Wrappers for WebGL Specification standards (both 1.0 and 2.0) More...

Functions
function	farbleNull (name, ctx,...fcarg)
	Returns null or output of given function. More...

function	farbleZero (name, ctx,...fcarg)
	Returns 0 or output of given function. More...

function	farbleMinusOne (name, ctx,...fcarg)
	Returns -1 or output of given function. More...

function	farbleNullArray (name, ctx,...fcarg)
	Returns [] or output of given function. More...

function	farbleGetPrecisionFormat (ctx,...fcarg)
	Returns empty WebGLShaderPrecisionFormat object or real value. More...

function	farbleGetActives (name, ctx,...fcarg)
	Returns empty WebGLActiveInfo object or real value. More...

function	farbleGetFramebufferAttachmentParameter (ctx, target, attachment, pname)
	Returns modified WebGLRenderingContext.getFramebufferAttachmentParameter output for some specific parameters, original value for the rest. More...

function	farbleGetVertexAttrib (ctx, index, pname)
	Returns modified WebGLRenderingContext.getVertexAttrib output for some specific parameters, original value for the rest. More...

function	farbleGetBufferParameter (ctx, target, pname)
	Returns modified WebGLRenderingContext.getBufferParameter output for some specific parameters, original value for the rest. More...

function	farbleGetShaderParameter (ctx, shader, pname)
	Returns modified WebGLRenderingContext.getShaderParameter output for some specific parameters, original value for the rest. More...

function	farbleGetRenderbufferParameter (ctx, target, pname)
	Returns modified WebGLRenderingContext.getRenderbufferParameter output for some specific parameters, original value for the rest. More...

function	farbleGetProgramParameter (ctx, program, pname)
	Returns modified WebGLRenderingContext.getProgramParameter output for some specific parameters, original value for the rest. More...

function	farblePixels (ctx, x, y, width, height, format, type, pixels, offset)
	Modifies pixels array. More...

	add_wrappers (wrappers)

Variables
var	wrappers

Detailed Description

Wrappers for WebGL Specification standards (both 1.0 and 2.0)

See also: https://www.khronos.org/registry/webgl/specs/latest/1.0/; https://www.khronos.org/registry/webgl/specs/latest/2.0/

Author: Copyright (C) 2021 Matus Svancar

License:: SPDX-License-Identifier: GPL-3.0-or-later

License:: SPDX-License-Identifier: MPL-2.0

This file contains wrappers for WebGL related calls

The goal is to prevent fingerprinting by modifying the values from certain WebGLRenderingContext API functions. This includes return values of various functions which can be hardware/software specific and image data reading.

Content is either modified according to domain and session keys to be different than the original albeit very similar or replaced by bottom value which is consistent every time. Both approaches are inspired by the algorithms created by Brave Software available here and here.

This wrapper operates with two levels of protection:

(0) - return modified results, such as slightly changed image, slightly changed number or random string
(1) - return bottom values - such as zero, empty string, empty image, null, etc.

Level 0 is trying to force WebGL fingeprint to be unique on every domain and every session. This can be effective when used with other wrappers with same options. This level causes breakage of websites using WebGL only rarely. Level 1 is trying to return as little information as possible while being consistent across domains and sessions. This level can cause breakage on majority of websites using WebGL.

Note: Both approaches are detectable by a fingerprinter that checks if a predetermined image is the same as the read one or if specific function returns expected value. Nevertheless, the aim of the wrappers is to limit the finerprintability.

Function Documentation

◆ add_wrappers()

add_wrappers ( wrappers wrappers )

Adds a list of wrapping objects to the build_wrapping_code.

This function is called from each wrapper in its file.

Here is the caller graph for this function:

◆ farbleGetActives()

function farbleGetActives	(	name,
		ctx,
		fcarg
	)

Returns empty WebGLActiveInfo object or real value.

