[RFC PATCH 2/3] UBIFS: ACL: add ACL support
Sheng Yong
shengyong1 at huawei.com
Wed Mar 25 04:46:04 PDT 2015
This implements ACL functionality. ACL is based on xattr.
Signed-off-by: Sheng Yong <shengyong1 at huawei.com>
---
fs/ubifs/acl.c | 316 +++++++++++++++++++++++++++++++++++++++++++++++++++++++
fs/ubifs/dir.c | 7 ++
fs/ubifs/file.c | 14 +++
fs/ubifs/super.c | 15 +++
fs/ubifs/ubifs.h | 5 +
fs/ubifs/xattr.c | 27 ++++-
6 files changed, 383 insertions(+), 1 deletion(-)
create mode 100644 fs/ubifs/acl.c
diff --git a/fs/ubifs/acl.c b/fs/ubifs/acl.c
new file mode 100644
index 0000000..a4cde8f
--- /dev/null
+++ b/fs/ubifs/acl.c
@@ -0,0 +1,316 @@
+/*
+ * This file is part of UBIFS.
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 as published by
+ * the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
+ * more details.
+ *
+ * You should have received a copy of the GNU General Public License along with
+ * this program; if not, write to the Free Software Foundation, Inc., 51
+ * Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
+ *
+ */
+
+/*
+ * ACL is based on Extended Attribute.
+ */
+
+#include <linux/fs.h>
+#include <linux/xattr.h>
+#include <linux/posix_acl_xattr.h>
+
+#include "ubifs.h"
+
+#define UBIFS_ACL_VERSION 0x0001
+
+struct ubifs_acl_entry {
+ __le16 e_tag;
+ __le16 e_perm;
+ __le32 e_id;
+};
+
+struct ubifs_acl_entry_short {
+ __le16 e_tag;
+ __le16 e_perm;
+};
+
+struct ubifs_acl_header {
+ __le32 a_version;
+};
+
+#define UBIFS_ACL_HEADER_SZ sizeof(struct ubifs_acl_header)
+#define UBIFS_ACL_ENTRY_SZ sizeof(struct ubifs_acl_entry)
+#define UBIFS_ACL_ENTRY_SHORT_SZ sizeof(struct ubifs_acl_entry_short)
+
+static inline size_t acl_size(int count)
+{
+ if (count <= 4) {
+ return UBIFS_ACL_HEADER_SZ +
+ count * UBIFS_ACL_ENTRY_SHORT_SZ;
+ } else {
+ return UBIFS_ACL_HEADER_SZ +
+ 4 * UBIFS_ACL_ENTRY_SHORT_SZ +
+ (count - 4) * UBIFS_ACL_ENTRY_SZ;
+ }
+}
+
+static inline int acl_count(size_t size)
+{
+ ssize_t s;
+
+ size -= UBIFS_ACL_HEADER_SZ;
+ s = size - 4 * UBIFS_ACL_ENTRY_SHORT_SZ;
+ if (s < 0) {
+ if (size % UBIFS_ACL_ENTRY_SHORT_SZ)
+ return -1;
+ return size / UBIFS_ACL_ENTRY_SHORT_SZ;
+ } else {
+ if (s % UBIFS_ACL_ENTRY_SZ)
+ return -1;
+ return s / UBIFS_ACL_ENTRY_SZ + 4;
+ }
+}
+
+/* convert from in-memory ACL to on-flash ACL */
+static void *acl_to_flash(const struct posix_acl *acl, size_t *size, int type)
+{
+ struct ubifs_acl_header *hdr;
+ struct ubifs_acl_entry *uae;
+ int i;
+
+ *size = acl_size(acl->a_count);
+ hdr = kmalloc(*size, GFP_KERNEL);
+ if (!hdr)
+ return ERR_PTR(-ENOMEM);
+
+ hdr->a_version = cpu_to_le32(UBIFS_ACL_VERSION);
+ uae = (struct ubifs_acl_entry *) (hdr + 1);
+
+ for (i = 0; i < acl->a_count; i++) {
+ const struct posix_acl_entry *ae = &acl->a_entries[i];
+ uae->e_tag = cpu_to_le16(ae->e_tag);
