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ubifs: Switch to generic xattr handlers
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Ubifs internally uses special inodes for storing xattrs. Those inodes
had NULL {get,set,remove}xattr inode operations before this change, so
xattr operations on them would fail. The super block's s_xattr field
would also apply to those special inodes. However, the inodes are not
visible outside of ubifs, and so no xattr operations will ever be
carried out on them anyway.

Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
Reviewed-by: Richard Weinberger <richard@nod.at>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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Andreas Gruenbacher authored and Al Viro committed May 17, 2016
1 parent c8b6056 commit 2b88fc2
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Showing 5 changed files with 79 additions and 90 deletions.
6 changes: 3 additions & 3 deletions fs/ubifs/dir.c
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Original file line number Diff line number Diff line change
Expand Up @@ -1182,10 +1182,10 @@ const struct inode_operations ubifs_dir_inode_operations = {
.rename = ubifs_rename,
.setattr = ubifs_setattr,
.getattr = ubifs_getattr,
.setxattr = ubifs_setxattr,
.getxattr = ubifs_getxattr,
.setxattr = generic_setxattr,
.getxattr = generic_getxattr,
.listxattr = ubifs_listxattr,
.removexattr = ubifs_removexattr,
.removexattr = generic_removexattr,
#ifdef CONFIG_UBIFS_ATIME_SUPPORT
.update_time = ubifs_update_time,
#endif
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12 changes: 6 additions & 6 deletions fs/ubifs/file.c
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Original file line number Diff line number Diff line change
Expand Up @@ -1597,10 +1597,10 @@ const struct address_space_operations ubifs_file_address_operations = {
const struct inode_operations ubifs_file_inode_operations = {
.setattr = ubifs_setattr,
.getattr = ubifs_getattr,
.setxattr = ubifs_setxattr,
.getxattr = ubifs_getxattr,
.setxattr = generic_setxattr,
.getxattr = generic_getxattr,
.listxattr = ubifs_listxattr,
.removexattr = ubifs_removexattr,
.removexattr = generic_removexattr,
#ifdef CONFIG_UBIFS_ATIME_SUPPORT
.update_time = ubifs_update_time,
#endif
Expand All @@ -1611,10 +1611,10 @@ const struct inode_operations ubifs_symlink_inode_operations = {
.get_link = simple_get_link,
.setattr = ubifs_setattr,
.getattr = ubifs_getattr,
.setxattr = ubifs_setxattr,
.getxattr = ubifs_getxattr,
.setxattr = generic_setxattr,
.getxattr = generic_getxattr,
.listxattr = ubifs_listxattr,
.removexattr = ubifs_removexattr,
.removexattr = generic_removexattr,
#ifdef CONFIG_UBIFS_ATIME_SUPPORT
.update_time = ubifs_update_time,
#endif
Expand Down
1 change: 1 addition & 0 deletions fs/ubifs/super.c
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Original file line number Diff line number Diff line change
Expand Up @@ -2040,6 +2040,7 @@ static int ubifs_fill_super(struct super_block *sb, void *data, int silent)
if (c->max_inode_sz > MAX_LFS_FILESIZE)
sb->s_maxbytes = c->max_inode_sz = MAX_LFS_FILESIZE;
sb->s_op = &ubifs_super_operations;
sb->s_xattr = ubifs_xattr_handlers;

mutex_lock(&c->umount_mutex);
err = mount_ubifs(c);
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7 changes: 2 additions & 5 deletions fs/ubifs/ubifs.h
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Original file line number Diff line number Diff line change
Expand Up @@ -37,6 +37,7 @@
#include <linux/pagemap.h>
#include <linux/backing-dev.h>
#include <linux/security.h>
#include <linux/xattr.h>
#include "ubifs-media.h"

/* Version of this UBIFS implementation */
Expand Down Expand Up @@ -1732,12 +1733,8 @@ int ubifs_getattr(struct vfsmount *mnt, struct dentry *dentry,
struct kstat *stat);

/* xattr.c */
int ubifs_setxattr(struct dentry *dentry, const char *name,
const void *value, size_t size, int flags);
ssize_t ubifs_getxattr(struct dentry *dentry, struct inode *host,
const char *name, void *buf, size_t size);
extern const struct xattr_handler *ubifs_xattr_handlers[];
ssize_t ubifs_listxattr(struct dentry *dentry, char *buffer, size_t size);
int ubifs_removexattr(struct dentry *dentry, const char *name);
int ubifs_init_security(struct inode *dentry, struct inode *inode,
const struct qstr *qstr);

