[PATCH] ntdll: Fix length calculation of generated SMBIOS tables.

[Brendan Shanks]

An extra byte for a null-terminator was added for every string, but not
used when the string was empty. This resulted in extra bytes at the end
of the buffer, causing parse errors in dmidecode.

Signed-off-by: Brendan Shanks <bshanks(a)codeweavers.com>
---
 dlls/ntdll/nt.c | 14 ++++++++------
 1 file changed, 8 insertions(+), 6 deletions(-)

diff --git a/dlls/ntdll/nt.c b/dlls/ntdll/nt.c
index 6c95517e79..4dced31641 100644
--- a/dlls/ntdll/nt.c
+++ b/dlls/ntdll/nt.c
@@ -2191,19 +2191,21 @@ static NTSTATUS get_firmware_info(SYSTEM_FIRMWARE_TABLE_INFORMATION *sfti, ULONG
 
             *required_len = sizeof(struct smbios_prologue);
 
+#define L(l) (l + (l ? 1 : 0))
             *required_len += sizeof(struct smbios_bios);
-            *required_len += max(bios_vendor_len + bios_version_len + bios_date_len + 4, 2);
+            *required_len += max(L(bios_vendor_len) + L(bios_version_len) + L(bios_date_len) + 1, 2);
 
             *required_len += sizeof(struct smbios_system);
-            *required_len += max(system_vendor_len + system_product_len + system_version_len +
-                                 system_serial_len + system_sku_len + system_family_len + 7, 2);
+            *required_len += max(L(system_vendor_len) + L(system_product_len) + L(system_version_len) +
+                                 L(system_serial_len) + L(system_sku_len) + L(system_family_len) + 1, 2);
 
             *required_len += sizeof(struct smbios_board);
-            *required_len += max(board_vendor_len + board_product_len + board_version_len + board_serial_len + 5, 2);
+            *required_len += max(L(board_vendor_len) + L(board_product_len) + L(board_version_len) + L(board_serial_len) + 1, 2);
 
             *required_len += sizeof(struct smbios_chassis);
-            *required_len += max(chassis_vendor_len + chassis_version_len + chassis_serial_len +
-                                 chassis_asset_tag_len + 5, 2);
+            *required_len += max(L(chassis_vendor_len) + L(chassis_version_len) + L(chassis_serial_len) +
+                                 L(chassis_asset_tag_len) + 1, 2);
+#undef L
 
             sfti->TableBufferLength = *required_len;
 
-- 
2.26.2