Files
karma/cmd/karma/auth.go
2021-10-23 14:38:54 +01:00

128 lines
3.5 KiB
Go

package main
import (
"context"
"net/http"
"strings"
"github.com/prymitive/karma/internal/config"
"github.com/prymitive/karma/internal/regex"
"github.com/prymitive/karma/internal/slices"
)
type authUserKey string
func userGroups(username string) []string {
groups := []string{}
for _, authGroup := range config.Config.Authorization.Groups {
if slices.StringInSlice(authGroup.Members, username) {
groups = append(groups, authGroup.Name)
}
}
return groups
}
func groupsFromHeaders(r *http.Request, groupName, groupValueRegex, groupValueSeparator string) []string {
groups := []string{}
groupRegex := regex.MustCompileAnchored(groupValueRegex)
rawGroups := groupRegex.FindAllStringSubmatch(r.Header.Get(groupName), 1)
if len(rawGroups) > 0 && len(rawGroups[0]) > 1 {
for _, group := range strings.Split(rawGroups[0][1], groupValueSeparator) {
if v := strings.TrimSpace(group); v != "" {
groups = append(groups, v)
}
}
}
return groups
}
func headerAuth(name, valueRegex, groupName, groupValueRegex, groupValueSeparator string, allowBypass []string) func(next http.Handler) http.Handler {
return func(next http.Handler) http.Handler {
return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
if slices.StringInSlice(allowBypass, r.URL.Path) {
next.ServeHTTP(w, r)
return
}
user := r.Header.Get(name)
if user == "" {
w.WriteHeader(http.StatusUnauthorized)
_, _ = w.Write([]byte("Access denied\n"))
return
}
reg := regex.MustCompileAnchored(valueRegex)
matches := reg.FindAllStringSubmatch(user, 1)
if len(matches) == 0 || len(matches[0]) <= 1 {
w.WriteHeader(http.StatusUnauthorized)
_, _ = w.Write([]byte("Access denied\n"))
return
}
userName := matches[0][1]
groups := userGroups(userName)
if groupName != "" {
groups = append(groups, groupsFromHeaders(r, groupName, groupValueRegex, groupValueSeparator)...)
}
ctx := context.WithValue(r.Context(), authUserKey("user"), userName)
ctx = context.WithValue(ctx, authUserKey("groups"), groups)
next.ServeHTTP(w, r.WithContext(ctx))
})
}
}
func getUserFromContext(r *http.Request) string {
username := r.Context().Value(authUserKey("user"))
if username == nil {
return ""
}
return username.(string)
}
func getGroupsFromContext(r *http.Request) []string {
groups := r.Context().Value(authUserKey("groups"))
if groups == nil {
return []string{}
}
return groups.([]string)
}
func basicAuth(creds map[string]string, groupName, groupValueRegex, groupValueSeparator string, allowBypass []string) func(next http.Handler) http.Handler {
return func(next http.Handler) http.Handler {
return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
if slices.StringInSlice(allowBypass, r.URL.Path) {
next.ServeHTTP(w, r)
return
}
user, pass, ok := r.BasicAuth()
if !ok {
basicAuthFailed(w)
return
}
credPass, credUserOk := creds[user]
if !credUserOk || pass != credPass {
basicAuthFailed(w)
return
}
groups := userGroups(user)
if groupName != "" {
groups = append(groups, groupsFromHeaders(r, groupName, groupValueRegex, groupValueSeparator)...)
}
ctx := context.WithValue(r.Context(), authUserKey("user"), user)
ctx = context.WithValue(ctx, authUserKey("groups"), groups)
next.ServeHTTP(w, r.WithContext(ctx))
})
}
}
func basicAuthFailed(w http.ResponseWriter) {
w.Header().Add("WWW-Authenticate", `Basic realm="karma"`)
w.WriteHeader(http.StatusUnauthorized)
}