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root/fs/reiserfs/xattr_acl.c

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DEFINITIONS

This source file includes following definitions.
  1. xattr_set_acl
  2. xattr_get_acl
  3. posix_acl_from_disk
  4. posix_acl_to_disk
  5. reiserfs_get_acl
  6. reiserfs_set_acl
  7. reiserfs_inherit_default_acl
  8. reiserfs_cache_default_acl
  9. reiserfs_acl_chmod
  10. posix_acl_access_get
  11. posix_acl_access_set
  12. posix_acl_access_del
  13. posix_acl_access_list
  14. posix_acl_default_get
  15. posix_acl_default_set
  16. posix_acl_default_del
  17. posix_acl_default_list

#include <linux/capability.h>
#include <linux/fs.h>
#include <linux/posix_acl.h>
#include <linux/reiserfs_fs.h>
#include <linux/errno.h>
#include <linux/pagemap.h>
#include <linux/xattr.h>
#include <linux/posix_acl_xattr.h>
#include <linux/reiserfs_xattr.h>
#include <linux/reiserfs_acl.h>
#include <asm/uaccess.h>

static int reiserfs_set_acl(struct inode *inode, int type,
                            struct posix_acl *acl);

static int
xattr_set_acl(struct inode *inode, int type, const void *value, size_t size)
{
        struct posix_acl *acl;
        int error;

        if (!reiserfs_posixacl(inode->i_sb))
                return -EOPNOTSUPP;
        if (!is_owner_or_cap(inode))
                return -EPERM;

        if (value) {
                acl = posix_acl_from_xattr(value, size);
                if (IS_ERR(acl)) {
                        return PTR_ERR(acl);
                } else if (acl) {
                        error = posix_acl_valid(acl);
                        if (error)
                                goto release_and_out;
                }
        } else
                acl = NULL;

        error = reiserfs_set_acl(inode, type, acl);

      release_and_out:
        posix_acl_release(acl);
        return error;
}

static int
xattr_get_acl(struct inode *inode, int type, void *buffer, size_t size)
{
        struct posix_acl *acl;
        int error;

        if (!reiserfs_posixacl(inode->i_sb))
                return -EOPNOTSUPP;

        acl = reiserfs_get_acl(inode, type);
        if (IS_ERR(acl))
                return PTR_ERR(acl);
        if (acl == NULL)
                return -ENODATA;
        error = posix_acl_to_xattr(acl, buffer, size);
        posix_acl_release(acl);

        return error;
}

/*
 * Convert from filesystem to in-memory representation.
 */
static struct posix_acl *posix_acl_from_disk(const void *value, size_t size)
{
        const char *end = (char *)value + size;
        int n, count;
        struct posix_acl *acl;

        if (!value)
                return NULL;
        if (size < sizeof(reiserfs_acl_header))
                return ERR_PTR(-EINVAL);
        if (((reiserfs_acl_header *) value)->a_version !=
            cpu_to_le32(REISERFS_ACL_VERSION))
                return ERR_PTR(-EINVAL);
        value = (char *)value + sizeof(reiserfs_acl_header);
        count = reiserfs_acl_count(size);
        if (count < 0)
                return ERR_PTR(-EINVAL);
        if (count == 0)
                return NULL;
        acl = posix_acl_alloc(count, GFP_NOFS);
        if (!acl)
                return ERR_PTR(-ENOMEM);
        for (n = 0; n < count; n++) {
                reiserfs_acl_entry *entry = (reiserfs_acl_entry *) value;
                if ((char *)value + sizeof(reiserfs_acl_entry_short) > end)
                        goto fail;
                acl->a_entries[n].e_tag = le16_to_cpu(entry->e_tag);
                acl->a_entries[n].e_perm = le16_to_cpu(entry->e_perm);
                switch (acl->a_entries[n].e_tag) {
                case ACL_USER_OBJ:
                case ACL_GROUP_OBJ:
                case ACL_MASK:
                case ACL_OTHER:
                        value = (char *)value +
                            sizeof(reiserfs_acl_entry_short);
                        acl->a_entries[n].e_id = ACL_UNDEFINED_ID;
                        break;

                case ACL_USER:
                case ACL_GROUP:
                        value = (char *)value + sizeof(reiserfs_acl_entry);
                        if ((char *)value > end)
                                goto fail;
                        acl->a_entries[n].e_id = le32_to_cpu(entry->e_id);
                        break;

                default:
                        goto fail;
                }
        }
        if (value != end)
                goto fail;
        return acl;

      fail:
        posix_acl_release(acl);
        return ERR_PTR(-EINVAL);
}

/*
 * Convert from in-memory to filesystem representation.
 */
static void *posix_acl_to_disk(const struct posix_acl *acl, size_t * size)
{
        reiserfs_acl_header *ext_acl;
        char *e;
        int n;

