Re: [PATCH RFC 13/15] LSM: restrict security_cred_getsecid() to a single LSM

On Jun 21, 2025 Casey Schaufler <[email protected]> wrote:
> 
> The LSM hook security_cred_getsecid() provides a single secid
> that is only used by the binder driver. Provide the first value
> available, and abandon any other hooks.
> 
> Signed-off-by: Casey Schaufler <[email protected]>
> ---
>  security/security.c | 7 ++++++-
>  1 file changed, 6 insertions(+), 1 deletion(-)
> 
> diff --git a/security/security.c b/security/security.c
> index dd167a872248..409b1cb10d35 100644
> --- a/security/security.c
> +++ b/security/security.c
> @@ -2740,8 +2740,13 @@ void security_transfer_creds(struct cred *new, const struct cred *old)
>   */
>  void security_cred_getsecid(const struct cred *c, u32 *secid)
>  {
> +	struct lsm_static_call *scall;
> +
>  	*secid = 0;
> -	call_void_hook(cred_getsecid, c, secid);
> +	lsm_for_each_hook(scall, cred_getsecid) {
> +		scall->hl->hook.cred_getsecid(c, secid);
> +		break;
> +	}
>  }
>  EXPORT_SYMBOL(security_cred_getsecid);

Another case of "would this be painful to do at registration time?"

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