dsl

package module

v0.0.17 Latest Latest Go to latest Published: Aug 1, 2023 License: MIT Imports: 50 Imported by: 39

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Repository

github.com/projectdiscovery/dsl

Links

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README ¶

DSL

DSL ease the creation of expressions by providing a set of built-in helper functions.

what is DSL?

DSL is a library allows to create and evaluate expressions. You can define expressions to compare, filter, or transform data, and then evaluate them against a set of data.

Example

package main

import (
	"fmt"
	"github.com/Knetic/govaluate"
	"github.com/projectdiscovery/dsl"
)

func main() {
	// Define the data to evaluate
	data := map[string]interface{}{
		"username": "johndoe",
		"email":    "johndoe@example.com",
		"password": "12345",
		"ip":       "127.0.0.1",
		"url":      "https://www.example.com",
		"date":     "2022-05-01",
	}

	// Define the expressions to evaluate
	expressions := map[string]string{
		"username_and_email_matcher": "contains(username, 'john') && contains(email, 'example.com')",
		"password_criteria":          "contains_any(password, '0123456789') && regex_any(password, '[A-Z]')",
		"sha256_username_matcher":    "sha256(username) == 'a0d95c8b32fa9b05a7d790a08e221c384b317ca05f66a7b84978d22c9838bb2a'",
		"ip_format_matcher":        "ip_format(ip, '1') == '127.0.0.1'",
		"url_valid_matcher":       "startswith(url, 'http') && contains(url, '://') && contains(url, '.') && !contains_any(url, ':@')",
	}

	for matcherName, expression := range expressions {
		compiledExpression, err := govaluate.NewEvaluableExpressionWithFunctions(expression, dsl.DefaultHelperFunctions)
		if err != nil {
			fmt.Printf("Fialed to compile expresion: %v\n", expression)
		}

		result, err := compiledExpression.Evaluate(data)
		if err != nil {
			fmt.Printf("Fialed to evaluate expresion: %v\n", expression)
		}

		if result == true {
			fmt.Printf("[%v] matches data\n", matcherName)
		} else {
			fmt.Printf("[%v] not matches data\n", matcherName)
		}
	}
}

