[PATCH v2 1/2] efi_loader: correct reported length in GetNextVariable()

[Heinrich Schuchardt]

The runtime service GetNextVariable() returns the length of the next
variable including the closing 0x0000. This length should be in bytes.

Comparing the output of EDK2 and U-Boot shows that this is currently not
correctly implemented:

EDK2:
OsIndicationsSupported: 46
PlatformLang: 26
PlatformLangCodes: 36

U-Boot:
OsIndicationsSupported: 23
PlatformLang: 13
PlatformLangCodes: 18

Provide correct length in GetNextVariable().

Fixes: d99a87f84b75 ("efi_loader: implement GetNextVariableName()")
Signed-off-by: Heinrich Schuchardt <xypron.glpk at gmx.de>
---
v2:
	correct return value of the initial call too
---
 lib/efi_loader/efi_variable.c | 11 ++++++-----
 1 file changed, 6 insertions(+), 5 deletions(-)

diff --git a/lib/efi_loader/efi_variable.c b/lib/efi_loader/efi_variable.c
index 99d2f01f57..3bec2d0d17 100644
--- a/lib/efi_loader/efi_variable.c
+++ b/lib/efi_loader/efi_variable.c
@@ -273,7 +273,8 @@ static efi_status_t parse_uboot_variable(char *variable,
 					 u32 *attributes)
 {
 	char *guid, *name, *end, c;
-	unsigned long name_len;
+	size_t name_len;
+	efi_uintn_t old_variable_name_size;
 	u16 *p;

 	guid = strchr(variable, '_');
@@ -289,17 +290,17 @@ static efi_status_t parse_uboot_variable(char *variable,
 		return EFI_INVALID_PARAMETER;

 	name_len = end - name;
-	if (*variable_name_size < (name_len + 1)) {
-		*variable_name_size = name_len + 1;
+	old_variable_name_size = *variable_name_size;
+	*variable_name_size = sizeof(u16) * (name_len + 1);
+	if (old_variable_name_size < *variable_name_size)
 		return EFI_BUFFER_TOO_SMALL;
-	}
+
 	end++; /* point to value */

 	/* variable name */
 	p = variable_name;
 	utf8_utf16_strncpy(&p, name, name_len);
 	variable_name[name_len] = 0;
-	*variable_name_size = name_len + 1;

 	/* guid */
 	c = *(name - 1);
--
2.25.1