Parameters

name	of original function
ctx	WebGLRenderingContext (https://developer.mozilla.org/en-US/docs/Web/API/WebGLRenderingContext)
...fcarg	delegated arguments depending on function

Depending on level chosen this function returns:

(0) - original value
(1) - WebGLActiveInfo object with empty attributes

◆ farbleGetBufferParameter()

function farbleGetBufferParameter	(	ctx,
		target,
		pname
	)

Returns modified WebGLRenderingContext.getBufferParameter output for some specific parameters, original value for the rest.

Parameters

ctx	WebGLRenderingContext (https://developer.mozilla.org/en-US/docs/Web/API/WebGLRenderingContext)
target	GLenum (https://developer.mozilla.org/en-US/docs/Web/API/WebGL_API/Constants)
pname	GLenum (https://developer.mozilla.org/en-US/docs/Web/API/WebGL_API/Constants)

Depending on level chosen this function returns:

(0) - original value
(1) - bottom value (0, 35044)

◆ farbleGetFramebufferAttachmentParameter()

function farbleGetFramebufferAttachmentParameter	(	ctx,
		target,
		attachment,
		pname
	)

Returns modified WebGLRenderingContext.getFramebufferAttachmentParameter output for some specific parameters, original value for the rest.

Parameters

ctx	WebGLRenderingContext (https://developer.mozilla.org/en-US/docs/Web/API/WebGLRenderingContext)
target	GLenum (https://developer.mozilla.org/en-US/docs/Web/API/WebGL_API/Constants)
attachment	GLenum (https://developer.mozilla.org/en-US/docs/Web/API/WebGL_API/Constants)
pname	GLenum (https://developer.mozilla.org/en-US/docs/Web/API/WebGL_API/Constants)

Depending on level chosen this function returns:

(0) - original value
(1) - bottom value (0, 34069, 9729, 5124)

◆ farbleGetPrecisionFormat()

function farbleGetPrecisionFormat	(	ctx,
		fcarg
	)

Returns empty WebGLShaderPrecisionFormat object or real value.

Parameters

ctx	WebGLRenderingContext (https://developer.mozilla.org/en-US/docs/Web/API/WebGLRenderingContext)
...fcarg	delegated arguments depending on function

Depending on level chosen this function returns:

(0) - original value
(1) - WebGLShaderPrecisionFormat object with empty attributes

◆ farbleGetProgramParameter()

function farbleGetProgramParameter	(	ctx,
		program,
		pname
	)

Returns modified WebGLRenderingContext.getProgramParameter output for some specific parameters, original value for the rest.

Parameters

ctx	WebGLRenderingContext (https://developer.mozilla.org/en-US/docs/Web/API/WebGLRenderingContext)
program	WebGLProgram object (https://developer.mozilla.org/en-US/docs/Web/API/WebGLProgram)
pname	GLenum (https://developer.mozilla.org/en-US/docs/Web/API/WebGL_API/Constants)

Depending on level chosen this function returns:

(0) - original value
(1) - bottom value (false, 0, 35981)

◆ farbleGetRenderbufferParameter()

function farbleGetRenderbufferParameter	(	ctx,
		target,
		pname
	)

Returns modified WebGLRenderingContext.getRenderbufferParameter output for some specific parameters, original value for the rest.

Parameters

ctx	WebGLRenderingContext (https://developer.mozilla.org/en-US/docs/Web/API/WebGLRenderingContext)
target	GLenum (https://developer.mozilla.org/en-US/docs/Web/API/WebGL_API/Constants)
pname	GLenum (https://developer.mozilla.org/en-US/docs/Web/API/WebGL_API/Constants)

Depending on level chosen this function returns:

(0) - original value
(1) - bottom value (0, 32854)

◆ farbleGetShaderParameter()

function farbleGetShaderParameter	(	ctx,
		shader,
		pname
	)

Returns modified WebGLRenderingContext.getShaderParameter output for some specific parameters, original value for the rest.

