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/**
* Provides abstract classes representing generic concepts such as file system
* access or system command execution, for which individual framework libraries
* provide concrete subclasses.
*/
import python
private import semmle.python.dataflow.new.DataFlow
private import semmle.python.dataflow.new.RemoteFlowSources
private import semmle.python.dataflow.new.TaintTracking
private import semmle.python.Frameworks
/**
* 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 {
SystemCommandExecution::Range range;
SystemCommandExecution() { this = range }
/** Gets the argument that specifies the command to be executed. */
DataFlow::Node getCommand() { result = range.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();
}
}
/**
* 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 {
FileSystemAccess::Range range;
FileSystemAccess() { this = range }
/** Gets an argument to this file system access that is interpreted as a path. */
DataFlow::Node getAPathArgument() { result = range.getAPathArgument() }
}
/** 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();
}
}
/** 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 {
PathNormalization::Range range;
PathNormalization() { this = range }
}
/** 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 { }
}
/** A data-flow node that checks that a path is safe to access. */
class SafeAccessCheck extends DataFlow::BarrierGuard {
SafeAccessCheck::Range range;
SafeAccessCheck() { this = range }
override predicate checks(ControlFlowNode node, boolean branch) { 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. */
abstract class Range extends DataFlow::BarrierGuard { }
}
}
/**
* 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 {
Decoding::Range range;
Decoding() { this = range }
/** Holds if this call may execute code embedded in its input. */
predicate mayExecuteInput() { range.mayExecuteInput() }
/** Gets an input that is decoded by this function. */
DataFlow::Node getAnInput() { result = range.getAnInput() }
/** Gets the output that contains the decoded data produced by this function. */
DataFlow::Node getOutput() { result = range.getOutput() }
/** Gets an identifier for the format this function decodes from, such as "JSON". */
string getFormat() { result = range.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) {
exists(Decoding decoding |
nodeFrom = decoding.getAnInput() and
nodeTo = decoding.getOutput()
)
}
}
/**
* 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 {
Encoding::Range range;
Encoding() { this = range }
/** Gets an input that is encoded by this function. */
DataFlow::Node getAnInput() { result = range.getAnInput() }
/** Gets the output that contains the encoded data produced by this function. */
DataFlow::Node getOutput() { result = range.getOutput() }
/** Gets an identifier for the format this function decodes from, such as "JSON". */
string getFormat() { result = range.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 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 {
CodeExecution::Range range;
CodeExecution() { this = range }
/** Gets the argument that specifies the code to be executed. */
DataFlow::Node getCode() { result = range.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 executes SQL statements.
*
* Extend this class to refine existing API models. If you want to model new APIs,
* extend `SqlExecution::Range` instead.
*/
class SqlExecution extends DataFlow::Node {
SqlExecution::Range range;
SqlExecution() { this = range }
/** Gets the argument that specifies the SQL statements to be executed. */
DataFlow::Node getSql() { result = range.getSql() }
}
/** Provides a class for modeling new SQL execution APIs. */
module SqlExecution {
/**
* A data-flow node that executes SQL statements.
*
* 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 classes for modeling HTTP-related APIs. */
module HTTP {
import semmle.python.web.HttpConstants
/** 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 {
RouteSetup::Range range;
RouteSetup() { this = range }
/** Gets the URL pattern for this route, if it can be statically determined. */
string getUrlPattern() { result = range.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 = range.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 = range.getARoutedParameter() }
/** Gets a string that identifies the framework used for this route setup. */
string getFramework() { result = range.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(StrConst str |
DataFlow::exprNode(str).(DataFlow::LocalSourceNode).flowsTo(this.getUrlPatternArg()) 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 {
RequestHandler::Range range;
RequestHandler() { this = range }
/**
* Gets a parameter that could receive parts of the url when handling incoming
* requests, if any. These automatically become a `RemoteFlowSource`.
*/
Parameter getARoutedParameter() { result = range.getARoutedParameter() }
/** Gets a string that identifies the framework used for this route setup. */
string getFramework() { result = range.getFramework() }
}
/** Provides a class for modeling new HTTP request handlers. */
module RequestHandler {
/**
* A function that will handle incoming HTTP requests.
*
* Extend this class to model new APIs. If you want to refine existing API models,
* extend `RequestHandler` instead.
*
* Only extend this class if you can't provide a `RouteSetup`, since we handle that case automatically.
*/
abstract class Range extends Function {
/**
* Gets a parameter that could receive parts of the url when handling incoming
* requests, if any. These automatically become a `RemoteFlowSource`.
