Merge pull request #3687 from brauner/2021-02-19/fixes

src/lxc/file_utils.c

@@ -455,12 +455,15 @@ int fd_to_buf(int fd, char **buf, size_t *length)
 
 		bytes_read = lxc_read_nointr(fd, chunk, sizeof(chunk));
 		if (bytes_read < 0)
-			return 0;
+			return -errno;
 
 		if (!bytes_read)
 			break;
 
-		copy = must_realloc(old, (*length + bytes_read) * sizeof(*old));
+		copy = realloc(old, (*length + bytes_read) * sizeof(*old));
+		if (!copy)
+			return ret_errno(ENOMEM);
+
 		memcpy(copy + *length, chunk, bytes_read);
 		*length += bytes_read;
 	}

src/lxc/lsm/apparmor.c

@@ -430,15 +430,21 @@ error:
 
 static char *apparmor_process_label_get(struct lsm_ops *ops, pid_t pid)
 {
-	int label_fd;
+	__do_close int fd_label = -EBADF;
 	__do_free char *label = NULL;
+	int ret;
 	size_t len;
 
-	label_fd = __apparmor_process_label_open(ops, pid, O_RDONLY, false);
-	if (label_fd < 0)
+	fd_label = __apparmor_process_label_open(ops, pid, O_RDONLY, false);
+	if (fd_label < 0)
+		return NULL;
+
+	ret = fd_to_buf(fd_label, &label, &len);
+	if (ret < 0)
 		return NULL;
 
-	fd_to_buf(label_fd, &label, &len);
+	if (len == 0)
+		return NULL;
 
 	len = strcspn(label, "\n \t");
 	if (len)