[PATCH v2] selinux: only filter copy-up xattrs following initialization

David Disseldorp
2024-02-02T06:41:02Z

Extended attribute copy-up functionality added via 19472b69d639d
("selinux: Implementation for inode_copy_up_xattr() hook") sees
"security.selinux" contexts dropped, instead relying on contexts
applied via the inode_copy_up() hook.

When copy-up takes place during early boot, prior to selinux
initialization / policy load, the context stripping can be unwanted
and unexpected.

With this change, filtering of "security.selinux" xattrs will only occur
after selinux initialization.

Signed-off-by: David Disseldorp <ddiss@suse.de>
---
Changes since v1:
- drop RFC
- slightly rework commit message and preceeding comment

security/selinux/hooks.c | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c
index a6bf90ace84c7..b17247d66b24f 100644
--- a/security/selinux/hooks.c
+++ b/security/selinux/hooks.c
@@ -3534,9 +3534,10 @@ static int selinux_inode_copy_up_xattr(const char *name)
{
/* The copy_up hook above sets the initial context on an inode, but we
* don't then want to overwrite it by blindly copying all the lower
- * xattrs up. Instead, we have to filter out SELinux-related xattrs.
+ * xattrs up. Instead, filter out SELinux-related xattrs following
+ * policy load.
*/
- if (strcmp(name, XATTR_NAME_SELINUX) == 0)
+ if (selinux_initialized() && strcmp(name, XATTR_NAME_SELINUX) == 0)
return 1; /* Discard */
/*
* Any other attribute apart from SELINUX is not claimed, supported
--
2.43.0