efi_dp_find_obj() should not return any handle with a partially matching device path but the handle with the maximum matching device path.
Signed-off-by: Heinrich Schuchardt heinrich.schuchardt@canonical.com --- v2: new patch --- include/efi_loader.h | 4 +- lib/efi_loader/efi_device_path.c | 110 +++++++++++++++++-------------- 2 files changed, 63 insertions(+), 51 deletions(-)
diff --git a/include/efi_loader.h b/include/efi_loader.h index 1ffcdfc485..6271d40125 100644 --- a/include/efi_loader.h +++ b/include/efi_loader.h @@ -730,8 +730,8 @@ struct efi_device_path *efi_dp_shorten(struct efi_device_path *dp); struct efi_device_path *efi_dp_next(const struct efi_device_path *dp); int efi_dp_match(const struct efi_device_path *a, const struct efi_device_path *b); -struct efi_object *efi_dp_find_obj(struct efi_device_path *dp, - struct efi_device_path **rem); +efi_handle_t efi_dp_find_obj(struct efi_device_path *dp, + struct efi_device_path **rem); /* get size of the first device path instance excluding end node */ efi_uintn_t efi_dp_instance_size(const struct efi_device_path *dp); /* size of multi-instance device path excluding end node */ diff --git a/lib/efi_loader/efi_device_path.c b/lib/efi_loader/efi_device_path.c index ddd5f132ec..aeb5264820 100644 --- a/lib/efi_loader/efi_device_path.c +++ b/lib/efi_loader/efi_device_path.c @@ -159,69 +159,81 @@ struct efi_device_path *efi_dp_shorten(struct efi_device_path *dp) return dp; }
-static struct efi_object *find_obj(struct efi_device_path *dp, bool short_path, - struct efi_device_path **rem) +/** + * find_handle() - find handle by device path + * + * If @rem is provided, the handle with the longest partial match is returned. + * + * @dp: device path to search + * @short_path: use short form device path for matching + * @rem: pointer to receive remaining device path + * Return: matching handle + */ +static efi_handle_t find_handle(struct efi_device_path *dp, bool short_path, + struct efi_device_path **rem) { - struct efi_object *efiobj; - efi_uintn_t dp_size = efi_dp_instance_size(dp); + efi_handle_t handle, best_handle = NULL; + efi_uintn_t len, best_len = 0; + + len = efi_dp_instance_size(dp);
- list_for_each_entry(efiobj, &efi_obj_list, link) { + list_for_each_entry(handle, &efi_obj_list, link) { struct efi_handler *handler; - struct efi_device_path *obj_dp; + struct efi_device_path *dp_current; + efi_uintn_t len_current; efi_status_t ret;
- ret = efi_search_protocol(efiobj, - &efi_guid_device_path, &handler); + ret = efi_search_protocol(handle, &efi_guid_device_path, + &handler); if (ret != EFI_SUCCESS) continue; - obj_dp = handler->protocol_interface; - - do { - if (efi_dp_match(dp, obj_dp) == 0) { - if (rem) { - /* - * Allow partial matches, but inform - * the caller. - */ - *rem = ((void *)dp) + - efi_dp_instance_size(obj_dp); - return efiobj; - } else { - /* Only return on exact matches */ - if (efi_dp_instance_size(obj_dp) == - dp_size) - return efiobj; - } - } - - obj_dp = efi_dp_shorten(efi_dp_next(obj_dp)); - } while (short_path && obj_dp); + dp_current = handler->protocol_interface; + if (short_path) { + dp_current = efi_dp_shorten(dp_current); + if (!dp_current) + continue; + } + len_current = efi_dp_instance_size(dp_current); + if (rem) { + if (len_current < len) + continue; + } else { + if (len_current != len) + continue; + } + if (memcmp(dp_current, dp, len)) + continue; + if (!rem) + return handle; + if (len_current > best_len) { + best_len = len_current; + best_handle = handle; + *rem = (void*)((u8 *)dp + len_current); + } } - - return NULL; + return best_handle; }
-/* - * Find an efiobj from device-path, if 'rem' is not NULL, returns the - * remaining part of the device path after the matched object. +/** + * efi_dp_find_obj() - find handle by device path + * + * If @rem is provided, the handle with the longest partial match is returned. + * + * @dp: device path to search + * @rem: pointer to receive remaining device path + * Return: matching handle */ -struct efi_object *efi_dp_find_obj(struct efi_device_path *dp, - struct efi_device_path **rem) +efi_handle_t efi_dp_find_obj(struct efi_device_path *dp, + struct efi_device_path **rem) { - struct efi_object *efiobj; - - /* Search for an exact match first */ - efiobj = find_obj(dp, false, NULL); - - /* Then for a fuzzy match */ - if (!efiobj) - efiobj = find_obj(dp, false, rem); + efi_handle_t handle;
- /* And now for a fuzzy short match */ - if (!efiobj) - efiobj = find_obj(dp, true, rem); + handle = find_handle(dp, false, rem); + if (!handle) + /* Match short form device path */ + handle = find_handle(dp, true, rem);
- return efiobj; + return handle; }
/*