[PATCH 3/4] virt-aa-helper: Purge profile if corrupted

[Ioanna Alifieraki]

This commit aims to address the bug reported in [1] and [2].
If the profile is corrupted (0-size) the VM cannot be launched.
To overcome this  check if the profile exists and if it has 0 size
remove it and create it again.

[1] https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=890084
[2] https://bugs.launchpad.net/bugs/1927519

Signed-off-by: Ioanna Alifieraki <ioanna-maria.alifieraki at canonical.com>
---
 src/security/virt-aa-helper.c | 23 +++++++++++++++++++++++
 1 file changed, 23 insertions(+)

diff --git a/src/security/virt-aa-helper.c b/src/security/virt-aa-helper.c
index 5ec0fb8807..5e13b29053 100644
--- a/src/security/virt-aa-helper.c
+++ b/src/security/virt-aa-helper.c
@@ -1489,6 +1489,7 @@ main(int argc, char **argv)
     int rc = -1;
     char *profile = NULL;
     char *include_file = NULL;
+    off_t size;
 
     if (virGettextInitialize() < 0 ||
         virErrorInitialize() < 0) {
@@ -1534,6 +1535,28 @@ main(int argc, char **argv)
         if (ctl->cmd == 'c' && virFileExists(profile))
             vah_error(ctl, 1, _("profile exists"));
 
+        /*
+         * Rare cases can leave corrupted empty files behind breaking
+         * the guest. An empty file is never correct as virt-aa-helper
+         * would at least add the basic rules, therefore clean this up
+         * for a proper refresh.
+         */
+
+        if (virFileExists(profile)) {
+            size = virFileLength(profile, -1);
+            if (size == 0) {
+                char temp;
+                vah_warning(_("Profile of 0 size detected, will attempt to remove and re-create it"));
+                temp = ctl->cmd;
+                ctl->cmd = 'P';
+                if ((rc = remove_profile(ctl, profile, include_file)) != 0)
+                    vah_error(ctl, 1, _("could not remove corrupted profile"));
+                ctl->cmd = temp;
+                if ((rc = create_profile(ctl, profile, include_file)) != 0)
+                    vah_error(ctl, 1, _("could not re-create profile"));
+            }
+        }
+
         if (ctl->append && ctl->newfile) {
             if (vah_add_file(&buf, ctl->newfile, "rwk") != 0)
                 goto cleanup;
-- 
2.17.1