nfs4acl.c

Go to the documentation of this file.

/*
 *  Common NFSv4 ACL handling code.
 *
 *  Copyright (c) 2002, 2003 The Regents of the University of Michigan.
 *  All rights reserved.
 *
 *  Marius Aamodt Eriksen <[email protected]>
 *  Jeff Sedlak <[email protected]>
 *  J. Bruce Fields <[email protected]>
 *
 *  Redistribution and use in source and binary forms, with or without
 *  modification, are permitted provided that the following conditions
 *  are met:
 *
 *  1. Redistributions of source code must retain the above copyright
 *     notice, this list of conditions and the following disclaimer.
 *  2. Redistributions in binary form must reproduce the above copyright
 *     notice, this list of conditions and the following disclaimer in the
 *     documentation and/or other materials provided with the distribution.
 *  3. Neither the name of the University nor the names of its
 *     contributors may be used to endorse or promote products derived
 *     from this software without specific prior written permission.
 *
 *  THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED
 *  WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
 *  MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 *  DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 *  FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 *  CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 *  SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR
 *  BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
 *  LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
 *  NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
 *  SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

#include <linux/slab.h>
#include <linux/nfs_fs.h>
#include <linux/export.h>
#include "acl.h"


/* mode bit translations: */
#define NFS4_READ_MODE (NFS4_ACE_READ_DATA)
#define NFS4_WRITE_MODE (NFS4_ACE_WRITE_DATA | NFS4_ACE_APPEND_DATA)
#define NFS4_EXECUTE_MODE NFS4_ACE_EXECUTE
#define NFS4_ANYONE_MODE (NFS4_ACE_READ_ATTRIBUTES | NFS4_ACE_READ_ACL | NFS4_ACE_SYNCHRONIZE)
#define NFS4_OWNER_MODE (NFS4_ACE_WRITE_ATTRIBUTES | NFS4_ACE_WRITE_ACL)

/* We don't support these bits; insist they be neither allowed nor denied */
#define NFS4_MASK_UNSUPP (NFS4_ACE_DELETE | NFS4_ACE_WRITE_OWNER \
        | NFS4_ACE_READ_NAMED_ATTRS | NFS4_ACE_WRITE_NAMED_ATTRS)

/* flags used to simulate posix default ACLs */
#define NFS4_INHERITANCE_FLAGS (NFS4_ACE_FILE_INHERIT_ACE \
        | NFS4_ACE_DIRECTORY_INHERIT_ACE)

#define NFS4_SUPPORTED_FLAGS (NFS4_INHERITANCE_FLAGS \
        | NFS4_ACE_INHERIT_ONLY_ACE \
        | NFS4_ACE_IDENTIFIER_GROUP)

#define MASK_EQUAL(mask1, mask2) \
    ( ((mask1) & NFS4_ACE_MASK_ALL) == ((mask2) & NFS4_ACE_MASK_ALL) )

static u32
mask_from_posix(unsigned short perm, unsigned int flags)
{
    int mask = NFS4_ANYONE_MODE;

    if (flags & NFS4_ACL_OWNER)
        mask |= NFS4_OWNER_MODE;
    if (perm & ACL_READ)
        mask |= NFS4_READ_MODE;
    if (perm & ACL_WRITE)
        mask |= NFS4_WRITE_MODE;
    if ((perm & ACL_WRITE) && (flags & NFS4_ACL_DIR))
        mask |= NFS4_ACE_DELETE_CHILD;
    if (perm & ACL_EXECUTE)
        mask |= NFS4_EXECUTE_MODE;
    return mask;
}

static u32
deny_mask_from_posix(unsigned short perm, u32 flags)
{
    u32 mask = 0;

    if (perm & ACL_READ)
        mask |= NFS4_READ_MODE;
    if (perm & ACL_WRITE)
        mask |= NFS4_WRITE_MODE;
    if ((perm & ACL_WRITE) && (flags & NFS4_ACL_DIR))
        mask |= NFS4_ACE_DELETE_CHILD;
    if (perm & ACL_EXECUTE)
        mask |= NFS4_EXECUTE_MODE;
    return mask;
}

/* XXX: modify functions to return NFS errors; they're only ever
 * used by nfs code, after all.... */

