[PATCH] uefirtvariable: Correct DataSize for GetVariable()

[Colin King]

From: Matt Fleming <matt.fleming at intel.com>

When calling GetVariable(), we need to fill out DataSize with the size
of the Data buffer instead of using whatever garbage value is left on
the stack.

Furthermore, the Data buffers are not strings in any of the tests, so
there's no need to NUL-terminate them or make them 1-byte larger than
datasize, e.g. there's no real need to do this,

    uint8_t data[datasize+1;

since the last element of data[] is never read back anyway.

Cc: Ivan Hu <ivan.hu at canonical.com>
Cc: Colin Ian King <colin.king at canonical.com>
Cc: Alex Hung <alex.hung at canonical.com>
Signed-off-by: Matt Fleming <matt.fleming at intel.com>
Acked-by: Colin Ian King <colin.king at canonical.com>
Acked-by: Alex Hung <alex.hung at canonical.com>
Acked-by: Ivan Hu <ivan.hu at canonical.com>
---
 src/uefi/uefirtvariable/uefirtvariable.c | 19 +++++++------------
 1 file changed, 7 insertions(+), 12 deletions(-)

diff --git a/src/uefi/uefirtvariable/uefirtvariable.c b/src/uefi/uefirtvariable/uefirtvariable.c
index e8aa041..e00b343 100644
--- a/src/uefi/uefirtvariable/uefirtvariable.c
+++ b/src/uefi/uefirtvariable/uefirtvariable.c
@@ -89,15 +89,14 @@ static int getvariable_test(fwts_framework *fw, uint64_t datasize, uint16_t *var
 	uint64_t status;
 	uint8_t testdata[MAX_DATA_LENGTH];
 	uint64_t dataindex;
-	uint64_t getdatasize;
+	uint64_t getdatasize = sizeof(testdata);
 	uint32_t attributestest;
 
-	uint8_t data[datasize+1];
+	uint8_t data[datasize];
 	uint32_t i;
 
 	for (dataindex = 0; dataindex < datasize; dataindex++)
 		data[dataindex] = (uint8_t)dataindex;
-	data[dataindex] = '\0';
 
 	setvariable.VariableName = varname;
 	setvariable.VendorGuid = &gtestguid1;
@@ -245,7 +244,6 @@ static int getnextvariable_test(fwts_framework *fw)
 
 	for (dataindex = 0; dataindex < datasize; dataindex++)
 		data[dataindex] = (uint8_t)dataindex;
-	data[dataindex] = '\0';
 
 	setvariable.VariableName = variablenametest;
 	setvariable.VendorGuid = &gtestguid1;
@@ -350,11 +348,10 @@ static int setvariable_insertvariable(fwts_framework *fw, uint32_t attributes, u
 	uint64_t status;
 	uint64_t dataindex;
 
-	uint8_t data[datasize+1];
+	uint8_t data[datasize];
 
 	for (dataindex = 0; dataindex < datasize; dataindex++)
 		data[dataindex] = (uint8_t)dataindex + datadiff;
-	data[dataindex] = '\0';
 
 	setvariable.VariableName = varname;
 	setvariable.VendorGuid = gtestguid;
@@ -392,9 +389,9 @@ static int setvariable_checkvariable(fwts_framework *fw, uint64_t datasize,
 	struct efi_getvariable getvariable;
 
 	uint64_t status;
-	uint8_t testdata[datasize+1];
+	uint8_t testdata[datasize];
 	uint64_t dataindex;
-	uint64_t getdatasize;
+	uint64_t getdatasize = sizeof(testdata);
 	uint32_t attributestest;
 
 	getvariable.VariableName = varname;
@@ -442,7 +439,7 @@ static int setvariable_checkvariable_notfound(fwts_framework *fw, uint16_t *varn
 
 	uint64_t status;
 	uint8_t testdata[MAX_DATA_LENGTH];
-	uint64_t getdatasize;
+	uint64_t getdatasize = sizeof(testdata);
 	uint32_t attributestest;
 
 	getvariable.VariableName = varname;
@@ -472,11 +469,10 @@ static int setvariable_invalidattr(fwts_framework *fw, uint32_t attributes, uint
 	struct efi_setvariable setvariable;
 	uint64_t status;
 	uint64_t dataindex;
-	uint8_t data[datasize+1];
+	uint8_t data[datasize];
 
 	for (dataindex = 0; dataindex < datasize; dataindex++)
 		data[dataindex] = (uint8_t)dataindex + datadiff;
-	data[dataindex] = '\0';
 
 	setvariable.VariableName = varname;
 	setvariable.VendorGuid = gtestguid;
@@ -775,7 +771,6 @@ static int getnextvariable_multitest(fwts_framework *fw, uint32_t multitesttime)
 
 	for (dataindex = 0; dataindex < datasize; dataindex++)
 		data[dataindex] = (uint8_t)dataindex;
-	data[dataindex] = '\0';
 
 	setvariable.VariableName = variablenametest;
 	setvariable.VendorGuid = &gtestguid1;
-- 
1.8.1.2