Default Helper functions list

Helper function	Description	Example	Output
aes_gcm(key, plaintext interface{}) []byte	AES GCM encrypts a string with key	`{{hex_encode(aes_gcm("AES256Key-32Characters1234567890", "exampleplaintext"))}}`	`ec183a153b8e8ae7925beed74728534b57a60920c0b009eaa7608a34e06325804c096d7eebccddea3e5ed6c4`
base64(src interface{}) string	Base64 encodes a string	`base64("Hello")`	`SGVsbG8=`
base64_decode(src interface{}) []byte	Base64 decodes a string	`base64_decode("SGVsbG8=")`	`Hello`
base64_py(src interface{}) string	Encodes string to base64 like python (with new lines)	`base64_py("Hello")`	`SGVsbG8=\n`
bin_to_dec(binaryNumber number \| string) float64	Transforms the input binary number into a decimal format	`bin_to_dec("0b1010")` `bin_to_dec(1010)`	`10`
compare_versions(versionToCheck string, constraints ...string) bool	Compares the first version argument with the provided constraints	`compare_versions('v1.0.0', '>v0.0.1', '<v1.0.1')`	`true`
concat(arguments ...interface{}) string	Concatenates the given number of arguments to form a string	`concat("Hello", 123, "world)`	`Hello123world`
contains(input, substring interface{}) bool	Verifies if a string contains a substring	`contains("Hello", "lo")`	`true`
contains_all(input interface{}, substrings ...string) bool	Verifies if any input contains all of the substrings	`contains("Hello everyone", "lo", "every")`	`true`
contains_any(input interface{}, substrings ...string) bool	Verifies if an input contains any of substrings	`contains("Hello everyone", "abc", "llo")`	`true`
date_time(dateTimeFormat string, optionalUnixTime interface{}) string	Returns the formatted date time using simplified or `go` style layout for the current or the given unix time	`date_time("%Y-%M-%D %H:%m")` `date_time("%Y-%M-%D %H:%m", 1654870680)` `date_time("2006-01-02 15:04", unix_time())`	`2022-06-10 14:18`
dec_to_hex(number number \| string) string	Transforms the input number into hexadecimal format	`dec_to_hex(7001)"`	`1b59`
deflate(input string) string	Compresses the input using DEFLATE	`deflate("Hello")`	`"\xf2\x48\xcd\xc9\xc9\x07\x04\x00\x00\xff\xff"`
ends_with(str string, suffix ...string) bool	Checks if the string ends with any of the provided substrings	`ends_with("Hello", "lo")`	`true`
generate_java_gadget(gadget, cmd, encoding interface{}) string	Generates a Java Deserialization Gadget	`generate_java_gadget("dns", "{{interactsh-url}}", "base64")`	`rO0ABXNyABFqYXZhLnV0aWwuSGFzaE1hcAUH2sHDFmDRAwACRgAKbG9hZEZhY3RvckkACXRocmVzaG9sZHhwP0AAAAAAAAx3CAAAABAAAAABc3IADGphdmEubmV0LlVSTJYlNzYa/ORyAwAHSQAIaGFzaENvZGVJAARwb3J0TAAJYXV0aG9yaXR5dAASTGphdmEvbGFuZy9TdHJpbmc7TAAEZmlsZXEAfgADTAAEaG9zdHEAfgADTAAIcHJvdG9jb2xxAH4AA0wAA3JlZnEAfgADeHD//////////3QAAHQAAHEAfgAFdAAFcHh0ACpjYWhnMmZiaW41NjRvMGJ0MHRzMDhycDdlZXBwYjkxNDUub2FzdC5mdW54`
generate_jwt(json, algorithm, signature, unixMaxAge) []byte	Generates a JSON Web Token (JWT) using the claims provided in a JSON string, the signature, and the specified algorithm	`generate_jwt("{\"name\":\"John Doe\",\"foo\":\"bar\"}", "HS256", "hello-world")`	`eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJmb28iOiJiYXIiLCJuYW1lIjoiSm9obiBEb2UifQ.EsrL8lIcYJR_Ns-JuhF3VCllCP7xwbpMCCfHin_WT6U`
gzip(input string) string	Compresses the input using GZip	`base64(gzip("Hello"))`	`+H4sIAAAAAAAA//JIzcnJBwQAAP//gonR9wUAAAA=`
gzip_decode(input string) string	Decompresses the input using GZip	`gzip_decode(hex_decode("1f8b08000000000000fff248cdc9c907040000ffff8289d1f705000000"))`	`Hello`
hex_decode(input interface{}) []byte	Hex decodes the given input	`hex_decode("6161")`	`aa`
hex_encode(input interface{}) string	Hex encodes the given input	`hex_encode("aa")`	`6161`
hex_to_dec(hexNumber number \| string) float64	Transforms the input hexadecimal number into decimal format	`hex_to_dec("ff")` `hex_to_dec("0xff")`	`255`
hmac(algorithm, data, secret) string	hmac function that accepts a hashing function type with data and secret	`hmac("sha1", "test", "scrt")`	`8856b111056d946d5c6c92a21b43c233596623c6`
html_escape(input interface{}) string	HTML escapes the given input	`html_escape("<body>test</body>")`	`<body>test</body>`
html_unescape(input interface{}) string	HTML un-escapes the given input	`html_unescape("<body>test</body>")`	`<body>test</body>`
index(slice, index) interface{}	Select item at index from slice or string (zero based)	`index("test",0)`	`t`
inflate(input string) string	Decompresses the input using DEFLATE	`inflate(hex_decode("f348cdc9c90700"))`	`Hello`
join(separator string, elements ...interface{}) string	Joins the given elements using the specified separator	`join("_", 123, "hello", "world")`	`123_hello_world`
jarm(hostport string) string	Calculate the jarm hash for the host:port combination	`jarm("127.0.0.1:443")`	`29d29d00029d29d00041d41d000000ad9bf51cc3f5a1e29eecb81d0c7b06eb`
json_minify(json) string	Minifies a JSON string by removing unnecessary whitespace	`json_minify("{ \"name\": \"John Doe\", \"foo\": \"bar\" }")`	`{"foo":"bar","name":"John Doe"}`
json_prettify(json) string	Prettifies a JSON string by adding indentation	`json_prettify("{\"foo\":\"bar\",\"name\":\"John Doe\"}")`	`{\n \"foo\": \"bar\",\n \"name\": \"John Doe\"\n}`
len(arg interface{}) int	Returns the length of the input	`len("Hello")`	`5`
line_ends_with(str string, suffix ...string) bool	Checks if any line of the string ends with any of the provided substrings	`line_ends_with("Hello\nHi", "lo")`	`true`
line_starts_with(str string, prefix ...string) bool	Checks if any line of the string starts with any of the provided substrings	`line_starts_with("Hi\nHello", "He")`	`true`
llm_prompt(str string) string	Query OpenAI LLM (default GPT 3.5) with the provided text prompt and result the result as string (requires api token as environment variable `OPENAI_API_KEY`)	`llm_prompt("produce a generic json")`	`{'a':'b'}`
