X-Git-Url: https://gerrit.automotivelinux.org/gerrit/gitweb?a=blobdiff_plain;f=src%2Fafb-cred.c;h=4639fa8e1d27cd3ef9df275b6364c7d5fa427c53;hb=6f13ad1989875b5a0ce50b24211fd1fba093735f;hp=87661f19985726445a73bec6525fcc4ba8b23b34;hpb=c623236073ec6cba38a5c02582cc24ad2f5e51c4;p=src%2Fapp-framework-binder.git

diff --git a/src/afb-cred.c b/src/afb-cred.c
index 87661f19..4639fa8e 100644
--- a/src/afb-cred.c
+++ b/src/afb-cred.c
@@ -1,5 +1,5 @@
 /*
- * Copyright (C) 2017 "IoT.bzh"
+ * Copyright (C) 2017-2019 "IoT.bzh"
  * Author: José Bollo <jose.bollo@iot.bzh>
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
@@ -18,6 +18,7 @@
 #define _GNU_SOURCE
 
 #include <stdlib.h>
+#include <stdio.h>
 #include <unistd.h>
 #include <string.h>
 #include <errno.h>
@@ -26,9 +27,15 @@
 #include <sys/socket.h>
 
 #include "afb-cred.h"
+#include "verbose.h"
+
 
 #define MAX_LABEL_LENGTH  1024
 
+#if !defined(NO_DEFAULT_PEERCRED) && !defined(ADD_DEFAULT_PEERCRED)
+#  define NO_DEFAULT_PEERCRED
+#endif
+
 #if !defined(DEFAULT_PEERSEC_LABEL)
 #  define DEFAULT_PEERSEC_LABEL "NoLabel"
 #endif
@@ -42,6 +49,10 @@
 #  define DEFAULT_PEERCRED_PID 0  /* no process */
 #endif
 
+static char on_behalf_credential_permission[] = "urn:AGL:permission:*:partner:on-behalf-credentials";
+static char export_format[] = "%x:%x:%x-%s";
+static char import_format[] = "%x:%x:%x-%n";
+
 static struct afb_cred *current;
 
 static struct afb_cred *mkcred(uid_t uid, gid_t gid, pid_t pid, const char *label, size_t size)
@@ -66,6 +77,7 @@ static struct afb_cred *mkcred(uid_t uid, gid_t gid, pid_t pid, const char *labe
 		cred->uid = uid;
 		cred->gid = gid;
 		cred->pid = pid;
+		cred->exported = NULL;
 		dest = (char*)(&cred[1]);
 		cred->user = dest;
 		while(i)
@@ -117,15 +129,15 @@ struct afb_cred *afb_cred_create_for_socket(int fd)
 	/* get the credentials */
 	length = (socklen_t)(sizeof ucred);
 	rc = getsockopt(fd, SOL_SOCKET, SO_PEERCRED, &ucred, &length);
-	if (rc < 0 || length != (socklen_t)(sizeof ucred)) {
+	if (rc < 0 || length != (socklen_t)(sizeof ucred) || !~ucred.uid) {
 #if !defined(NO_DEFAULT_PEERCRED)
-		if (!rc)
-			errno = EINVAL;
-		return NULL;
-#else
 		ucred.uid = DEFAULT_PEERCRED_UID;
 		ucred.gid = DEFAULT_PEERCRED_GID;
 		ucred.pid = DEFAULT_PEERCRED_PID;
+#else
+		if (!rc)
+			errno = EINVAL;
+		return NULL;
 #endif
 	}
 
@@ -157,10 +169,12 @@ struct afb_cred *afb_cred_addref(struct afb_cred *cred)
 void afb_cred_unref(struct afb_cred *cred)
 {
 	if (cred && !__atomic_sub_fetch(&cred->refcount, 1, __ATOMIC_RELAXED)) {
-		if (cred != current)
-			free(cred);
-		else
+		if (cred == current)
 			cred->refcount = 1;
+		else {
+			free((void*)cred->exported);
+			free(cred);
+		}
 	}
 }
 
@@ -171,3 +185,105 @@ struct afb_cred *afb_cred_current()
 	return afb_cred_addref(current);
 }
 
+const char *afb_cred_export(struct afb_cred *cred)
+{
+	int rc;
+
+	if (!cred->exported) {
+		rc = asprintf((char**)&cred->exported,
+			export_format,
+				(int)cred->uid,
+				(int)cred->gid,
+				(int)cred->pid,
+				cred->label);
+		if (rc < 0) {
+			errno = ENOMEM;
+			cred->exported = NULL;
+		}
+	}
+	return cred->exported;
+}
+
+struct afb_cred *afb_cred_import(const char *string)
+{
+	struct afb_cred *cred;
+	int rc, uid, gid, pid, pos;
+
+	rc = sscanf(string, import_format, &uid, &gid, &pid, &pos);
+	if (rc == 3)
+		cred = afb_cred_create((uid_t)uid, (gid_t)gid, (pid_t)pid, &string[pos]);
+	else {
+		errno = EINVAL;
+		cred = NULL;
+	}
+	return cred;
+}
+
+struct afb_cred *afb_cred_mixed_on_behalf_import(struct afb_cred *cred, const char *context, const char *exported)
+
+{
+	struct afb_cred *imported;
+	if (exported) {
+		if (afb_cred_has_permission(cred, on_behalf_credential_permission, context)) {
+			imported = afb_cred_import(exported);
+			if (imported)
+				return imported;
+			ERROR("Can't import on behalf credentials: %m");
+		} else {
+			ERROR("On behalf credentials refused");
+		}
+	}
+	return afb_cred_addref(cred);
+}
+
+/*********************************************************************************/
+#ifdef BACKEND_PERMISSION_IS_CYNARA
+
+#include <pthread.h>
+#include <cynara-client.h>
+
+static cynara *handle;
+static pthread_mutex_t mutex = PTHREAD_MUTEX_INITIALIZER;
+
+int afb_cred_has_permission(struct afb_cred *cred, const char *permission, const char *context)
+{
+	int rc;
+
+	if (!cred) {
+		/* case of permission for self */
+		return 1;
+	}
+	if (!permission) {
+		ERROR("Got a null permission!");
+		return 0;
+	}
+
+	/* cynara isn't reentrant */
+	pthread_mutex_lock(&mutex);
+
+	/* lazy initialisation */
+	if (!handle) {
+		rc = cynara_initialize(&handle, NULL);
+		if (rc != CYNARA_API_SUCCESS) {
+			handle = NULL;
+			ERROR("cynara initialisation failed with code %d", rc);
+			return 0;
+		}
+	}
+
+	/* query cynara permission */
+	rc = cynara_check(handle, cred->label, context ?: "", cred->user, permission);
+
+	pthread_mutex_unlock(&mutex);
+	return rc == CYNARA_API_ACCESS_ALLOWED;
+}
+
+/*********************************************************************************/
+#else
+int afb_cred_has_permission(struct afb_cred *cred, const char *permission, const char *context)
+{
+	WARNING("Granting permission %s by default of backend", permission ?: "(null)");
+	return !!permission;
+}
+#endif
+