cregit-Linux how code gets into the kernel

Release 4.7 fs/ubifs/xattr.c

Directory: fs/ubifs
/*
 * This file is part of UBIFS.
 *
 * Copyright (C) 2006-2008 Nokia Corporation.
 *
 * 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
 *
 * Authors: Artem Bityutskiy (Битюцкий Артём)
 *          Adrian Hunter
 */

/*
 * This file implements UBIFS extended attributes support.
 *
 * Extended attributes are implemented as regular inodes with attached data,
 * which limits extended attribute size to UBIFS block size (4KiB). Names of
 * extended attributes are described by extended attribute entries (xentries),
 * which are almost identical to directory entries, but have different key type.
 *
 * In other words, the situation with extended attributes is very similar to
 * directories. Indeed, any inode (but of course not xattr inodes) may have a
 * number of associated xentries, just like directory inodes have associated
 * directory entries. Extended attribute entries store the name of the extended
 * attribute, the host inode number, and the extended attribute inode number.
 * Similarly, direntries store the name, the parent and the target inode
 * numbers. Thus, most of the common UBIFS mechanisms may be re-used for
 * extended attributes.
 *
 * The number of extended attributes is not limited, but there is Linux
 * limitation on the maximum possible size of the list of all extended
 * attributes associated with an inode (%XATTR_LIST_MAX), so UBIFS makes sure
 * the sum of all extended attribute names of the inode does not exceed that
 * limit.
 *
 * Extended attributes are synchronous, which means they are written to the
 * flash media synchronously and there is no write-back for extended attribute
 * inodes. The extended attribute values are not stored in compressed form on
 * the media.
 *
 * Since extended attributes are represented by regular inodes, they are cached
 * in the VFS inode cache. The xentries are cached in the LNC cache (see
 * tnc.c).
 *
 * ACL support is not implemented.
 */

#include "ubifs.h"
#include <linux/fs.h>
#include <linux/slab.h>
#include <linux/xattr.h>

/*
 * Limit the number of extended attributes per inode so that the total size
 * (@xattr_size) is guaranteeded to fit in an 'unsigned int'.
 */

#define MAX_XATTRS_PER_INODE 65535

/*
 * Extended attribute type constants.
 *
 * USER_XATTR: user extended attribute ("user.*")
 * TRUSTED_XATTR: trusted extended attribute ("trusted.*)
 * SECURITY_XATTR: security extended attribute ("security.*")
 */
enum {
	
USER_XATTR,
	
TRUSTED_XATTR,
	
SECURITY_XATTR,
};


static const struct inode_operations empty_iops;

static const struct file_operations empty_fops;

/**
 * create_xattr - create an extended attribute.
 * @c: UBIFS file-system description object
 * @host: host inode
 * @nm: extended attribute name
 * @value: extended attribute value
 * @size: size of extended attribute value
 *
 * This is a helper function which creates an extended attribute of name @nm
 * and value @value for inode @host. The host inode is also updated on flash
 * because the ctime and extended attribute accounting data changes. This
 * function returns zero in case of success and a negative error code in case
 * of failure.
 */

