/* SPDX-License-Identifier: GPL-2.0 */
#ifndef __LINUX_NET_SCM_H
#define __LINUX_NET_SCM_H

#include <linux/limits.h>
#include <linux/net.h>
#include <linux/cred.h>
#include <linux/file.h>
#include <linux/security.h>
#include <linux/pid.h>
#include <linux/nsproxy.h>
#include <linux/sched/signal.h>
#include <net/compat.h>

/* Well, we should have at least one descriptor open
 * to accept passed FDs 8)
 */
#define SCM_MAX_FD      253

struct scm_creds {
        u32     pid;
        kuid_t  uid;
        kgid_t  gid;
};

#ifdef CONFIG_UNIX
struct unix_edge;
#endif

struct scm_fp_list {
        short                   count;
        short                   count_unix;
        short                   max;
#ifdef CONFIG_UNIX
        bool                    inflight;
        bool                    dead;
        struct list_head        vertices;
        struct unix_edge        *edges;
#endif
        struct user_struct      *user;
        struct file             *fp[SCM_MAX_FD];
};

struct scm_cookie {
        struct pid              *pid;           /* Skb credentials */
        struct scm_fp_list      *fp;            /* Passed files         */
        struct scm_creds        creds;          /* Skb credentials      */
#ifdef CONFIG_SECURITY_NETWORK
        u32                     secid;          /* Passed security ID   */
#endif
};

void scm_detach_fds(struct msghdr *msg, struct scm_cookie *scm);
void scm_detach_fds_compat(struct msghdr *msg, struct scm_cookie *scm);
int __scm_send(struct socket *sock, struct msghdr *msg, struct scm_cookie *scm);
void __scm_destroy(struct scm_cookie *scm);
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_set_cred(struct scm_cookie *scm,
                                    struct pid *pid, kuid_t uid, kgid_t gid)
{
        scm->pid = get_pid(pid);
        scm->creds.pid = pid_vnr(pid);
        scm->creds.uid = uid;
        scm->creds.gid = gid;
}

static __inline__ void scm_destroy_cred(struct scm_cookie *scm)
{
        put_pid(scm->pid);
        scm->pid = NULL;
}

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

static __inline__ int scm_send(struct socket *sock, struct msghdr *msg,
                               struct scm_cookie *scm, bool forcecreds)
{
        memset(scm, 0, sizeof(*scm));
        scm->creds.uid = INVALID_UID;
        scm->creds.gid = INVALID_GID;
        if (forcecreds)
                scm_set_cred(scm, task_tgid(current), current_uid(), current_gid());
        unix_get_peersec_dgram(sock, scm);
        if (msg->msg_controllen <= 0)
                return 0;
        return __scm_send(sock, msg, scm);
}

void scm_recv(struct socket *sock, struct msghdr *msg,
              struct scm_cookie *scm, int flags);
void scm_recv_unix(struct socket *sock, struct msghdr *msg,
                   struct scm_cookie *scm, int flags);

static inline int scm_recv_one_fd(struct file *f, int __user *ufd,
                                  unsigned int flags)
{
        if (!ufd)
                return -EFAULT;
        return receive_fd(f, ufd, flags);
}

#endif /* __LINUX_NET_SCM_H */