        *size = reiserfs_acl_size(acl->a_count);
        ext_acl = kmalloc(sizeof(reiserfs_acl_header) +
                                                  acl->a_count *
                                                  sizeof(reiserfs_acl_entry),
                                                  GFP_NOFS);
        if (!ext_acl)
                return ERR_PTR(-ENOMEM);
        ext_acl->a_version = cpu_to_le32(REISERFS_ACL_VERSION);
        e = (char *)ext_acl + sizeof(reiserfs_acl_header);
        for (n = 0; n < acl->a_count; n++) {
                reiserfs_acl_entry *entry = (reiserfs_acl_entry *) e;
                entry->e_tag = cpu_to_le16(acl->a_entries[n].e_tag);
                entry->e_perm = cpu_to_le16(acl->a_entries[n].e_perm);
                switch (acl->a_entries[n].e_tag) {
                case ACL_USER:
                case ACL_GROUP:
                        entry->e_id = cpu_to_le32(acl->a_entries[n].e_id);
                        e += sizeof(reiserfs_acl_entry);
                        break;

                case ACL_USER_OBJ:
                case ACL_GROUP_OBJ:
                case ACL_MASK:
                case ACL_OTHER:
                        e += sizeof(reiserfs_acl_entry_short);
                        break;

                default:
                        goto fail;
                }
        }
        return (char *)ext_acl;

      fail:
        kfree(ext_acl);
        return ERR_PTR(-EINVAL);
}

/*
 * Inode operation get_posix_acl().
 *
 * inode->i_mutex: down
 * BKL held [before 2.5.x]
 */
struct posix_acl *reiserfs_get_acl(struct inode *inode, int type)
{
        char *name, *value;
        struct posix_acl *acl, **p_acl;
        int size;
        int retval;
        struct reiserfs_inode_info *reiserfs_i = REISERFS_I(inode);

        switch (type) {
        case ACL_TYPE_ACCESS:
                name = POSIX_ACL_XATTR_ACCESS;
                p_acl = &reiserfs_i->i_acl_access;
                break;
        case ACL_TYPE_DEFAULT:
                name = POSIX_ACL_XATTR_DEFAULT;
                p_acl = &reiserfs_i->i_acl_default;
                break;
        default:
                return ERR_PTR(-EINVAL);
        }

        if (IS_ERR(*p_acl)) {
                if (PTR_ERR(*p_acl) == -ENODATA)
                        return NULL;
        } else if (*p_acl != NULL)
                return posix_acl_dup(*p_acl);

        size = reiserfs_xattr_get(inode, name, NULL, 0);
        if (size < 0) {
                if (size == -ENODATA || size == -ENOSYS) {
                        *p_acl = ERR_PTR(-ENODATA);
                        return NULL;
                }
                return ERR_PTR(size);
        }

        value = kmalloc(size, GFP_NOFS);
        if (!value)
                return ERR_PTR(-ENOMEM);

        retval = reiserfs_xattr_get(inode, name, value, size);
        if (retval == -ENODATA || retval == -ENOSYS) {
                /* This shouldn't actually happen as it should have
                   been caught above.. but just in case */
                acl = NULL;
                *p_acl = ERR_PTR(-ENODATA);
        } else if (retval < 0) {
                acl = ERR_PTR(retval);
        } else {
                acl = posix_acl_from_disk(value, retval);
                if (!IS_ERR(acl))
                        *p_acl = posix_acl_dup(acl);
        }

        kfree(value);
        return acl;
}

/*
 * Inode operation set_posix_acl().
 *
 * inode->i_mutex: down
 * BKL held [before 2.5.x]
 */
static int
reiserfs_set_acl(struct inode *inode, int type, struct posix_acl *acl)
{
        char *name;
        void *value = NULL;
        struct posix_acl **p_acl;
        size_t size;
        int error;
        struct reiserfs_inode_info *reiserfs_i = REISERFS_I(inode);

        if (S_ISLNK(inode->i_mode))
                return -EOPNOTSUPP;

        switch (type) {
        case ACL_TYPE_ACCESS:
                name = POSIX_ACL_XATTR_ACCESS;
                p_acl = &reiserfs_i->i_acl_access;
                if (acl) {
                        mode_t mode = inode->i_mode;
                        error = posix_acl_equiv_mode(acl, &mode);
                        if (error < 0)
                                return error;
                        else {
                                inode->i_mode = mode;
                                if (error == 0)
                                        acl = NULL;
                        }
                }
                break;
        case ACL_TYPE_DEFAULT:
                name = POSIX_ACL_XATTR_DEFAULT;
                p_acl = &reiserfs_i->i_acl_default;
                if (!S_ISDIR(inode->i_mode))
                        return acl ? -EACCES : 0;
                break;
        default:
                return -EINVAL;
        }