static int create_xattr(struct ubifs_info *c, struct inode *host, const struct qstr *nm, const void *value, int size) { int err, names_len; struct inode *inode; struct ubifs_inode *ui, *host_ui = ubifs_inode(host); struct ubifs_budget_req req = { .new_ino = 1, .new_dent = 1, .new_ino_d = ALIGN(size, 8), .dirtied_ino = 1, .dirtied_ino_d = ALIGN(host_ui->data_len, 8) }; if (host_ui->xattr_cnt >= MAX_XATTRS_PER_INODE) { ubifs_err(c, "inode %lu already has too many xattrs (%d), cannot create more", host->i_ino, host_ui->xattr_cnt); return -ENOSPC; } /* * Linux limits the maximum size of the extended attribute names list * to %XATTR_LIST_MAX. This means we should not allow creating more * extended attributes if the name list becomes larger. This limitation * is artificial for UBIFS, though. */ names_len = host_ui->xattr_names + host_ui->xattr_cnt + nm->len + 1; if (names_len > XATTR_LIST_MAX) { ubifs_err(c, "cannot add one more xattr name to inode %lu, total names length would become %d, max. is %d", host->i_ino, names_len, XATTR_LIST_MAX); return -ENOSPC; } err = ubifs_budget_space(c, &req); if (err) return err; inode = ubifs_new_inode(c, host, S_IFREG | S_IRWXUGO); if (IS_ERR(inode)) { err = PTR_ERR(inode); goto out_budg; } /* Re-define all operations to be "nothing" */ inode->i_mapping->a_ops = &empty_aops; inode->i_op = &empty_iops; inode->i_fop = &empty_fops; inode->i_flags |= S_SYNC | S_NOATIME | S_NOCMTIME | S_NOQUOTA; ui = ubifs_inode(inode); ui->xattr = 1; ui->flags |= UBIFS_XATTR_FL; ui->data = kmemdup(value, size, GFP_NOFS); if (!ui->data) { err = -ENOMEM; goto out_free; } inode->i_size = ui->ui_size = size; ui->data_len = size; mutex_lock(&host_ui->ui_mutex); host->i_ctime = ubifs_current_time(host); host_ui->xattr_cnt += 1; host_ui->xattr_size += CALC_DENT_SIZE(nm->len); host_ui->xattr_size += CALC_XATTR_BYTES(size); host_ui->xattr_names += nm->len; err = ubifs_jnl_update(c, host, nm, inode, 0, 1); if (err) goto out_cancel; mutex_unlock(&host_ui->ui_mutex); ubifs_release_budget(c, &req); insert_inode_hash(inode); iput(inode); return 0; out_cancel: host_ui->xattr_cnt -= 1; host_ui->xattr_size -= CALC_DENT_SIZE(nm->len); host_ui->xattr_size -= CALC_XATTR_BYTES(size); mutex_unlock(&host_ui->ui_mutex); out_free: make_bad_inode(inode); iput(inode); out_budg: ubifs_release_budget(c, &req); return err; }

Contributors

PersonTokensPropCommitsCommitProp
artem bityutskiyartem bityutskiy42989.00%333.33%
subodh nijsuresubodh nijsure387.88%111.11%
zoltan sogorzoltan sogor51.04%111.11%
sheng yongsheng yong40.83%111.11%
thomas meyerthomas meyer30.62%111.11%
sedat dileksedat dilek20.41%111.11%
jens axboejens axboe10.21%111.11%
Total482100.00%9100.00%

/** * change_xattr - change an extended attribute. * @c: UBIFS file-system description object * @host: host inode * @inode: extended attribute inode * @value: extended attribute value * @size: size of extended attribute value * * This helper function changes the value of extended attribute @inode with new * data from @value. Returns zero in case of success and a negative error code * in case of failure. */
static int change_xattr(struct ubifs_info *c, struct inode *host, struct inode *inode, const void *value, int size) { int err; struct ubifs_inode *host_ui = ubifs_inode(host); struct ubifs_inode *ui = ubifs_inode(inode); void *buf = NULL; struct ubifs_budget_req req = { .dirtied_ino = 2, .dirtied_ino_d = ALIGN(size, 8) + ALIGN(host_ui->data_len, 8) }; ubifs_assert(ui->data_len == inode->i_size); err = ubifs_budget_space(c, &req); if (err) return err; buf = kmemdup(value, size, GFP_NOFS); if (!buf) { err = -ENOMEM; goto out_free; } mutex_lock(&ui->ui_mutex); kfree(ui->data); ui->data = buf; inode->i_size = ui->ui_size = size; ui->data_len = size; mutex_unlock(&ui->ui_mutex); mutex_lock(&host_ui->ui_mutex); host->i_ctime = ubifs_current_time(host); host_ui->xattr_size -= CALC_XATTR_BYTES(ui->data_len); host_ui->xattr_size += CALC_XATTR_BYTES(size); /* * It is important to write the host inode after the xattr inode * because if the host inode gets synchronized (via 'fsync()'), then * the extended attribute inode gets synchronized, because it goes * before the host inode in the write-buffer. */ err = ubifs_jnl_change_xattr(c, inode, host); if (err) goto out_cancel; mutex_unlock(&host_ui->ui_mutex); ubifs_release_budget(c, &req); return 0; out_cancel: host_ui->xattr_size -= CALC_XATTR_BYTES(size); host_ui->xattr_size += CALC_XATTR_BYTES(ui->data_len); mutex_unlock(&host_ui->ui_mutex); make_bad_inode(inode); out_free: ubifs_release_budget(c, &req); return err; }

