efi_loadopt_optional_data_size: add efi_error() trace code

Signed-off-by: Peter Jones <pjones@redhat.com>

diff --git a/src/loadopt.c b/src/loadopt.c
index 64e333f..a63ca79 100644 (file)
--- a/src/loadopt.c
+++ b/src/loadopt.c
@@ -88,28 +88,49 @@ __attribute__((__nonnull__ (1)))
 __attribute__((__visibility__ ("default")))
 efi_loadopt_optional_data_size(efi_load_option *opt, size_t size)
 {
-       size_t sz;
+       ssize_t sz;
+       ssize_t ret;
        uint8_t *p;
 
-       if (size < sizeof(*opt))
+       ret = size;
+       if (ret < (ssize_t)sizeof(*opt)) {
+               efi_error("load option size is too small for header (%zd/%zd)",
+                         ret, sizeof(*opt));
                return -1;
-       size -= sizeof(*opt);
-       if (size < opt->file_path_list_length)
+       }
+       ret -= sizeof(*opt);
+       if (ret < opt->file_path_list_length) {
+               efi_error("load option size is too small for path (%zd/%d)",
+                         size, opt->file_path_list_length);
                return -1;
-       size -= opt->file_path_list_length;
+       }
+       ret -= opt->file_path_list_length;
+       if (ret < 0) {
+               efi_error("leftover size is negative (%zd)", ret);
+               return -1;
+       }
        /* "size" as the limit means sz will be size or less in all cases; no
         * need to test it.  if it /is/ size, there's no optional data. */
-       sz = ucs2size(opt->description, size);
+       sz = ucs2size(opt->description, ret);
        p = (uint8_t *)(opt->description) + sz;
-       size -= sz;
+       ret -= sz;
+       if (ret < 0) {
+               efi_error("leftover size is negative (%zd)", ret);
+               return -1;
+       }
 
-       if (!efidp_is_valid((const_efidp)p, opt->file_path_list_length))
+       if (!efidp_is_valid((const_efidp)p, opt->file_path_list_length)) {
+               efi_error("efi device path is not valid");
                return -1;
+       }
        sz = efidp_size((const_efidp)p);
-       if (sz != opt->file_path_list_length)
+       if (sz != opt->file_path_list_length) {
+               efi_error("size does not match file path size (%zd/%d)",
+                         sz, opt->file_path_list_length);
                return -1;
+       }
 
-       return size;
+       return ret;
 }
 
 int