nfs4acl.c

来自「Linux Kernel 2.6.9 for OMAP1710」· C语言 代码 · 共 975 行 · 第 1/2 页

		if (*mask_ace &&
			!MASK_EQUAL(ace->access_mask, (*mask_ace)->access_mask))
			goto out;
		*mask_ace = ace;
		ace = get_next_v4_ace(p, &n4acl->ace_head);
		if (ace == NULL)
			goto out;
		if (ace->type != NFS4_ACE_ACCESS_ALLOWED_ACE_TYPE)
			goto out;
		error = write_pace(ace, pacl, pace, ACL_USER, flags);
		if (error < 0)
			goto out;
		error = -EINVAL;
		ace2 = get_next_v4_ace(p, &n4acl->ace_head);
		if (ace2 == NULL)
			goto out;
		if (!complementary_ace_pair(ace, ace2, flags))
			goto out;
		if ((*mask_ace)->flag != ace2->flag ||
				!same_who(*mask_ace, ace2))
			goto out;
		ace = get_next_v4_ace(p, &n4acl->ace_head);
		if (ace == NULL)
			goto out;
	}
	error = 0;
out:
	return error;
}

static inline int
group_obj_and_groups_from_v4(struct nfs4_acl *n4acl, struct list_head **p,
		struct nfs4_ace **mask_ace,
		struct posix_acl *pacl, struct posix_acl_entry **pace,
		unsigned int flags)
{
	int error = -EINVAL;
	struct nfs4_ace *ace, *ace2;
	struct ace_container *ac;
	struct list_head group_l;

	INIT_LIST_HEAD(&group_l);
	ace = list_entry(*p, struct nfs4_ace, l_ace);

	/* group owner (mask and allow aces) */

	if (pacl->a_count != 3) {
		/* then the group owner should be preceded by mask */
		if (ace->type != NFS4_ACE_ACCESS_DENIED_ACE_TYPE)
			goto out;
		if (*mask_ace &&
			!MASK_EQUAL(ace->access_mask, (*mask_ace)->access_mask))
			goto out;
		*mask_ace = ace;
		ace = get_next_v4_ace(p, &n4acl->ace_head);
		if (ace == NULL)
			goto out;

		if ((*mask_ace)->flag != ace->flag || !same_who(*mask_ace, ace))
			goto out;
	}

	if (ace2type(ace) != ACL_GROUP_OBJ)
		goto out;

	ac = kmalloc(sizeof(*ac), GFP_KERNEL);
	error = -ENOMEM;
	if (ac == NULL)
		goto out;
	ac->ace = ace;
	list_add_tail(&ac->ace_l, &group_l);

	error = -EINVAL;
	if (ace->type != NFS4_ACE_ACCESS_ALLOWED_ACE_TYPE)
		goto out;

	error = write_pace(ace, pacl, pace, ACL_GROUP_OBJ, flags);
	if (error < 0)
		goto out;

	error = -EINVAL;
	ace = get_next_v4_ace(p, &n4acl->ace_head);
	if (ace == NULL)
		goto out;

	/* groups (mask and allow aces) */

	while (ace2type(ace) == ACL_GROUP) {
		if (*mask_ace == NULL)
			goto out;

		if (ace->type != NFS4_ACE_ACCESS_DENIED_ACE_TYPE ||
			!MASK_EQUAL(ace->access_mask, (*mask_ace)->access_mask))
			goto out;
		*mask_ace = ace;

		ace = get_next_v4_ace(p, &n4acl->ace_head);
		if (ace == NULL)
			goto out;
		ac = kmalloc(sizeof(*ac), GFP_KERNEL);
		error = -ENOMEM;
		if (ac == NULL)
			goto out;
		error = -EINVAL;
		if (ace->type != NFS4_ACE_ACCESS_ALLOWED_ACE_TYPE ||
				!same_who(ace, *mask_ace))
			goto out;

		ac->ace = ace;
		list_add_tail(&ac->ace_l, &group_l);

		error = write_pace(ace, pacl, pace, ACL_GROUP, flags);
		if (error < 0)
			goto out;
		error = -EINVAL;
		ace = get_next_v4_ace(p, &n4acl->ace_head);
		if (ace == NULL)
			goto out;
	}