/* We only map from NFSv4 to POSIX ACLs when setting ACLs, when we err on the
 * side of being more restrictive, so the mode bit mapping below is
 * pessimistic.  An optimistic version would be needed to handle DENY's,
 * but we espect to coalesce all ALLOWs and DENYs before mapping to mode
 * bits. */

static void
low_mode_from_nfs4(u32 perm, unsigned short *mode, unsigned int flags)
{
    u32 write_mode = NFS4_WRITE_MODE;

    if (flags & NFS4_ACL_DIR)
        write_mode |= NFS4_ACE_DELETE_CHILD;
    *mode = 0;
    if ((perm & NFS4_READ_MODE) == NFS4_READ_MODE)
        *mode |= ACL_READ;
    if ((perm & write_mode) == write_mode)
        *mode |= ACL_WRITE;
    if ((perm & NFS4_EXECUTE_MODE) == NFS4_EXECUTE_MODE)
        *mode |= ACL_EXECUTE;
}

struct ace_container {
    struct nfs4_ace  *ace;
    struct list_head  ace_l;
};

static short ace2type(struct nfs4_ace *);
static void _posix_to_nfsv4_one(struct posix_acl *, struct nfs4_acl *,
                unsigned int);

struct nfs4_acl *
nfs4_acl_posix_to_nfsv4(struct posix_acl *pacl, struct posix_acl *dpacl,
            unsigned int flags)
{
    struct nfs4_acl *acl;
    int size = 0;

    if (pacl) {
        if (posix_acl_valid(pacl) < 0)
            return ERR_PTR(-EINVAL);
        size += 2*pacl->a_count;
    }
    if (dpacl) {
        if (posix_acl_valid(dpacl) < 0)
            return ERR_PTR(-EINVAL);
        size += 2*dpacl->a_count;
    }

    /* Allocate for worst case: one (deny, allow) pair each: */
    acl = nfs4_acl_new(size);
    if (acl == NULL)
        return ERR_PTR(-ENOMEM);

    if (pacl)
        _posix_to_nfsv4_one(pacl, acl, flags & ~NFS4_ACL_TYPE_DEFAULT);

    if (dpacl)
        _posix_to_nfsv4_one(dpacl, acl, flags | NFS4_ACL_TYPE_DEFAULT);

    return acl;
}

struct posix_acl_summary {
    unsigned short owner;
    unsigned short users;
    unsigned short group;
    unsigned short groups;
    unsigned short other;
    unsigned short mask;
};

static void
summarize_posix_acl(struct posix_acl *acl, struct posix_acl_summary *pas)
{
    struct posix_acl_entry *pa, *pe;

    /*
     * Only pas.users and pas.groups need initialization; previous
     * posix_acl_valid() calls ensure that the other fields will be
     * initialized in the following loop.  But, just to placate gcc:
     */
    memset(pas, 0, sizeof(*pas));
    pas->mask = 07;

    pe = acl->a_entries + acl->a_count;

    FOREACH_ACL_ENTRY(pa, acl, pe) {
        switch (pa->e_tag) {
            case ACL_USER_OBJ:
                pas->owner = pa->e_perm;
                break;
            case ACL_GROUP_OBJ:
                pas->group = pa->e_perm;
                break;
            case ACL_USER:
                pas->users |= pa->e_perm;
                break;
            case ACL_GROUP:
                pas->groups |= pa->e_perm;
                break;
            case ACL_OTHER:
                pas->other = pa->e_perm;
                break;
            case ACL_MASK:
                pas->mask = pa->e_perm;
                break;
        }
    }
    /* We'll only care about effective permissions: */
    pas->users &= pas->mask;
    pas->group &= pas->mask;
    pas->groups &= pas->mask;
}

/* We assume the acl has been verified with posix_acl_valid. */
static void
_posix_to_nfsv4_one(struct posix_acl *pacl, struct nfs4_acl *acl,
                        unsigned int flags)
{
    struct posix_acl_entry *pa, *group_owner_entry;
    struct nfs4_ace *ace;
    struct posix_acl_summary pas;
    unsigned short deny;
    int eflag = ((flags & NFS4_ACL_TYPE_DEFAULT) ?
        NFS4_INHERITANCE_FLAGS | NFS4_ACE_INHERIT_ONLY_ACE : 0);

