Skip to content

Commit

Permalink
specify json schema draft
Browse files Browse the repository at this point in the history
  • Loading branch information
gabe committed Jun 26, 2024
1 parent 83dc30d commit debb2dd
Showing 1 changed file with 32 additions and 21 deletions.
53 changes: 32 additions & 21 deletions spec/spec.md
Original file line number Diff line number Diff line change
Expand Up @@ -365,7 +365,7 @@ be ignored, unless otherwise specified by a [[ref:Feature]];

An illustrative example containing all of the formats in use by the
specifying implementers at time of writing (also reflected in the provided
JSON Schema) is as follows::
[[ref:JSON Schema]]) is as follows:

```json
[[insert: ./test/presentation-definition/format_example.json]]
Expand Down Expand Up @@ -454,7 +454,7 @@ property. Its value ****MUST**** be an object composed as follows, and it
human-friendly name that describes what the target field represents.
- The _fields object_ ****MAY**** contain a `filter` property, and if
present its value ****MUST**** be a
[JSON Schema](https://json-schema.org/specification.html) descriptor
[[ref:JSON Schema] descriptor
used to filter against the values returned from evaluation of the
[JSONPath](https://ietf-wg-jsonpath.github.io/draft-ietf-jsonpath-base/draft-ietf-jsonpath-base.html) string
expressions in the `path` array.
Expand All @@ -463,9 +463,9 @@ property. Its value ****MUST**** be an object composed as follows, and it
field is optional, and `false` or non-presence of the property indicates
the field is required. Even when the `optional` property is present, the value
located at the indicated `path` of the field ****MUST**** validate against
the JSON Schema `filter`, if a `filter` is present.
the [[ref:JSON Schema]] `filter`, if a `filter` is present.
:::note IDO Filter
Remember a valid JSON Schema ****MAY**** contain [additional keywords](https://datatracker.ietf.org/doc/html/draft-handrews-json-schema-01#section-6.4) (e.g., `formatMinimum` and `formatMaximum`) that require extensions to handle properly.
Remember a valid [[ref:JSON Schema]] ****MAY**** contain [additional keywords](https://datatracker.ietf.org/doc/html/draft-handrews-json-schema-01#section-6.4) (e.g., `formatMinimum` and `formatMaximum`) that require extensions to handle properly.

A [[ref: Holder]] ****SHOULD**** be able to gracefully handle additional properties, even if this just means ignoring the added keywords.
:::
Expand Down Expand Up @@ -961,7 +961,7 @@ present, the `filter` property ****MUST**** also be present.
of the [JSONPath](https://ietf-wg-jsonpath.github.io/draft-ietf-jsonpath-base/draft-ietf-jsonpath-base.html) string
expressions in the `path` array. The boolean returned is the result
of using the `filter` property's
[JSON Schema](https://json-schema.org/specification.html)
[[ref:JSON Schema]]
descriptors against the evaluated value. Exclusion of the `predicate`
property indicates that the [[ref:Conformant Consumer]] returns the value
returned from evaluation of the
Expand Down Expand Up @@ -992,7 +992,7 @@ If the [`predicate` property](#predicate-filters) is present, the set of JSON Sc
descriptors which comprise the value of the `filter` property
****MUST**** be restricted according to the desired predicate
operation, as follows:
- To express the following range proofs, use the JSON Schema
- To express the following range proofs, use the [[ref:JSON Schema]]
[numeric range](https://json-schema.org/understanding-json-schema/reference/numeric.html#range)
properties:
- `greater-than` - Use the `exclusiveMinimum` descriptor. For
Expand Down Expand Up @@ -1033,7 +1033,7 @@ operation, as follows:
"maximum": 65536,
}
```
- to express the following equality proofs, use the JSON Schema
- to express the following equality proofs, use the [[ref:JSON Schema]]
`const` descriptor:
- `equal-to` - Use the `const` descriptor. For example to
request proof that an attribute has the value "Chad", use the
Expand All @@ -1054,7 +1054,7 @@ operation, as follows:
}
}
```
- to express set-membership proofs, use the JSON Schema `enum`
- to express set-membership proofs, use the [[ref:JSON Schema]] `enum`
descriptor:
- `in-set` - Use the `enum` descriptor. For example, to
request proof that an attribute is contained in the set of
Expand Down Expand Up @@ -1119,7 +1119,7 @@ When using this [[ref:Feature]]:
users to enter the data required by an [[ref:Input Descriptor]] that has its
`subject_is_issuer` property set to either `required` or `preferred`. An example
of this would be a user agent wallet app providing a form generated using the
JSON Schema `filter` objects present in the `fields` of an [[ref:Input Descriptor]]
[[ref:JSON Schema]] `filter` objects present in the `fields` of an [[ref:Input Descriptor]]
that are subsequently packaged up in accordance with the structure the
[[ref:Input Descriptor]] defines for submission as _self-attested_ data.
:::
Expand Down Expand Up @@ -1243,7 +1243,6 @@ The values of all status properties are objects, composed as follows:
presentation protocols.
:::


### JSON-LD Framing Feature

The JSON-LD Framing [[ref:Feature]] extends [[ref:Presentation Definition]] to support
Expand Down Expand Up @@ -1308,13 +1307,13 @@ For each candidate input:
`path` array element.
2. Else, evaluate the first JSONPath match (_candidate_) as follows:
1. If the _fields object_ has no `filter`, or if _candidate_ validates against the
[JSON Schema](https://json-schema.org/specification.html)
[[ref:JSON Schema]]