md5(input interface{}) string	Calculates the MD5 (Message Digest) hash of the input	`md5("Hello")`	`8b1a9953c4611296a827abf8c47804d7`
mmh3(input interface{}) string	Calculates the MMH3 (MurmurHash3) hash of an input	`mmh3("Hello")`	`316307400`
oct_to_dec(octalNumber number \| string) float64	Transforms the input octal number into a decimal format	`oct_to_dec("0o1234567")` `oct_to_dec(1234567)`	`342391`
print_debug(args ...interface{})	Prints the value of a given input or expression. Used for debugging.	`print_debug(1+2, "Hello")`	`3 Hello`
rand_base(length uint, optionalCharSet string) string	Generates a random sequence of given length string from an optional charset (defaults to letters and numbers)	`rand_base(5, "abc")`	`caccb`
rand_char(optionalCharSet string) string	Generates a random character from an optional character set (defaults to letters and numbers)	`rand_char("abc")`	`a`
rand_int(optionalMin, optionalMax uint) int	Generates a random integer between the given optional limits (defaults to 0 - MaxInt32)	`rand_int(1, 10)`	`6`
rand_ip(cidr ...string) string	Generates a random IP address	`rand_ip("192.168.0.0/24")`	`192.168.0.171`
rand_text_alpha(length uint, optionalBadChars string) string	Generates a random string of letters, of given length, excluding the optional cutset characters	`rand_text_alpha(10, "abc")`	`WKozhjJWlJ`
rand_text_alphanumeric(length uint, optionalBadChars string) string	Generates a random alphanumeric string, of given length without the optional cutset characters	`rand_text_alphanumeric(10, "ab12")`	`NthI0IiY8r`
rand_text_numeric(length uint, optionalBadNumbers string) string	Generates a random numeric string of given length without the optional set of undesired numbers	`rand_text_numeric(10, 123)`	`0654087985`
regex(pattern, input string) bool	Tests the given regular expression against the input string	`regex("H([a-z]+)o", "Hello")`	`true`
remove_bad_chars(input, cutset interface{}) string	Removes the desired characters from the input	`remove_bad_chars("abcd", "bc")`	`ad`
repeat(str string, count uint) string	Repeats the input string the given amount of times	`repeat("../", 5)`	`../../../../../`
replace(str, old, new string) string	Replaces a given substring in the given input	`replace("Hello", "He", "Ha")`	`Hallo`
replace_regex(source, regex, replacement string) string	Replaces substrings matching the given regular expression in the input	`replace_regex("He123llo", "(\\d+)", "")`	`Hello`
reverse(input string) string	Reverses the given input	`reverse("abc")`	`cba`
sha1(input interface{}) string	Calculates the SHA1 (Secure Hash 1) hash of the input	`sha1("Hello")`	`f7ff9e8b7bb2e09b70935a5d785e0cc5d9d0abf0`
sha256(input interface{}) string	Calculates the SHA256 (Secure Hash 256) hash of the input	`sha256("Hello")`	`185f8db32271fe25f561a6fc938b2e264306ec304eda518007d1764826381969`
starts_with(str string, prefix ...string) bool	Checks if the string starts with any of the provided substrings	`starts_with("Hello", "He")`	`true`
to_lower(input string) string	Transforms the input into lowercase characters	`to_lower("HELLO")`	`hello`
to_unix_time(input string, layout string) int	Parses a string date time using default or user given layouts, then returns its Unix timestamp	`to_unix_time("2022-01-13T16:30:10+00:00")` `to_unix_time("2022-01-13 16:30:10")` `to_unix_time("13-01-2022 16:30:10". "02-01-2006 15:04:05")`	`1642091410`
to_upper(input string) string	Transforms the input into uppercase characters	`to_upper("hello")`	`HELLO`
trim(input, cutset string) string	Returns a slice of the input with all leading and trailing Unicode code points contained in cutset removed	`trim("aaaHelloddd", "ad")`	`Hello`
trim_left(input, cutset string) string	Returns a slice of the input with all leading Unicode code points contained in cutset removed	`trim_left("aaaHelloddd", "ad")`	`Helloddd`
trim_prefix(input, prefix string) string	Returns the input without the provided leading prefix string	`trim_prefix("aaHelloaa", "aa")`	`Helloaa`
trim_right(input, cutset string) string	Returns a string, with all trailing Unicode code points contained in cutset removed	`trim_right("aaaHelloddd", "ad")`	`aaaHello`
trim_space(input string) string	Returns a string, with all leading and trailing white space removed, as defined by Unicode	`trim_space(" Hello ")`	`"Hello"`
trim_suffix(input, suffix string) string	Returns input without the provided trailing suffix string	`trim_suffix("aaHelloaa", "aa")`	`aaHello`
unix_time(optionalSeconds uint) float64	Returns the current Unix time (number of seconds elapsed since January 1, 1970 UTC) with the added optional seconds	`unix_time(10)`	`1639568278`
unpack(format string, sequence string/bytes) {}interface	Returns the result of python binary unpack for the first operand in the sequence (endianess+operand)	`unpack('>I', '\xac\xd7\t\xd0')`	`-272646673`
url_decode(input string) string	URL decodes the input string	`url_decode("https:%2F%2Fprojectdiscovery.io%3Ftest=1")`	`https://projectdiscovery.io?test=1`
url_encode(input string) string	URL encodes the input string	`url_encode("https://projectdiscovery.io/test?a=1")`	`https%3A%2F%2Fprojectdiscovery.io%2Ftest%3Fa%3D1`
wait_for(seconds uint)	Pauses the execution for the given amount of seconds	`wait_for(10)`	`true`
xor(sequences ...strings/bytes)	Perform xor on sequences of same length	`xor('abc','def')`	`50705` in hex
zlib(input string) string	Compresses the input using Zlib	`base64(zlib("Hello"))`	`eJzySM3JyQcEAAD//wWMAfU=`
zlib_decode(input string) string	Decompresses the input using Zlib	`zlib_decode(hex_decode("789cf248cdc9c907040000ffff058c01f5"))`	`Hello`

