Re: [PATCH 1/1] selinux: add the processing of the failure of avc_add_xperms_decision()

[Stephen Smalley]

On Wed, Aug 7, 2024 at 5:02 AM <thunder.leizhen@xxxxxxxxxxxxxxx> wrote:
>
> From: Zhen Lei <thunder.leizhen@xxxxxxxxxx>
>
> When avc_add_xperms_decision() fails, the information recorded by the new
> avc node is incomplete. In this case, the new avc node should be released
> instead of replacing the old avc node.
>
> Fixes: fa1aa143ac4a ("selinux: extended permissions for ioctls")
> Suggested-by: Stephen Smalley <stephen.smalley.work@xxxxxxxxx>
> Signed-off-by: Zhen Lei <thunder.leizhen@xxxxxxxxxx>

Acked-by: Stephen Smalley <stephen.smalley.work@xxxxxxxxx>

> ---
>  security/selinux/avc.c | 6 +++++-
>  1 file changed, 5 insertions(+), 1 deletion(-)
>
> diff --git a/security/selinux/avc.c b/security/selinux/avc.c
> index 7087cd2b802d8d8..b49c44869dc4627 100644
> --- a/security/selinux/avc.c
> +++ b/security/selinux/avc.c
> @@ -907,7 +907,11 @@ static int avc_update_node(u32 event, u32 perms, u8 driver, u8 xperm, u32 ssid,
>                 node->ae.avd.auditdeny &= ~perms;
>                 break;
>         case AVC_CALLBACK_ADD_XPERMS:
> -               avc_add_xperms_decision(node, xpd);
> +               rc = avc_add_xperms_decision(node, xpd);
> +               if (rc) {
> +                       avc_node_kill(node);
> +                       goto out_unlock;
> +               }
>                 break;
>         }
>         avc_node_replace(node, orig);
> --
> 2.34.1
>