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root/fs/jffs2/acl.c

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DEFINITIONS

This source file includes following definitions.
  1. jffs2_acl_size
  2. jffs2_acl_count
  3. jffs2_acl_from_medium
  4. jffs2_acl_to_medium
  5. jffs2_iget_acl
  6. jffs2_iset_acl
  7. jffs2_get_acl
  8. __jffs2_set_acl
  9. jffs2_set_acl
  10. jffs2_check_acl
  11. jffs2_permission
  12. jffs2_init_acl_pre
  13. jffs2_init_acl_post
  14. jffs2_clear_acl
  15. jffs2_acl_chmod
  16. jffs2_acl_access_listxattr
  17. jffs2_acl_default_listxattr
  18. jffs2_acl_getxattr
  19. jffs2_acl_access_getxattr
  20. jffs2_acl_default_getxattr
  21. jffs2_acl_setxattr
  22. jffs2_acl_access_setxattr
  23. jffs2_acl_default_setxattr

/*
 * JFFS2 -- Journalling Flash File System, Version 2.
 *
 * Copyright © 2006  NEC Corporation
 *
 * Created by KaiGai Kohei <kaigai@ak.jp.nec.com>
 *
 * For licensing information, see the file 'LICENCE' in this directory.
 *
 */

#include <linux/kernel.h>
#include <linux/slab.h>
#include <linux/fs.h>
#include <linux/sched.h>
#include <linux/time.h>
#include <linux/crc32.h>
#include <linux/jffs2.h>
#include <linux/xattr.h>
#include <linux/posix_acl_xattr.h>
#include <linux/mtd/mtd.h>
#include "nodelist.h"

static size_t jffs2_acl_size(int count)
{
        if (count <= 4) {
                return sizeof(struct jffs2_acl_header)
                       + count * sizeof(struct jffs2_acl_entry_short);
        } else {
                return sizeof(struct jffs2_acl_header)
                       + 4 * sizeof(struct jffs2_acl_entry_short)
                       + (count - 4) * sizeof(struct jffs2_acl_entry);
        }
}

static int jffs2_acl_count(size_t size)
{
        size_t s;

        size -= sizeof(struct jffs2_acl_header);
        s = size - 4 * sizeof(struct jffs2_acl_entry_short);
        if (s < 0) {
                if (size % sizeof(struct jffs2_acl_entry_short))
                        return -1;
                return size / sizeof(struct jffs2_acl_entry_short);
        } else {
                if (s % sizeof(struct jffs2_acl_entry))
                        return -1;
                return s / sizeof(struct jffs2_acl_entry) + 4;
        }
}

static struct posix_acl *jffs2_acl_from_medium(void *value, size_t size)
{
        void *end = value + size;
        struct jffs2_acl_header *header = value;
        struct jffs2_acl_entry *entry;
        struct posix_acl *acl;
        uint32_t ver;
        int i, count;

        if (!value)
                return NULL;
        if (size < sizeof(struct jffs2_acl_header))
                return ERR_PTR(-EINVAL);
        ver = je32_to_cpu(header->a_version);
        if (ver != JFFS2_ACL_VERSION) {
                JFFS2_WARNING("Invalid ACL version. (=%u)\n", ver);
                return ERR_PTR(-EINVAL);
        }

        value += sizeof(struct jffs2_acl_header);
        count = jffs2_acl_count(size);
        if (count < 0)
                return ERR_PTR(-EINVAL);
        if (count == 0)
                return NULL;

        acl = posix_acl_alloc(count, GFP_KERNEL);
        if (!acl)
                return ERR_PTR(-ENOMEM);

        for (i=0; i < count; i++) {
                entry = value;
                if (value + sizeof(struct jffs2_acl_entry_short) > end)
                        goto fail;
                acl->a_entries[i].e_tag = je16_to_cpu(entry->e_tag);
                acl->a_entries[i].e_perm = je16_to_cpu(entry->e_perm);
                switch (acl->a_entries[i].e_tag) {
                        case ACL_USER_OBJ:
                        case ACL_GROUP_OBJ:
                        case ACL_MASK:
                        case ACL_OTHER:
                                value += sizeof(struct jffs2_acl_entry_short);
                                acl->a_entries[i].e_id = ACL_UNDEFINED_ID;
                                break;