    BUG_ON(pacl->a_count < 3);
    summarize_posix_acl(pacl, &pas);

    pa = pacl->a_entries;
    ace = acl->aces + acl->naces;

    /* We could deny everything not granted by the owner: */
    deny = ~pas.owner;
    /*
     * but it is equivalent (and simpler) to deny only what is not
     * granted by later entries:
     */
    deny &= pas.users | pas.group | pas.groups | pas.other;
    if (deny) {
        ace->type = NFS4_ACE_ACCESS_DENIED_ACE_TYPE;
        ace->flag = eflag;
        ace->access_mask = deny_mask_from_posix(deny, flags);
        ace->whotype = NFS4_ACL_WHO_OWNER;
        ace++;
        acl->naces++;
    }

    ace->type = NFS4_ACE_ACCESS_ALLOWED_ACE_TYPE;
    ace->flag = eflag;
    ace->access_mask = mask_from_posix(pa->e_perm, flags | NFS4_ACL_OWNER);
    ace->whotype = NFS4_ACL_WHO_OWNER;
    ace++;
    acl->naces++;
    pa++;

    while (pa->e_tag == ACL_USER) {
        deny = ~(pa->e_perm & pas.mask);
        deny &= pas.groups | pas.group | pas.other;
        if (deny) {
            ace->type = NFS4_ACE_ACCESS_DENIED_ACE_TYPE;
            ace->flag = eflag;
            ace->access_mask = deny_mask_from_posix(deny, flags);
            ace->whotype = NFS4_ACL_WHO_NAMED;
            ace->who = pa->e_id;
            ace++;
            acl->naces++;
        }
        ace->type = NFS4_ACE_ACCESS_ALLOWED_ACE_TYPE;
        ace->flag = eflag;
        ace->access_mask = mask_from_posix(pa->e_perm & pas.mask,
                           flags);
        ace->whotype = NFS4_ACL_WHO_NAMED;
        ace->who = pa->e_id;
        ace++;
        acl->naces++;
        pa++;
    }

    /* In the case of groups, we apply allow ACEs first, then deny ACEs,
     * since a user can be in more than one group.  */

    /* allow ACEs */

    group_owner_entry = pa;

    ace->type = NFS4_ACE_ACCESS_ALLOWED_ACE_TYPE;
    ace->flag = eflag;
    ace->access_mask = mask_from_posix(pas.group, flags);
    ace->whotype = NFS4_ACL_WHO_GROUP;
    ace++;
    acl->naces++;
    pa++;

    while (pa->e_tag == ACL_GROUP) {
        ace->type = NFS4_ACE_ACCESS_ALLOWED_ACE_TYPE;
        ace->flag = eflag | NFS4_ACE_IDENTIFIER_GROUP;
        ace->access_mask = mask_from_posix(pa->e_perm & pas.mask,
                           flags);
        ace->whotype = NFS4_ACL_WHO_NAMED;
        ace->who = pa->e_id;
        ace++;
        acl->naces++;
        pa++;
    }

    /* deny ACEs */

    pa = group_owner_entry;

    deny = ~pas.group & pas.other;
    if (deny) {
        ace->type = NFS4_ACE_ACCESS_DENIED_ACE_TYPE;
        ace->flag = eflag;
        ace->access_mask = deny_mask_from_posix(deny, flags);
        ace->whotype = NFS4_ACL_WHO_GROUP;
        ace++;
        acl->naces++;
    }
    pa++;

    while (pa->e_tag == ACL_GROUP) {
        deny = ~(pa->e_perm & pas.mask);
        deny &= pas.other;
        if (deny) {
            ace->type = NFS4_ACE_ACCESS_DENIED_ACE_TYPE;
            ace->flag = eflag | NFS4_ACE_IDENTIFIER_GROUP;
            ace->access_mask = deny_mask_from_posix(deny, flags);
            ace->whotype = NFS4_ACL_WHO_NAMED;
            ace->who = pa->e_id;
            ace++;
            acl->naces++;
        }
        pa++;
    }

    if (pa->e_tag == ACL_MASK)
        pa++;
    ace->type = NFS4_ACE_ACCESS_ALLOWED_ACE_TYPE;
    ace->flag = eflag;
    ace->access_mask = mask_from_posix(pa->e_perm, flags);
    ace->whotype = NFS4_ACL_WHO_EVERYONE;
    acl->naces++;
}

static void
sort_pacl_range(struct posix_acl *pacl, int start, int end) {
    int sorted = 0, i;
    struct posix_acl_entry tmp;

