The bug has been fixed on v1.22 but not backport to v1.21.
This original PR have many refactors so I don't think it's necessary to
backport all of them.

Fix #28667

Backport #28636

Fix #28231, and remove some unused code.

manually backport for https://github.com/go-gitea/gitea/pull/27995
The conflict is `ctx` and `db.Defaultctx`.

Part of #27065

Next step of #27065

Co-authored-by: wxiaoguang <wxiaoguang@gmail.com>

Fix #26526

This PR is an extended implementation of #25189 and builds upon the
proposal by @hickford in #25653, utilizing some ideas proposed
internally by @wxiaoguang.

Mainly, this PR consists of a mechanism to pre-register OAuth2
applications on startup, which can be enabled or disabled by modifying
the `[oauth2].DEFAULT_APPLICATIONS` parameter in app.ini. The OAuth2
applications registered this way are being marked as "locked" and
neither be deleted nor edited over UI to prevent confusing/unexpected
behavior. Instead, they're being removed if no longer enabled in config.


![grafik](https://github.com/go-gitea/gitea/assets/47871822/81a78b1c-4b68-40a7-9e99-c272ebb8f62e)

The implemented mechanism can also be used to pre-register other OAuth2
applications in the future, if wanted.

Co-authored-by: hickford <mirth.hickford@gmail.com>
Co-authored-by: wxiaoguang <wxiaoguang@gmail.com>

---------

Co-authored-by: M Hickford <mirth.hickford@gmail.com>
Co-authored-by: wxiaoguang <wxiaoguang@gmail.com>

Fix #26035

just a step towards  #25655

and some related refactoring

OAuth applications can already have multiple redirect URIs if
created/edited over API.

This change allows for setting multiple redirect URIs through the UI as
a comma-separated list (e. g.
`https://example.org/redirect,https://redirect.example.org`)

<details>
<summary>Screenshots</summary>

![Bildschirmfoto vom 2023-06-04
17-14-40](https://github.com/go-gitea/gitea/assets/47871822/2206dc32-e7e4-4953-9ecb-e098890b3f54)
![Bildschirmfoto vom 2023-06-04
17-14-50](https://github.com/go-gitea/gitea/assets/47871822/cd97c73c-9310-44ee-a83a-b927a1ef94da)

</details>

Closes #25068

## Changes
- Adds the following high level access scopes, each with `read` and
`write` levels:
    - `activitypub`
    - `admin` (hidden if user is not a site admin)
    - `misc`
    - `notification`
    - `organization`
    - `package`
    - `issue`
    - `repository`
    - `user`
- Adds new middleware function `tokenRequiresScopes()` in addition to
`reqToken()`
  -  `tokenRequiresScopes()` is used for each high-level api section
- _if_ a scoped token is present, checks that the required scope is
included based on the section and HTTP method
  - `reqToken()` is used for individual routes
- checks that required authentication is present (but does not check
scope levels as this will already have been handled by
`tokenRequiresScopes()`
- Adds migration to convert old scoped access tokens to the new set of
scopes
- Updates the user interface for scope selection

### User interface example
<img width="903" alt="Screen Shot 2023-05-31 at 1 56 55 PM"
src="https://github.com/go-gitea/gitea/assets/23248839/654766ec-2143-4f59-9037-3b51600e32f3">
<img width="917" alt="Screen Shot 2023-05-31 at 1 56 43 PM"
src="https://github.com/go-gitea/gitea/assets/23248839/1ad64081-012c-4a73-b393-66b30352654c">

## tokenRequiresScopes  Design Decision
- `tokenRequiresScopes()` was added to more reliably cover api routes.
For an incoming request, this function uses the given scope category
(say `AccessTokenScopeCategoryOrganization`) and the HTTP method (say
`DELETE`) and verifies that any scoped tokens in use include
`delete:organization`.
- `reqToken()` is used to enforce auth for individual routes that
require it. If a scoped token is not present for a request,
`tokenRequiresScopes()` will not return an error

