Re: [PATCH v2 3/9] efi_loader: efi_dp_find_obj() add protocol check

On Sat, Mar 19, 2022 at 10:11:42AM +0100, Heinrich Schuchardt wrote:

Let function efi_dp_find_obj() additionally check if a given protocol is installed on the handle relating to the device-path.

Please describe why you want to add another parameter to the function. Otherwise, we don't understand why the change is necessary. The caller can simply call efi_search_protocol() to determine whether the given protocol is installed or not on the handle.

Signed-off-by: Heinrich Schuchardt heinrich.schuchardt@canonical.com

v2: new patch

---

include/efi_loader.h | 1 + lib/efi_loader/efi_boottime.c | 2 +- lib/efi_loader/efi_capsule.c | 2 +- lib/efi_loader/efi_device_path.c | 23 ++++++++++++++++------- lib/efi_loader/efi_disk.c | 2 +- 5 files changed, 20 insertions(+), 10 deletions(-)

diff --git a/include/efi_loader.h b/include/efi_loader.h index 6271d40125..1ae47a8713 100644 --- a/include/efi_loader.h +++ b/include/efi_loader.h @@ -731,6 +731,7 @@ 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); efi_handle_t efi_dp_find_obj(struct efi_device_path *dp,

• 	     const efi_guid_t *guid,
       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); diff --git a/lib/efi_loader/efi_boottime.c b/lib/efi_loader/efi_boottime.c index d0f3e05e70..a7bc371f54 100644 --- a/lib/efi_loader/efi_boottime.c +++ b/lib/efi_loader/efi_boottime.c @@ -1750,7 +1750,7 @@ efi_status_t efi_setup_loaded_image(struct efi_device_path *device_path, info->system_table = &systab;

if (device_path) {

• info->device_handle = efi_dp_find_obj(device_path, NULL);
  

• info->device_handle = efi_dp_find_obj(device_path, NULL, NULL);
  
  

  dp = efi_dp_append(device_path, file_path); if (!dp) {

diff --git a/lib/efi_loader/efi_capsule.c b/lib/efi_loader/efi_capsule.c index c8e2d510a5..3d80d98c1f 100644 --- a/lib/efi_loader/efi_capsule.c +++ b/lib/efi_loader/efi_capsule.c @@ -681,7 +681,7 @@ static bool device_is_present_and_system_part(struct efi_device_path *dp) { efi_handle_t handle;

• handle = efi_dp_find_obj(dp, NULL);

• handle = efi_dp_find_obj(dp, NULL, NULL); if (!handle) return false;

diff --git a/lib/efi_loader/efi_device_path.c b/lib/efi_loader/efi_device_path.c index aeb5264820..0a8802903d 100644 --- a/lib/efi_loader/efi_device_path.c +++ b/lib/efi_loader/efi_device_path.c @@ -160,17 +160,19 @@ struct efi_device_path *efi_dp_shorten(struct efi_device_path *dp) }

/**

• • find_handle() - find handle by device path

• • find_handle() - find handle by device path and installed protocol
  • If @rem is provided, the handle with the longest partial match is returned.
  • @dp: device path to search
• • @guid: GUID of protocol that must be installed on path or NULL
  • @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)
  

+static efi_handle_t find_handle(struct efi_device_path *dp,

• 		const efi_guid_t *guid, bool short_path,
  

• 		struct efi_device_path **rem)
  

{ efi_handle_t handle, best_handle = NULL; efi_uintn_t len, best_len = 0; @@ -183,6 +185,11 @@ static efi_handle_t find_handle(struct efi_device_path *dp, bool short_path, efi_uintn_t len_current; efi_status_t ret;

• if (guid) {
  

• 	ret = efi_search_protocol(handle, guid, &handler);
  

• 	if (ret != EFI_SUCCESS)
  

• 		continue;
  

• }
  

  ret = efi_search_protocol(handle, &efi_guid_device_path, &handler); if (ret != EFI_SUCCESS)

@@ -195,13 +202,13 @@ static efi_handle_t find_handle(struct efi_device_path *dp, bool short_path, } len_current = efi_dp_instance_size(dp_current); if (rem) {

• 	if (len_current < len)
  

• 	if (len_current > len)
  

It looks a bug fix, but it's not related to this patch?

-Takahiro Akashi

		continue;
} else {
	if (len_current != len)
		continue;
}

• if (memcmp(dp_current, dp, len))
  

• if (memcmp(dp_current, dp, len_current))
  continue;
  

  if (!rem) return handle;

@@ -220,18 +227,20 @@ static efi_handle_t find_handle(struct efi_device_path *dp, bool short_path,

• If @rem is provided, the handle with the longest partial match is returned.
• @dp: device path to search

• • @guid: GUID of protocol that must be installed on path or NULL
  • @rem: pointer to receive remaining device path
  • Return: matching handle
  */

efi_handle_t efi_dp_find_obj(struct efi_device_path *dp,

• 	     const efi_guid_t *guid,
       struct efi_device_path **rem)
  

{ efi_handle_t handle;

• handle = find_handle(dp, false, rem);

• handle = find_handle(dp, guid, false, rem); if (!handle) /* Match short form device path */

• handle = find_handle(dp, true, rem);
  

• handle = find_handle(dp, guid, true, rem);
  
  

  return handle;

} diff --git a/lib/efi_loader/efi_disk.c b/lib/efi_loader/efi_disk.c index 45127d1768..d36a35d94f 100644 --- a/lib/efi_loader/efi_disk.c +++ b/lib/efi_loader/efi_disk.c @@ -302,7 +302,7 @@ efi_fs_from_path(struct efi_device_path *full_path) efi_free_pool(file_path);

/* Get the EFI object for the partition */

• efiobj = efi_dp_find_obj(device_path, NULL);

• efiobj = efi_dp_find_obj(device_path, NULL, NULL); efi_free_pool(device_path); if (!efiobj) return NULL;

-- 2.34.1