--- /dev/null
+/*
+ * linux/fs/ext4/acl.c
+ *
+ * Copyright (C) 2001-2003 Andreas Gruenbacher, <agruen@suse.de>
+ */
+
+#include <linux/init.h>
+#include <linux/sched.h>
+#include <linux/slab.h>
+#include <linux/capability.h>
+#include <linux/fs.h>
+#include <linux/ext4_jbd2.h>
+#include <linux/ext4_fs.h>
+#include "xattr.h"
+#include "acl.h"
+
+/*
+ * Convert from filesystem to in-memory representation.
+ */
+static struct posix_acl *
+ext4_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(ext4_acl_header))
+ return ERR_PTR(-EINVAL);
+ if (((ext4_acl_header *)value)->a_version !=
+ cpu_to_le32(EXT4_ACL_VERSION))
+ return ERR_PTR(-EINVAL);
+ value = (char *)value + sizeof(ext4_acl_header);
+ count = ext4_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 (n=0; n < count; n++) {
+ ext4_acl_entry *entry =
+ (ext4_acl_entry *)value;
+ if ((char *)value + sizeof(ext4_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(ext4_acl_entry_short);
+ acl->a_entries[n].e_id = ACL_UNDEFINED_ID;
+ break;
+
+ case ACL_USER:
+ case ACL_GROUP:
+ value = (char *)value + sizeof(ext4_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 *
+ext4_acl_to_disk(const struct posix_acl *acl, size_t *size)
+{
+ ext4_acl_header *ext_acl;
+ char *e;
+ size_t n;
+
+ *size = ext4_acl_size(acl->a_count);
+ ext_acl = kmalloc(sizeof(ext4_acl_header) + acl->a_count *
+ sizeof(ext4_acl_entry), GFP_KERNEL);
+ if (!ext_acl)
+ return ERR_PTR(-ENOMEM);
+ ext_acl->a_version = cpu_to_le32(EXT4_ACL_VERSION);
+ e = (char *)ext_acl + sizeof(ext4_acl_header);
+ for (n=0; n < acl->a_count; n++) {
+ ext4_acl_entry *entry = (ext4_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(ext4_acl_entry);
+ break;
+
+ case ACL_USER_OBJ:
+ case ACL_GROUP_OBJ:
+ case ACL_MASK:
+ case ACL_OTHER:
+ e += sizeof(ext4_acl_entry_short);
+ break;
+
+ default:
+ goto fail;
+ }
+ }
+ return (char *)ext_acl;
+
+fail:
+ kfree(ext_acl);
+ return ERR_PTR(-EINVAL);
+}
+
+static inline struct posix_acl *
+ext4_iget_acl(struct inode *inode, struct posix_acl **i_acl)
+{
+ struct posix_acl *acl = EXT4_ACL_NOT_CACHED;
+
+ spin_lock(&inode->i_lock);
+ if (*i_acl != EXT4_ACL_NOT_CACHED)
+ acl = posix_acl_dup(*i_acl);
+ spin_unlock(&inode->i_lock);
+
+ return acl;
+}
+
+static inline void
+ext4_iset_acl(struct inode *inode, struct posix_acl **i_acl,
+ struct posix_acl *acl)
+{
+ spin_lock(&inode->i_lock);
+ if (*i_acl != EXT4_ACL_NOT_CACHED)
+ posix_acl_release(*i_acl);
+ *i_acl = posix_acl_dup(acl);
+ spin_unlock(&inode->i_lock);
+}
+
+/*
+ * Inode operation get_posix_acl().