Parameters

ctx	WebGLRenderingContext (https://developer.mozilla.org/en-US/docs/Web/API/WebGLRenderingContext)
program	WebGLShader object (https://developer.mozilla.org/en-US/docs/Web/API/WebGLShader)
pname	GLenum (https://developer.mozilla.org/en-US/docs/Web/API/WebGL_API/Constants)

Depending on level chosen this function returns:

(0) - original value
(1) - bottom value (false, 35633)

◆ farbleGetVertexAttrib()

function farbleGetVertexAttrib	(	ctx,
		index,
		pname
	)

Returns modified WebGLRenderingContext.getVertexAttrib output for some specific parameters, original value for the rest.

Parameters

ctx	WebGLRenderingContext (https://developer.mozilla.org/en-US/docs/Web/API/WebGLRenderingContext)
index	GLuint specifying index
pname	GLenum (https://developer.mozilla.org/en-US/docs/Web/API/WebGL_API/Constants)

Depending on level chosen this function returns:

(0) - original value
(1) - bottom value (false, 0, 5120, empty Float32Array)

◆ farbleMinusOne()

function farbleMinusOne	(	name,
		ctx,
		fcarg
	)

Returns -1 or output of given function.

Parameters

name	of original function
ctx	WebGLRenderingContext (https://developer.mozilla.org/en-US/docs/Web/API/WebGLRenderingContext)
...fcarg	delegated arguments depending on function

Depending on level chosen this function returns:

(0) - original value
(1) - minus one

◆ farbleNull()

function farbleNull	(	name,
		ctx,
		fcarg
	)

Returns null or output of given function.

Parameters

name	of original function
ctx	WebGLRenderingContext (https://developer.mozilla.org/en-US/docs/Web/API/WebGLRenderingContext)
...fcarg	delegated arguments depending on function

Depending on level chosen this function returns:

(0) - original value
(1) - null

◆ farbleNullArray()

function farbleNullArray	(	name,
		ctx,
		fcarg
	)

Returns [] or output of given function.

Parameters

name	of original function
ctx	WebGLRenderingContext (https://developer.mozilla.org/en-US/docs/Web/API/WebGLRenderingContext)
...fcarg	delegated arguments depending on function

Depending on level chosen this function returns:

(0) - original value
(1) - empty array

◆ farblePixels()

function farblePixels	(	ctx,
		x,
		y,
		width,
		height,
		format,
		type,
		pixels,
		offset
	)

Modifies pixels array.

Parameters

ctx	WebGLRenderingContext (https://developer.mozilla.org/en-US/docs/Web/API/WebGLRenderingContext)
x	starting x position
y	starting y position
width	width to be read (in pixels)
height	height to be read (in pixels)
format	format of read pixel data
type	specifies data type of pixels
pixels	typed array to return result
offset	optional offset

Depending on level chosen this function returns to pixels array:

(0) - slightly changed image data according to domain and session keys
(1) - empty array

◆ farbleZero()

function farbleZero	(	name,
		ctx,
		fcarg
	)

Returns 0 or output of given function.

Parameters

name	of original function
ctx	WebGLRenderingContext (https://developer.mozilla.org/en-US/docs/Web/API/WebGLRenderingContext)
...fcarg	delegated arguments depending on function

Depending on level chosen this function returns:

(0) - original value
(1) - zero

Variable Documentation

◆ wrappers

var wrappers

Functions

Variables

Detailed Description

Function Documentation

◆ add_wrappers()

◆ farbleGetActives()

◆ farbleGetBufferParameter()

◆ farbleGetFramebufferAttachmentParameter()

◆ farbleGetPrecisionFormat()

◆ farbleGetProgramParameter()

◆ farbleGetRenderbufferParameter()

◆ farbleGetShaderParameter()

◆ farbleGetVertexAttrib()

◆ farbleMinusOne()

◆ farbleNull()

◆ farbleNullArray()

◆ farblePixels()

◆ farbleZero()

Variable Documentation

◆ wrappers