Hi Juergen,
On 20/07/2023 16:08, Juergen Gross wrote:
In case get_spec_node() is being called for a special node starting
with '@' it won't set *canonical_name. This can result in a crash of
xenstored due to dereferencing the uninitialized name in
fire_watches().
This is no security issue as it requires either a privileged caller or
ownership of the special node in question by an unprivileged caller
(which is questionable, as this would make the owner privileged in some
way).
Fixes: d6bb63924fc2 ("tools/xenstore: introduce dummy nodes for special watch
paths")
Signed-off-by: Juergen Gross <jgr...@suse.com>
---
tools/xenstore/xenstored_core.c | 5 ++++-
1 file changed, 4 insertions(+), 1 deletion(-)
diff --git a/tools/xenstore/xenstored_core.c b/tools/xenstore/xenstored_core.c
index a1d3047e48..790c403904 100644
--- a/tools/xenstore/xenstored_core.c
+++ b/tools/xenstore/xenstored_core.c
@@ -1252,8 +1252,11 @@ static struct node *get_spec_node(struct connection
*conn, const void *ctx,
const char *name, char **canonical_name,
unsigned int perm)
{
- if (name[0] == '@')
+ if (name[0] == '@') {
+ if (canonical_name)
+ *canonical_name = (char *)name;
eww. Let's not continue the bad practice in Xenstored to cast away the
const. I will have a look to remove the const and you can rebase your
patch on top.
Cheers,
--
Julien Grall