gotosocial/internal/api/security/signaturecheck.go

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package security
import (
"net/http"
"net/url"
"github.com/sirupsen/logrus"
"github.com/superseriousbusiness/gotosocial/internal/ap"
"github.com/gin-gonic/gin"
"github.com/go-fed/httpsig"
)
// SignatureCheck checks whether an incoming http request has been signed. If so, it will check if the domain
// that signed the request is permitted to access the server. If it is permitted, the handler will set the key
// verifier and the signature in the gin context for use down the line.
func (m *Module) SignatureCheck(c *gin.Context) {
l := logrus.WithField("func", "DomainBlockChecker")
// create the verifier from the request
// if the request is signed, it will have a signature header
verifier, err := httpsig.NewVerifier(c.Request)
if err == nil {
// the request was signed!
// The key ID should be given in the signature so that we know where to fetch it from the remote server.
// This will be something like https://example.org/users/whatever_requesting_user#main-key
requestingPublicKeyID, err := url.Parse(verifier.KeyId())
if err == nil && requestingPublicKeyID != nil {
// we managed to parse the url!
// if the domain is blocked we want to bail as early as possible
blocked, err := m.db.IsURIBlocked(c.Request.Context(), requestingPublicKeyID)
if err != nil {
l.Errorf("could not tell if domain %s was blocked or not: %s", requestingPublicKeyID.Host, err)
c.AbortWithStatus(http.StatusInternalServerError)
return
}
if blocked {
l.Infof("domain %s is blocked", requestingPublicKeyID.Host)
c.AbortWithStatus(http.StatusForbidden)
return
}
// set the verifier and signature on the context here to save some work further down the line
c.Set(string(ap.ContextRequestingPublicKeyVerifier), verifier)
signature := c.GetHeader("Signature")
if signature != "" {
c.Set(string(ap.ContextRequestingPublicKeySignature), signature)
}
}
}
}