*/
abstract Parameter getARoutedParameter();
/** Gets a string that identifies the framework used for this request handler. */
abstract string getFramework();
}
}
private class RequestHandlerFromRouteSetup extends RequestHandler::Range {
RouteSetup rs;
RequestHandlerFromRouteSetup() { this = rs.getARequestHandler() }
override Parameter getARoutedParameter() {
result = rs.getARoutedParameter() and
result in [this.getArg(_), this.getArgByName(_)]
}
override string getFramework() { result = rs.getFramework() }
}
/** A parameter that will receive parts of the url when handling an incoming request. */
private class RoutedParameter extends RemoteFlowSource::Range, DataFlow::ParameterNode {
RequestHandler handler;
RoutedParameter() { this.getParameter() = handler.getARoutedParameter() }
override string getSourceType() { result = handler.getFramework() + " RoutedParameter" }
}
/**
* A data-flow node that creates a HTTP response on a server.
*
* Note: we don't require that this response must be sent to a client (a kind of
* "if a tree falls in a forest and nobody hears it" situation).
*
* Extend this class to refine existing API models. If you want to model new APIs,
* extend `HttpResponse::Range` instead.
*/
class HttpResponse extends DataFlow::Node {
HttpResponse::Range range;
HttpResponse() { this = range }
/** Gets the data-flow node that specifies the body of this HTTP response. */
DataFlow::Node getBody() { result = range.getBody() }
/** Gets the mimetype of this HTTP response, if it can be statically determined. */
string getMimetype() { result = range.getMimetype() }
}
/** Provides a class for modeling new HTTP response APIs. */
module HttpResponse {
/**
* A data-flow node that creates a HTTP response on a server.
*
* Note: we don't require that this response must be sent to a client (a kind of
* "if a tree falls in a forest and nobody hears it" situation).
*
* Extend this class to model new APIs. If you want to refine existing API models,
* extend `HttpResponse` instead.
*/
abstract class Range extends DataFlow::Node {
/** Gets the data-flow node that specifies the body of this HTTP response. */
abstract DataFlow::Node getBody();
/** Gets the data-flow node that specifies the content-type/mimetype of this HTTP response, if any. */
abstract DataFlow::Node getMimetypeOrContentTypeArg();
/** Gets the default mimetype that should be used if `getMimetypeOrContentTypeArg` has no results. */
abstract string getMimetypeDefault();
/** Gets the mimetype of this HTTP response, if it can be statically determined. */
string getMimetype() {
exists(StrConst str |
DataFlow::exprNode(str)
.(DataFlow::LocalSourceNode)
.flowsTo(this.getMimetypeOrContentTypeArg()) and
result = str.getText().splitAt(";", 0)
)
or
not exists(this.getMimetypeOrContentTypeArg()) and
result = this.getMimetypeDefault()
}
}
}
/**
* A data-flow node that creates a HTTP redirect response on a server.
*
* Note: we don't require that this redirect must be sent to a client (a kind of
* "if a tree falls in a forest and nobody hears it" situation).
*
* Extend this class to refine existing API models. If you want to model new APIs,
* extend `HttpRedirectResponse::Range` instead.
*/
class HttpRedirectResponse extends HttpResponse {
override HttpRedirectResponse::Range range;
HttpRedirectResponse() { this = range }
/** Gets the data-flow node that specifies the location of this HTTP redirect response. */
DataFlow::Node getRedirectLocation() { result = range.getRedirectLocation() }
}
/** Provides a class for modeling new HTTP redirect response APIs. */
module HttpRedirectResponse {
/**
* A data-flow node that creates a HTTP redirect response on a server.
*
* Note: we don't require that this redirect must be sent to a client (a kind of
* "if a tree falls in a forest and nobody hears it" situation).
*
* Extend this class to model new APIs. If you want to refine existing API models,
* extend `HttpResponse` instead.
*/
abstract class Range extends HTTP::Server::HttpResponse::Range {
/** Gets the data-flow node that specifies the location of this HTTP redirect response. */
abstract DataFlow::Node getRedirectLocation();
}
}
}
}
/**
* Provides models for cryptographic things.
*
* Note: The `CryptographicAlgorithm` class currently doesn't take weak keys into
* consideration for the `isWeak` member predicate. So RSA is always considered
* secure, although using a low number of bits will actually make it insecure. We plan
* to improve our libraries in the future to more precisely capture this aspect.
*/
module Cryptography {
/** Provides models for public-key cryptography, also called asymmetric cryptography. */
module PublicKey {
/**
* A data-flow node that generates a new key-pair for use with public-key cryptography.
*
* Extend this class to refine existing API models. If you want to model new APIs,
* extend `KeyGeneration::Range` instead.