## TODO
- [x] Alphabetize scope categories
- [x] Change 'public repos only' to a radio button (private vs public).
Also expand this to organizations
- [X] Disable token creation if no scopes selected. Alternatively, show
warning
- [x] `reqToken()` is missing from many `POST/DELETE` routes in the api.
`tokenRequiresScopes()` only checks that a given token has the correct
scope, `reqToken()` must be used to check that a token (or some other
auth) is present.
   -  _This should be addressed in this PR_
- [x] The migration should be reviewed very carefully in order to
minimize access changes to existing user tokens.
   - _This should be addressed in this PR_
- [x] Link to api to swagger documentation, clarify what
read/write/delete levels correspond to
- [x] Review cases where more than one scope is needed as this directly
deviates from the api definition.
   - _This should be addressed in this PR_
   - For example: 
   ```go
	m.Group("/users/{username}/orgs", func() {
		m.Get("", reqToken(), org.ListUserOrgs)
		m.Get("/{org}/permissions", reqToken(), org.GetUserOrgsPermissions)
}, tokenRequiresScopes(auth_model.AccessTokenScopeCategoryUser,
auth_model.AccessTokenScopeCategoryOrganization),
context_service.UserAssignmentAPI())
   ```

## Future improvements
- [ ] Add required scopes to swagger documentation
- [ ] Redesign `reqToken()` to be opt-out rather than opt-in
- [ ] Subdivide scopes like `repository`
- [ ] Once a token is created, if it has no scopes, we should display
text instead of an empty bullet point
- [ ] If the 'public repos only' option is selected, should read
categories be selected by default

Closes #24501
Closes #24799

Co-authored-by: Jonathan Tran <jon@allspice.io>
Co-authored-by: Kyle D <kdumontnu@gmail.com>
Co-authored-by: silverwind <me@silverwind.io>

Currently we can add webhooks for organizations but not for users. This
PR adds the latter. You can access it from the current users settings.


![grafik](https://user-images.githubusercontent.com/1666336/197391408-15dfdc23-b476-4d0c-82f7-9bc9b065988f.png)

minio/sha256-simd provides additional acceleration for SHA256 using
AVX512, SHA Extensions for x86 and ARM64 for ARM.

It provides a drop-in replacement for crypto/sha256 and if the
extensions are not available it falls back to standard crypto/sha256.

---------

Signed-off-by: Andrew Thornton <art27@cantab.net>
Co-authored-by: John Olheiser <john.olheiser@gmail.com>

The API to create tokens is missing the ability to set the required
scopes for tokens, and to show them on the API and on the UI.

This PR adds this functionality.

Signed-off-by: Andrew Thornton <art27@cantab.net>

This PR adds the support for scopes of access tokens, mimicking the
design of GitHub OAuth scopes.

The changes of the core logic are in `models/auth` that `AccessToken`
struct will have a `Scope` field. The normalized (no duplication of
scope), comma-separated scope string will be stored in `access_token`
table in the database.
In `services/auth`, the scope will be stored in context, which will be
used by `reqToken` middleware in API calls. Only OAuth2 tokens will have
granular token scopes, while others like BasicAuth will default to scope
`all`.
A large amount of work happens in `routers/api/v1/api.go` and the
corresponding `tests/integration` tests, that is adding necessary scopes
to each of the API calls as they fit.


- [x] Add `Scope` field to `AccessToken`
- [x] Add access control to all API endpoints
- [x] Update frontend & backend for when creating tokens
- [x] Add a database migration for `scope` column (enable 'all' access
to past tokens)

I'm aiming to complete it before Gitea 1.19 release.

Fixes #4300

Fix #22052

Co-authored-by: Lunny Xiao <xiaolunwen@gmail.com>

- Move the file `compare.go` and `slice.go` to `slice.go`.
- Fix `ExistsInSlice`, it's buggy
  - It uses `sort.Search`, so it assumes that the input slice is sorted.
- It passes `func(i int) bool { return slice[i] == target })` to
`sort.Search`, that's incorrect, check the doc of `sort.Search`.
- Conbine `IsInt64InSlice(int64, []int64)` and `ExistsInSlice(string,
[]string)` to `SliceContains[T]([]T, T)`.
- Conbine `IsSliceInt64Eq([]int64, []int64)` and `IsEqualSlice([]string,
[]string)` to `SliceSortedEqual[T]([]T, T)`.
- Add `SliceEqual[T]([]T, T)` as a distinction from
`SliceSortedEqual[T]([]T, T)`.
- Redesign `RemoveIDFromList([]int64, int64) ([]int64, bool)` to
`SliceRemoveAll[T]([]T, T) []T`.
- Add `SliceContainsFunc[T]([]T, func(T) bool)` and
`SliceRemoveAllFunc[T]([]T, func(T) bool)` for general use.
- Add comments to explain why not `golang.org/x/exp/slices`.
- Add unit tests.