+ *
+ * inode->i_mutex: don't care
+ */
+static struct posix_acl *
+ext4_get_acl(struct inode *inode, int type)
+{
+ struct ext4_inode_info *ei = EXT4_I(inode);
+ int name_index;
+ char *value = NULL;
+ struct posix_acl *acl;
+ int retval;
+
+ if (!test_opt(inode->i_sb, POSIX_ACL))
+ return NULL;
+
+ switch(type) {
+ case ACL_TYPE_ACCESS:
+ acl = ext4_iget_acl(inode, &ei->i_acl);
+ if (acl != EXT4_ACL_NOT_CACHED)
+ return acl;
+ name_index = EXT4_XATTR_INDEX_POSIX_ACL_ACCESS;
+ break;
+
+ case ACL_TYPE_DEFAULT:
+ acl = ext4_iget_acl(inode, &ei->i_default_acl);
+ if (acl != EXT4_ACL_NOT_CACHED)
+ return acl;
+ name_index = EXT4_XATTR_INDEX_POSIX_ACL_DEFAULT;
+ break;
+
+ default:
+ return ERR_PTR(-EINVAL);
+ }
+ retval = ext4_xattr_get(inode, name_index, "", NULL, 0);
+ if (retval > 0) {
+ value = kmalloc(retval, GFP_KERNEL);
+ if (!value)
+ return ERR_PTR(-ENOMEM);
+ retval = ext4_xattr_get(inode, name_index, "", value, retval);
+ }
+ if (retval > 0)
+ acl = ext4_acl_from_disk(value, retval);
+ else if (retval == -ENODATA || retval == -ENOSYS)
+ acl = NULL;
+ else
+ acl = ERR_PTR(retval);
+ kfree(value);
+
+ if (!IS_ERR(acl)) {
+ switch(type) {
+ case ACL_TYPE_ACCESS:
+ ext4_iset_acl(inode, &ei->i_acl, acl);
+ break;
+
+ case ACL_TYPE_DEFAULT:
+ ext4_iset_acl(inode, &ei->i_default_acl, acl);
+ break;
+ }
+ }
+ return acl;
+}
+
+/*
+ * Set the access or default ACL of an inode.
+ *
+ * inode->i_mutex: down unless called from ext4_new_inode
+ */
+static int
+ext4_set_acl(handle_t *handle, struct inode *inode, int type,
+ struct posix_acl *acl)
+{
+ struct ext4_inode_info *ei = EXT4_I(inode);
+ int name_index;
+ void *value = NULL;
+ size_t size = 0;
+ int error;
+
+ if (S_ISLNK(inode->i_mode))
+ return -EOPNOTSUPP;
+
+ switch(type) {
+ case ACL_TYPE_ACCESS:
+ name_index = EXT4_XATTR_INDEX_POSIX_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;
+ ext4_mark_inode_dirty(handle, inode);
+ if (error == 0)
+ acl = NULL;
+ }
+ }
+ break;
+
+ case ACL_TYPE_DEFAULT:
+ name_index = EXT4_XATTR_INDEX_POSIX_ACL_DEFAULT;
+ if (!S_ISDIR(inode->i_mode))
+ return acl ? -EACCES : 0;
+ break;
+
+ default:
+ return -EINVAL;
+ }
+ if (acl) {
+ value = ext4_acl_to_disk(acl, &size);
+ if (IS_ERR(value))
+ return (int)PTR_ERR(value);
+ }
+
+ error = ext4_xattr_set_handle(handle, inode, name_index, "",
+ value, size, 0);
+
+ kfree(value);
+ if (!error) {
+ switch(type) {
+ case ACL_TYPE_ACCESS:
+ ext4_iset_acl(inode, &ei->i_acl, acl);
+ break;
+
+ case ACL_TYPE_DEFAULT:
+ ext4_iset_acl(inode, &ei->i_default_acl, acl);
+ break;
+ }
+ }
+ return error;
+}
+
+static int
+ext4_check_acl(struct inode *inode, int mask)
+{
+ struct posix_acl *acl = ext4_get_acl(inode, ACL_TYPE_ACCESS);
+
+ if (IS_ERR(acl))
+ return PTR_ERR(acl);
+ if (acl) {
+ int error = posix_acl_permission(inode, acl, mask);
+ posix_acl_release(acl);
+ return error;
+ }
+
+ return -EAGAIN;
+}
+
+int
+ext4_permission(struct inode *inode, int mask, struct nameidata *nd)
+{
+ return generic_permission(inode, mask, ext4_check_acl);
+}
+
+/*
+ * Initialize the ACLs of a new inode. Called from ext4_new_inode.
