root/include/net/scm.h

INCLUDED FROM

DEFINITIONS

1. unix_get_peersec_dgram
2. unix_get_peersec_dgram
3. scm_destroy
4. scm_send
5. scm_passec
6. scm_passec
7. scm_recv

#ifndef __LINUX_NET_SCM_H
#define __LINUX_NET_SCM_H

#include <linux/limits.h>
#include <linux/net.h>
#include <linux/security.h>
#include <linux/pid.h>
#include <linux/nsproxy.h>

/* Well, we should have at least one descriptor open
 * to accept passed FDs 8)
 */
#define SCM_MAX_FD      255

struct scm_fp_list
{
        int             count;
        struct file     *fp[SCM_MAX_FD];
};

struct scm_cookie
{
        struct ucred            creds;          /* Skb credentials      */
        struct scm_fp_list      *fp;            /* Passed files         */
#ifdef CONFIG_SECURITY_NETWORK
        u32                     secid;          /* Passed security ID   */
#endif
        unsigned long           seq;            /* Connection seqno     */
};

extern void scm_detach_fds(struct msghdr *msg, struct scm_cookie *scm);
extern void scm_detach_fds_compat(struct msghdr *msg, struct scm_cookie *scm);
extern int __scm_send(struct socket *sock, struct msghdr *msg, struct scm_cookie *scm);
extern void __scm_destroy(struct scm_cookie *scm);
extern struct scm_fp_list * scm_fp_dup(struct scm_fp_list *fpl);

#ifdef CONFIG_SECURITY_NETWORK
static __inline__ void unix_get_peersec_dgram(struct socket *sock, struct scm_cookie *scm)
{
        security_socket_getpeersec_dgram(sock, NULL, &scm->secid);
}
#else
static __inline__ void unix_get_peersec_dgram(struct socket *sock, struct scm_cookie *scm)
{ }
#endif /* CONFIG_SECURITY_NETWORK */

static __inline__ void scm_destroy(struct scm_cookie *scm)
{
        if (scm && scm->fp)
                __scm_destroy(scm);
}

static __inline__ int scm_send(struct socket *sock, struct msghdr *msg,
                               struct scm_cookie *scm)
{
        struct task_struct *p = current;
        scm->creds.uid = p->uid;
        scm->creds.gid = p->gid;
        scm->creds.pid = task_tgid_vnr(p);
        scm->fp = NULL;
        scm->seq = 0;
        unix_get_peersec_dgram(sock, scm);
        if (msg->msg_controllen <= 0)
                return 0;
        return __scm_send(sock, msg, scm);
}

#ifdef CONFIG_SECURITY_NETWORK
static inline void scm_passec(struct socket *sock, struct msghdr *msg, struct scm_cookie *scm)
{
        char *secdata;
        u32 seclen;
        int err;

        if (test_bit(SOCK_PASSSEC, &sock->flags)) {
                err = security_secid_to_secctx(scm->secid, &secdata, &seclen);

                if (!err) {
                        put_cmsg(msg, SOL_SOCKET, SCM_SECURITY, seclen, secdata);
                        security_release_secctx(secdata, seclen);
                }
        }
}
#else
static inline void scm_passec(struct socket *sock, struct msghdr *msg, struct scm_cookie *scm)
{ }
#endif /* CONFIG_SECURITY_NETWORK */

static __inline__ void scm_recv(struct socket *sock, struct msghdr *msg,
                                struct scm_cookie *scm, int flags)
{
        if (!msg->msg_control)
        {
                if (test_bit(SOCK_PASSCRED, &sock->flags) || scm->fp)
                        msg->msg_flags |= MSG_CTRUNC;
                scm_destroy(scm);
                return;
        }

        if (test_bit(SOCK_PASSCRED, &sock->flags))
                put_cmsg(msg, SOL_SOCKET, SCM_CREDENTIALS, sizeof(scm->creds), &scm->creds);

        scm_passec(sock, msg, scm);

        if (!scm->fp)
                return;
        
        scm_detach_fds(msg, scm);
}


#endif /* __LINUX_NET_SCM_H */