	/* group owner (deny ace) */

	if (ace2type(ace) != ACL_GROUP_OBJ)
		goto out;
	ac = list_entry(group_l.next, struct ace_container, ace_l);
	ace2 = ac->ace;
	if (!complementary_ace_pair(ace2, ace, flags))
		goto out;
	list_del(group_l.next);
	kfree(ac);

	/* groups (deny aces) */

	while (!list_empty(&group_l)) {
		ace = get_next_v4_ace(p, &n4acl->ace_head);
		if (ace == NULL)
			goto out;
		if (ace2type(ace) != ACL_GROUP)
			goto out;
		ac = list_entry(group_l.next, struct ace_container, ace_l);
		ace2 = ac->ace;
		if (!complementary_ace_pair(ace2, ace, flags))
			goto out;
		list_del(group_l.next);
		kfree(ac);
	}

	ace = get_next_v4_ace(p, &n4acl->ace_head);
	if (ace == NULL)
		goto out;
	if (ace2type(ace) != ACL_OTHER)
		goto out;
	error = 0;
out:
	while (!list_empty(&group_l)) {
		ac = list_entry(group_l.next, struct ace_container, ace_l);
		list_del(group_l.next);
		kfree(ac);
	}
	return error;
}

static inline int
mask_from_v4(struct nfs4_acl *n4acl, struct list_head **p,
		struct nfs4_ace **mask_ace,
		struct posix_acl *pacl, struct posix_acl_entry **pace,
		unsigned int flags)
{
	int error = -EINVAL;
	struct nfs4_ace *ace;

	ace = list_entry(*p, struct nfs4_ace, l_ace);
	if (pacl->a_count != 3) {
		if (*mask_ace == NULL)
			goto out;
		(*mask_ace)->access_mask = deny_mask((*mask_ace)->access_mask, flags);
		write_pace(*mask_ace, pacl, pace, ACL_MASK, flags);
	}
	error = 0;
out:
	return error;
}

static inline int
other_from_v4(struct nfs4_acl *n4acl, struct list_head **p,
		struct posix_acl *pacl, struct posix_acl_entry **pace,
		unsigned int flags)
{
	int error = -EINVAL;
	struct nfs4_ace *ace, *ace2;

	ace = list_entry(*p, struct nfs4_ace, l_ace);
	if (ace->type != NFS4_ACE_ACCESS_ALLOWED_ACE_TYPE)
		goto out;
	error = write_pace(ace, pacl, pace, ACL_OTHER, flags);
	if (error < 0)
		goto out;
	error = -EINVAL;
	ace2 = get_next_v4_ace(p, &n4acl->ace_head);
	if (ace2 == NULL)
		goto out;
	if (!complementary_ace_pair(ace, ace2, flags))
		goto out;
	error = 0;
out:
	return error;
}

static int
calculate_posix_ace_count(struct nfs4_acl *n4acl)
{
	if (n4acl->naces == 6) /* owner, owner group, and other only */
		return 3;
	else { /* Otherwise there must be a mask entry. */
		/* Also, the remaining entries are for named users and
		 * groups, and come in threes (mask, allow, deny): */
		if (n4acl->naces < 7)
			return -1;
		if ((n4acl->naces - 7) % 3)
			return -1;
		return 4 + (n4acl->naces - 7)/3;
	}
}


static struct posix_acl *
_nfsv4_to_posix_one(struct nfs4_acl *n4acl, unsigned int flags)
{
	struct posix_acl *pacl;
	int error = -EINVAL, nace = 0;
	struct list_head *p;
	struct nfs4_ace *mask_ace = NULL;
	struct posix_acl_entry *pace;

	nace = calculate_posix_ace_count(n4acl);
	if (nace < 0)
		goto out_err;

	pacl = posix_acl_alloc(nace, GFP_KERNEL);
	error = -ENOMEM;
	if (pacl == NULL)
		goto out_err;

	pace = &pacl->a_entries[0];
	p = &n4acl->ace_head;

	error = user_obj_from_v4(n4acl, &p, pacl, &pace, flags);
	if (error)
		goto out_acl;

	error = users_from_v4(n4acl, &p, &mask_ace, pacl, &pace, flags);
	if (error)
		goto out_acl;

	error = group_obj_and_groups_from_v4(n4acl, &p, &mask_ace, pacl, &pace,
						flags);
	if (error)
		goto out_acl;

	error = mask_from_v4(n4acl, &p, &mask_ace, pacl, &pace, flags);
	if (error)
		goto out_acl;
	error = other_from_v4(n4acl, &p, pacl, &pace, flags);
	if (error)
		goto out_acl;

	error = -EINVAL;
	if (p->next != &n4acl->ace_head)
		goto out_acl;
	if (pace != pacl->a_entries + pacl->a_count)
		goto out_acl;

	sort_pacl(pacl);

