efi_loader: fix efi_dp_from_name()

Correctly check the return value of efi_dp_from_file().
If we can determine device path for the file, should not depend on the
device path for the device being requested.
Provide a function description for efi_dp_from_name().

Reported-by: Coverity CID 273159, CID 273158
Fixes: 08c51fff30cc ("efi_loader: device_path: check against file path length")
Signed-off-by: Heinrich Schuchardt <xypron.glpk@gmx.de>

diff --git a/lib/efi_loader/efi_device_path.c b/lib/efi_loader/efi_device_path.c
index ac5e6f7e14f443978323e93b0eebb22f2fd3ccf6..17a0c5bb450cc6aef769c5866b722aaf9d389533 100644 (file)
--- a/lib/efi_loader/efi_device_path.c
+++ b/lib/efi_loader/efi_device_path.c
@@ -1032,6 +1032,16 @@ out:
        return EFI_SUCCESS;
 }
 
+/**
+ * efi_dp_from_name() - convert U-Boot device and file path to device path
+ *
+ * @dev:       U-Boot device, e.g. 'mmc'
+ * @devnr:     U-Boot device number, e.g. 1 for 'mmc:1'
+ * @path:      file path relative to U-Boot device, may be NULL
+ * @device:    pointer to receive device path of the device
+ * @file:      pointer to receive device path for the file
+ * Return:     status code
+ */
 efi_status_t efi_dp_from_name(const char *dev, const char *devnr,
                              const char *path,
                              struct efi_device_path **device,
@@ -1071,10 +1081,9 @@ efi_status_t efi_dp_from_name(const char *dev, const char *devnr,
        s = filename;
        while ((s = strchr(s, '/')))
                *s++ = '\\';
-       *file = efi_dp_from_file(((!is_net && device) ? desc : NULL),
-                                part, filename);
+       *file = efi_dp_from_file(is_net ? NULL : desc, part, filename);
 
-       if (!file)
+       if (!*file)
                return EFI_INVALID_PARAMETER;
 
        return EFI_SUCCESS;