+ uae->e_perm = cpu_to_le16(ae->e_perm);
+ switch (ae->e_tag) {
+ case ACL_USER_OBJ:
+ case ACL_GROUP_OBJ:
+ case ACL_MASK:
+ case ACL_OTHER:
+ /* for the 4 options, id is not used */
+ uae = (struct ubifs_acl_entry *) ((char *) uae +
+ UBIFS_ACL_ENTRY_SHORT_SZ);
+ break;
+ case ACL_USER:
+ {
+ uid_t u = from_kuid(&init_user_ns, ae->e_uid);
+ uae->e_id = cpu_to_le32(u);
+ uae = (struct ubifs_acl_entry *) ((char *) uae +
+ UBIFS_ACL_ENTRY_SZ);
+ break;
+ }
+ case ACL_GROUP:
+ {
+ gid_t g = from_kgid(&init_user_ns, ae->e_gid);
+ uae->e_id = cpu_to_le32(g);
+ uae = (struct ubifs_acl_entry *) ((char *) uae +
+ UBIFS_ACL_ENTRY_SZ);
+ break;
+ }
+ default:
+ goto fail;
+ }
+ }
+
+ return (void *) hdr;
+
+fail:
+ kfree(hdr);
+ return ERR_PTR(-EINVAL);
+}
+
+/* convert from on-flash ACL to in-memory ACL */
+static struct posix_acl *acl_from_flash(const void *value, size_t size)
+{
+ struct posix_acl *acl;
+ struct ubifs_acl_header *hdr = (struct ubifs_acl_header *) value;
+ struct ubifs_acl_entry *uae = (struct ubifs_acl_entry *) (hdr + 1);
+ const char *end = value + size;
+ int count, i;
+
+ if (!value)
+ return NULL;
+ if (size < UBIFS_ACL_HEADER_SZ)
+ return ERR_PTR(-EINVAL);
+ if (hdr->a_version != cpu_to_le32(UBIFS_ACL_VERSION))
+ return ERR_PTR(-EINVAL);
+
+ count = 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++) {
+ if ((char *) uae > end)
+ goto fail;
+
+ acl->a_entries[i].e_tag = le16_to_cpu(uae->e_tag);
+ acl->a_entries[i].e_perm = le16_to_cpu(uae->e_perm);
+ switch (acl->a_entries[i].e_tag) {
+ case ACL_USER_OBJ:
+ case ACL_GROUP_OBJ:
+ case ACL_MASK:
+ case ACL_OTHER:
+ /* for the 4 options, no id */
+ uae = (struct ubifs_acl_entry *) ((char *) uae +
+ UBIFS_ACL_ENTRY_SHORT_SZ);
+ break;
+ case ACL_USER:
+ {
+ uid_t u = le32_to_cpu(uae->e_id);
+ acl->a_entries[i].e_uid = make_kuid(&init_user_ns, u);
+ uae = (struct ubifs_acl_entry *) ((char *) uae +
+ UBIFS_ACL_ENTRY_SZ);
+ break;
+ }
+ case ACL_GROUP:
+ {
+ gid_t g = le32_to_cpu(uae->e_id);
+ acl->a_entries[i].e_gid = make_kgid(&init_user_ns, g);
+ uae = (struct ubifs_acl_entry *) ((char *) uae +
+ UBIFS_ACL_ENTRY_SZ);
+ break;
+ }
+ default:
+ goto fail;
+ }
+ }
+
+ if ((char *) uae != end)
+ goto fail;
+
+ return acl;
+
+fail:
+ posix_acl_release(acl);
+ return ERR_PTR(-EINVAL);
+}
+
+struct posix_acl *ubifs_get_acl(struct inode *inode, int type)
+{
+ struct posix_acl *acl;
+ char *name, *value = NULL;
+ int size = 0;
+
+ switch (type) {
+ case ACL_TYPE_ACCESS:
+ name = XATTR_NAME_POSIX_ACL_ACCESS;
+ break;
+ case ACL_TYPE_DEFAULT:
+ name = XATTR_NAME_POSIX_ACL_DEFAULT;
+ break;
+ default:
+ BUG();
+ }
+
+ size = __ubifs_getxattr(inode, name, NULL, 0);
+ if (size > 0) {
+ value = kmalloc(size, GFP_KERNEL);
+ if (!value)
+ return ERR_PTR(-ENOMEM);
+ size = __ubifs_getxattr(inode, name, value, size);
+ }
+ if (size > 0)