Contributors

PersonTokensPropCommitsCommitProp
artem bityutskiyartem bityutskiy25783.44%240.00%
dongsheng yangdongsheng yang3712.01%120.00%
zoltan sogorzoltan sogor113.57%120.00%
thomas meyerthomas meyer30.97%120.00%
Total308100.00%5100.00%


static struct inode *iget_xattr(struct ubifs_info *c, ino_t inum) { struct inode *inode; inode = ubifs_iget(c->vfs_sb, inum); if (IS_ERR(inode)) { ubifs_err(c, "dead extended attribute entry, error %d", (int)PTR_ERR(inode)); return inode; } if (ubifs_inode(inode)->xattr) return inode; ubifs_err(c, "corrupt extended attribute entry"); iput(inode); return ERR_PTR(-EINVAL); }

Contributors

PersonTokensPropCommitsCommitProp
artem bityutskiyartem bityutskiy8695.56%150.00%
sheng yongsheng yong44.44%150.00%
Total90100.00%2100.00%


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; ubifs_assert(inode_is_locked(host)); if (size > UBIFS_MAX_INO_DATA) return -ERANGE; if (nm.len > UBIFS_MAX_NLEN) return -ENAMETOOLONG; xent = kmalloc(UBIFS_MAX_XENT_NODE_SZ, GFP_NOFS); if (!xent) return -ENOMEM; /* * The extended attribute entries are stored in LNC, so multiple * look-ups do not involve reading the flash. */ xent_key_init(c, &key, host->i_ino, &nm); err = ubifs_tnc_lookup_nm(c, &key, xent, &nm); if (err) { if (err != -ENOENT) goto out_free; if (flags & XATTR_REPLACE) /* We are asked not to create the xattr */ err = -ENODATA; else err = create_xattr(c, host, &nm, value, size); goto out_free; } if (flags & XATTR_CREATE) { /* We are asked not to replace the xattr */ err = -EEXIST; goto out_free; } inode = iget_xattr(c, le64_to_cpu(xent->inum)); if (IS_ERR(inode)) { err = PTR_ERR(inode); goto out_free; } err = change_xattr(c, host, inode, value, size); iput(inode); out_free: kfree(xent); return err; }

Contributors

PersonTokensPropCommitsCommitProp
artem bityutskiyartem bityutskiy25993.84%233.33%
andreas gruenbacherandreas gruenbacher82.90%116.67%
linus torvaldslinus torvalds51.81%116.67%
subodh nijsuresubodh nijsure31.09%116.67%
al viroal viro10.36%116.67%
Total276100.00%6100.00%


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; struct qstr nm = QSTR_INIT(name, strlen(name)); struct ubifs_inode *ui; struct ubifs_dent_node *xent; union ubifs_key key; int err; if (nm.len > UBIFS_MAX_NLEN) return -ENAMETOOLONG; xent = kmalloc(UBIFS_MAX_XENT_NODE_SZ, GFP_NOFS); if (!xent) return -ENOMEM; xent_key_init(c, &key, host->i_ino, &nm); err = ubifs_tnc_lookup_nm(c, &key, xent, &nm); if (err) { if (err == -ENOENT) err = -ENODATA; goto out_unlock; } inode = iget_xattr(c, le64_to_cpu(xent->inum)); if (IS_ERR(inode)) { err = PTR_ERR(inode); goto out_unlock; } ui = ubifs_inode(inode); ubifs_assert(inode->i_size == ui->data_len); ubifs_assert(ubifs_inode(host)->xattr_size > ui->data_len); mutex_lock(&ui->ui_mutex); if (buf) { /* If @buf is %NULL we are supposed to return the length */ if (ui->data_len > size) { ubifs_err(c, "buffer size %zd, xattr len %d", size, ui->data_len); err = -ERANGE; goto out_iput; } memcpy(buf, ui->data, ui->data_len); } err = ui->data_len; out_iput: mutex_unlock(&ui->ui_mutex); iput(inode); out_unlock: kfree(xent); return err; }

