression. */

string getRegexKind() { result = "regex" }

/**

* Gets the escape-kind for escaping a string so it can safely be used as a

* distinguished name (DN) in an LDAP search.

*/

string getLdapDnKind() { result = "ldap_dn" }

/**

* Gets the escape-kind for escaping a string so it can safely be used as a

* filter in an LDAP search.

*/

string getLdapFilterKind() { result = "ldap_filter" }

// TODO: If adding an XML kind, update the modeling of the `MarkupSafe` PyPI package.

//

// Technically it claims to escape for both HTML and XML, but for now we don't have

// anything that relies on XML escaping, so I'm going to defer deciding whether they

// should be the same kind, or whether they deserve to be treated differently.

}

/**

* An escape of a string so it can be safely included in

* the body of an HTML element, for example, replacing `{}` in

* `<p>{}</p>`.

*/

class HtmlEscaping extends Escaping {

HtmlEscaping() { super.getKind() = Escaping::getHtmlKind() }

}

/**

* An escape of a string so it can be safely included in

* the body of an XML element, for example, replacing `&` and `<>` in

* `<foo>&xxe;<foo>`.

*/

class XmlEscaping extends Escaping {

XmlEscaping() { super.getKind() = Escaping::getXmlKind() }

}

/**

* An escape of a string so it can be safely included in

* the body of a regex.

*/

class RegexEscaping extends Escaping {

RegexEscaping() { super.getKind() = Escaping::getRegexKind() }

}

/**

* An escape of a string so it can be safely used as a distinguished name (DN)

* in an LDAP search.

*/

class LdapDnEscaping extends Escaping {

LdapDnEscaping() { super.getKind() = Escaping::getLdapDnKind() }

}

/**

* An escape of a string so it can be safely used as a filter in an LDAP search.

*/

class LdapFilterEscaping extends Escaping {

LdapFilterEscaping() { super.getKind() = Escaping::getLdapFilterKind() }

}

/**

* A data-flow node that constructs a template in a templating engine.

*

* Extend this class to refine existing API models. If you want to model new APIs,

* extend `TemplateConstruction::Range` instead.

*/

class TemplateConstruction extends DataFlow::Node instanceof TemplateConstruction::Range {

/** Gets the argument that specifies the template source. */

DataFlow::Node getSourceArg() { result = super.getSourceArg() }

}

/** Provides classes for modeling template construction APIs. */

module TemplateConstruction {

/**

* A data-flow node that constructs a template in a templating engine.

*

* Extend this class to model new APIs. If you want to refine existing API models,

* extend `TemplateConstruction` instead.

*/

abstract class Range extends DataFlow::Node {

/** Gets the argument that specifies the template source. */

abstract DataFlow::Node getSourceArg();

}

}

/** Provides classes for modeling HTTP-related APIs. */

module Http {

/** Gets an HTTP verb, in upper case */

string httpVerb() { result in ["GET", "POST", "PUT", "PATCH", "DELETE", "OPTIONS", "HEAD"] }

/** Gets an HTTP verb, in lower case */

string httpVerbLower() { result = httpVerb().toLowerCase() }

/** Provides classes for modeling HTTP servers. */

module Server {

/**

* A data-flow node that sets up a route on a server.

*

* Extend this class to refine existing API models. If you want to model new APIs,

* extend `RouteSetup::Range` instead.

*/

class RouteSetup extends DataFlow::Node instanceof RouteSetup::Range {

/** Gets the URL pattern for this route, if it can be statically determined. */

string getUrlPattern() { result = super.getUrlPattern() }

/**

* Gets a function that will handle incoming requests for this route, if any.

*

* NOTE: This will be modified in the near future to have a `RequestHandler` result, instead of a `Function`.

*/

Function getARequestHandler() { result = super.getARequestHandler() }

/**

* Gets a parameter that will receive parts of the url when handling incoming

* requests for this route, if any. These automatically become a `RemoteFlowSource`.

*/

Parameter getARoutedParameter() { result = super.getARoutedParameter() }

/** Gets a string that identifies the framework used for this route setup. */

string getFramework() { result = super.getFramework() }

}

/** Provides a class for modeling new HTTP routing APIs. */

module RouteSetup {

/**

* A data-flow node that sets up a route on a server.

*

* Extend this class to model new APIs. If you want to refine existing API models,

* extend `RouteSetup` instead.

*/

abstract class Range extends DataFlow::Node {

/** Gets the argument used to set the URL pattern. */

abstract DataFlow::Node getUrlPatternArg();

/** Gets the URL pattern for this route, if it can be statically determined. */

string getUrlPattern() {

exists(StringLiteral str |

this.getUrlPatternArg().getALocalSource() = DataFlow::exprNode(str) and

result = str.getText()

)

}

/**

* Gets a function that will handle incoming requests for this route, if any.

*

* NOTE: This will be modified in the near future to have a `RequestHandler` result, instead of a `Function`.

*/

abstract Function getARequestHandler();

/**

* Gets a parameter that will receive parts of the url when handling incoming

* requests for this route, if any. These automatically become a `RemoteFlowSource`.

*/

abstract Parameter getARoutedParameter();

/** Gets a string that identifies the framework used for this route setup. */

abstract string getFramework();

}

}

/**

* A function that will handle incoming HTTP requests.

*

* Extend this class to refine existing API models. If you want to model new APIs,

* extend `RequestHandler::Range` instead.

*/

class RequestHandler extends Function instanceof RequestHandler::Range {

/**

* Gets a parameter that could receive parts of the url when handling incoming