    /* We just do a bubble sort; easy to do in place, and we're not
     * expecting acl's to be long enough to justify anything more. */
    while (!sorted) {
        sorted = 1;
        for (i = start; i < end; i++) {
            if (pacl->a_entries[i].e_id
                    > pacl->a_entries[i+1].e_id) {
                sorted = 0;
                tmp = pacl->a_entries[i];
                pacl->a_entries[i] = pacl->a_entries[i+1];
                pacl->a_entries[i+1] = tmp;
            }
        }
    }
}

static void
sort_pacl(struct posix_acl *pacl)
{
    /* posix_acl_valid requires that users and groups be in order
     * by uid/gid. */
    int i, j;

    if (pacl->a_count <= 4)
        return; /* no users or groups */
    i = 1;
    while (pacl->a_entries[i].e_tag == ACL_USER)
        i++;
    sort_pacl_range(pacl, 1, i-1);

    BUG_ON(pacl->a_entries[i].e_tag != ACL_GROUP_OBJ);
    j = ++i;
    while (pacl->a_entries[j].e_tag == ACL_GROUP)
        j++;
    sort_pacl_range(pacl, i, j-1);
    return;
}

/*
 * While processing the NFSv4 ACE, this maintains bitmasks representing
 * which permission bits have been allowed and which denied to a given
 * entity: */
struct posix_ace_state {
    u32 allow;
    u32 deny;
};

struct posix_user_ace_state {
    uid_t uid;
    struct posix_ace_state perms;
};

struct posix_ace_state_array {
    int n;
    struct posix_user_ace_state aces[];
};

/*
 * While processing the NFSv4 ACE, this maintains the partial permissions
 * calculated so far: */

struct posix_acl_state {
    int empty;
    struct posix_ace_state owner;
    struct posix_ace_state group;
    struct posix_ace_state other;
    struct posix_ace_state everyone;
    struct posix_ace_state mask; /* Deny unused in this case */
    struct posix_ace_state_array *users;
    struct posix_ace_state_array *groups;
};

static int
init_state(struct posix_acl_state *state, int cnt)
{
    int alloc;

    memset(state, 0, sizeof(struct posix_acl_state));
    state->empty = 1;
    /*
     * In the worst case, each individual acl could be for a distinct
     * named user or group, but we don't no which, so we allocate
     * enough space for either:
     */
    alloc = sizeof(struct posix_ace_state_array)
        + cnt*sizeof(struct posix_user_ace_state);
    state->users = kzalloc(alloc, GFP_KERNEL);
    if (!state->users)
        return -ENOMEM;
    state->groups = kzalloc(alloc, GFP_KERNEL);
    if (!state->groups) {
        kfree(state->users);
        return -ENOMEM;
    }
    return 0;
}

static void
free_state(struct posix_acl_state *state) {
    kfree(state->users);
    kfree(state->groups);
}

static inline void add_to_mask(struct posix_acl_state *state, struct posix_ace_state *astate)
{
    state->mask.allow |= astate->allow;
}

/*
 * Certain bits (SYNCHRONIZE, DELETE, WRITE_OWNER, READ/WRITE_NAMED_ATTRS,
 * READ_ATTRIBUTES, READ_ACL) are currently unenforceable and don't translate
 * to traditional read/write/execute permissions.
 *
 * It's problematic to reject acls that use certain mode bits, because it
 * places the burden on users to learn the rules about which bits one
 * particular server sets, without giving the user a lot of help--we return an
 * error that could mean any number of different things.  To make matters
 * worse, the problematic bits might be introduced by some application that's
 * automatically mapping from some other acl model.
 *
 * So wherever possible we accept anything, possibly erring on the side of
 * denying more permissions than necessary.
 *
 * However we do reject *explicit* DENY's of a few bits representing
 * permissions we could never deny:
 */

