On Fri, Jan 26, 2024 at 1:45 PM Ondrej Mosnacek <omosnace@xxxxxxxxxx> wrote:
>
> For these hooks the true "neutral" value is -EOPNOTSUPP, which is
> currently what is returned when no LSM provides this hook and what LSMs
> return when there is no security context set on the socket. Correct the
> value in <linux/lsm_hooks.h> and adjust the dispatch functions in
> security/security.c to avoid issues when the BPF LSM is enabled.
>
> Fixes: 98e828a0650f ("security: Refactor declaration of LSM hooks")
> Signed-off-by: Ondrej Mosnacek <omosnace@xxxxxxxxxx>
> ---
> include/linux/lsm_hook_defs.h | 4 ++--
> security/security.c | 31 +++++++++++++++++++++++++++----
> 2 files changed, 29 insertions(+), 6 deletions(-)
>
> diff --git a/include/linux/lsm_hook_defs.h b/include/linux/lsm_hook_defs.h
> index 185924c56378..76458b6d53da 100644
> --- a/include/linux/lsm_hook_defs.h
> +++ b/include/linux/lsm_hook_defs.h
> @@ -315,9 +315,9 @@ LSM_HOOK(int, 0, socket_getsockopt, struct socket *sock, int level, int optname)
> LSM_HOOK(int, 0, socket_setsockopt, struct socket *sock, int level, int optname)
> LSM_HOOK(int, 0, socket_shutdown, struct socket *sock, int how)
> LSM_HOOK(int, 0, socket_sock_rcv_skb, struct sock *sk, struct sk_buff *skb)
> -LSM_HOOK(int, 0, socket_getpeersec_stream, struct socket *sock,
> +LSM_HOOK(int, -ENOPROTOOPT, socket_getpeersec_stream, struct socket *sock,
> sockptr_t optval, sockptr_t optlen, unsigned int len)
> -LSM_HOOK(int, 0, socket_getpeersec_dgram, struct socket *sock,
> +LSM_HOOK(int, -ENOPROTOOPT, socket_getpeersec_dgram, struct socket *sock,
> struct sk_buff *skb, u32 *secid)
> LSM_HOOK(int, 0, sk_alloc_security, struct sock *sk, int family, gfp_t priority)
> LSM_HOOK(void, LSM_RET_VOID, sk_free_security, struct sock *sk)
> diff --git a/security/security.c b/security/security.c
> index 6196ccaba433..3aaad75c9ce8 100644
> --- a/security/security.c
> +++ b/security/security.c
> @@ -4624,8 +4624,20 @@ EXPORT_SYMBOL(security_sock_rcv_skb);
> int security_socket_getpeersec_stream(struct socket *sock, sockptr_t optval,
> sockptr_t optlen, unsigned int len)
> {
> - return call_int_hook(socket_getpeersec_stream, -ENOPROTOOPT, sock,
> - optval, optlen, len);
> + struct security_hook_list *hp;
> + int rc;
> +
> + /*
> + * Only one module will provide a security context.
> + */
> + hlist_for_each_entry(hp, &security_hook_heads.socket_getpeersec_stream,
> + list) {
> + rc = hp->hook.socket_getpeersec_stream(sock, optval, optlen,
> + len);
> + if (rc != LSM_RET_DEFAULT(socket_getpeersec_stream))
> + return rc;
> + }
> + return LSM_RET_DEFAULT(socket_getpeersec_stream);
> }
I'm beginning to wonder if we shouldn't update call_int_hook() so that
it works for LSM_RET_DEFAULT() instead of assuming a zero/0 return
value. Thoughts?
--
paul-moore.com
