lsm: twek apparmor_process_label_get()

Fixes: Coverity 1473189 Fixes: Coverity 1473190 Fixes: 47f4914d ("apparmor: prefer /proc/.../attr/apparmor/current over legacy interface") Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>

lsm: twek apparmor_process_label_get()
ba9055c9 · Christian Brauner · 8b145a87 · ba9055c9
Unverified Commit ba9055c9 authored Feb 19, 2021 by Christian Brauner
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Showing with 10 additions and 4 deletions

apparmor.c src/lxc/lsm/apparmor.c +10 -4

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--- a/src/lxc/lsm/apparmor.c
+++ b/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)