`hex.EncodeToString` has better performance than `fmt.Sprintf("%x",
[]byte)`, we should use it as much as possible.

I'm not an extreme fan of performance, so I think there are some
exceptions:

- `fmt.Sprintf("%x", func(...)[N]byte())`
- We can't slice the function return value directly, and it's not worth
adding lines.
    ```diff
    func A()[20]byte { ... }
    - a := fmt.Sprintf("%x", A())
    - a := hex.EncodeToString(A()[:]) // invalid
    + tmp := A()
    + a := hex.EncodeToString(tmp[:])
    ```
- `fmt.Sprintf("%X", []byte)`
- `strings.ToUpper(hex.EncodeToString(bytes))` has even worse
performance.

Change all license headers to comply with REUSE specification.

Fix #16132

Co-authored-by: flynnnnnnnnnn <flynnnnnnnnnn@github>
Co-authored-by: John Olheiser <john.olheiser@gmail.com>

The `token_last_eight` field has been used in `GetAccessTokenBySHA `:

Fix #19513

This PR introduce a new db method `InTransaction(context.Context)`,
and also builtin check on `db.TxContext` and `db.WithTx`.
There is also a new method `db.AutoTx` has been introduced but could be used by other PRs.

`WithTx` will always open a new transaction, if a transaction exist in context, return an error.
`AutoTx` will try to open a new transaction if no transaction exist in context.
That means it will always enter a transaction if there is no error.

Co-authored-by: delvh <dev.lh@web.de>
Co-authored-by: 6543 <6543@obermui.de>

Found using
`find . -type f -name '*.go' -print -exec vim {} -c
':%s/fmt\.Errorf(\(.*\)%v\(.*\)err/fmt.Errorf(\1%w\2err/g' -c ':wq' \;`

Co-authored-by: 6543 <6543@obermui.de>
Co-authored-by: Andrew Thornton <art27@cantab.net>
Co-authored-by: wxiaoguang <wxiaoguang@gmail.com>

The OAuth spec [defines two types of
client](https://datatracker.ietf.org/doc/html/rfc6749#section-2.1),
confidential and public. Previously Gitea assumed all clients to be
confidential.

> OAuth defines two client types, based on their ability to authenticate
securely with the authorization server (i.e., ability to
>   maintain the confidentiality of their client credentials):
>
>   confidential
> Clients capable of maintaining the confidentiality of their
credentials (e.g., client implemented on a secure server with
> restricted access to the client credentials), or capable of secure
client authentication using other means.
>
>   **public
> Clients incapable of maintaining the confidentiality of their
credentials (e.g., clients executing on the device used by the resource
owner, such as an installed native application or a web browser-based
application), and incapable of secure client authentication via any
other means.**
>
> The client type designation is based on the authorization server's
definition of secure authentication and its acceptable exposure levels
of client credentials. The authorization server SHOULD NOT make
assumptions about the client type.

 https://datatracker.ietf.org/doc/html/rfc8252#section-8.4

> Authorization servers MUST record the client type in the client
registration details in order to identify and process requests
accordingly.

Require PKCE for public clients:
https://datatracker.ietf.org/doc/html/rfc8252#section-8.1

> Authorization servers SHOULD reject authorization requests from native
apps that don't use PKCE by returning an error message

Fixes #21299

Co-authored-by: wxiaoguang <wxiaoguang@gmail.com>
Co-authored-by: Lunny Xiao <xiaolunwen@gmail.com>

A lot of our code is repeatedly testing if individual errors are
specific types of Not Exist errors. This is repetitative and unnecesary.
`Unwrap() error` provides a common way of labelling an error as a
NotExist error and we can/should use this.

