Allow for PKCE flow without client secret + add docs (#25033)

The PKCE flow according to [RFC
7636](https://datatracker.ietf.org/doc/html/rfc7636) allows for secure
authorization without the requirement to provide a client secret for the
OAuth app.

It is implemented in Gitea since #5378 (v1.8.0), however without being
able to omit client secret.
Since #21316 Gitea supports setting client type at OAuth app
registration.

As public clients are already forced to use PKCE since #21316, in this
PR the client secret check is being skipped if a public client is
detected. As Gitea seems to implement PKCE authorization correctly
according to the spec, this would allow for PKCE flow without providing
a client secret.

Also add some docs for it, please check language as I'm not a native
English speaker.

Closes #17107
Closes #25047
This commit is contained in:
Denys Konovalov 2023-06-03 05:59:28 +02:00 committed by GitHub
parent 7fca4056c4
commit 7d855efb1f
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3 changed files with 96 additions and 9 deletions

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@ -695,7 +695,7 @@ func handleRefreshToken(ctx *context.Context, form forms.AccessTokenForm, server
}
// "The authorization server MUST ... require client authentication for confidential clients"
// https://datatracker.ietf.org/doc/html/rfc6749#section-6
if !app.ValidateClientSecret([]byte(form.ClientSecret)) {
if app.ConfidentialClient && !app.ValidateClientSecret([]byte(form.ClientSecret)) {
errorDescription := "invalid client secret"
if form.ClientSecret == "" {
errorDescription = "invalid empty client secret"
@ -753,7 +753,7 @@ func handleAuthorizationCode(ctx *context.Context, form forms.AccessTokenForm, s
})
return
}
if !app.ValidateClientSecret([]byte(form.ClientSecret)) {
if app.ConfidentialClient && !app.ValidateClientSecret([]byte(form.ClientSecret)) {
errorDescription := "invalid client secret"
if form.ClientSecret == "" {
errorDescription = "invalid empty client secret"