Subject: Re: [RFC v3 02/10] Revert "lsm: Remove the socket_post_accept() hook"

From: Paul Moore <[email-masked]>
Date: Tue, 3 May 2011 18:02:34 -0400

On Tuesday, May 03, 2011 10:24:15 AM Samir Bellabes wrote:
> snet needs to reintroduce this hook, as it was designed to be: a hook for
> updating security informations on objects.

Looking at this and 5/10 again, it seems that you should be able to do what 
you need with the sock_graft() hook.  Am I missing something?

My apologies if we've already discussed this approach previously ...

> Originally, This was a direct revert of commit
> 8651d5c0b1f874c5b8307ae2b858bc40f9f02482.
> 
> But from the comment of Tetsuo Handa <[email-masked]> :
> > Please move security_socket_post_accept() to before fd_install().
> > Otherwise, other threads which share fd tables can use
> > security-informations-not-yet-updated accept()ed sockets.
> 
> Signed-off-by: Samir Bellabes <[email-masked]>
> Acked-by: Serge Hallyn <[email-masked]>
> 
> snet needs to reintroduce this hook, as it was designed to be: a hook for
> updating security informations on objects.
> 
> Signed-off-by: Samir Bellabes <[email-masked]>
> ---
>  include/linux/security.h |   13 +++++++++++++
>  net/socket.c             |    2 ++
>  security/capability.c    |    5 +++++
>  security/security.c      |    5 +++++
>  4 files changed, 25 insertions(+), 0 deletions(-)
> 
> diff --git a/include/linux/security.h b/include/linux/security.h
> index da0d59e..02effe5 100644
> --- a/include/linux/security.h
> +++ b/include/linux/security.h
> @@ -875,6 +875,11 @@ static inline void security_free_mnt_opts(struct
> security_mnt_opts *opts) *	@sock contains the listening socket structure.
>   *	@newsock contains the newly created server socket for connection.
>   *	Return 0 if permission is granted.
> + * @socket_post_accept:
> + *	This hook allows a security module to copy security
> + *	information into the newly created socket's inode.
> + *	@sock contains the listening socket structure.
> + *	@newsock contains the newly created server socket for connection.
>   * @socket_sendmsg:
>   *	Check permission before transmitting a message to another socket.
>   *	@sock contains the socket structure.
> @@ -1587,6 +1592,8 @@ struct security_operations {
>  			       struct sockaddr *address, int addrlen);
>  	int (*socket_listen) (struct socket *sock, int backlog);
>  	int (*socket_accept) (struct socket *sock, struct socket *newsock);
> +	void (*socket_post_accept) (struct socket *sock,
> +				    struct socket *newsock);
>  	int (*socket_sendmsg) (struct socket *sock,
>  			       struct msghdr *msg, int size);
>  	int (*socket_recvmsg) (struct socket *sock,
> @@ -2555,6 +2562,7 @@ int security_socket_bind(struct socket *sock, struct
> sockaddr *address, int addr int security_socket_connect(struct socket
> *sock, struct sockaddr *address, int addrlen); int
> security_socket_listen(struct socket *sock, int backlog);
>  int security_socket_accept(struct socket *sock, struct socket *newsock);
> +void security_socket_post_accept(struct socket *sock, struct socket
> *newsock); int security_socket_sendmsg(struct socket *sock, struct msghdr
> *msg, int size); int security_socket_recvmsg(struct socket *sock, struct
> msghdr *msg, int size, int flags);
> @@ -2640,6 +2648,11 @@ static inline int security_socket_accept(struct
> socket *sock, return 0;
>  }
> 
> +static inline void security_socket_post_accept(struct socket *sock,
> +					       struct socket *newsock)
> +{
> +}
> +
>  static inline int security_socket_sendmsg(struct socket *sock,
>  					  struct msghdr *msg, int size)
>  {
> diff --git a/net/socket.c b/net/socket.c
> index d588e9e..7807904 100644
> --- a/net/socket.c
> +++ b/net/socket.c
> @@ -1535,6 +1535,8 @@ SYSCALL_DEFINE4(accept4, int, fd, struct sockaddr
> __user *, upeer_sockaddr, goto out_fd;
>  	}
> 
> +	security_socket_post_accept(sock, newsock);
> +
>  	/* File flags are not inherited via accept() unlike another OSes. */
> 
>  	fd_install(newfd, newfile);
> diff --git a/security/capability.c b/security/capability.c
> index 1f8bbe2..da68c60 100644
> --- a/security/capability.c
> +++ b/security/capability.c
> @@ -593,6 +593,10 @@ static int cap_socket_accept(struct socket *sock,
> struct socket *newsock) return 0;
>  }
> 
> +static void cap_socket_post_accept(struct socket *sock, struct socket
> *newsock) +{
> +}
> +
>  static int cap_socket_sendmsg(struct socket *sock, struct msghdr *msg, int
> size) {
>  	return 0;
> @@ -1022,6 +1026,7 @@ void __init security_fixup_ops(struct
> security_operations *ops) set_to_cap_if_null(ops, socket_connect);
>  	set_to_cap_if_null(ops, socket_listen);
>  	set_to_cap_if_null(ops, socket_accept);
> +	set_to_cap_if_null(ops, socket_post_accept);
>  	set_to_cap_if_null(ops, socket_sendmsg);
>  	set_to_cap_if_null(ops, socket_recvmsg);
>  	set_to_cap_if_null(ops, socket_getsockname);
> diff --git a/security/security.c b/security/security.c
> index 84187d8..eda2b75 100644
> --- a/security/security.c
> +++ b/security/security.c
> @@ -1038,6 +1038,11 @@ int security_socket_accept(struct socket *sock,
> struct socket *newsock) return security_ops->socket_accept(sock, newsock);
>  }
> 
> +void security_socket_post_accept(struct socket *sock, struct socket
> *newsock) +{
> +	security_ops->socket_post_accept(sock, newsock);
> +}
> +
>  int security_socket_sendmsg(struct socket *sock, struct msghdr *msg, int
> size) {
>  	return security_ops->socket_sendmsg(sock, msg, size);

--
paul moore
linux @ hp