        if (acl) {
                value = posix_acl_to_disk(acl, &size);
                if (IS_ERR(value))
                        return (int)PTR_ERR(value);
                error = reiserfs_xattr_set(inode, name, value, size, 0);
        } else {
                error = reiserfs_xattr_del(inode, name);
                if (error == -ENODATA) {
                        /* This may seem odd here, but it means that the ACL was set
                         * with a value representable with mode bits. If there was
                         * an ACL before, reiserfs_xattr_del already dirtied the inode.
                         */
                        mark_inode_dirty(inode);
                        error = 0;
                }
        }

        kfree(value);

        if (!error) {
                /* Release the old one */
                if (!IS_ERR(*p_acl) && *p_acl)
                        posix_acl_release(*p_acl);

                if (acl == NULL)
                        *p_acl = ERR_PTR(-ENODATA);
                else
                        *p_acl = posix_acl_dup(acl);
        }

        return error;
}

/* dir->i_mutex: locked,
 * inode is new and not released into the wild yet */
int
reiserfs_inherit_default_acl(struct inode *dir, struct dentry *dentry,
                             struct inode *inode)
{
        struct posix_acl *acl;
        int err = 0;

        /* ACLs only get applied to files and directories */
        if (S_ISLNK(inode->i_mode))
                return 0;

        /* ACLs can only be used on "new" objects, so if it's an old object
         * there is nothing to inherit from */
        if (get_inode_sd_version(dir) == STAT_DATA_V1)
                goto apply_umask;

        /* Don't apply ACLs to objects in the .reiserfs_priv tree.. This
         * would be useless since permissions are ignored, and a pain because
         * it introduces locking cycles */
        if (is_reiserfs_priv_object(dir)) {
                reiserfs_mark_inode_private(inode);
                goto apply_umask;
        }

        acl = reiserfs_get_acl(dir, ACL_TYPE_DEFAULT);
        if (IS_ERR(acl)) {
                if (PTR_ERR(acl) == -ENODATA)
                        goto apply_umask;
                return PTR_ERR(acl);
        }

        if (acl) {
                struct posix_acl *acl_copy;
                mode_t mode = inode->i_mode;
                int need_acl;

                /* Copy the default ACL to the default ACL of a new directory */
                if (S_ISDIR(inode->i_mode)) {
                        err = reiserfs_set_acl(inode, ACL_TYPE_DEFAULT, acl);
                        if (err)
                                goto cleanup;
                }

                /* Now we reconcile the new ACL and the mode,
                   potentially modifying both */
                acl_copy = posix_acl_clone(acl, GFP_NOFS);
                if (!acl_copy) {
                        err = -ENOMEM;
                        goto cleanup;
                }

                need_acl = posix_acl_create_masq(acl_copy, &mode);
                if (need_acl >= 0) {
                        if (mode != inode->i_mode) {
                                inode->i_mode = mode;
                        }

                        /* If we need an ACL.. */
                        if (need_acl > 0) {
                                err =
                                    reiserfs_set_acl(inode, ACL_TYPE_ACCESS,
                                                     acl_copy);
                                if (err)
                                        goto cleanup_copy;
                        }
                }
              cleanup_copy:
                posix_acl_release(acl_copy);
              cleanup:
                posix_acl_release(acl);
        } else {
              apply_umask:
                /* no ACL, apply umask */
                inode->i_mode &= ~current->fs->umask;
        }

        return err;
}

/* Looks up and caches the result of the default ACL.
 * We do this so that we don't need to carry the xattr_sem into
 * reiserfs_new_inode if we don't need to */
int reiserfs_cache_default_acl(struct inode *inode)
{
        int ret = 0;
        if (reiserfs_posixacl(inode->i_sb) && !is_reiserfs_priv_object(inode)) {
                struct posix_acl *acl;
                reiserfs_read_lock_xattr_i(inode);
                reiserfs_read_lock_xattrs(inode->i_sb);
                acl = reiserfs_get_acl(inode, ACL_TYPE_DEFAULT);
                reiserfs_read_unlock_xattrs(inode->i_sb);
                reiserfs_read_unlock_xattr_i(inode);
                ret = (acl && !IS_ERR(acl));
                if (ret)
                        posix_acl_release(acl);
        }

        return ret;
}

int reiserfs_acl_chmod(struct inode *inode)
{
        struct posix_acl *acl, *clone;
        int error;

        if (S_ISLNK(inode->i_mode))
                return -EOPNOTSUPP;

        if (get_inode_sd_version(inode) == STAT_DATA_V1 ||
            !reiserfs_posixacl(inode->i_sb)) {
                return 0;
        }