Expand Down
143 changes: 67 additions & 76 deletions fs/ubifs/xattr.c
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Original file line number Diff line number Diff line change
Expand Up @@ -249,42 +249,6 @@ static int change_xattr(struct ubifs_info *c, struct inode *host,
return err;
}

/**
* check_namespace - check extended attribute name-space.
* @nm: extended attribute name
*
* This function makes sure the extended attribute name belongs to one of the
* supported extended attribute name-spaces. Returns name-space index in case
* of success and a negative error code in case of failure.
*/
static int check_namespace(const struct qstr *nm)
{
int type;

if (nm->len > UBIFS_MAX_NLEN)
return -ENAMETOOLONG;

if (!strncmp(nm->name, XATTR_TRUSTED_PREFIX,
XATTR_TRUSTED_PREFIX_LEN)) {
if (nm->name[XATTR_TRUSTED_PREFIX_LEN] == '\0')
return -EINVAL;
type = TRUSTED_XATTR;
} else if (!strncmp(nm->name, XATTR_USER_PREFIX,
XATTR_USER_PREFIX_LEN)) {
if (nm->name[XATTR_USER_PREFIX_LEN] == '\0')
return -EINVAL;
type = USER_XATTR;
} else if (!strncmp(nm->name, XATTR_SECURITY_PREFIX,
XATTR_SECURITY_PREFIX_LEN)) {
if (nm->name[XATTR_SECURITY_PREFIX_LEN] == '\0')
return -EINVAL;
type = SECURITY_XATTR;
} else
return -EOPNOTSUPP;

return type;
}

static struct inode *iget_xattr(struct ubifs_info *c, ino_t inum)
{
struct inode *inode;
Expand All @@ -302,24 +266,23 @@ static struct inode *iget_xattr(struct ubifs_info *c, ino_t inum)
return ERR_PTR(-EINVAL);
}

static int setxattr(struct inode *host, const char *name, const void *value,
size_t size, int flags)
static int __ubifs_setxattr(struct inode *host, const char *name,
const void *value, size_t size, int flags)
{
struct inode *inode;
struct ubifs_info *c = host->i_sb->s_fs_info;
struct qstr nm = QSTR_INIT(name, strlen(name));
struct ubifs_dent_node *xent;
union ubifs_key key;
int err, type;
int err;

ubifs_assert(inode_is_locked(host));

if (size > UBIFS_MAX_INO_DATA)
return -ERANGE;

type = check_namespace(&nm);
if (type < 0)
return type;
if (nm.len > UBIFS_MAX_NLEN)
return -ENAMETOOLONG;

xent = kmalloc(UBIFS_MAX_XENT_NODE_SZ, GFP_NOFS);
if (!xent)
Expand Down Expand Up @@ -363,17 +326,8 @@ static int setxattr(struct inode *host, const char *name, const void *value,
return err;
}

int ubifs_setxattr(struct dentry *dentry, const char *name,
const void *value, size_t size, int flags)
{
dbg_gen("xattr '%s', host ino %lu ('%pd'), size %zd",
name, d_inode(dentry)->i_ino, dentry, size);

return setxattr(d_inode(dentry), name, value, size, flags);
}

ssize_t ubifs_getxattr(struct dentry *dentry, struct inode *host,
const char *name, void *buf, size_t size)
static ssize_t __ubifs_getxattr(struct inode *host, const char *name,
void *buf, size_t size)
{
struct inode *inode;
struct ubifs_info *c = host->i_sb->s_fs_info;
Expand All @@ -383,12 +337,8 @@ ssize_t ubifs_getxattr(struct dentry *dentry, struct inode *host,
union ubifs_key key;
int err;

dbg_gen("xattr '%s', ino %lu ('%pd'), buf size %zd", name,
host->i_ino, dentry, size);

err = check_namespace(&nm);
if (err < 0)
return err;
if (nm.len > UBIFS_MAX_NLEN)
return -ENAMETOOLONG;

xent = kmalloc(UBIFS_MAX_XENT_NODE_SZ, GFP_NOFS);
if (!xent)
Expand Down Expand Up @@ -460,8 +410,6 @@ ssize_t ubifs_listxattr(struct dentry *dentry, char *buffer, size_t size)

