tests: fix a memory leak

2021-10-12T12:04:30.8634717Z ==13254==ERROR: LeakSanitizer: detected memory leaks
2021-10-12T12:04:30.8635500Z
2021-10-12T12:04:30.8636953Z Direct leak of 823 byte(s) in 1 object(s) allocated from:
2021-10-12T12:04:30.8638969Z     #0 0x7ff702a82bc8 in malloc (/lib/x86_64-linux-gnu/libasan.so.5+0x10dbc8)
2021-10-12T12:04:30.8640457Z     #1 0x559506e3b99c in write_test_policy_from_file /home/runner/work/selinux/selinux/libsemanage/tests/utilities.c:112
2021-10-12T12:04:30.8642027Z     #2 0x559506e1ddba in iface_test_init /home/runner/work/selinux/selinux/libsemanage/tests/test_iface.c:73
2021-10-12T12:04:30.8643708Z     #3 0x7ff702769e0d  (/lib/x86_64-linux-gnu/libcunit.so.1+0x3e0d)

Signed-off-by: Evgeny Vereshchagin <[email protected]>

Author: evverx

libsemanage/tests/utilities.c

@@ -99,10 +99,11 @@ int write_test_policy_from_file(const char *filename) {
 	char *buf = NULL;
 	size_t len = 0;
 	FILE *fptr = fopen(filename, "rb");
+	int ret = -1;
 
 	if (!fptr) {
 		perror("fopen");
-		return -1;
+		return ret;
 	}
 
 	fseek(fptr, 0, SEEK_END);
@@ -114,13 +115,15 @@ int write_test_policy_from_file(const char *filename) {
 	if (!buf) {
 		perror("malloc");
 		fclose(fptr);
-		return -1;
+		return ret;
 	}
 
 	fread(buf, len, 1, fptr);
 	fclose(fptr);
 
-	return write_test_policy(buf, len);
+	ret = write_test_policy(buf, len);
+	free(buf);
+	return ret;
 }
 
 int write_test_policy_src(unsigned char *data, unsigned int data_len) {