        reiserfs_read_lock_xattrs(inode->i_sb);
        acl = reiserfs_get_acl(inode, ACL_TYPE_ACCESS);
        reiserfs_read_unlock_xattrs(inode->i_sb);
        if (!acl)
                return 0;
        if (IS_ERR(acl))
                return PTR_ERR(acl);
        clone = posix_acl_clone(acl, GFP_NOFS);
        posix_acl_release(acl);
        if (!clone)
                return -ENOMEM;
        error = posix_acl_chmod_masq(clone, inode->i_mode);
        if (!error) {
                int lock = !has_xattr_dir(inode);
                reiserfs_write_lock_xattr_i(inode);
                if (lock)
                        reiserfs_write_lock_xattrs(inode->i_sb);
                else
                        reiserfs_read_lock_xattrs(inode->i_sb);
                error = reiserfs_set_acl(inode, ACL_TYPE_ACCESS, clone);
                if (lock)
                        reiserfs_write_unlock_xattrs(inode->i_sb);
                else
                        reiserfs_read_unlock_xattrs(inode->i_sb);
                reiserfs_write_unlock_xattr_i(inode);
        }
        posix_acl_release(clone);
        return error;
}

static int
posix_acl_access_get(struct inode *inode, const char *name,
                     void *buffer, size_t size)
{
        if (strlen(name) != sizeof(POSIX_ACL_XATTR_ACCESS) - 1)
                return -EINVAL;
        return xattr_get_acl(inode, ACL_TYPE_ACCESS, buffer, size);
}

static int
posix_acl_access_set(struct inode *inode, const char *name,
                     const void *value, size_t size, int flags)
{
        if (strlen(name) != sizeof(POSIX_ACL_XATTR_ACCESS) - 1)
                return -EINVAL;
        return xattr_set_acl(inode, ACL_TYPE_ACCESS, value, size);
}

static int posix_acl_access_del(struct inode *inode, const char *name)
{
        struct reiserfs_inode_info *reiserfs_i = REISERFS_I(inode);
        struct posix_acl **acl = &reiserfs_i->i_acl_access;
        if (strlen(name) != sizeof(POSIX_ACL_XATTR_ACCESS) - 1)
                return -EINVAL;
        if (!IS_ERR(*acl) && *acl) {
                posix_acl_release(*acl);
                *acl = ERR_PTR(-ENODATA);
        }

        return 0;
}

static int
posix_acl_access_list(struct inode *inode, const char *name, int namelen,
                      char *out)
{
        int len = namelen;
        if (!reiserfs_posixacl(inode->i_sb))
                return 0;
        if (out)
                memcpy(out, name, len);

        return len;
}

struct reiserfs_xattr_handler posix_acl_access_handler = {
        .prefix = POSIX_ACL_XATTR_ACCESS,
        .get = posix_acl_access_get,
        .set = posix_acl_access_set,
        .del = posix_acl_access_del,
        .list = posix_acl_access_list,
};

static int
posix_acl_default_get(struct inode *inode, const char *name,
                      void *buffer, size_t size)
{
        if (strlen(name) != sizeof(POSIX_ACL_XATTR_DEFAULT) - 1)
                return -EINVAL;
        return xattr_get_acl(inode, ACL_TYPE_DEFAULT, buffer, size);
}

static int
posix_acl_default_set(struct inode *inode, const char *name,
                      const void *value, size_t size, int flags)
{
        if (strlen(name) != sizeof(POSIX_ACL_XATTR_DEFAULT) - 1)
                return -EINVAL;
        return xattr_set_acl(inode, ACL_TYPE_DEFAULT, value, size);
}

static int posix_acl_default_del(struct inode *inode, const char *name)
{
        struct reiserfs_inode_info *reiserfs_i = REISERFS_I(inode);
        struct posix_acl **acl = &reiserfs_i->i_acl_default;
        if (strlen(name) != sizeof(POSIX_ACL_XATTR_DEFAULT) - 1)
                return -EINVAL;
        if (!IS_ERR(*acl) && *acl) {
                posix_acl_release(*acl);
                *acl = ERR_PTR(-ENODATA);
        }

        return 0;
}

static int
posix_acl_default_list(struct inode *inode, const char *name, int namelen,
                       char *out)
{
        int len = namelen;
        if (!reiserfs_posixacl(inode->i_sb))
                return 0;
        if (out)
                memcpy(out, name, len);

        return len;
}

struct reiserfs_xattr_handler posix_acl_default_handler = {
        .prefix = POSIX_ACL_XATTR_DEFAULT,
        .get = posix_acl_default_get,
        .set = posix_acl_default_set,
        .del = posix_acl_default_del,
        .list = posix_acl_default_list,
};

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