+ *
+ * dir->i_mutex: down
+ * inode->i_mutex: up (access to inode is still exclusive)
+ */
+int
+ext4_init_acl(handle_t *handle, struct inode *inode, struct inode *dir)
+{
+ struct posix_acl *acl = NULL;
+ int error = 0;
+
+ if (!S_ISLNK(inode->i_mode)) {
+ if (test_opt(dir->i_sb, POSIX_ACL)) {
+ acl = ext4_get_acl(dir, ACL_TYPE_DEFAULT);
+ if (IS_ERR(acl))
+ return PTR_ERR(acl);
+ }
+ if (!acl)
+ inode->i_mode &= ~current->fs->umask;
+ }
+ if (test_opt(inode->i_sb, POSIX_ACL) && acl) {
+ struct posix_acl *clone;
+ mode_t mode;
+
+ if (S_ISDIR(inode->i_mode)) {
+ error = ext4_set_acl(handle, inode,
+ ACL_TYPE_DEFAULT, acl);
+ if (error)
+ goto cleanup;
+ }
+ clone = posix_acl_clone(acl, GFP_KERNEL);
+ error = -ENOMEM;
+ if (!clone)
+ goto cleanup;
+
+ mode = inode->i_mode;
+ error = posix_acl_create_masq(clone, &mode);
+ if (error >= 0) {
+ inode->i_mode = mode;
+ if (error > 0) {
+ /* This is an extended ACL */
+ error = ext4_set_acl(handle, inode,
+ ACL_TYPE_ACCESS, clone);
+ }
+ }
+ posix_acl_release(clone);
+ }
+cleanup:
+ posix_acl_release(acl);
+ return error;
+}
+
+/*
+ * Does chmod for an inode that may have an Access Control List. The
+ * inode->i_mode field must be updated to the desired value by the caller
+ * before calling this function.
+ * Returns 0 on success, or a negative error number.
+ *
+ * We change the ACL rather than storing some ACL entries in the file
+ * mode permission bits (which would be more efficient), because that
+ * would break once additional permissions (like ACL_APPEND, ACL_DELETE
+ * for directories) are added. There are no more bits available in the
+ * file mode.
+ *
+ * inode->i_mutex: down
+ */
+int
+ext4_acl_chmod(struct inode *inode)
+{
+ struct posix_acl *acl, *clone;
+ int error;
+
+ if (S_ISLNK(inode->i_mode))
+ return -EOPNOTSUPP;
+ if (!test_opt(inode->i_sb, POSIX_ACL))
+ return 0;
+ acl = ext4_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;
+ error = posix_acl_chmod_masq(clone, inode->i_mode);
+ if (!error) {
+ handle_t *handle;
+ int retries = 0;
+
+ retry:
+ handle = ext4_journal_start(inode,
+ EXT4_DATA_TRANS_BLOCKS(inode->i_sb));
+ if (IS_ERR(handle)) {
+ error = PTR_ERR(handle);
+ ext4_std_error(inode->i_sb, error);
+ goto out;
+ }
+ error = ext4_set_acl(handle, inode, ACL_TYPE_ACCESS, clone);
+ ext4_journal_stop(handle);
+ if (error == -ENOSPC &&
+ ext4_should_retry_alloc(inode->i_sb, &retries))
+ goto retry;
+ }
+out:
+ posix_acl_release(clone);
+ return error;
+}
+
+/*
+ * Extended attribute handlers
+ */
+static size_t
+ext4_xattr_list_acl_access(struct inode *inode, char *list, size_t list_len,
+ const char *name, size_t name_len)
+{
+ const size_t size = sizeof(POSIX_ACL_XATTR_ACCESS);
+
+ if (!test_opt(inode->i_sb, POSIX_ACL))
+ return 0;
+ if (list && size <= list_len)