static inline int check_deny(u32 mask, int isowner)
{
    if (mask & (NFS4_ACE_READ_ATTRIBUTES | NFS4_ACE_READ_ACL))
        return -EINVAL;
    if (!isowner)
        return 0;
    if (mask & (NFS4_ACE_WRITE_ATTRIBUTES | NFS4_ACE_WRITE_ACL))
        return -EINVAL;
    return 0;
}

static struct posix_acl *
posix_state_to_acl(struct posix_acl_state *state, unsigned int flags)
{
    struct posix_acl_entry *pace;
    struct posix_acl *pacl;
    int nace;
    int i, error = 0;

    /*
     * ACLs with no ACEs are treated differently in the inheritable
     * and effective cases: when there are no inheritable ACEs, we
     * set a zero-length default posix acl:
     */
    if (state->empty && (flags & NFS4_ACL_TYPE_DEFAULT)) {
        pacl = posix_acl_alloc(0, GFP_KERNEL);
        return pacl ? pacl : ERR_PTR(-ENOMEM);
    }
    /*
     * When there are no effective ACEs, the following will end
     * up setting a 3-element effective posix ACL with all
     * permissions zero.
     */
    nace = 4 + state->users->n + state->groups->n;
    pacl = posix_acl_alloc(nace, GFP_KERNEL);
    if (!pacl)
        return ERR_PTR(-ENOMEM);

    pace = pacl->a_entries;
    pace->e_tag = ACL_USER_OBJ;
    error = check_deny(state->owner.deny, 1);
    if (error)
        goto out_err;
    low_mode_from_nfs4(state->owner.allow, &pace->e_perm, flags);
    pace->e_id = ACL_UNDEFINED_ID;

    for (i=0; i < state->users->n; i++) {
        pace++;
        pace->e_tag = ACL_USER;
        error = check_deny(state->users->aces[i].perms.deny, 0);
        if (error)
            goto out_err;
        low_mode_from_nfs4(state->users->aces[i].perms.allow,
                    &pace->e_perm, flags);
        pace->e_id = state->users->aces[i].uid;
        add_to_mask(state, &state->users->aces[i].perms);
    }

    pace++;
    pace->e_tag = ACL_GROUP_OBJ;
    error = check_deny(state->group.deny, 0);
    if (error)
        goto out_err;
    low_mode_from_nfs4(state->group.allow, &pace->e_perm, flags);
    pace->e_id = ACL_UNDEFINED_ID;
    add_to_mask(state, &state->group);

    for (i=0; i < state->groups->n; i++) {
        pace++;
        pace->e_tag = ACL_GROUP;
        error = check_deny(state->groups->aces[i].perms.deny, 0);
        if (error)
            goto out_err;
        low_mode_from_nfs4(state->groups->aces[i].perms.allow,
                    &pace->e_perm, flags);
        pace->e_id = state->groups->aces[i].uid;
        add_to_mask(state, &state->groups->aces[i].perms);
    }

    pace++;
    pace->e_tag = ACL_MASK;
    low_mode_from_nfs4(state->mask.allow, &pace->e_perm, flags);
    pace->e_id = ACL_UNDEFINED_ID;

    pace++;
    pace->e_tag = ACL_OTHER;
    error = check_deny(state->other.deny, 0);
    if (error)
        goto out_err;
    low_mode_from_nfs4(state->other.allow, &pace->e_perm, flags);
    pace->e_id = ACL_UNDEFINED_ID;

    return pacl;
out_err:
    posix_acl_release(pacl);
    return ERR_PTR(error);
}

static inline void allow_bits(struct posix_ace_state *astate, u32 mask)
{
    /* Allow all bits in the mask not already denied: */
    astate->allow |= mask & ~astate->deny;
}

static inline void deny_bits(struct posix_ace_state *astate, u32 mask)
{
    /* Deny all bits in the mask not already allowed: */
    astate->deny |= mask & ~astate->allow;
}

static int find_uid(struct posix_acl_state *state, struct posix_ace_state_array *a, uid_t uid)
{
    int i;

