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/*

 * linux/net/sunrpc/rpcauth_unix.c

 *

 * UNIX-style authentication; no AUTH_SHORT support

 *

 * Copyright (C) 1996, Olaf Kirch <okir@monad.swb.de>

 */

#include <linux/types.h>

#include <linux/slab.h>

#include <linux/socket.h>

#include <linux/in.h>

#include <linux/sunrpc/clnt.h>

#include <linux/sunrpc/auth.h>

#define NFS_NGROUPS     16

struct unx_cred {

        struct rpc_cred         uc_base;

        uid_t                   uc_fsuid;

        gid_t                   uc_gid, uc_fsgid;

        gid_t                   uc_gids[NFS_NGROUPS];

};

#define uc_uid                  uc_base.cr_uid

#define uc_count                uc_base.cr_count

#define uc_flags                uc_base.cr_flags

#define uc_expire               uc_base.cr_expire

#define UNX_CRED_EXPIRE         (60 * HZ)

#define UNX_WRITESLACK          (21 + (UNX_MAXNODENAME >> 2))

#ifdef RPC_DEBUG

# define RPCDBG_FACILITY        RPCDBG_AUTH

#endif

static struct rpc_credops       unix_credops;

static struct rpc_auth *

unx_create(struct rpc_clnt *clnt)

{

        struct rpc_auth *auth;

        dprintk("RPC: creating UNIX authenticator for client %p\n", clnt);

        if (!(auth = (struct rpc_auth *) rpc_allocate(0, sizeof(*auth))))

                return NULL;

        auth->au_cslack = UNX_WRITESLACK;

        auth->au_rslack = 2;    /* assume AUTH_NULL verf */

        auth->au_expire = UNX_CRED_EXPIRE;

        auth->au_ops = &authunix_ops;

        rpcauth_init_credcache(auth);

        return auth;

}

static void

unx_destroy(struct rpc_auth *auth)

{

        dprintk("RPC: destroying UNIX authenticator %p\n", auth);

        rpcauth_free_credcache(auth);

        rpc_free(auth);

}

static struct rpc_cred *

unx_create_cred(int flags)

{

        struct unx_cred *cred;

        int             i;

        dprintk("RPC:      allocating UNIX cred for uid %d gid %d\n",

                                current->uid, current->gid);

        if (!(cred = (struct unx_cred *) rpc_allocate(flags, sizeof(*cred))))

                return NULL;

        atomic_set(&cred->uc_count, 0);

        cred->uc_flags = RPCAUTH_CRED_UPTODATE;

        if (flags & RPC_TASK_ROOTCREDS) {

                cred->uc_uid = cred->uc_fsuid = 0;

                cred->uc_gid = cred->uc_fsgid = 0;

                cred->uc_gids[0] = NOGROUP;

        } else {

                int groups = current->ngroups;

                if (groups > NFS_NGROUPS)

                        groups = NFS_NGROUPS;

                cred->uc_uid = current->uid;

                cred->uc_gid = current->gid;

                cred->uc_fsuid = current->fsuid;

                cred->uc_fsgid = current->fsgid;

                for (i = 0; i < groups; i++)

                        cred->uc_gids[i] = (gid_t) current->groups[i];

                if (i < NFS_NGROUPS)

                  cred->uc_gids[i] = NOGROUP;

        }

        cred->uc_base.cr_ops = &unix_credops;

        return (struct rpc_cred *) cred;

}

struct rpc_cred *

authunix_fake_cred(struct rpc_task *task, uid_t uid, gid_t gid)

{

        struct unx_cred *cred;

        dprintk("RPC:      allocating fake UNIX cred for uid %d gid %d\n",

                                uid, gid);

        if (!(cred = (struct unx_cred *) rpc_malloc(task, sizeof(*cred))))

                return NULL;

        atomic_set(&cred->uc_count, 1);

        cred->uc_flags = RPCAUTH_CRED_DEAD|RPCAUTH_CRED_UPTODATE;

        cred->uc_uid   = uid;

        cred->uc_gid   = gid;

        cred->uc_fsuid = uid;

        cred->uc_fsgid = gid;

        cred->uc_gids[0] = (gid_t) NOGROUP;

        return task->tk_msg.rpc_cred = (struct rpc_cred *) cred;

}

static void

unx_destroy_cred(struct rpc_cred *cred)

{

        rpc_free(cred);

}

/*

 * Match credentials against current process creds.

