s3-mdssvc: call [un]become_authenticated_pipe_user()

This ensures we're running as the authenticated user int the tevent
callback which might be running in an arbitrary impersonation context.

Signed-off-by: Ralph Boehme <slow@samba.org>
Reviewed-by: Noel Power <npower@samba.org>

diff --git a/source3/rpc_server/mdssvc/mdssvc.c b/source3/rpc_server/mdssvc/mdssvc.c
index ea676f48681275d1aad622315b9692b98afff810..f03cb9d7ebd4a19c3b06739447ff458f78efc9a5 100644 (file)
--- a/source3/rpc_server/mdssvc/mdssvc.c
+++ b/source3/rpc_server/mdssvc/mdssvc.c
@@ -810,20 +810,39 @@ static void tracker_cursor_cb(GObject *object,
                return;
        }
 
+       /*
+        * We're in a tevent callback which means in the case of
+        * running as external RPC service we're running as root and
+        * not as the user.
+        */
+       if (!become_authenticated_pipe_user(slq->mds_ctx->pipe_session_info)) {
+               DBG_ERR("can't become authenticated user: %d\n", slq->mds_ctx->uid);
+               smb_panic("can't become authenticated user");
+       }
+
        if (geteuid() != slq->mds_ctx->uid) {
                DEBUG(0, ("uid mismatch: %d/%d\n", geteuid(), slq->mds_ctx->uid));
                smb_panic("uid mismatch");
        }
 
+       /*
+        * We've changed identity to the authenticated pipe user, so
+        * any function exit below must ensure we switch back
+        */
+
        result = sys_stat(path, &sb, false);
        if (result != 0) {
+               unbecome_authenticated_pipe_user();
                goto done;
        }
        result = access(path, R_OK);
        if (result != 0) {
+               unbecome_authenticated_pipe_user();
                goto done;
        }
 
+       unbecome_authenticated_pipe_user();
+
        ino64 = sb.st_ex_ino;
        if (slq->cnids) {
                /*
@@ -1823,7 +1842,7 @@ static gboolean gmainloop_timer(gpointer user_data)
  **/
 struct mds_ctx *mds_init_ctx(TALLOC_CTX *mem_ctx,
                             struct tevent_context *ev,
-                            const struct auth_session_info *session_info,
+                            struct auth_session_info *session_info,
                             const char *path)
 {
        struct mds_ctx *mds_ctx;
@@ -1839,6 +1858,8 @@ struct mds_ctx *mds_init_ctx(TALLOC_CTX *mem_ctx,
                goto error;
        }
 
+       mds_ctx->pipe_session_info = session_info;
+
        if (session_info->security_token->num_sids < 1) {
                goto error;
        }

diff --git a/source3/rpc_server/mdssvc/mdssvc.h b/source3/rpc_server/mdssvc/mdssvc.h
index 310e59582ed06d454d1604f3835cb06681b7d3c3..e1b1ccfc34d53f4bf062a8312d88afd458686dfe 100644 (file)
--- a/source3/rpc_server/mdssvc/mdssvc.h
+++ b/source3/rpc_server/mdssvc/mdssvc.h
@@ -97,6 +97,7 @@ struct sl_inode_path_map {
 };
 
 struct mds_ctx {
+       struct auth_session_info *pipe_session_info;
        struct dom_sid sid;
        uid_t uid;
        const char *spath;
@@ -119,7 +120,7 @@ extern bool mds_init(struct messaging_context *msg_ctx);
 extern bool mds_shutdown(void);
 extern struct mds_ctx *mds_init_ctx(TALLOC_CTX *mem_ctx,
                                    struct tevent_context *ev,
-                                   const struct auth_session_info *session_info,
+                                   struct auth_session_info *session_info,
                                    const char *path);
 extern int mds_ctx_destructor_cb(struct mds_ctx *mds_ctx);
 extern bool mds_dispatch(struct mds_ctx *query_ctx,