Contributors

PersonTokensPropCommitsCommitProp
artem bityutskiyartem bityutskiy27088.24%228.57%
dongsheng yangdongsheng yang165.23%114.29%
andreas gruenbacherandreas gruenbacher92.94%114.29%
linus torvaldslinus torvalds51.63%114.29%
al viroal viro41.31%114.29%
sheng yongsheng yong20.65%114.29%
Total306100.00%7100.00%


ssize_t ubifs_listxattr(struct dentry *dentry, char *buffer, size_t size) { union ubifs_key key; struct inode *host = d_inode(dentry); struct ubifs_info *c = host->i_sb->s_fs_info; struct ubifs_inode *host_ui = ubifs_inode(host); struct ubifs_dent_node *xent, *pxent = NULL; int err, len, written = 0; struct qstr nm = { .name = NULL }; dbg_gen("ino %lu ('%pd'), buffer size %zd", host->i_ino, dentry, size); len = host_ui->xattr_names + host_ui->xattr_cnt; if (!buffer) /* * We should return the minimum buffer size which will fit a * null-terminated list of all the extended attribute names. */ return len; if (len > size) return -ERANGE; lowest_xent_key(c, &key, host->i_ino); while (1) { xent = ubifs_tnc_next_ent(c, &key, &nm); if (IS_ERR(xent)) { err = PTR_ERR(xent); break; } nm.name = xent->name; nm.len = le16_to_cpu(xent->nlen); /* Show trusted namespace only for "power" users */ 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; } kfree(pxent); pxent = xent; key_read(c, &xent->key, &key); } kfree(pxent); if (err != -ENOENT) { ubifs_err(c, "cannot find next direntry, error %d", err); return err; } ubifs_assert(written <= size); return written; }

Contributors

PersonTokensPropCommitsCommitProp
artem bityutskiyartem bityutskiy27994.58%120.00%
andreas gruenbacherandreas gruenbacher103.39%120.00%
david howellsdavid howells31.02%120.00%
sheng yongsheng yong20.68%120.00%
al viroal viro10.34%120.00%
Total295100.00%5100.00%


static int remove_xattr(struct ubifs_info *c, struct inode *host, struct inode *inode, const struct qstr *nm) { int err; struct ubifs_inode *host_ui = ubifs_inode(host); struct ubifs_inode *ui = ubifs_inode(inode); struct ubifs_budget_req req = { .dirtied_ino = 2, .mod_dent = 1, .dirtied_ino_d = ALIGN(host_ui->data_len, 8) }; ubifs_assert(ui->data_len == inode->i_size); err = ubifs_budget_space(c, &req); if (err) return err; mutex_lock(&host_ui->ui_mutex); host->i_ctime = ubifs_current_time(host); host_ui->xattr_cnt -= 1; host_ui->xattr_size -= CALC_DENT_SIZE(nm->len); host_ui->xattr_size -= CALC_XATTR_BYTES(ui->data_len); host_ui->xattr_names -= nm->len; err = ubifs_jnl_delete_xattr(c, host, inode, nm); if (err) goto out_cancel; mutex_unlock(&host_ui->ui_mutex); ubifs_release_budget(c, &req); return 0; out_cancel: host_ui->xattr_cnt += 1; host_ui->xattr_size += CALC_DENT_SIZE(nm->len); host_ui->xattr_size += CALC_XATTR_BYTES(ui->data_len); mutex_unlock(&host_ui->ui_mutex); ubifs_release_budget(c, &req); make_bad_inode(inode); return err; }