                        case ACL_USER:
                        case ACL_GROUP:
                                value += sizeof(struct jffs2_acl_entry);
                                if (value > end)
                                        goto fail;
                                acl->a_entries[i].e_id = je32_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);
}

static void *jffs2_acl_to_medium(const struct posix_acl *acl, size_t *size)
{
        struct jffs2_acl_header *header;
        struct jffs2_acl_entry *entry;
        void *e;
        size_t i;

        *size = jffs2_acl_size(acl->a_count);
        header = kmalloc(sizeof(*header) + acl->a_count * sizeof(*entry), GFP_KERNEL);
        if (!header)
                return ERR_PTR(-ENOMEM);
        header->a_version = cpu_to_je32(JFFS2_ACL_VERSION);
        e = header + 1;
        for (i=0; i < acl->a_count; i++) {
                entry = e;
                entry->e_tag = cpu_to_je16(acl->a_entries[i].e_tag);
                entry->e_perm = cpu_to_je16(acl->a_entries[i].e_perm);
                switch(acl->a_entries[i].e_tag) {
                        case ACL_USER:
                        case ACL_GROUP:
                                entry->e_id = cpu_to_je32(acl->a_entries[i].e_id);
                                e += sizeof(struct jffs2_acl_entry);
                                break;

                        case ACL_USER_OBJ:
                        case ACL_GROUP_OBJ:
                        case ACL_MASK:
                        case ACL_OTHER:
                                e += sizeof(struct jffs2_acl_entry_short);
                                break;

                        default:
                                goto fail;
                }
        }
        return header;
 fail:
        kfree(header);
        return ERR_PTR(-EINVAL);
}

static struct posix_acl *jffs2_iget_acl(struct inode *inode, struct posix_acl **i_acl)
{
        struct posix_acl *acl = JFFS2_ACL_NOT_CACHED;

        spin_lock(&inode->i_lock);
        if (*i_acl != JFFS2_ACL_NOT_CACHED)
                acl = posix_acl_dup(*i_acl);
        spin_unlock(&inode->i_lock);
        return acl;
}

static void jffs2_iset_acl(struct inode *inode, struct posix_acl **i_acl, struct posix_acl *acl)
{
        spin_lock(&inode->i_lock);
        if (*i_acl != JFFS2_ACL_NOT_CACHED)
                posix_acl_release(*i_acl);
        *i_acl = posix_acl_dup(acl);
        spin_unlock(&inode->i_lock);
}

static struct posix_acl *jffs2_get_acl(struct inode *inode, int type)
{
        struct jffs2_inode_info *f = JFFS2_INODE_INFO(inode);
        struct posix_acl *acl;
        char *value = NULL;
        int rc, xprefix;

        switch (type) {
        case ACL_TYPE_ACCESS:
                acl = jffs2_iget_acl(inode, &f->i_acl_access);
                if (acl != JFFS2_ACL_NOT_CACHED)
                        return acl;
                xprefix = JFFS2_XPREFIX_ACL_ACCESS;
                break;
        case ACL_TYPE_DEFAULT:
                acl = jffs2_iget_acl(inode, &f->i_acl_default);
                if (acl != JFFS2_ACL_NOT_CACHED)
                        return acl;
                xprefix = JFFS2_XPREFIX_ACL_DEFAULT;
                break;
        default:
                return ERR_PTR(-EINVAL);
        }
        rc = do_jffs2_getxattr(inode, xprefix, "", NULL, 0);
        if (rc > 0) {
                value = kmalloc(rc, GFP_KERNEL);
                if (!value)
                        return ERR_PTR(-ENOMEM);
                rc = do_jffs2_getxattr(inode, xprefix, "", value, rc);
        }
        if (rc > 0) {
                acl = jffs2_acl_from_medium(value, rc);
        } else if (rc == -ENODATA || rc == -ENOSYS) {
                acl = NULL;
        } else {
                acl = ERR_PTR(rc);
        }
        if (value)
                kfree(value);
        if (!IS_ERR(acl)) {
                switch (type) {
                case ACL_TYPE_ACCESS:
                        jffs2_iset_acl(inode, &f->i_acl_access, acl);
                        break;
                case ACL_TYPE_DEFAULT:
                        jffs2_iset_acl(inode, &f->i_acl_default, acl);
                        break;
                }
        }
        return acl;
}

static int __jffs2_set_acl(struct inode *inode, int xprefix, struct posix_acl *acl)
{
        char *value = NULL;
        size_t size = 0;
        int rc;

        if (acl) {
                value = jffs2_acl_to_medium(acl, &size);
                if (IS_ERR(value))
                        return PTR_ERR(value);
        }
        rc = do_jffs2_setxattr(inode, xprefix, "", value, size, 0);
        if (!value && rc == -ENODATA)
                rc = 0;
        kfree(value);

        return rc;
}

static int jffs2_set_acl(struct inode *inode, int type, struct posix_acl *acl)
{
        struct jffs2_inode_info *f = JFFS2_INODE_INFO(inode);
        int rc, xprefix;