    for (i = 0; i < a->n; i++)
        if (a->aces[i].uid == uid)
            return i;
    /* Not found: */
    a->n++;
    a->aces[i].uid = uid;
    a->aces[i].perms.allow = state->everyone.allow;
    a->aces[i].perms.deny  = state->everyone.deny;

    return i;
}

static void deny_bits_array(struct posix_ace_state_array *a, u32 mask)
{
    int i;

    for (i=0; i < a->n; i++)
        deny_bits(&a->aces[i].perms, mask);
}

static void allow_bits_array(struct posix_ace_state_array *a, u32 mask)
{
    int i;

    for (i=0; i < a->n; i++)
        allow_bits(&a->aces[i].perms, mask);
}

static void process_one_v4_ace(struct posix_acl_state *state,
                struct nfs4_ace *ace)
{
    u32 mask = ace->access_mask;
    int i;

    state->empty = 0;

    switch (ace2type(ace)) {
    case ACL_USER_OBJ:
        if (ace->type == NFS4_ACE_ACCESS_ALLOWED_ACE_TYPE) {
            allow_bits(&state->owner, mask);
        } else {
            deny_bits(&state->owner, mask);
        }
        break;
    case ACL_USER:
        i = find_uid(state, state->users, ace->who);
        if (ace->type == NFS4_ACE_ACCESS_ALLOWED_ACE_TYPE) {
            allow_bits(&state->users->aces[i].perms, mask);
        } else {
            deny_bits(&state->users->aces[i].perms, mask);
            mask = state->users->aces[i].perms.deny;
            deny_bits(&state->owner, mask);
        }
        break;
    case ACL_GROUP_OBJ:
        if (ace->type == NFS4_ACE_ACCESS_ALLOWED_ACE_TYPE) {
            allow_bits(&state->group, mask);
        } else {
            deny_bits(&state->group, mask);
            mask = state->group.deny;
            deny_bits(&state->owner, mask);
            deny_bits(&state->everyone, mask);
            deny_bits_array(state->users, mask);
            deny_bits_array(state->groups, mask);
        }
        break;
    case ACL_GROUP:
        i = find_uid(state, state->groups, ace->who);
        if (ace->type == NFS4_ACE_ACCESS_ALLOWED_ACE_TYPE) {
            allow_bits(&state->groups->aces[i].perms, mask);
        } else {
            deny_bits(&state->groups->aces[i].perms, mask);
            mask = state->groups->aces[i].perms.deny;
            deny_bits(&state->owner, mask);
            deny_bits(&state->group, mask);
            deny_bits(&state->everyone, mask);
            deny_bits_array(state->users, mask);
            deny_bits_array(state->groups, mask);
        }
        break;
    case ACL_OTHER:
        if (ace->type == NFS4_ACE_ACCESS_ALLOWED_ACE_TYPE) {
            allow_bits(&state->owner, mask);
            allow_bits(&state->group, mask);
            allow_bits(&state->other, mask);
            allow_bits(&state->everyone, mask);
            allow_bits_array(state->users, mask);
            allow_bits_array(state->groups, mask);
        } else {
            deny_bits(&state->owner, mask);
            deny_bits(&state->group, mask);
            deny_bits(&state->other, mask);
            deny_bits(&state->everyone, mask);
            deny_bits_array(state->users, mask);
            deny_bits_array(state->groups, mask);
        }
    }
}

int nfs4_acl_nfsv4_to_posix(struct nfs4_acl *acl, struct posix_acl **pacl,
                struct posix_acl **dpacl, unsigned int flags)
{
    struct posix_acl_state effective_acl_state, default_acl_state;
    struct nfs4_ace *ace;
    int ret;