lowest_xent_key(c, &key, host->i_ino);
while (1) {
int type;

xent = ubifs_tnc_next_ent(c, &key, &nm);
if (IS_ERR(xent)) {
err = PTR_ERR(xent);
Expand All @@ -471,14 +419,10 @@ ssize_t ubifs_listxattr(struct dentry *dentry, char *buffer, size_t size)
nm.name = xent->name;
nm.len = le16_to_cpu(xent->nlen);

type = check_namespace(&nm);
if (unlikely(type < 0)) {
err = type;
break;
}

/* Show trusted namespace only for "power" users */
if (type != TRUSTED_XATTR || capable(CAP_SYS_ADMIN)) {
if (strncmp(xent->name, XATTR_TRUSTED_PREFIX,
XATTR_TRUSTED_PREFIX_LEN) ||
capable(CAP_SYS_ADMIN)) {
memcpy(buffer + written, nm.name, nm.len + 1);
written += nm.len + 1;
}
Expand Down Expand Up @@ -538,22 +482,19 @@ static int remove_xattr(struct ubifs_info *c, struct inode *host,
return err;
}

int ubifs_removexattr(struct dentry *dentry, const char *name)
static int __ubifs_removexattr(struct inode *host, const char *name)
{
struct inode *inode, *host = d_inode(dentry);
struct inode *inode;
struct ubifs_info *c = host->i_sb->s_fs_info;
struct qstr nm = QSTR_INIT(name, strlen(name));
struct ubifs_dent_node *xent;
union ubifs_key key;
int err;

dbg_gen("xattr '%s', ino %lu ('%pd')", name,
host->i_ino, dentry);
ubifs_assert(inode_is_locked(host));

err = check_namespace(&nm);
if (err < 0)
return err;
if (nm.len > UBIFS_MAX_NLEN)
return -ENAMETOOLONG;

xent = kmalloc(UBIFS_MAX_XENT_NODE_SZ, GFP_NOFS);
if (!xent)
Expand Down Expand Up @@ -603,7 +544,7 @@ static int init_xattrs(struct inode *inode, const struct xattr *xattr_array,
}
strcpy(name, XATTR_SECURITY_PREFIX);
strcpy(name + XATTR_SECURITY_PREFIX_LEN, xattr->name);
err = setxattr(inode, name, xattr->value, xattr->value_len, 0);
err = __ubifs_setxattr(inode, name, xattr->value, xattr->value_len, 0);
kfree(name);
if (err < 0)
break;
Expand All @@ -626,3 +567,53 @@ int ubifs_init_security(struct inode *dentry, struct inode *inode,
}
return err;
}

static int ubifs_xattr_get(const struct xattr_handler *handler,
struct dentry *dentry, struct inode *inode,
const char *name, void *buffer, size_t size)
{
dbg_gen("xattr '%s', ino %lu ('%pd'), buf size %zd", name,
inode->i_ino, dentry, size);

return __ubifs_getxattr(inode, name, buffer, size);
}

static int ubifs_xattr_set(const struct xattr_handler *handler,
struct dentry *dentry, const char *name,
const void *value, size_t size, int flags)
{
struct inode *inode = d_inode(dentry);

dbg_gen("xattr '%s', host ino %lu ('%pd'), size %zd",
name, inode->i_ino, dentry, size);

if (value)
return __ubifs_setxattr(inode, name, value, size, flags);
else
return __ubifs_removexattr(inode, name);
}

const struct xattr_handler ubifs_user_xattr_handler = {
.prefix = XATTR_USER_PREFIX,
.get = ubifs_xattr_get,
.set = ubifs_xattr_set,
};

const struct xattr_handler ubifs_trusted_xattr_handler = {
.prefix = XATTR_TRUSTED_PREFIX,
.get = ubifs_xattr_get,
.set = ubifs_xattr_set,
};

const struct xattr_handler ubifs_security_xattr_handler = {
.prefix = XATTR_SECURITY_PREFIX,
.get = ubifs_xattr_get,
.set = ubifs_xattr_set,
};

const struct xattr_handler *ubifs_xattr_handlers[] = {
&ubifs_user_xattr_handler,
&ubifs_trusted_xattr_handler,
&ubifs_security_xattr_handler,
NULL
};

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