Supported encodings:

base64 (default)
gzip-base64
gzip
hex
raw

Deserialization helper function format:

{{generate_java_gadget(payload, cmd, encoding}}

Deserialization helper function example:

{{generate_java_gadget("commons-collections3.1", "wget http://{{interactsh-url}}", "base64")}}

Binary pack/unpack

The gostruct package provides functionality for converting Go values represented as byte slices. It uses format strings to describe the layout of the Go structs. The format characters include boolean, big endian, little endian, int, float32, float64, and string types with different packed sizes. Currently, only binary unpack of the first operand after endianess has been supported.

JSON helper functions

Nuclei allows manipulate JSON strings in different ways, here is a list of its functions:

generate_jwt, to generates a JSON Web Token (JWT) using the claims provided in a JSON string, the signature, and the specified algorithm.
json_minify, to minifies a JSON string by removing unnecessary whitespace.
json_prettify, to prettifies a JSON string by adding indentation.

Examples

generate_jwt

To generate a JSON Web Token (JWT), you have to supply the JSON that you want to sign, at least.

Here is a list of supported algorithms for generating JWTs with generate_jwt function (case-insensitive):

HS256
HS384
HS512
RS256
RS384
RS512
PS256
PS384
PS512
ES256
ES384
ES512
EdDSA
NONE

Empty string ("") also means NONE.

Format:

{{generate_jwt(json, algorithm, signature, maxAgeUnix)}}

Arguments other than json are optional.

Example:

variables:
  json: | # required
    {
      "foo": "bar",
      "name": "John Doe"
    }
  alg: "HS256" # optional
  sig: "this_is_secret" # optional
  age: '{{to_unix_time("2032-12-30T16:30:10+00:00")}}' # optional
  jwt: '{{generate_jwt(json, "{{alg}}", "{{sig}}", "{{age}}")}}'

The maxAgeUnix argument is to set the expiration "exp" JWT standard claim, as well as the "iat" claim when you call the function.

json_minify

Format:

{{json_minify(json)}}

Example:

variables:
  json: |
    {
      "foo": "bar",
      "name": "John Doe"
    }
  minify: '{{json_minify(json}}'

minify variable output:

{"foo":"bar","name":"John Doe"}

json_prettify

Format:

{{json_prettify(json)}}

Example:

variables:
  json: '{"foo":"bar","name":"John Doe"}'
  pretty: '{{json_prettify(json}}'

pretty variable output:

{
  "foo": "bar",
  "name": "John Doe"
}

Caching layer

DSL helpers that given the same input have deterministic output and are I/O intensive, should set the Cacheable property to true. This avoids to invoke the function multiple times and return always the same result.

Thanks

Knetic/govaluate - For providing a powerful expression evaluation package.