    ret = init_state(&effective_acl_state, acl->naces);
    if (ret)
        return ret;
    ret = init_state(&default_acl_state, acl->naces);
    if (ret)
        goto out_estate;
    ret = -EINVAL;
    for (ace = acl->aces; ace < acl->aces + acl->naces; ace++) {
        if (ace->type != NFS4_ACE_ACCESS_ALLOWED_ACE_TYPE &&
            ace->type != NFS4_ACE_ACCESS_DENIED_ACE_TYPE)
            goto out_dstate;
        if (ace->flag & ~NFS4_SUPPORTED_FLAGS)
            goto out_dstate;
        if ((ace->flag & NFS4_INHERITANCE_FLAGS) == 0) {
            process_one_v4_ace(&effective_acl_state, ace);
            continue;
        }
        if (!(flags & NFS4_ACL_DIR))
            goto out_dstate;
        /*
         * Note that when only one of FILE_INHERIT or DIRECTORY_INHERIT
         * is set, we're effectively turning on the other.  That's OK,
         * according to rfc 3530.
         */
        process_one_v4_ace(&default_acl_state, ace);

        if (!(ace->flag & NFS4_ACE_INHERIT_ONLY_ACE))
            process_one_v4_ace(&effective_acl_state, ace);
    }
    *pacl = posix_state_to_acl(&effective_acl_state, flags);
    if (IS_ERR(*pacl)) {
        ret = PTR_ERR(*pacl);
        *pacl = NULL;
        goto out_dstate;
    }
    *dpacl = posix_state_to_acl(&default_acl_state,
                        flags | NFS4_ACL_TYPE_DEFAULT);
    if (IS_ERR(*dpacl)) {
        ret = PTR_ERR(*dpacl);
        *dpacl = NULL;
        posix_acl_release(*pacl);
        *pacl = NULL;
        goto out_dstate;
    }
    sort_pacl(*pacl);
    sort_pacl(*dpacl);
    ret = 0;
out_dstate:
    free_state(&default_acl_state);
out_estate:
    free_state(&effective_acl_state);
    return ret;
}

static short
ace2type(struct nfs4_ace *ace)
{
    switch (ace->whotype) {
        case NFS4_ACL_WHO_NAMED:
            return (ace->flag & NFS4_ACE_IDENTIFIER_GROUP ?
                    ACL_GROUP : ACL_USER);
        case NFS4_ACL_WHO_OWNER:
            return ACL_USER_OBJ;
        case NFS4_ACL_WHO_GROUP:
            return ACL_GROUP_OBJ;
        case NFS4_ACL_WHO_EVERYONE:
            return ACL_OTHER;
    }
    BUG();
    return -1;
}

EXPORT_SYMBOL(nfs4_acl_posix_to_nfsv4);
EXPORT_SYMBOL(nfs4_acl_nfsv4_to_posix);

struct nfs4_acl *
nfs4_acl_new(int n)
{
    struct nfs4_acl *acl;

    acl = kmalloc(sizeof(*acl) + n*sizeof(struct nfs4_ace), GFP_KERNEL);
    if (acl == NULL)
        return NULL;
    acl->naces = 0;
    return acl;
}

static struct {
    char *string;
    int   stringlen;
    int type;
} s2t_map[] = {
    {
        .string    = "OWNER@",
        .stringlen = sizeof("OWNER@") - 1,
        .type      = NFS4_ACL_WHO_OWNER,
    },
    {
        .string    = "GROUP@",
        .stringlen = sizeof("GROUP@") - 1,
        .type      = NFS4_ACL_WHO_GROUP,
    },
    {
        .string    = "EVERYONE@",
        .stringlen = sizeof("EVERYONE@") - 1,
        .type      = NFS4_ACL_WHO_EVERYONE,
    },
};

int
nfs4_acl_get_whotype(char *p, u32 len)
{
    int i;

    for (i = 0; i < ARRAY_SIZE(s2t_map); i++) {
        if (s2t_map[i].stringlen == len &&
                0 == memcmp(s2t_map[i].string, p, len))
            return s2t_map[i].type;
    }
    return NFS4_ACL_WHO_NAMED;
}

int
nfs4_acl_write_who(int who, char *p)
{
    int i;

    for (i = 0; i < ARRAY_SIZE(s2t_map); i++) {
        if (s2t_map[i].type == who) {
            memcpy(p, s2t_map[i].string, s2t_map[i].stringlen);
            return s2t_map[i].stringlen;
        }
    }
    BUG();
    return -1;
}

EXPORT_SYMBOL(nfs4_acl_new);
EXPORT_SYMBOL(nfs4_acl_get_whotype);
EXPORT_SYMBOL(nfs4_acl_write_who);