+ acl = acl_from_flash(value, size);
+ else if (size == -ENODATA)
+ acl = NULL;
+ else if (size < 0)
+ return ERR_PTR(size);
+
+ kfree(value);
+ if (!IS_ERR(acl))
+ set_cached_acl(inode, type, acl);
+
+ return acl;
+}
+
+int ubifs_set_acl(struct inode *inode, struct posix_acl *acl, int type)
+{
+ char *name;
+ void *value = NULL;
+ size_t size = 0;
+ int err;
+
+ switch (type) {
+ case ACL_TYPE_ACCESS:
+ name = XATTR_NAME_POSIX_ACL_ACCESS;
+ if (acl) {
+ err = posix_acl_equiv_mode(acl, &inode->i_mode);
+ if (err < 0)
+ return err;
+ if (err == 0)
+ acl = NULL;
+ }
+ break;
+
+ case ACL_TYPE_DEFAULT:
+ name = XATTR_NAME_POSIX_ACL_DEFAULT;
+ if (!S_ISDIR(inode->i_mode))
+ return acl ? -EACCES : 0;
+ break;
+
+ default:
+ BUG();
+ }
+
+ if (acl) {
+ value = acl_to_flash(acl, &size, type);
+ if (IS_ERR(value))
+ return (int) PTR_ERR(value);
+ }
+
+ err = __ubifs_setxattr(inode, name, value, size, 0);
+ kfree(value);
+ if (!err)
+ set_cached_acl(inode, type, acl);
+ return err;
+}
+
+/*
+ * Initialize the ACLs of a new inode.
+ */
+int ubifs_init_acl(struct inode *inode, struct inode *dir)
+{
+ struct posix_acl *default_acl, *acl;
+ int err;
+
+ err = posix_acl_create(dir, &inode->i_mode, &default_acl, &acl);
+ if (err)
+ return err;
+
+ if (default_acl) {
+ mutex_lock(&inode->i_mutex);
+ err = ubifs_set_acl(inode, default_acl, ACL_TYPE_DEFAULT);
+ mutex_unlock(&inode->i_mutex);
+ posix_acl_release(default_acl);
+ }
+
+ if (acl) {
+ if (!err) {
+ mutex_lock(&inode->i_mutex);
+ err = ubifs_set_acl(inode, acl, ACL_TYPE_ACCESS);
+ mutex_unlock(&inode->i_mutex);
+ }
+ posix_acl_release(acl);
+ }
+
+ return err;
+}
diff --git a/fs/ubifs/dir.c b/fs/ubifs/dir.c
index f7e8f76..d5435dc 100644
--- a/fs/ubifs/dir.c
+++ b/fs/ubifs/dir.c
@@ -167,6 +167,9 @@ struct inode *ubifs_new_inode(struct ubifs_info *c, const struct inode *dir,
*/
ui->creat_sqnum = ++c->max_sqnum;
spin_unlock(&c->cnt_lock);
+#ifdef CONFIG_UBIFS_FS_POSIX_ACL
+ ubifs_init_acl(inode, (struct inode *) dir);
+#endif
return inode;
}
@@ -1186,6 +1189,10 @@ const struct inode_operations ubifs_dir_inode_operations = {
.getxattr = ubifs_getxattr,
.listxattr = ubifs_listxattr,
.removexattr = ubifs_removexattr,
+#ifdef CONFIG_UBIFS_FS_POSIX_ACL
+ .get_acl = ubifs_get_acl,
+ .set_acl = ubifs_set_acl,
+#endif
};
const struct file_operations ubifs_dir_operations = {
diff --git a/fs/ubifs/file.c b/fs/ubifs/file.c
index 4855abc..1d4e498 100644
--- a/fs/ubifs/file.c
+++ b/fs/ubifs/file.c
@@ -54,6 +54,7 @@
#include <linux/mount.h>
#include <linux/namei.h>
#include <linux/slab.h>
+#include <linux/posix_acl.h>
static int read_block(struct inode *inode, void *addr, unsigned int block,
struct ubifs_data_node *dn)
@@ -1226,6 +1227,11 @@ static int do_setattr(struct ubifs_info *c, struct inode *inode,
truncate_setsize(inode, new_size);
}