descriptor specified in `filter`, then:
- If not using the **Predicate Feature**, set _Field Query Result_ to be _candidate_.
- If using the **Predicate Feature**:
- If the _fields object_ has a `predicate`, set _Field Query Result_ to the
boolean value resulting from evaluating the _Field Query Result_ against
the [JSON Schema](https://json-schema.org/specification.html) descriptor
the [[ref:JSON Schema]] descriptor
value of the `filter` property.
- Else, set _Field Query Result_ to be _candidate_.
2. Else, skip to the next `path` array element.
Expand Down Expand Up @@ -1369,7 +1368,7 @@ specifications handle these concepts in different ways.
[[ref:Presentation Definitions]] have a need to specify whether expired,
revoked, or [[ref:Claims]] of other statuses can be accepted. For [[ref:Claims]]
that have simple status properties,
[Input Descriptor Filters](#input-descriptor-objects) JSON Schema can be used to
[Input Descriptor Filters](#input-descriptor-objects) [[ref:JSON Schema]] can be used to
specify acceptable criteria.

The first example below demonstrates _expiry_ using the [VC Data Model's
Expand Down Expand Up @@ -1474,7 +1473,7 @@ variants they can receive or are submitting. These formats are codified by
abbreviation tags which are defined in a separate
[registry](https://identity.foundation/claim-format-registry/#registry) also
hosted at the DIF, and maintained by the same authors as this specification.
The registry includes JSON Schema documents, which are referenced in schemas
The registry includes [[ref:JSON Schema]] documents, which are referenced in schemas
defined in this specification. To add abbreviations for a claim format supported
by a working implementation, please follow
[these instructions](https://identity.foundation/claim-format-registry/#structure-of-the-registry)
Expand All @@ -1484,15 +1483,24 @@ This registry is not meant to be exhaustive nor
restrictive; an implementation that supports additional claim formats can still
be considered fully conformant.

## JSON Schemas
## JSON Schema

This specification leverages [[ref:JSON Schema]] in multiple places: for processing
[Input Descriptors](#input-descriptor), as well as for evaluating the data objects
defined by Presentation Exchange itself for conformance with the specification.

To facilitate consistent implementation of the specification and to facilitate interoperability
implementers ****MUST*** use [[ref:JSON Schema Draft 7]]. Draft 7 is widely used, adopted,
has significant support in open source software, and supports the features of [[ref:JSON Schema]] used by this specification.

The relevant links to the Draft 7 specifications can [be found here](https://json-schema.org/specification-links#draft-7).

### Vocabulary Definition

The _Presentation Exchange_ specification adopts and defines the following JSON
Schema data format and processing variant, which implementers ****MUST****
support for evaluation of the portions of the _Presentation Exchange_
specification that call for JSON Schema validation:
https://tools.ietf.org/html/draft-handrews-json-schema-02
specification that call for [[ref:JSON Schema]] validation.

### Presentation Definition (in an envelope)

Expand Down Expand Up @@ -1619,6 +1627,9 @@ JSONPath | Description
[[def: Linked Data Proof, Linked Data Proofs]]
~ [Data Integrity 1.0](https://w3c-ccg.github.io/data-integrity-spec/). Dave Longley, Manu Sporny. 2022-03. Status: Draft Community Group Report.

[[def: JSON Schema, JSON Schema Draft 7]]
~ [JSON Schema Draft-07](https://json-schema.org/draft-07/json-schema-release-notes.html). OpenJS Foundation. 2018-03-19. Status: Internet-Draft.

[[spec]]

## Informative References
Expand Down Expand Up @@ -1659,17 +1670,17 @@ On the Presentation Submission side, JSONPath filtering features can typically b

If use is necessary, implementations should use proper security and execution time guards, e.g., through sandboxed execution with a timeout.

### JSONSchema-specific Considerations
### JSON Schema-specific Considerations

#### Attack Vectors on JSON Schema
JSON Schema allows the use of Regular Expressions, to which the security considerations mentioned above apply.

Further, implementations that support validating or evaluating instance string data based on "contentEncoding" and/or "contentMediaType" are at risk of evaluating data in an unsafe way based on misleading information. Applications can mitigate this risk by only performing such processing when a relationship between the schema and instance is established (e.g., they share the same authority)
[[ref:JSON Schema]] allows the use of Regular Expressions, to which the security considerations mentioned above apply.

Further, implementations that support validating or evaluating instance string data based on "contentEncoding" and/or "contentMediaType" are at risk of evaluating data in an unsafe way based on misleading information. Applications can mitigate this risk by only performing such processing when a relationship between the schema and instance is established (e.g., they share the same authority).

#### Recommendations and Alternatives
Not using Regular Expressions mainly applies to the `pattern` property of the filter. This specification recommends using other means, such as `const`, `format`, and `enum` to filter values.


### What is new
The summary and details below highlight the differences between V1 and V2 of this specification.

Expand Down

0 comments on commit debb2dd

Please sign in to comment.