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

int
nfs4_acl_split(struct nfs4_acl *acl, struct nfs4_acl *dacl)
{
	struct list_head *h, *n;
	struct nfs4_ace *ace;
	int error = 0;

	list_for_each_safe(h, n, &acl->ace_head) {
		ace = list_entry(h, struct nfs4_ace, l_ace);

		if ((ace->flag & NFS4_INHERITANCE_FLAGS)
				!= NFS4_INHERITANCE_FLAGS)
			continue;

		error = nfs4_acl_add_ace(dacl, ace->type, ace->flag,
				ace->access_mask, ace->whotype, ace->who) == -1;
		if (error < 0)
			goto out;

		list_del(h);
		kfree(ace);
		acl->naces--;
	}

out:
	return error;
}

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(void)
{
	struct nfs4_acl *acl;

	if ((acl = kmalloc(sizeof(*acl), GFP_KERNEL)) == NULL)
		return NULL;

	acl->naces = 0;
	INIT_LIST_HEAD(&acl->ace_head);

	return acl;
}

void
nfs4_acl_free(struct nfs4_acl *acl)
{
	struct list_head *h;
	struct nfs4_ace *ace;

	if (!acl)
		return;

	while (!list_empty(&acl->ace_head)) {
		h = acl->ace_head.next;
		list_del(h);
		ace = list_entry(h, struct nfs4_ace, l_ace);
		kfree(ace);
	}

	kfree(acl);

	return;
}

int
nfs4_acl_add_ace(struct nfs4_acl *acl, u32 type, u32 flag, u32 access_mask,
		int whotype, uid_t who)
{
	struct nfs4_ace *ace;

	if ((ace = kmalloc(sizeof(*ace), GFP_KERNEL)) == NULL)
		return -1;

	ace->type = type;
	ace->flag = flag;
	ace->access_mask = access_mask;
	ace->whotype = whotype;
	ace->who = who;

	list_add_tail(&ace->l_ace, &acl->ace_head);
	acl->naces++;

	return 0;
}

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 < sizeof(s2t_map) / sizeof(*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 < sizeof(s2t_map) / sizeof(*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;
}

static inline int
match_who(struct nfs4_ace *ace, uid_t owner, gid_t group, uid_t who)
{
	switch (ace->whotype) {
		case NFS4_ACL_WHO_NAMED:
			return who == ace->who;
		case NFS4_ACL_WHO_OWNER:
			return who == owner;
		case NFS4_ACL_WHO_GROUP:
			return who == group;
		case NFS4_ACL_WHO_EVERYONE:
			return 1;
		default:
			return 0;
	}
}

/* 0 = granted, -EACCES = denied; mask is an nfsv4 mask, not mode bits */
int
nfs4_acl_permission(struct nfs4_acl *acl, uid_t owner, gid_t group,
			uid_t who, u32 mask)
{
	struct nfs4_ace *ace;
	u32 allowed = 0;

	list_for_each_entry(ace, &acl->ace_head, l_ace) {
		if (!match_who(ace, group, owner, who))
			continue;
		switch (ace->type) {
			case NFS4_ACE_ACCESS_ALLOWED_ACE_TYPE:
				allowed |= ace->access_mask;
				if ((allowed & mask) == mask)
					return 0;
				break;
			case NFS4_ACE_ACCESS_DENIED_ACE_TYPE:
				if (ace->access_mask & mask)
					return -EACCES;
				break;
		}
	}
	return -EACCES;
}

EXPORT_SYMBOL(nfs4_acl_new);
EXPORT_SYMBOL(nfs4_acl_free);
EXPORT_SYMBOL(nfs4_acl_add_ace);
EXPORT_SYMBOL(nfs4_acl_get_whotype);
EXPORT_SYMBOL(nfs4_acl_write_who);
EXPORT_SYMBOL(nfs4_acl_permission);