+ if (attr->ia_valid & ATTR_MODE)
+ err = posix_acl_chmod(inode, inode->i_mode);
+ if (err)
+ return err;
+
mutex_lock(&ui->ui_mutex);
if (attr->ia_valid & ATTR_SIZE) {
/* Truncation changes inode [mc]time */
@@ -1567,6 +1573,10 @@ const struct inode_operations ubifs_file_inode_operations = {
.getxattr = ubifs_getxattr,
.listxattr = ubifs_listxattr,
.removexattr = ubifs_removexattr,
+#ifdef CONFIG_UBIFS_FS_POSIX_ACL
+ .get_acl = ubifs_get_acl,
+ .set_acl = ubifs_set_acl,
+#endif
};
const struct inode_operations ubifs_symlink_inode_operations = {
@@ -1578,6 +1588,10 @@ const struct inode_operations ubifs_symlink_inode_operations = {
.getxattr = ubifs_getxattr,
.listxattr = ubifs_listxattr,
.removexattr = ubifs_removexattr,
+#ifdef CONFIG_UBIFS_FS_POSIX_ACL
+ .get_acl = ubifs_get_acl,
+ .set_acl = ubifs_set_acl,
+#endif
};
const struct file_operations ubifs_file_operations = {
diff --git a/fs/ubifs/super.c b/fs/ubifs/super.c
index e642067..05334e8 100644
--- a/fs/ubifs/super.c
+++ b/fs/ubifs/super.c
@@ -443,6 +443,9 @@ static int ubifs_show_options(struct seq_file *s, struct dentry *root)
ubifs_compr_name(c->mount_opts.compr_type));
}
+ if (c->vfs_sb->s_flags & MS_POSIXACL)
+ seq_printf(s, ",acl");
+
return 0;
}
@@ -928,6 +931,8 @@ enum {
Opt_chk_data_crc,
Opt_no_chk_data_crc,
Opt_override_compr,
+ Opt_acl,
+ Opt_noacl,
Opt_err,
};
@@ -939,6 +944,8 @@ static const match_table_t tokens = {
{Opt_chk_data_crc, "chk_data_crc"},
{Opt_no_chk_data_crc, "no_chk_data_crc"},
{Opt_override_compr, "compr=%s"},
+ {Opt_acl, "acl"},
+ {Opt_noacl, "noacl"},
{Opt_err, NULL},
};
@@ -1038,6 +1045,14 @@ static int ubifs_parse_options(struct ubifs_info *c, char *options,
c->default_compr = c->mount_opts.compr_type;
break;
}
+#ifdef CONFIG_UBIFS_FS_POSIX_ACL
+ case Opt_acl:
+ c->vfs_sb->s_flags |= MS_POSIXACL;
+ break;
+ case Opt_noacl:
+ c->vfs_sb->s_flags &= ~MS_POSIXACL;
+ break;
+#endif
default:
{
unsigned long flag;
diff --git a/fs/ubifs/ubifs.h b/fs/ubifs/ubifs.h
index 2cb4297..a72b8bf 100644
--- a/fs/ubifs/ubifs.h
+++ b/fs/ubifs/ubifs.h
@@ -1761,6 +1761,11 @@ int ubifs_init_security(struct inode *dentry, struct inode *inode,
int __ubifs_setxattr(struct inode *, const char *, const void *, size_t, int);
ssize_t __ubifs_getxattr(struct inode *, const char *, void *, size_t);
+/* acl.c */
+int ubifs_init_acl(struct inode *inode, struct inode *dir);
+int ubifs_set_acl(struct inode *inode, struct posix_acl *acl, int type);
+struct posix_acl *ubifs_get_acl(struct inode *inode, int type);
+
/* super.c */
struct inode *ubifs_iget(struct super_block *sb, unsigned long inum);
diff --git a/fs/ubifs/xattr.c b/fs/ubifs/xattr.c
index c11c1f6..2272476 100644
--- a/fs/ubifs/xattr.c
+++ b/fs/ubifs/xattr.c
@@ -52,7 +52,6 @@
* in the VFS inode cache. The xentries are cached in the LNC cache (see
* tnc.c).
