Re: [PATCH 09/10] Fix efi_bind_block.

On 23.11.24 20:55, Matthew Garrett wrote:

From: Janis Danisevskis jdanisevskis@aurora.tech

efi_bind_block had two issues.

1. A pointer to a the stack was inserted as plat structure and thus used

beyond its life time. 2. Only the first segment of the device path was copied into the platfom data structure resulting in an unterminated device path.

Signed-off-by: Janis Danisevskis jdanisevskis@aurora.tech Signed-off-by: Matthew Garrett mgarrett@aurora.tech

---

lib/efi/efi_app_init.c | 29 +++++++++++++++++++++-------- 1 file changed, 21 insertions(+), 8 deletions(-)

diff --git a/lib/efi/efi_app_init.c b/lib/efi/efi_app_init.c index 9704020b749..cc91e1d74b8 100644 --- a/lib/efi/efi_app_init.c +++ b/lib/efi/efi_app_init.c @@ -19,6 +19,15 @@

DECLARE_GLOBAL_DATA_PTR;

+static size_t device_path_length(const struct efi_device_path *device_path) +{

• const struct efi_device_path *d;
• for (d = device_path; d->type != DEVICE_PATH_TYPE_END; d = (void *)d + d->length) {
• }
• return (void *)d - (void *)device_path + d->length;

+}

• /**
  • efi_bind_block() - bind a new block device to an EFI device

@@ -39,19 +48,23 @@ int efi_bind_block(efi_handle_t handle, struct efi_block_io *blkio, struct efi_device_path *device_path, int len, struct udevice **devp) {

• struct efi_media_plat plat;

• struct efi_media_plat *plat; struct udevice *dev; char name[18]; int ret;

• plat.handle = handle;
• plat.blkio = blkio;
• plat.device_path = malloc(device_path->length);
• if (!plat.device_path)

• size_t device_path_len = device_path_length(device_path);
• plat = malloc(sizeof(struct efi_media_plat));
• if (!plat)

• return log_msg_ret("plat", -ENOMEM);
  

• plat->handle = handle;
• plat->blkio = blkio;
• plat->device_path = malloc(device_path_len);
• if (!plat->device_path) return log_msg_ret("path", -ENOMEM);

• memcpy(plat.device_path, device_path, device_path->length);

• memcpy(plat->device_path, device_path, device_path_len); ret = device_bind(dm_root(), DM_DRIVER_GET(efi_media), "efi_media",

• 	  &plat, ofnode_null(), &dev);
  

• 	  plat, ofnode_null(), &dev);
  

  if (ret) return log_msg_ret("bind", ret);

Here you have a memory leak for pointer plat if ret != 0.

Simon suggested a follow up patch. Instead we should fix it in this patch.

@Simon The logic in the caller setup_block() looks wrong.

LocateHandle() does not ensure that when you try to read from the block device the same still does exist. E.g. if a USB device is removed the block IO protocol could be uninstalled and the handle deleted and the EFI app may crash. Please, call OpenProtocol() with attribute BY_DRIVER.

HandleProtocol() is considered deprecated. Please, use OpenProtocol() instead.

Best regards

Heinrich