[xen staging] tools/xenstore: call remove_domid_from_perm() for special nodes

[patchbot@xxxxxxx]

commit 0751a75e3996cf6efd3925a90b4776660d8df2bc
Author:     Juergen Gross <jgross@xxxxxxxx>
AuthorDate: Wed Nov 2 12:08:22 2022 +0100
Commit:     Jan Beulich <jbeulich@xxxxxxxx>
CommitDate: Wed Nov 2 12:08:22 2022 +0100

    tools/xenstore: call remove_domid_from_perm() for special nodes
    
    When destroying a domain, any stale permissions of the domain must be
    removed from the special nodes "@...", too. This was not done in the
    fix for XSA-322.
    
    Fixes: 496306324d8d ("tools/xenstore: revoke access rights for removed 
domains")
    Signed-off-by: Juergen Gross <jgross@xxxxxxxx>
    Reviewed-by: Julien Grall <jgrall@xxxxxxxxxx>
    Release-acked-by: Henry Wang <Henry.Wang@xxxxxxx>
---
 tools/xenstore/xenstored_domain.c | 24 ++++++++++++++++++++++++
 1 file changed, 24 insertions(+)

diff --git a/tools/xenstore/xenstored_domain.c 
b/tools/xenstore/xenstored_domain.c
index 84b7817cd5..aa86892fed 100644
--- a/tools/xenstore/xenstored_domain.c
+++ b/tools/xenstore/xenstored_domain.c
@@ -227,6 +227,27 @@ static void unmap_interface(void *interface)
        xengnttab_unmap(*xgt_handle, interface, 1);
 }
 
+static void remove_domid_from_perm(struct node_perms *perms,
+                                  struct domain *domain)
+{
+       unsigned int cur, new;
+
+       if (perms->p[0].id == domain->domid)
+               perms->p[0].id = priv_domid;
+
+       for (cur = new = 1; cur < perms->num; cur++) {
+               if (perms->p[cur].id == domain->domid)
+                       continue;
+
+               if (new != cur)
+                       perms->p[new] = perms->p[cur];
+
+               new++;
+       }
+
+       perms->num = new;
+}
+
 static int domain_tree_remove_sub(const void *ctx, struct connection *conn,
                                  struct node *node, void *arg)
 {
@@ -277,6 +298,9 @@ static void domain_tree_remove(struct domain *domain)
                        syslog(LOG_ERR,
                               "error when looking for orphaned nodes\n");
        }
+
+       remove_domid_from_perm(&dom_release_perms, domain);
+       remove_domid_from_perm(&dom_introduce_perms, domain);
 }
 
 static int destroy_domain(void *_domain)
--
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