+ memcpy(list, POSIX_ACL_XATTR_ACCESS, size);
+ return size;
+}
+
+static size_t
+ext4_xattr_list_acl_default(struct inode *inode, char *list, size_t list_len,
+ const char *name, size_t name_len)
+{
+ const size_t size = sizeof(POSIX_ACL_XATTR_DEFAULT);
+
+ if (!test_opt(inode->i_sb, POSIX_ACL))
+ return 0;
+ if (list && size <= list_len)
+ memcpy(list, POSIX_ACL_XATTR_DEFAULT, size);
+ return size;
+}
+
+static int
+ext4_xattr_get_acl(struct inode *inode, int type, void *buffer, size_t size)
+{
+ struct posix_acl *acl;
+ int error;
+
+ if (!test_opt(inode->i_sb, POSIX_ACL))
+ return -EOPNOTSUPP;
+
+ acl = ext4_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;
+}
+
+static int
+ext4_xattr_get_acl_access(struct inode *inode, const char *name,
+ void *buffer, size_t size)
+{
+ if (strcmp(name, "") != 0)
+ return -EINVAL;
+ return ext4_xattr_get_acl(inode, ACL_TYPE_ACCESS, buffer, size);
+}
+
+static int
+ext4_xattr_get_acl_default(struct inode *inode, const char *name,
+ void *buffer, size_t size)
+{
+ if (strcmp(name, "") != 0)
+ return -EINVAL;
+ return ext4_xattr_get_acl(inode, ACL_TYPE_DEFAULT, buffer, size);
+}
+
+static int
+ext4_xattr_set_acl(struct inode *inode, int type, const void *value,
+ size_t size)
+{
+ handle_t *handle;
+ struct posix_acl *acl;
+ int error, retries = 0;
+
+ if (!test_opt(inode->i_sb, POSIX_ACL))
+ return -EOPNOTSUPP;
+ if ((current->fsuid != inode->i_uid) && !capable(CAP_FOWNER))
+ 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;
+
+retry:
+ handle = ext4_journal_start(inode, EXT4_DATA_TRANS_BLOCKS(inode->i_sb));
+ if (IS_ERR(handle))
+ return PTR_ERR(handle);
+ error = ext4_set_acl(handle, inode, type, acl);
+ ext4_journal_stop(handle);
+ if (error == -ENOSPC && ext4_should_retry_alloc(inode->i_sb, &retries))
+ goto retry;
+
+release_and_out:
+ posix_acl_release(acl);
+ return error;
+}
+
+static int
+ext4_xattr_set_acl_access(struct inode *inode, const char *name,
+ const void *value, size_t size, int flags)
+{
+ if (strcmp(name, "") != 0)
+ return -EINVAL;
+ return ext4_xattr_set_acl(inode, ACL_TYPE_ACCESS, value, size);
+}
+
+static int
+ext4_xattr_set_acl_default(struct inode *inode, const char *name,
+ const void *value, size_t size, int flags)
+{
+ if (strcmp(name, "") != 0)
+ return -EINVAL;
+ return ext4_xattr_set_acl(inode, ACL_TYPE_DEFAULT, value, size);
+}
+
+struct xattr_handler ext4_xattr_acl_access_handler = {
+ .prefix = POSIX_ACL_XATTR_ACCESS,
+ .list = ext4_xattr_list_acl_access,
+ .get = ext4_xattr_get_acl_access,
+ .set = ext4_xattr_set_acl_access,
+};
+
+struct xattr_handler ext4_xattr_acl_default_handler = {
+ .prefix = POSIX_ACL_XATTR_DEFAULT,
+ .list = ext4_xattr_list_acl_default,
+ .get = ext4_xattr_get_acl_default,
+ .set = ext4_xattr_set_acl_default,
+};
git://git.onelab.eu / linux-2.6.git / blobdiff