Check success of mallocs + assign buf to NULL after free + moved free of buf under loop

- `malloc()` now gets checked for success. If they fail we goto cleanup.
- `buf` now gets assigned to `NULL` after being freed.
- `free()` of `buf` got moved immediately under loop that uses it.

Author: s.hasert

src/ltsmc.c

@@ -494,6 +494,10 @@ int main(int argc, char *argv[])
 		}
 
 		char* buf = malloc(TSM_BUF_LENGTH);
+		if (!buf) {
+			goto cleanup_tsm;
+		}
+
 		size_t size;
 		do {
 			size = fread(buf, 1, TSM_BUF_LENGTH, stdin);
@@ -511,16 +515,16 @@ int main(int argc, char *argv[])
 			}
 		} while (!feof(stdin));
 
+		if (buf) free(buf);
+		buf = NULL;
+
 		rc = tsm_fclose(&session);
 		if (rc)
 			CT_ERROR(errno, "tsm_fclose failed");
 
-		free(buf);
-
 		goto cleanup_tsm;
 	}
 
-
 	session.progress = progress_callback;
 
 	rc = tsm_connect(&login, &session);