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UBIFS: xattr bugfixes

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Xattr code has not been tested for a while and there were
serveral bugs. One of them is using wrong inode in
'ubifs_jnl_change_xattr()'. The other is a deadlock in
'ubifs_setxattr()': the i_mutex is locked in
'cap_inode_need_killpriv()' path, so deadlock happens when
'ubifs_setxattr()' tries to lock it again.

Thanks to Zoltan Sogor for finding these bugs.

Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
This commit is contained in:
Artem Bityutskiy 2008-08-12 16:30:12 +03:00
parent 720b499c80
commit c78c7e35a4
2 changed files with 18 additions and 28 deletions
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2
fs/ubifs/journal.c
View file

@ -1374,7 +1374,7 @@ int ubifs_jnl_change_xattr(struct ubifs_info *c, const struct inode *inode,
const struct inode *host)
{
int err, len1, len2, aligned_len, aligned_len1, lnum, offs;
struct ubifs_inode *host_ui = ubifs_inode(inode);
struct ubifs_inode *host_ui = ubifs_inode(host);
struct ubifs_ino_node *ino;
union ubifs_key key;
int sync = IS_DIRSYNC(host);

44
fs/ubifs/xattr.c
View file

@ -61,7 +61,7 @@
/*
* Limit the number of extended attributes per inode so that the total size
* (xattr_size) is guaranteeded to fit in an 'unsigned int'.
* (@xattr_size) is guaranteeded to fit in an 'unsigned int'.
*/
#define MAX_XATTRS_PER_INODE 65535
@ -110,7 +110,7 @@ static int create_xattr(struct ubifs_info *c, struct inode *host,
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*
* 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.
*/
@ -128,7 +128,6 @@ static int create_xattr(struct ubifs_info *c, struct inode *host,
goto out_budg;
}
mutex_lock(&host_ui->ui_mutex);
/* Re-define all operations to be "nothing" */
inode->i_mapping->a_ops = &none_address_operations;
inode->i_op = &none_inode_operations;
@ -141,23 +140,19 @@ static int create_xattr(struct ubifs_info *c, struct inode *host,
ui->data = kmalloc(size, GFP_NOFS);
if (!ui->data) {
err = -ENOMEM;
goto out_unlock;
goto out_free;
}
memcpy(ui->data, value, size);
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;
/*
* We do not use i_size_write() because nobody can race with us as we
* are holding host @host->i_mutex - every xattr operation for this
* inode is serialized by it.
*/
inode->i_size = ui->ui_size = size;
ui->data_len = size;
err = ubifs_jnl_update(c, host, nm, inode, 0, 1);
if (err)
goto out_cancel;
@ -172,8 +167,8 @@ out_cancel:
host_ui->xattr_cnt -= 1;
host_ui->xattr_size -= CALC_DENT_SIZE(nm->len);
host_ui->xattr_size -= CALC_XATTR_BYTES(size);
out_unlock:
mutex_unlock(&host_ui->ui_mutex);
out_free:
make_bad_inode(inode);
iput(inode);
out_budg:
@ -207,22 +202,21 @@ static int change_xattr(struct ubifs_info *c, struct inode *host,
if (err)
return err;
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);
kfree(ui->data);
ui->data = kmalloc(size, GFP_NOFS);
if (!ui->data) {
err = -ENOMEM;
goto out_unlock;
goto out_free;
}
memcpy(ui->data, value, size);
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_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
@ -240,9 +234,9 @@ static int change_xattr(struct ubifs_info *c, struct inode *host,
out_cancel:
host_ui->xattr_size -= CALC_XATTR_BYTES(size);
host_ui->xattr_size += CALC_XATTR_BYTES(ui->data_len);
make_bad_inode(inode);
out_unlock:
mutex_unlock(&host_ui->ui_mutex);
make_bad_inode(inode);
out_free:
ubifs_release_budget(c, &req);
return err;
}
@ -312,6 +306,7 @@ int ubifs_setxattr(struct dentry *dentry, const char *name,
dbg_gen("xattr '%s', host ino %lu ('%.*s'), size %zd", name,
host->i_ino, dentry->d_name.len, dentry->d_name.name, size);
ubifs_assert(mutex_is_locked(&host->i_mutex));
if (size > UBIFS_MAX_INO_DATA)
return -ERANGE;
@ -384,7 +379,6 @@ ssize_t ubifs_getxattr(struct dentry *dentry, const char *name, void *buf,
if (!xent)
return -ENOMEM;
mutex_lock(&host->i_mutex);
xent_key_init(c, &key, host->i_ino, &nm);
err = ubifs_tnc_lookup_nm(c, &key, xent, &nm);
if (err) {
@ -419,7 +413,6 @@ ssize_t ubifs_getxattr(struct dentry *dentry, const char *name, void *buf,
out_iput:
iput(inode);
out_unlock:
mutex_unlock(&host->i_mutex);
kfree(xent);
return err;
}
@ -449,8 +442,6 @@ ssize_t ubifs_listxattr(struct dentry *dentry, char *buffer, size_t size)
return -ERANGE;
lowest_xent_key(c, &key, host->i_ino);
mutex_lock(&host->i_mutex);
while (1) {
int type;
@ -479,7 +470,6 @@ ssize_t ubifs_listxattr(struct dentry *dentry, char *buffer, size_t size)
pxent = xent;
key_read(c, &xent->key, &key);
}
mutex_unlock(&host->i_mutex);
kfree(pxent);
if (err != -ENOENT) {