mail storage service: Fixed chroot handling.

--HG--
branch : HEAD

diff --git a/src/lib-storage/mail-storage-service.c b/src/lib-storage/mail-storage-service.c
index c4e7aab201038631b078a60125ab846bfbb6c06b..d2e1c8080bd47c12a67aad6598543218dab31a07 100644 (file)
--- a/src/lib-storage/mail-storage-service.c
+++ b/src/lib-storage/mail-storage-service.c
@@ -296,6 +296,7 @@ service_drop_privileges(const struct mail_user_settings *set,
 {
        struct restrict_access_settings rset;
        uid_t current_euid, setuid_uid = 0;
+       const char *cur_chroot;
 
        current_euid = geteuid();
        restrict_access_init(&rset);
@@ -349,6 +350,23 @@ service_drop_privileges(const struct mail_user_settings *set,
        rset.chroot_dir = *chroot == '\0' || keep_setuid_root ? NULL : chroot;
        rset.system_groups_user = system_groups_user;
 
+       cur_chroot = restrict_access_get_current_chroot();
+       if (cur_chroot != NULL) {
+               if (rset.chroot_dir == NULL) {
+                       *error_r = "Process is already chrooted, "
+                               "can't un-chroot for this user";
+                       return -1;
+               }
+               if (strcmp(rset.chroot_dir, cur_chroot) != 0) {
+                       *error_r = t_strdup_printf(
+                               "Process is already chrooted to %s, "
+                               "can't chroot to %s", cur_chroot, chroot);
+                       return -1;
+               }
+               /* chrooting to same directory where we're already chrooted */
+               rset.chroot_dir = NULL;
+       }
+
        if (disallow_root &&
            (rset.uid == 0 || (rset.uid == (uid_t)-1 && current_euid == 0))) {
                *error_r = "Mail access not allowed for root";
@@ -753,7 +771,7 @@ int mail_storage_service_lookup(struct mail_storage_service_ctx *ctx,
 
        user->set_parser = settings_parser_dup(set_parser, user_pool);
        if (!settings_parser_check(user->set_parser, user_pool, &error))
-               i_unreached();
+               i_panic("settings_parser_check() failed: %s", error);
 
        user->user_set = settings_parser_get_list(user->set_parser)[1];
 
@@ -810,6 +828,27 @@ int mail_storage_service_next(struct mail_storage_service_ctx *ctx,
                return -2;
        }
 
+       len = strlen(chroot);
+       if (len > 2 && strcmp(chroot + len - 2, "/.") == 0 &&
+           strncmp(home, chroot, len - 2) == 0) {
+               /* mail_chroot = /chroot/. means that the home dir already
+                  contains the chroot dir. remove it from home. */
+               if (!temp_priv_drop) {
+                       home += len - 2;
+                       if (*home == '\0')
+                               home = "/";
+                       chroot = t_strndup(chroot, len - 2);
+
+                       set_keyval(ctx, user, "mail_home", home);
+                       set_keyval(ctx, user, "mail_chroot", chroot);
+               }
+       } else if (len > 0 && temp_priv_drop) {
+               /* we're dropping privileges only temporarily, so we can't
+                  chroot. fix home directory so we can access it. */
+               set_keyval(ctx, user, "mail_home",
+                          t_strconcat(chroot, "/", home, NULL));
+       }
+
        if ((ctx->flags & MAIL_STORAGE_SERVICE_FLAG_NO_LOG_INIT) == 0)
                mail_storage_service_init_log(ctx->service, user);
 
@@ -830,24 +869,6 @@ int mail_storage_service_next(struct mail_storage_service_ctx *ctx,
           initialized yet. */
        module_dir_init(mail_storage_service_modules);
 
-       /* we couldn't do chrooting, so if chrooting was enabled fix
-          the home directory */
-       len = strlen(chroot);
-       if (len > 2 && strcmp(chroot + len - 2, "/.") == 0 &&
-           strncmp(home, chroot, len - 2) == 0) {
-               /* home dir already contains the chroot dir */
-               if (!temp_priv_drop) {
-                       home += len - 2;
-                       if (*home == '\0')
-                               home = "/";
-
-                       set_keyval(ctx, user, "mail_home", home);
-                       chroot = t_strndup(chroot, len - 2);
-               }
-       } else if (len > 0 && temp_priv_drop) {
-               set_keyval(ctx, user, "mail_home",
-                          t_strconcat(chroot, "/", home, NULL));
-       }
        if (mail_storage_service_init_post(ctx, user, home,
                                           mail_user_r, &error) < 0) {
                i_error("user %s: Initialization failed: %s",