[PATCH] uefirtvariable: modify getnextvariablename test for VariableNameSize smaller than 2 (LP: #1593597)

[Ivan Hu]

Some firmwares (mostly on AMI Bios), the implementation limitation was seen
that the VariableNameSize of the GetNextVariableName should lager or equal to 2.
They believe that it should at least have a Null-terminated(2 bytes) for the
name buffer.

So test getnextvariablename with VariableNameSize 0 and 1 will get the
EFI_INVALID_PARAMETER, not expected EFI_BUFFER_TOO_SMALL.

UEFI spec doesn't describe it clearly, VariableName is the Null-treminated
string, so the EFI_INVALID_PARAMETER seems also a resonable return when
VariableNameSize smaller than 2.
Before the spec has a clearly description, for the fwts getnextvariablename
buffer too small test(getnextvariable_test4),
1. add the VariableNameSize 2 for the test, if VariableNameSize 2 without
returning EFI_BUFFER_TOO_SMALL, then test fail.
2. if VariableNameSize is 0 or 1, allow the extra return EFI_INVALID_PARAMETER.

Signed-off-by: Ivan Hu <ivan.hu at canonical.com>
---
 src/uefi/uefirtvariable/uefirtvariable.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/src/uefi/uefirtvariable/uefirtvariable.c b/src/uefi/uefirtvariable/uefirtvariable.c
index 0514805..aca0202 100644
--- a/src/uefi/uefirtvariable/uefirtvariable.c
+++ b/src/uefi/uefirtvariable/uefirtvariable.c
@@ -812,8 +812,7 @@ static int getnextvariable_test4(fwts_framework *fw)
 		goto err;
 	}
 
-	/* No first result can be 0 or 1 byte in size. */
-	for (i = 0; i < 2; i++) {
+	for (i = 0; i < 3; i++) {
 		variablenamesize = i;
 		getnextvariablename.VariableNameSize = &variablenamesize;
 
@@ -831,6 +830,8 @@ static int getnextvariable_test4(fwts_framework *fw)
 		 * EFI_NOT_FOUND at this point.
 		 */
 		if (ioret != -1 || status != EFI_BUFFER_TOO_SMALL) {
+			if (i != 2 && status == EFI_INVALID_PARAMETER)
+				continue;
 			fwts_failed(fw, LOG_LEVEL_HIGH,
 				"UEFIRuntimeGetNextVariableName",
 				"Expected EFI_BUFFER_TOO_SMALL with small "
-- 
2.7.4