*
- * ACL support is not implemented.
*/
#include "ubifs.h"
@@ -78,6 +77,10 @@ enum {
USER_XATTR,
TRUSTED_XATTR,
SECURITY_XATTR,
+#ifdef CONFIG_UBIFS_FS_POSIX_ACL
+ POSIX_ACL_DEFAULT,
+ POSIX_ACL_ACCESS,
+#endif
};
static const struct inode_operations empty_iops;
@@ -276,6 +279,18 @@ static int check_namespace(const struct qstr *nm)
if (nm->name[sizeof(XATTR_SECURITY_PREFIX) - 1] == '\0')
return -EINVAL;
type = SECURITY_XATTR;
+#ifdef CONFIG_UBIFS_FS_POSIX_ACL
+ } else if (!strncmp(nm->name, XATTR_NAME_POSIX_ACL_DEFAULT,
+ sizeof(XATTR_NAME_POSIX_ACL_DEFAULT) - 1)) {
+ if (nm->name[sizeof(XATTR_NAME_POSIX_ACL_DEFAULT) - 1] != '\0')
+ return -EINVAL;
+ type = POSIX_ACL_DEFAULT;
+ } else if (!strncmp(nm->name, XATTR_NAME_POSIX_ACL_ACCESS,
+ sizeof(XATTR_NAME_POSIX_ACL_ACCESS) - 1)) {
+ if (nm->name[sizeof(XATTR_NAME_POSIX_ACL_ACCESS) - 1] != '\0')
+ return -EINVAL;
+ type = POSIX_ACL_ACCESS;
+#endif
} else
return -EOPNOTSUPP;
@@ -366,6 +381,9 @@ int ubifs_setxattr(struct dentry *dentry, const char *name,
dbg_gen("xattr '%s', host ino %lu ('%pd'), size %zd",
name, dentry->d_inode->i_ino, dentry, size);
+ if (!strncmp(name, XATTR_SYSTEM_PREFIX, XATTR_SYSTEM_PREFIX_LEN))
+ return generic_setxattr(dentry, name, value, size, flags);
+
return __ubifs_setxattr(dentry->d_inode, name, value, size, flags);
}
@@ -432,6 +450,9 @@ ssize_t ubifs_getxattr(struct dentry *dentry, const char *name, void *buf,
dbg_gen("xattr '%s', ino %lu ('%pd'), buf size %zd", name,
dentry->d_inode->i_ino, dentry, size);
+ if (!strncmp(name, XATTR_SYSTEM_PREFIX, XATTR_SYSTEM_PREFIX_LEN))
+ return generic_getxattr(dentry, name, buf, size);
+
return __ubifs_getxattr(dentry->d_inode, name, buf, size);
}
@@ -625,6 +646,10 @@ static const struct xattr_handler ubifs_xattr_security_handler = {
const struct xattr_handler *ubifs_xattr_handlers[] = {
&ubifs_xattr_security_handler,
+#ifdef CONFIG_UBIFS_FS_POSIX_ACL
+ &posix_acl_access_xattr_handler,
+ &posix_acl_default_xattr_handler,
+#endif
NULL,
};
--
1.8.3.4
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