diff --git a/fs/overlayfs/params.c b/fs/overlayfs/params.c index e42546c6c5df..1115c22deca0 100644 --- a/fs/overlayfs/params.c +++ b/fs/overlayfs/params.c @@ -141,10 +141,10 @@ static int ovl_verity_mode_def(void) const struct fs_parameter_spec ovl_parameter_spec[] = { fsparam_string_empty("lowerdir", Opt_lowerdir), - fsparam_string("lowerdir+", Opt_lowerdir_add), - fsparam_string("datadir+", Opt_datadir_add), - fsparam_string("upperdir", Opt_upperdir), - fsparam_string("workdir", Opt_workdir), + fsparam_file_or_string("lowerdir+", Opt_lowerdir_add), + fsparam_file_or_string("datadir+", Opt_datadir_add), + fsparam_file_or_string("upperdir", Opt_upperdir), + fsparam_file_or_string("workdir", Opt_workdir), fsparam_flag("default_permissions", Opt_default_permissions), fsparam_enum("redirect_dir", Opt_redirect_dir, ovl_parameter_redirect_dir), fsparam_enum("index", Opt_index, ovl_parameter_bool), @@ -367,40 +367,100 @@ static void ovl_add_layer(struct fs_context *fc, enum ovl_opt layer, } } -static int ovl_parse_layer(struct fs_context *fc, const char *layer_name, enum ovl_opt layer) +static inline bool is_upper_layer(enum ovl_opt layer) +{ + return layer == Opt_upperdir || layer == Opt_workdir; +} + +/* Handle non-file descriptor-based layer options that require path lookup. */ +static inline int ovl_kern_path(const char *layer_name, struct path *layer_path, + enum ovl_opt layer) { - char *name = kstrdup(layer_name, GFP_KERNEL); - bool upper = (layer == Opt_upperdir || layer == Opt_workdir); - struct path path; int err; + switch (layer) { + case Opt_upperdir: + fallthrough; + case Opt_workdir: + fallthrough; + case Opt_lowerdir: + err = ovl_mount_dir(layer_name, layer_path); + break; + case Opt_lowerdir_add: + fallthrough; + case Opt_datadir_add: + err = ovl_mount_dir_noesc(layer_name, layer_path); + break; + default: + WARN_ON_ONCE(true); + err = -EINVAL; + } + + return err; +} + +static int ovl_do_parse_layer(struct fs_context *fc, const char *layer_name, + struct path *layer_path, enum ovl_opt layer) +{ + char *name __free(kfree) = kstrdup(layer_name, GFP_KERNEL); + bool upper; + int err = 0; + if (!name) return -ENOMEM; - if (upper || layer == Opt_lowerdir) - err = ovl_mount_dir(name, &path); - else - err = ovl_mount_dir_noesc(name, &path); + upper = is_upper_layer(layer); + err = ovl_mount_dir_check(fc, layer_path, layer, name, upper); if (err) - goto out_free; - - err = ovl_mount_dir_check(fc, &path, layer, name, upper); - if (err) - goto out_put; + return err; if (!upper) { err = ovl_ctx_realloc_lower(fc); if (err) - goto out_put; + return err; } /* Store the user provided path string in ctx to show in mountinfo */ - ovl_add_layer(fc, layer, &path, &name); + ovl_add_layer(fc, layer, layer_path, &name); + return err; +} + +static int ovl_parse_layer(struct fs_context *fc, struct fs_parameter *param, + enum ovl_opt layer) +{ + struct path layer_path __free(path_put) = {}; + int err = 0; + + switch (param->type) { + case fs_value_is_string: + err = ovl_kern_path(param->string, &layer_path, layer); + if (err) + return err; + err = ovl_do_parse_layer(fc, param->string, &layer_path, layer); + break; + case fs_value_is_file: { + char *buf __free(kfree); + char *layer_name; + + buf = kmalloc(PATH_MAX, GFP_KERNEL_ACCOUNT); + if (!buf) + return -ENOMEM; + + layer_path = param->file->f_path; + path_get(&layer_path); + + layer_name = d_path(&layer_path, buf, PATH_MAX); + if (IS_ERR(layer_name)) + return PTR_ERR(layer_name); + + err = ovl_do_parse_layer(fc, layer_name, &layer_path, layer); + break; + } + default: + WARN_ON_ONCE(true); + err = -EINVAL; + } -out_put: - path_put(&path); -out_free: - kfree(name); return err; } @@ -474,7 +534,13 @@ static int ovl_parse_param_lowerdir(const char *name, struct fs_context *fc) iter = dup; for (nr = 0; nr < nr_lower; nr++) { - err = ovl_parse_layer(fc, iter, Opt_lowerdir); + struct path path __free(path_put) = {}; + + err = ovl_kern_path(iter, &path, Opt_lowerdir); + if (err) + goto out_err; + + err = ovl_do_parse_layer(fc, iter, &path, Opt_lowerdir); if (err) goto out_err; @@ -555,7 +621,7 @@ static int ovl_parse_param(struct fs_context *fc, struct fs_parameter *param) case Opt_datadir_add: case Opt_upperdir: case Opt_workdir: - err = ovl_parse_layer(fc, param->string, opt); + err = ovl_parse_layer(fc, param, opt); break; case Opt_default_permissions: config->default_permissions = true;