[PATCH] uefirtvariable: fix decalred VLA have zero size (LP: #1526815)

[Ivan Hu]

Static analysis from clang scan-build found a declared variable-length
array(VLA) has zero size, setvariable_insertvariable() declares data[datasize],
however, it is called when delete a variable as follows:
ret = setvariable_insertvariable(fw, attributes, 0, variablenametest,
&gtestguid1, datadiff);
so got a declared data[0] declared.

Signed-off-by: Ivan Hu <ivan.hu at canonical.com>
---
 src/uefi/uefirtvariable/uefirtvariable.c | 15 ++++++++++++++-
 1 file changed, 14 insertions(+), 1 deletion(-)

diff --git a/src/uefi/uefirtvariable/uefirtvariable.c b/src/uefi/uefirtvariable/uefirtvariable.c
index b3c7559..27aa9a1 100644
--- a/src/uefi/uefirtvariable/uefirtvariable.c
+++ b/src/uefi/uefirtvariable/uefirtvariable.c
@@ -867,7 +867,11 @@ static int setvariable_insertvariable(
 	uint64_t status;
 	uint64_t dataindex;
 
-	uint8_t data[datasize];
+	uint8_t *data = malloc (datasize);
+	if ((datasize != 0) && !data) {
+		fwts_skipped(fw, "Unable to alloc memory for data");
+		return FWTS_SKIP;
+	}
 
 	for (dataindex = 0; dataindex < datasize; dataindex++)
 		data[dataindex] = (uint8_t)dataindex + datadiff;
@@ -892,6 +896,8 @@ static int setvariable_insertvariable(
 				"with EFI_VARIABLE_AUTHENTICATED_WRITE_ACCESS or "
 				"EFI_VARIABLE_TIME_BASED_AUTHENTICATED_WRITE_ACCESS "
 				"EFI_VARIABLE_APPEND_WRITE attributes is set.");
+			if (data)
+				free(data);
 			return FWTS_SKIP;
 		}
 		if (datasize == 0)
@@ -910,6 +916,8 @@ static int setvariable_insertvariable(
 					"after rebooting. Reboot and test "
 					"again may be helpful to continue "
 					"the test.");
+				if (data)
+					free(data);
 				return FWTS_SKIP;
 			}
 			fwts_failed(fw, LOG_LEVEL_HIGH,
@@ -918,8 +926,13 @@ static int setvariable_insertvariable(
 				"runtime service.");
 		}
 		fwts_uefi_print_status_info(fw, status);
+		if (data)
+			free(data);
 		return FWTS_ERROR;
 	}
+
+	if (data)
+		free(data);
 	return FWTS_OK;
 }
 
-- 
1.9.1