Documentation ¶

Index ¶

Variables
func AddFunction(function dslFunction) error
func AddMultiSignatureHelperFunction(key string, signatureparts []string, cacheable bool, ...) error
func EvalExpr(expr string, vars map[string]interface{}) (interface{}, error)
func GetFunctionNames(heperFunctions map[string]govaluate.ExpressionFunction) []string
func GetPrintableDslFunctionSignatures(noColor bool) string
func GetPublicIP() string
func HelperFunctions() map[string]govaluate.ExpressionFunction
func MustAddFunction(function dslFunction)
func NewWithMultipleSignatures(name string, signatures []string, cacheable bool, ...) dslFunction
func NewWithPositionalArgs(name string, numberOfArgs int, cacheable bool, ...) dslFunction
func NewWithSingleSignature(name, signature string, cacheable bool, logic govaluate.ExpressionFunction) dslFunction
func RandSeq(base string, n int) string
func Regex(regxp string) (*regexp.Regexp, error)
func TrimAll(s, cutset string) string
type Engine
- func NewEngine() (*Engine, error)
- func (e *Engine) EvalExpr(expr string, vars map[string]interface{}) (interface{}, error)
- func (e *Engine) EvalExprFromCache(expr string, vars map[string]interface{}) (interface{}, error)

Constants ¶

This section is empty.

Variables ¶

View Source

var (
	// FunctionNames is a list of function names for expression evaluation usages
	FunctionNames []string

	// DefaultHelperFunctions is a pre-compiled list of govaluate DSL functions
	DefaultHelperFunctions map[string]govaluate.ExpressionFunction

	// ErrParsingArg is error when parsing value of argument
	// Use With Caution: Nuclei ignores this error in extractors(ref: https://github.com/projectdiscovery/nuclei/issues/3950)
	ErrParsingArg = errors.New("error parsing argument value")

	DefaultCacheSize = 250
)

View Source

var ErrInvalidDslFunction = errors.New("invalid DSL function signature")

View Source

var PrintDebugCallback func(args ...interface{}) error

View Source

var (
	RegexStore = &mapsutil.SyncLockMap[string, *regexp.Regexp]{Map: make(mapsutil.Map[string, *regexp.Regexp])}
)

Functions ¶

func AddFunction ¶ added in v0.0.6

func AddFunction(function dslFunction) error

func AddMultiSignatureHelperFunction ¶ added in v0.0.4

func AddMultiSignatureHelperFunction(key string, signatureparts []string, cacheable bool, value func(args ...interface{}) (interface{}, error)) error

AddMultiSignatureHelperFunction allows creation of additional helper functions to be supported with templates Deprecated: Use AddFunction(NewWithMultipleSignatures(...)) - kept for backward compatibility

func EvalExpr ¶

func EvalExpr(expr string, vars map[string]interface{}) (interface{}, error)

func GetFunctionNames ¶ added in v0.0.4

func GetFunctionNames(heperFunctions map[string]govaluate.ExpressionFunction) []string

func GetPrintableDslFunctionSignatures ¶

func GetPrintableDslFunctionSignatures(noColor bool) string

func GetPublicIP ¶ added in v0.0.11

func GetPublicIP() string

GetPublicIp of the host

func HelperFunctions ¶ added in v0.0.4

func HelperFunctions() map[string]govaluate.ExpressionFunction

HelperFunctions returns the dsl helper functions

func MustAddFunction ¶ added in v0.0.6

func MustAddFunction(function dslFunction)

func NewWithMultipleSignatures ¶ added in v0.0.6

func NewWithMultipleSignatures(name string, signatures []string, cacheable bool, expr govaluate.ExpressionFunction) dslFunction

func NewWithPositionalArgs ¶ added in v0.0.6

func NewWithPositionalArgs(name string, numberOfArgs int, cacheable bool, expr govaluate.ExpressionFunction) dslFunction

func NewWithSingleSignature ¶ added in v0.0.6

func NewWithSingleSignature(name, signature string, cacheable bool, logic govaluate.ExpressionFunction) dslFunction

func RandSeq ¶

func RandSeq(base string, n int) string

func Regex ¶

func Regex(regxp string) (*regexp.Regexp, error)

func TrimAll ¶

func TrimAll(s, cutset string) string

Types ¶

type Engine ¶

type Engine struct {
	HelperFunctions map[string]govaluate.ExpressionFunction
	ExpressionStore map[string]*govaluate.EvaluableExpression
	// contains filtered or unexported fields
}

func NewEngine ¶

func NewEngine() (*Engine, error)

func (*Engine) EvalExpr ¶

func (e *Engine) EvalExpr(expr string, vars map[string]interface{}) (interface{}, error)

func (*Engine) EvalExprFromCache ¶

func (e *Engine) EvalExprFromCache(expr string, vars map[string]interface{}) (interface{}, error)

Source Files ¶

View all Source files

Directories ¶

Path	Synopsis
deserialization
llm
randomip

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