 * The root_override argument takes care of cases where the caller may

 * request root creds (e.g. for NFS swapping).

 */

static int

unx_match(struct rpc_cred *rcred, int taskflags)

{

        struct unx_cred *cred = (struct unx_cred *) rcred;

        int             i;

        if (!(taskflags & RPC_TASK_ROOTCREDS)) {

                int groups;

                if (cred->uc_uid != current->uid

                 || cred->uc_gid != current->gid

                 || cred->uc_fsuid != current->fsuid

                 || cred->uc_fsgid != current->fsgid)

                        return 0;

                groups = current->ngroups;

                if (groups > NFS_NGROUPS)

                        groups = NFS_NGROUPS;

                for (i = 0; i < groups ; i++)

                        if (cred->uc_gids[i] != (gid_t) current->groups[i])

                                return 0;

                return 1;

        }

        return (cred->uc_uid == 0 && cred->uc_fsuid == 0

             && cred->uc_gid == 0 && cred->uc_fsgid == 0

             && cred->uc_gids[0] == (gid_t) NOGROUP);

}

/*

 * Marshal credentials.

 * Maybe we should keep a cached credential for performance reasons.

 */

static u32 *

unx_marshal(struct rpc_task *task, u32 *p, int ruid)

{

        struct rpc_clnt *clnt = task->tk_client;

        struct unx_cred *cred = (struct unx_cred *) task->tk_msg.rpc_cred;

        u32             *base, *hold;

        int             i, n;

        *p++ = htonl(RPC_AUTH_UNIX);

        base = p++;

        *p++ = htonl(jiffies/HZ);

        /*

         * Copy the UTS nodename captured when the client was created.

         */

        n = clnt->cl_nodelen;

        *p++ = htonl(n);

        memcpy(p, clnt->cl_nodename, n);

        p += (n + 3) >> 2;

        /* Note: we don't use real uid if it involves raising priviledge */

        if (ruid && cred->uc_uid != 0 && cred->uc_gid != 0) {

                *p++ = htonl((u32) cred->uc_uid);

                *p++ = htonl((u32) cred->uc_gid);

        } else {

                *p++ = htonl((u32) cred->uc_fsuid);

                *p++ = htonl((u32) cred->uc_fsgid);

        }

        hold = p++;

        for (i = 0; i < 16 && cred->uc_gids[i] != (gid_t) NOGROUP; i++)

                *p++ = htonl((u32) cred->uc_gids[i]);

        *hold = htonl(p - hold - 1);            /* gid array length */

        *base = htonl((p - base - 1) << 2);     /* cred length */

        *p++ = htonl(RPC_AUTH_NULL);

        *p++ = htonl(0);

        return p;

}

/*

 * Refresh credentials. This is a no-op for AUTH_UNIX

 */

static int

unx_refresh(struct rpc_task *task)

{

        task->tk_msg.rpc_cred->cr_flags |= RPCAUTH_CRED_UPTODATE;

        return task->tk_status = -EACCES;

}

static u32 *

unx_validate(struct rpc_task *task, u32 *p)

{

        u32             n = ntohl(*p++);

        if (n != RPC_AUTH_NULL && n != RPC_AUTH_UNIX && n != RPC_AUTH_SHORT) {

                printk("RPC: bad verf flavor: %ld\n", (unsigned long) n);

                return NULL;

        }

        if ((n = ntohl(*p++)) > 400) {

                printk("RPC: giant verf size: %ld\n", (unsigned long) n);

                return NULL;

        }

        task->tk_auth->au_rslack = (n >> 2) + 2;

        p += (n >> 2);

        return p;

}

struct rpc_authops      authunix_ops = {

        RPC_AUTH_UNIX,

#ifdef RPC_DEBUG

        "UNIX",

#endif

        unx_create,

        unx_destroy,

        unx_create_cred

};

static

struct rpc_credops      unix_credops = {

        unx_destroy_cred,

        unx_match,

        unx_marshal,

        unx_refresh,

        unx_validate

};