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SubjectRe: [PATCH 3/7] SELinux: Stub in copy-up handling
Date
On Wednesday, November 05, 2014 03:42:48 PM David Howells wrote:
> Provide stubs for union/overlay copy-up handling. The xattr copy up stub
> discards lower SELinux xattrs rather than letting them be copied up so that
> the security label on the copy doesn't get corrupted.
>
> Signed-off-by: David Howells <dhowells@redhat.com>
> ---
>
> security/selinux/hooks.c | 15 +++++++++++++++
> 1 file changed, 15 insertions(+)
>
> diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c
> index e66314138b38..f3fe7dbbf741 100644
> --- a/security/selinux/hooks.c
> +++ b/security/selinux/hooks.c
> @@ -3142,6 +3142,19 @@ static void selinux_inode_getsecid(const struct inode
> *inode, u32 *secid) *secid = isec->sid;
> }
>
> +static int selinux_inode_copy_up(struct dentry *src, struct dentry *dst)
> +{
> + return 0;
> +}
> +
> +static int selinux_inode_copy_up_xattr(struct dentry *src, struct dentry
> ...*dst,
> + const char *name, void *value, size_t *size)
> +{
> + if (strcmp(name, XATTR_NAME_SELINUX) == 0)
> + return 1; /* Discard */

I understand that this is just a stub, but I we need to discuss this at some
point and I figure better in this patch than elsewhere where it might get
lost.

For the docker, context= mount use case (similar to SELinux/sVirt) dropping
the SELinux xattr is probably an okay behavior. However, I would expect that
ultimately this is something we would want to control by policy and/or the
presence of a context= label.

> + return 0;
> +}
> +
> /* file security operations */
>
> static int selinux_revalidate_file_permission(struct file *file, int mask)
> @@ -5868,6 +5881,8 @@ static struct security_operations selinux_ops = {
> .inode_setsecurity = selinux_inode_setsecurity,
> .inode_listsecurity = selinux_inode_listsecurity,
> .inode_getsecid = selinux_inode_getsecid,
> + .inode_copy_up = selinux_inode_copy_up,
> + .inode_copy_up_xattr = selinux_inode_copy_up_xattr,
>
> .file_permission = selinux_file_permission,
> .file_alloc_security = selinux_file_alloc_security,
>
> --
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--
paul moore
www.paul-moore.com



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