Contributors

PersonTokensPropCommitsCommitProp
artem bityutskiyartem bityutskiy24397.20%150.00%
zoltan sogorzoltan sogor72.80%150.00%
Total250100.00%2100.00%


static int __ubifs_removexattr(struct inode *host, const char *name) { 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; ubifs_assert(inode_is_locked(host)); if (nm.len > UBIFS_MAX_NLEN) return -ENAMETOOLONG; xent = kmalloc(UBIFS_MAX_XENT_NODE_SZ, GFP_NOFS); if (!xent) return -ENOMEM; xent_key_init(c, &key, host->i_ino, &nm); err = ubifs_tnc_lookup_nm(c, &key, xent, &nm); if (err) { if (err == -ENOENT) err = -ENODATA; goto out_free; } inode = iget_xattr(c, le64_to_cpu(xent->inum)); if (IS_ERR(inode)) { err = PTR_ERR(inode); goto out_free; } ubifs_assert(inode->i_nlink == 1); clear_nlink(inode); err = remove_xattr(c, host, inode, &nm); if (err) set_nlink(inode, 1); /* If @i_nlink is 0, 'iput()' will delete the inode */ iput(inode); out_free: kfree(xent); return err; }

Contributors

PersonTokensPropCommitsCommitProp
artem bityutskiyartem bityutskiy21189.79%116.67%
andreas gruenbacherandreas gruenbacher114.68%116.67%
miklos szeredimiklos szeredi72.98%233.33%
linus torvaldslinus torvalds52.13%116.67%
al viroal viro10.43%116.67%
Total235100.00%6100.00%


static int init_xattrs(struct inode *inode, const struct xattr *xattr_array, void *fs_info) { const struct xattr *xattr; char *name; int err = 0; for (xattr = xattr_array; xattr->name != NULL; xattr++) { name = kmalloc(XATTR_SECURITY_PREFIX_LEN + strlen(xattr->name) + 1, GFP_NOFS); if (!name) { err = -ENOMEM; break; } strcpy(name, XATTR_SECURITY_PREFIX); strcpy(name + XATTR_SECURITY_PREFIX_LEN, xattr->name); err = __ubifs_setxattr(inode, name, xattr->value, xattr->value_len, 0); kfree(name); if (err < 0) break; } return err; }

Contributors

PersonTokensPropCommitsCommitProp
subodh nijsuresubodh nijsure13599.26%150.00%
andreas gruenbacherandreas gruenbacher10.74%150.00%
Total136100.00%2100.00%


int ubifs_init_security(struct inode *dentry, struct inode *inode, const struct qstr *qstr) { int err; err = security_inode_init_security(inode, dentry, qstr, &init_xattrs, 0); if (err) { struct ubifs_info *c = dentry->i_sb->s_fs_info; ubifs_err(c, "cannot initialize security for inode %lu, error %d", inode->i_ino, err); } return err; }

Contributors

PersonTokensPropCommitsCommitProp
subodh nijsuresubodh nijsure5879.45%266.67%
sheng yongsheng yong1520.55%133.33%
Total73100.00%3100.00%


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); }

Contributors

PersonTokensPropCommitsCommitProp
andreas gruenbacherandreas gruenbacher61100.00%1100.00%
Total61100.00%1100.00%


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

Contributors

PersonTokensPropCommitsCommitProp
andreas gruenbacherandreas gruenbacher7593.75%150.00%
al viroal viro56.25%150.00%
Total80100.00%2100.00%

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 };

Overall Contributors

PersonTokensPropCommitsCommitProp
artem bityutskiyartem bityutskiy206775.96%520.00%
andreas gruenbacherandreas gruenbacher2619.59%14.00%
subodh nijsuresubodh nijsure2348.60%312.00%
dongsheng yangdongsheng yang531.95%14.00%
sheng yongsheng yong270.99%14.00%
zoltan sogorzoltan sogor230.85%14.00%
linus torvaldslinus torvalds150.55%14.00%
al viroal viro140.51%520.00%
miklos szeredimiklos szeredi70.26%28.00%
thomas meyerthomas meyer60.22%14.00%
sedat dileksedat dilek40.15%14.00%
jens axboejens axboe40.15%14.00%
david howellsdavid howells30.11%14.00%
tejun heotejun heo30.11%14.00%
Total2721100.00%25100.00%
Directory: fs/ubifs
Information contained on this website is for historical information purposes only and does not indicate or represent copyright ownership.
{% endraw %}