*/
class KeyGeneration extends DataFlow::Node {
KeyGeneration::Range range;
KeyGeneration() { this = range }
/** Gets the name of the cryptographic algorithm (for example `"RSA"` or `"AES"`). */
string getName() { result = range.getName() }
/** Gets the argument that specifies the size of the key in bits, if available. */
DataFlow::Node getKeySizeArg() { result = range.getKeySizeArg() }
/**
* Gets the size of the key generated (in bits), as well as the `origin` that
* explains how we obtained this specific key size.
*/
int getKeySizeWithOrigin(DataFlow::Node origin) {
result = range.getKeySizeWithOrigin(origin)
}
/** Gets the minimum key size (in bits) for this algorithm to be considered secure. */
int minimumSecureKeySize() { result = range.minimumSecureKeySize() }
}
/** Provides classes for modeling new key-pair generation APIs. */
module KeyGeneration {
/** Gets a back-reference to the keysize argument `arg` that was used to generate a new key-pair. */
private DataFlow::LocalSourceNode keysizeBacktracker(
DataFlow::TypeBackTracker t, DataFlow::Node arg
) {
t.start() and
arg = any(KeyGeneration::Range r).getKeySizeArg() and
result = arg.getALocalSource()
or
exists(DataFlow::TypeBackTracker t2 | result = keysizeBacktracker(t2, arg).backtrack(t2, t))
}
/** Gets a back-reference to the keysize argument `arg` that was used to generate a new key-pair. */
DataFlow::LocalSourceNode keysizeBacktracker(DataFlow::Node arg) {
result = keysizeBacktracker(DataFlow::TypeBackTracker::end(), arg)
}
/**
* A data-flow node that generates a new key-pair for use with public-key cryptography.
*
* Extend this class to model new APIs. If you want to refine existing API models,
* extend `KeyGeneration` instead.
*/
abstract class Range extends DataFlow::Node {
/** Gets the name of the cryptographic algorithm (for example `"RSA"`). */
abstract string getName();
/** Gets the argument that specifies the size of the key in bits, if available. */
abstract DataFlow::Node getKeySizeArg();
/**
* Gets the size of the key generated (in bits), as well as the `origin` that
* explains how we obtained this specific key size.
*/
int getKeySizeWithOrigin(DataFlow::Node origin) {
origin = keysizeBacktracker(this.getKeySizeArg()) and
result = origin.asExpr().(IntegerLiteral).getValue()
}
/** Gets the minimum key size (in bits) for this algorithm to be considered secure. */
abstract int minimumSecureKeySize();
}
/** A data-flow node that generates a new RSA key-pair. */
abstract class RsaRange extends Range {
final override string getName() { result = "RSA" }
final override int minimumSecureKeySize() { result = 2048 }
}
/** A data-flow node that generates a new DSA key-pair. */
abstract class DsaRange extends Range {
final override string getName() { result = "DSA" }
final override int minimumSecureKeySize() { result = 2048 }
}
/** A data-flow node that generates a new ECC key-pair. */
abstract class EccRange extends Range {
final override string getName() { result = "ECC" }
final override int minimumSecureKeySize() { result = 224 }
}
}
}
import semmle.python.concepts.CryptoAlgorithms
/**
* A data-flow node that is an application of a cryptographic algorithm. For example,
* encryption, decryption, signature-validation.
*
* Extend this class to refine existing API models. If you want to model new APIs,
* extend `CryptographicOperation::Range` instead.
*/
class CryptographicOperation extends DataFlow::Node {
CryptographicOperation::Range range;
CryptographicOperation() { this = range }
/** Gets the algorithm used, if it matches a known `CryptographicAlgorithm`. */
CryptographicAlgorithm getAlgorithm() { result = range.getAlgorithm() }
/** Gets an input the algorithm is used on, for example the plain text input to be encrypted. */
DataFlow::Node getAnInput() { result = range.getAnInput() }
}
/** Provides classes for modeling new applications of a cryptographic algorithms. */
module CryptographicOperation {
/**
* A data-flow node that is an application of a cryptographic algorithm. For example,
* encryption, decryption, signature-validation.
*
* Extend this class to model new APIs. If you want to refine existing API models,
* extend `CryptographicOperation` instead.
*/
abstract class Range extends DataFlow::Node {
/** Gets the algorithm used, if it matches a known `CryptographicAlgorithm`. */
abstract CryptographicAlgorithm getAlgorithm();
/** Gets an input the algorithm is used on, for example the plain text input to be encrypted. */
abstract DataFlow::Node getAnInput();
}
}
}