mok: Fix memory leak in mok mirroring

Currently valgrind shows a minor issue which is not introduced in this
patch series:

==2595397==
==2595397== HEAP SUMMARY:
==2595397==     in use at exit: 16,368 bytes in 48 blocks
==2595397==   total heap usage: 6,953 allocs, 6,905 frees, 9,146,749 bytes allocated
==2595397==
==2595397== 16,368 bytes in 48 blocks are definitely lost in loss record 1 of 1
==2595397==    at 0x4845464: calloc (vg_replace_malloc.c:1117)
==2595397==    by 0x4087F2: mock_efi_allocate_pool (test.c:72)
==2595397==    by 0x4098DE: UnknownInlinedFun (misc.c:33)
==2595397==    by 0x4098DE: AllocateZeroPool (misc.c:48)
==2595397==    by 0x403D40: get_variable_attr (variables.c:301)
==2595397==    by 0x4071C4: import_one_mok_state (mok.c:831)
==2595397==    by 0x4072F4: import_mok_state (mok.c:908)
==2595397==    by 0x407FA6: test_mok_mirror_0 (test-mok-mirror.c:205)
==2595397==    by 0x4035B2: main (test-mok-mirror.c:378)
==2595397==
==2595397== LEAK SUMMARY:
==2595397==    definitely lost: 16,368 bytes in 48 blocks
==2595397==    indirectly lost: 0 bytes in 0 blocks
==2595397==      possibly lost: 0 bytes in 0 blocks
==2595397==    still reachable: 0 bytes in 0 blocks
==2595397==         suppressed: 0 bytes in 0 blocks
==2595397==

This is because we're doing get_variable_attr() on the same variable
more than once and saving the value to our variables table.  Each
additional time we do so leaks the previous one.

This patch solves the issue by not getting the variable again if it's
already set in the table, and adds a test case to check if we're doing
get_variable() of any variety on the same variable more than once.

Signed-off-by: Peter Jones <pjones@redhat.com>

3 files changed, 48 insertions, 23 deletions

diff --git a/include/mock-variables.h b/include/mock-variables.h
index 3f282a68..9f276e63 100644
--- a/include/mock-variables.h
+++ b/include/mock-variables.h
@@ -122,6 +122,7 @@ typedef enum {
 	DELETE,
 	APPEND,
 	REPLACE,
+	GET,
 } mock_variable_op_t;
 
 static inline const char *
@@ -133,6 +134,7 @@ format_var_op(mock_variable_op_t op)
 		"DELETE",
 		"APPEND",
 		"REPLACE",
+		"GET",
 		NULL
 	};
 
diff --git a/mok.c b/mok.c
index 801379ee..7755eea9 100644
--- a/mok.c
+++ b/mok.c
@@ -828,30 +828,32 @@ EFI_STATUS import_one_mok_state(struct mok_state_variable *v,
 
 	dprint(L"importing mok state for \"%s\"\n", v->name);
 
-	efi_status = get_variable_attr(v->name,
-				       &v->data, &v->data_size,
-				       *v->guid, &attrs);
-	if (efi_status == EFI_NOT_FOUND) {
-		v->data = NULL;
-		v->data_size = 0;
-	} else if (EFI_ERROR(efi_status)) {
-		perror(L"Could not verify %s: %r\n", v->name,
-		       efi_status);
-		delete = TRUE;
-	} else {
-		if (!(attrs & v->yes_attr)) {
-			perror(L"Variable %s is missing attributes:\n",
-			       v->name);
-			perror(L"  0x%08x should have 0x%08x set.\n",
-			       attrs, v->yes_attr);
-			delete = TRUE;
-		}
-		if (attrs & v->no_attr) {
-			perror(L"Variable %s has incorrect attribute:\n",
-			       v->name);
-			perror(L"  0x%08x should not have 0x%08x set.\n",
-			       attrs, v->no_attr);
+	if (!v->data && !v->data_size) {
+		efi_status = get_variable_attr(v->name,
+					       &v->data, &v->data_size,
+					       *v->guid, &attrs);
+		if (efi_status == EFI_NOT_FOUND) {
+			v->data = NULL;
+			v->data_size = 0;
+		} else if (EFI_ERROR(efi_status)) {
+			perror(L"Could not verify %s: %r\n", v->name,
+			       efi_status);
 			delete = TRUE;
+		} else {
+			if (!(attrs & v->yes_attr)) {
+				perror(L"Variable %s is missing attributes:\n",
+				       v->name);
+				perror(L"  0x%08x should have 0x%08x set.\n",
+				       attrs, v->yes_attr);
+				delete = TRUE;
+			}
+			if (attrs & v->no_attr) {
+				perror(L"Variable %s has incorrect attribute:\n",
+				       v->name);
+				perror(L"  0x%08x should not have 0x%08x set.\n",
+				       attrs, v->no_attr);
+				delete = TRUE;
+			}
 		}
 	}
 	if (delete == TRUE) {
diff --git a/test-mok-mirror.c b/test-mok-mirror.c
index d7829843..3479ddf8 100644
--- a/test-mok-mirror.c
+++ b/test-mok-mirror.c
@@ -78,6 +78,20 @@ getvar_post(CHAR16 *name, EFI_GUID *guid,
 			printf("attrs:NULL\n");
 		printf("failed:%s\n", efi_strerror(*status));
 	}
+
+	if (!test_vars)
+		return;
+
+	for (UINTN i = 0; test_vars[i].name != NULL; i++) {
+		struct test_var *tv = &test_vars[i];
+
+		if (CompareGuid(&tv->guid, guid) != 0 ||
+		    StrCmp(tv->name, name) != 0)
+			continue;
+		tv->ops[tv->n_ops] = GET;
+		tv->results[tv->n_ops] = *status;
+		tv->n_ops += 1;
+	}
 }
 
 static int
@@ -201,6 +215,7 @@ test_mok_mirror_0(void)
 			struct mock_variable *var;
 			bool deleted;
 			bool created;
+			int gets = 0;
 
 			var = list_entry(pos, struct mock_variable, list);
 			if (CompareGuid(&tv->guid, &var->guid) != 0 ||
@@ -238,8 +253,14 @@ test_mok_mirror_0(void)
 					assert_goto(false, err,
 						    "No replace action should have been tested\n");
 					break;
+				case GET:
+					if (tv->results[j] == EFI_SUCCESS)
+						gets += 1;
+					break;
 				}
 			}
+			assert_goto(gets == 0 || gets == 1, err,
+				    "Variable should not be read %d times.\n", gets);
 		}
 		if (tv->must_be_present) {
 			assert_goto(found == true, err,