This PR has chosen to use the common `io/fs` errors e.g.
`fs.ErrNotExist` for our errors. This is in some ways not completely
correct as these are not filesystem errors but it seems like a
reasonable thing to do and would allow us to simplify a lot of our code
to `errors.Is(err, fs.ErrNotExist)` instead of
`package.IsErr...NotExist(err)`

I am open to suggestions to use a different base error - perhaps
`models/db.ErrNotExist` if that would be felt to be better.


Signed-off-by: Andrew Thornton <art27@cantab.net>
Co-authored-by: delvh <dev.lh@web.de>

Adds the settings pages to create OAuth2 apps also to the org settings
and allows to create apps for orgs.

Refactoring: the oauth2 related templates are shared for
instance-wide/org/user, and the backend code uses `OAuth2CommonHandlers`
to share code for instance-wide/org/user.

Co-authored-by: wxiaoguang <wxiaoguang@gmail.com>

Following https://datatracker.ietf.org/doc/html/rfc8252#section-7.3

Fixes #21285

* Move some files into models' sub packages

* Move functions

* merge main branch

* Fix check

* fix check

* Fix some tests

* Fix lint

* Fix lint

* Revert lint changes

* Fix error comments

* Fix lint

Co-authored-by: 6543 <6543@obermui.de>

* Refactor AssertExistsAndLoadBean to use generics

* Fix tests

Co-authored-by: zeripath <art27@cantab.net>

WebAuthn have updated their specification to set the maximum size of the
CredentialID to 1023 bytes. This is somewhat larger than our current
size and therefore we need to migrate.

The PR changes the struct to add CredentialIDBytes and migrates the CredentialID string 
to the bytes field before another migration drops the old CredentialID field. Another migration
renames this field back.

Fix #20457

Signed-off-by: Andrew Thornton <art27@cantab.net>

Add nakedret, unconvert, wastedassign, stylecheck and nolintlint linters to improve code readability

- nakedret - https://github.com/alexkohler/nakedret - nakedret is a Go static analysis tool to find naked returns in functions greater than a specified function length.
- unconvert - https://github.com/mdempsky/unconvert - Remove unnecessary type conversions
- wastedassign - https://github.com/sanposhiho/wastedassign -  wastedassign finds wasted assignment statements.
- notlintlint -  Reports ill-formed or insufficient nolint directives
- stylecheck - https://staticcheck.io/docs/checks/#ST - keep style consistent
  - excluded: [ST1003 - Poorly chosen identifier](https://staticcheck.io/docs/checks/#ST1003) and [ST1005 - Incorrectly formatted error string](https://staticcheck.io/docs/checks/#ST1005)

* Move almost all functions' parameter db.Engine to context.Context
* remove some unnecessary wrap functions

* delete user related oauth stuff on user deletion too

* extend doctor check-db-consistency

* Use a struct as test options

* Fix name

* Fix test

v208.go is seriously broken as it misses an ID() check. We need to no-op and remigrate all of the u2f keys.

See #18756

Signed-off-by: Andrew Thornton <art27@cantab.net>

- Switch to use `CryptoRandomBytes` instead of `CryptoRandomString`, OAuth's secrets are copied pasted and don't need to avoid dubious characters etc.
- `CryptoRandomBytes` gives ![2^256 = 1.15 * 10^77](https://render.githubusercontent.com/render/math?math=2^256%20=%201.15%20\cdot%2010^77) `CryptoRandomString` gives ![62^44 = 7.33 * 10^78](https://render.githubusercontent.com/render/math?math=62^44%20=%207.33%20\cdot%2010^78) possible states.
- Add a prefix, such that code scanners can easily grep these in source code.
- 32 Bytes + prefix

* Use base32 for 2FA scratch token
* rename Secure* to Crypto*, add comments

* gofumpt -w -l .

* gofumpt -w -l -extra .

* Add linter

* manual fix

* change make fmt

This contains some additional fixes and small nits related to #17957 

Signed-off-by: Andrew Thornton <art27@cantab.net>
Co-authored-by: 6543 <6543@obermui.de>
Co-authored-by: wxiaoguang <wxiaoguang@gmail.com>

Migrate from U2F to Webauthn

Co-authored-by: Andrew Thornton <art27@cantab.net>
Co-authored-by: 6543 <6543@obermui.de>
Co-authored-by: wxiaoguang <wxiaoguang@gmail.com>