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

        switch (type) {
        case ACL_TYPE_ACCESS:
                xprefix = JFFS2_XPREFIX_ACL_ACCESS;
                if (acl) {
                        mode_t mode = inode->i_mode;
                        rc = posix_acl_equiv_mode(acl, &mode);
                        if (rc < 0)
                                return rc;
                        if (inode->i_mode != mode) {
                                struct iattr attr;

                                attr.ia_valid = ATTR_MODE;
                                attr.ia_mode = mode;
                                rc = jffs2_do_setattr(inode, &attr);
                                if (rc < 0)
                                        return rc;
                        }
                        if (rc == 0)
                                acl = NULL;
                }
                break;
        case ACL_TYPE_DEFAULT:
                xprefix = JFFS2_XPREFIX_ACL_DEFAULT;
                if (!S_ISDIR(inode->i_mode))
                        return acl ? -EACCES : 0;
                break;
        default:
                return -EINVAL;
        }
        rc = __jffs2_set_acl(inode, xprefix, acl);
        if (!rc) {
                switch(type) {
                case ACL_TYPE_ACCESS:
                        jffs2_iset_acl(inode, &f->i_acl_access, acl);
                        break;
                case ACL_TYPE_DEFAULT:
                        jffs2_iset_acl(inode, &f->i_acl_default, acl);
                        break;
                }
        }
        return rc;
}

static int jffs2_check_acl(struct inode *inode, int mask)
{
        struct posix_acl *acl;
        int rc;

        acl = jffs2_get_acl(inode, ACL_TYPE_ACCESS);
        if (IS_ERR(acl))
                return PTR_ERR(acl);
        if (acl) {
                rc = posix_acl_permission(inode, acl, mask);
                posix_acl_release(acl);
                return rc;
        }
        return -EAGAIN;
}

int jffs2_permission(struct inode *inode, int mask)
{
        return generic_permission(inode, mask, jffs2_check_acl);
}

int jffs2_init_acl_pre(struct inode *dir_i, struct inode *inode, int *i_mode)
{
        struct jffs2_inode_info *f = JFFS2_INODE_INFO(inode);
        struct posix_acl *acl, *clone;
        int rc;

        f->i_acl_default = NULL;
        f->i_acl_access = NULL;

        if (S_ISLNK(*i_mode))
                return 0;       /* Symlink always has no-ACL */

        acl = jffs2_get_acl(dir_i, ACL_TYPE_DEFAULT);
        if (IS_ERR(acl))
                return PTR_ERR(acl);

        if (!acl) {
                *i_mode &= ~current->fs->umask;
        } else {
                if (S_ISDIR(*i_mode))
                        jffs2_iset_acl(inode, &f->i_acl_default, acl);

                clone = posix_acl_clone(acl, GFP_KERNEL);
                if (!clone)
                        return -ENOMEM;
                rc = posix_acl_create_masq(clone, (mode_t *)i_mode);
                if (rc < 0) {
                        posix_acl_release(clone);
                        return rc;
                }
                if (rc > 0)
                        jffs2_iset_acl(inode, &f->i_acl_access, clone);

                posix_acl_release(clone);
        }
        return 0;
}

int jffs2_init_acl_post(struct inode *inode)
{
        struct jffs2_inode_info *f = JFFS2_INODE_INFO(inode);
        int rc;

        if (f->i_acl_default) {
                rc = __jffs2_set_acl(inode, JFFS2_XPREFIX_ACL_DEFAULT, f->i_acl_default);
                if (rc)
                        return rc;
        }

        if (f->i_acl_access) {
                rc = __jffs2_set_acl(inode, JFFS2_XPREFIX_ACL_ACCESS, f->i_acl_access);
                if (rc)
                        return rc;
        }

