CodeQL library for Python
Search

Class Configuration

A configuration of interprocedural data flow analysis. This defines sources, sinks, and any other configurable aspect of the analysis. Each use of the global data flow library must define its own unique extension of this abstract class. To create a configuration, extend this class with a subclass whose characteristic predicate is a unique singleton string. For example, write

class MyAnalysisConfiguration extends DataFlow::Configuration {
  MyAnalysisConfiguration() { this = "MyAnalysisConfiguration" }
  // Override `isSource` and `isSink`.
  // Optionally override `isBarrier`.
  // Optionally override `isAdditionalFlowStep`.
}

Conceptually, this defines a graph where the nodes are DataFlow::Nodes and the edges are those data-flow steps that preserve the value of the node along with any additional edges defined by isAdditionalFlowStep. Specifying nodes in isBarrier will remove those nodes from the graph, and specifying nodes in isBarrierIn and/or isBarrierOut will remove in-going and/or out-going edges from those nodes, respectively.

Then, to query whether there is flow between some source and sink, write

exists(MyAnalysisConfiguration cfg | cfg.hasFlow(source, sink))

Multiple configurations can coexist, but two classes extending DataFlow::Configuration should never depend on each other. One of them should instead depend on a DataFlow2::Configuration, a DataFlow3::Configuration, or a DataFlow4::Configuration.

Import path

import semmle.python.dataflow.new.internal.DataFlowImpl

Direct supertypes

Known direct subtypes

Predicates

allowImplicitRead

Holds if an arbitrary number of implicit read steps of content c may be taken at node.

explorationLimit

Gets the exploration limit for hasPartialFlow and hasPartialFlowRev measured in approximate number of interprocedural steps.

fieldFlowBranchLimit

Gets the virtual dispatch branching limit when calculating field flow. This can be overridden to a smaller value to improve performance (a value of 0 disables field flow), or a larger value to get more results.

hasFlow

Holds if data may flow from source to sink for this configuration.

hasFlowPath

Holds if data may flow from source to sink for this configuration.

hasFlowTo

Holds if data may flow from some source to sink for this configuration.

hasFlowToExpr

Holds if data may flow from some source to sink for this configuration.

hasPartialFlow

Holds if there is a partial data flow path from source to node. The approximate distance between node and the closest source is dist and is restricted to be less than or equal to explorationLimit(). This predicate completely disregards sink definitions.

hasPartialFlowRev

Holds if there is a partial data flow path from node to sink. The approximate distance between node and the closest sink is dist and is restricted to be less than or equal to explorationLimit(). This predicate completely disregards source definitions.

isAdditionalFlowStep

Holds if the additional flow step from node1 to node2 must be taken into account in the analysis.

isBarrier

Holds if data flow through node is prohibited. This completely removes node from the data flow graph.

isBarrierGuard

Holds if data flow through nodes guarded by guard is prohibited.

isBarrierIn

Holds if data flow into node is prohibited.

isBarrierOut

Holds if data flow out of node is prohibited.

isSink

Holds if sink is a relevant data flow sink.

isSource

Holds if source is a relevant data flow source.

Inherited predicates

charAt

Returns a one-character string containing the character in the receiver at the given index (which ranges from 0 through length minus one)

from string
indexOf

Returns all the offsets (starting at 0) at which the given string occurs in the receiver. Has no result if the string does not occur in the receiver.

from string
indexOf

Returns the index of the n’th (starting at 0) occurrence of the given string within the receiver, starting at the given 0-based offset. Has no result if the string does not occur in the receiver.

from string
isLowercase

Holds when the receiver contains no upper-case letters. This includes the case where the receiver contains no letters at all, for example, if it’s an empty string or only consists of non-letter symbols.

from string
isUppercase

Holds when the receiver contains no lower-case letters. This includes the case where the receiver contains no letters at all, for example, if it’s an empty string or only consists of non-letter symbols.

from string
length

Returns the length of the receiver (in UTF-16 code units)

from string
matches

Holds when the receiver matches the pattern. Patterns are matched by case sensitive string matching, and there are two wildcards: _ matches a single character, and % matches any sequence of characters. To match the actual characters _ or % in the pattern, they must be escaped using backslashes. For example, "anythingstring%".matches("%string\\%") holds. To match a literal backslash in front of _ or %, you must escape the backslash. In other cases, you don’t need to escape the backslash.

from string
prefix

Returns the substring of the receiver ending at the given 0-based exclusive offset

from string
regexpCapture

When the given regular expression matches the entire receiver, returns the substring matched by the given capture group (starting at 1). The regex format used is Java’s Pattern.

from string
regexpFind

Returns a substring of the receiver which matches the given regular expression. Also returns the offset within the receiver (starting at 0) at which the match occurred (occurrenceOffset), and the number of matches which occur at smaller offsets (occurrenceIndex). The regex format used is Java’s Pattern.

from string
regexpMatch

Holds when the given regular expression matches the entire receiver. The regex format used is Java’s Pattern.

from string
regexpReplaceAll

Returns a copy of the receiver with every substring which matches the given regular expression is replaced by the replacement. The regex format used is Java’s Pattern. The replacement string can contain references to captured groups as described in Java’s appendReplacement docs.

from string
replaceAll

Returns a copy of the receiver with all occurrences of the target replaced by the replacement

from string
splitAt

Returns all the substrings obtained by splitting the receiver at every occurrence of the argument. Trailing empty substrings are omitted. Splitting at an empty string returns all the characters that the receiver consists of.

from string
splitAt

Returns the n’th (starting at 0) substring obtained by splitting the receiver at every occurrence of the argument. Trailing empty substrings are omitted. Splitting at an empty string returns all the characters that the receiver consists of.

from string
substring

Returns the substring of the receiver which starts and ends at the given indices. Both indices are 0-based. The start index is inclusive and the end index is exclusive.

from string
suffix

Returns the substring of the receiver starting at the given 0-based inclusive offset

from string
toDate

Returns the date, if any, obtained by parsing the receiver. The recognized formats are described in the documentation.

from string
toFloat

Returns the 64-bit floating point number, if any, obtained by parsing the receiver. The parsing rules are described in Java’s valueOf docs.

from string
toInt

Returns the 32-bit signed integer, if any, obtained by parsing the receiver. The number may consist of an optional leading + or -, followed by one or more digits. Has no result if the value exceeds the value range supported by the int type.

from string
toLowerCase

Returns a copy of the receiver with all uppercase characters replaced by lowercase ones according to Unicode case conversion rules.

from string
toString

Returns the receiver

from string
toUpperCase

Returns a copy of the receiver with all lowercase characters replaced by uppercase ones according to Unicode case conversion rules.

from string
trim

Returns a copy of the receiver with all whitespace removed from the beginning and end of the string (where whitespace is defined as Unicode code points ‘\u0000’ through ‘\u0020’ inclusive)

from string

Charpred