efi_loader: optional data in load options are binary

The field boot OptionalData in structure _EFI_LOAD_OPTIONS is for binary
data.

When we use `efidebug boot add` we should convert the 5th argument from
UTF-8 to UTF-16 before putting it into the BootXXXX variable.

When printing boot variables with `efidebug boot dump` we should support
the OptionalData being arbitrary binary data. So let's dump the data as
hexadecimal values.

Here is an example session protocol:

=> efidebug boot add 00a1 label1 scsi 0:1 doit1 'my option'
=> efidebug boot add 00a2 label2 scsi 0:1 doit2
=> efidebug boot dump
Boot00A0:
  attributes: A-- (0x00000001)
  label: label1
  file_path: .../HD(1,MBR,0xeac4e18b,0x800,0x3fffe)/doit1
  data:
    00000000: 6d 00 79 00 20 00 6f 00 70 00 74 00 69 00 6f 00  m.y. .o.p.t.i.o.
    00000010: 6e 00 00 00                                      n...
Boot00A1:
  attributes: A-- (0x00000001)
  label: label2
  file_path: .../HD(1,MBR,0xeac4e18b,0x800,0x3fffe)/doit2
  data:

Signed-off-by: Heinrich Schuchardt <xypron.glpk@gmx.de>

cmd/efidebug.c

@@ -11,6 +11,7 @@
 #include <efi_loader.h>
 #include <environment.h>
 #include <exports.h>
+#include <hexdump.h>
 #include <malloc.h>
 #include <search.h>
 #include <linux/ctype.h>
@@ -545,7 +546,10 @@ static int do_efi_boot_add(cmd_tbl_t *cmdtp, int flag,
 				+ sizeof(struct efi_device_path); /* for END */
 
 	/* optional data */
-	lo.optional_data = (u8 *)(argc == 6 ? "" : argv[6]);
+	if (argc < 6)
+		lo.optional_data = NULL;
+	else
+		lo.optional_data = (const u8 *)argv[6];
 
 	size = efi_serialize_load_option(&lo, (u8 **)&data);
 	if (!size) {
@@ -615,12 +619,13 @@ static int do_efi_boot_rm(cmd_tbl_t *cmdtp, int flag,
 /**
  * show_efi_boot_opt_data() - dump UEFI load option
  *
- * @id:		Load option number
- * @data:	Value of UEFI load option variable
+ * @id:		load option number
+ * @data:	value of UEFI load option variable
+ * @size:	size of the boot option
  *
  * Decode the value of UEFI load option variable and print information.
  */
-static void show_efi_boot_opt_data(int id, void *data)
+static void show_efi_boot_opt_data(int id, void *data, size_t size)
 {
 	struct efi_load_option lo;
 	char *label, *p;
@@ -638,7 +643,7 @@ static void show_efi_boot_opt_data(int id, void *data)
 	utf16_utf8_strncpy(&p, lo.label, label_len16);
 
 	printf("Boot%04X:\n", id);
-	printf("\tattributes: %c%c%c (0x%08x)\n",
+	printf("  attributes: %c%c%c (0x%08x)\n",
 	       /* ACTIVE */
 	       lo.attributes & LOAD_OPTION_ACTIVE ? 'A' : '-',
 	       /* FORCE RECONNECT */
@@ -646,14 +651,16 @@ static void show_efi_boot_opt_data(int id, void *data)
 	       /* HIDDEN */
 	       lo.attributes & LOAD_OPTION_HIDDEN ? 'H' : '-',
 	       lo.attributes);
-	printf("\tlabel: %s\n", label);
+	printf("  label: %s\n", label);
 
 	dp_str = efi_dp_str(lo.file_path);
-	printf("\tfile_path: %ls\n", dp_str);
+	printf("  file_path: %ls\n", dp_str);
 	efi_free_pool(dp_str);
 
-	printf("\tdata: %s\n", lo.optional_data);
-
+	printf("  data:\n");
+	print_hex_dump("    ", DUMP_PREFIX_OFFSET, 16, 1,
+		       lo.optional_data, size + (u8 *)data -
+		       (u8 *)lo.optional_data, true);
 	free(label);
 }
 
@@ -686,7 +693,7 @@ static void show_efi_boot_opt(int id)
 						data));
 	}
 	if (ret == EFI_SUCCESS)
-		show_efi_boot_opt_data(id, data);
+		show_efi_boot_opt_data(id, data, size);
 	else if (ret == EFI_NOT_FOUND)
 		printf("Boot%04X: not found\n", id);
 

include/efi_loader.h

@@ -560,7 +560,7 @@ struct efi_load_option {
 	u16 file_path_length;
 	u16 *label;
 	struct efi_device_path *file_path;
-	u8 *optional_data;
+	const u8 *optional_data;
 };
 
 void efi_deserialize_load_option(struct efi_load_option *lo, u8 *data);

lib/efi_loader/efi_bootmgr.c

@@ -53,19 +53,20 @@ void efi_deserialize_load_option(struct efi_load_option *lo, u8 *data)
  */
 unsigned long efi_serialize_load_option(struct efi_load_option *lo, u8 **data)
 {
-	unsigned long label_len, option_len;
+	unsigned long label_len;
 	unsigned long size;
 	u8 *p;
 
 	label_len = (u16_strlen(lo->label) + 1) * sizeof(u16);
-	option_len = strlen((char *)lo->optional_data);
 
 	/* total size */
 	size = sizeof(lo->attributes);
 	size += sizeof(lo->file_path_length);
 	size += label_len;
 	size += lo->file_path_length;
-	size += option_len + 1;
+	if (lo->optional_data)
+		size += (utf8_utf16_strlen((const char *)lo->optional_data)
+					   + 1) * sizeof(u16);
 	p = malloc(size);
 	if (!p)
 		return 0;
@@ -84,10 +85,10 @@ unsigned long efi_serialize_load_option(struct efi_load_option *lo, u8 **data)
 	memcpy(p, lo->file_path, lo->file_path_length);
 	p += lo->file_path_length;
 
-	memcpy(p, lo->optional_data, option_len);
-	p += option_len;
-	*(char *)p = '\0';
-
+	if (lo->optional_data) {
+		utf8_utf16_strcpy((u16 **)&p, (const char *)lo->optional_data);
+		p += sizeof(u16); /* size of trailing \0 */
+	}
 	return size;
 }