        return 0;
}

void jffs2_clear_acl(struct jffs2_inode_info *f)
{
        if (f->i_acl_access && f->i_acl_access != JFFS2_ACL_NOT_CACHED) {
                posix_acl_release(f->i_acl_access);
                f->i_acl_access = JFFS2_ACL_NOT_CACHED;
        }
        if (f->i_acl_default && f->i_acl_default != JFFS2_ACL_NOT_CACHED) {
                posix_acl_release(f->i_acl_default);
                f->i_acl_default = JFFS2_ACL_NOT_CACHED;
        }
}

int jffs2_acl_chmod(struct inode *inode)
{
        struct posix_acl *acl, *clone;
        int rc;

        if (S_ISLNK(inode->i_mode))
                return -EOPNOTSUPP;
        acl = jffs2_get_acl(inode, ACL_TYPE_ACCESS);
        if (IS_ERR(acl) || !acl)
                return PTR_ERR(acl);
        clone = posix_acl_clone(acl, GFP_KERNEL);
        posix_acl_release(acl);
        if (!clone)
                return -ENOMEM;
        rc = posix_acl_chmod_masq(clone, inode->i_mode);
        if (!rc)
                rc = jffs2_set_acl(inode, ACL_TYPE_ACCESS, clone);
        posix_acl_release(clone);
        return rc;
}

static size_t jffs2_acl_access_listxattr(struct inode *inode, char *list, size_t list_size,
                                         const char *name, size_t name_len)
{
        const int retlen = sizeof(POSIX_ACL_XATTR_ACCESS);

        if (list && retlen <= list_size)
                strcpy(list, POSIX_ACL_XATTR_ACCESS);
        return retlen;
}

static size_t jffs2_acl_default_listxattr(struct inode *inode, char *list, size_t list_size,
                                          const char *name, size_t name_len)
{
        const int retlen = sizeof(POSIX_ACL_XATTR_DEFAULT);

        if (list && retlen <= list_size)
                strcpy(list, POSIX_ACL_XATTR_DEFAULT);
        return retlen;
}

static int jffs2_acl_getxattr(struct inode *inode, int type, void *buffer, size_t size)
{
        struct posix_acl *acl;
        int rc;

        acl = jffs2_get_acl(inode, type);
        if (IS_ERR(acl))
                return PTR_ERR(acl);
        if (!acl)
                return -ENODATA;
        rc = posix_acl_to_xattr(acl, buffer, size);
        posix_acl_release(acl);

        return rc;
}

static int jffs2_acl_access_getxattr(struct inode *inode, const char *name, void *buffer, size_t size)
{
        if (name[0] != '\0')
                return -EINVAL;
        return jffs2_acl_getxattr(inode, ACL_TYPE_ACCESS, buffer, size);
}

static int jffs2_acl_default_getxattr(struct inode *inode, const char *name, void *buffer, size_t size)
{
        if (name[0] != '\0')
                return -EINVAL;
        return jffs2_acl_getxattr(inode, ACL_TYPE_DEFAULT, buffer, size);
}

static int jffs2_acl_setxattr(struct inode *inode, int type, const void *value, size_t size)
{
        struct posix_acl *acl;
        int rc;

        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);
                if (acl) {
                        rc = posix_acl_valid(acl);
                        if (rc)
                                goto out;
                }
        } else {
                acl = NULL;
        }
        rc = jffs2_set_acl(inode, type, acl);
 out:
        posix_acl_release(acl);
        return rc;
}

static int jffs2_acl_access_setxattr(struct inode *inode, const char *name,
                                     const void *buffer, size_t size, int flags)
{
        if (name[0] != '\0')
                return -EINVAL;
        return jffs2_acl_setxattr(inode, ACL_TYPE_ACCESS, buffer, size);
}

static int jffs2_acl_default_setxattr(struct inode *inode, const char *name,
                                      const void *buffer, size_t size, int flags)
{
        if (name[0] != '\0')
                return -EINVAL;
        return jffs2_acl_setxattr(inode, ACL_TYPE_DEFAULT, buffer, size);
}

struct xattr_handler jffs2_acl_access_xattr_handler = {
        .prefix = POSIX_ACL_XATTR_ACCESS,
        .list   = jffs2_acl_access_listxattr,
        .get    = jffs2_acl_access_getxattr,
        .set    = jffs2_acl_access_setxattr,
};

struct xattr_handler jffs2_acl_default_xattr_handler = {
        .prefix = POSIX_ACL_XATTR_DEFAULT,
        .list   = jffs2_acl_default_listxattr,
        .get    = jffs2_acl_default_getxattr,
        .set    = jffs2_acl_default_setxattr,
};

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