[PATCH 4/4] efi_loader: validate device path length in boot manager

[Heinrich Schuchardt]

Bootxxxx variables are provided by the user and therefore cannot be
trusted. We have to validate them before usage.

A device path provided by a Bootxxxx variable must have an end node within
the indicated device path length.

Signed-off-by: Heinrich Schuchardt <xypron.glpk at gmx.de>
---
 lib/efi_loader/efi_bootmgr.c | 6 ++----
 1 file changed, 2 insertions(+), 4 deletions(-)

diff --git a/lib/efi_loader/efi_bootmgr.c b/lib/efi_loader/efi_bootmgr.c
index 1e06e60963..61dc72a23d 100644
--- a/lib/efi_loader/efi_bootmgr.c
+++ b/lib/efi_loader/efi_bootmgr.c
@@ -105,10 +105,8 @@ efi_status_t efi_deserialize_load_option(struct efi_load_option *lo, u8 *data,
 	if (*size < len)
 		return EFI_INVALID_PARAMETER;
 	lo->file_path = (struct efi_device_path *)data;
-	 /*
-	  * TODO: validate device path. There should be an end node within
-	  * the indicated file_path_length.
-	  */
+	if (efi_dp_check_length(lo->file_path, len) < 0)
+		return EFI_INVALID_PARAMETER;
 	data += len;
 	*size -= len;

--
2.28.0