leandrof/linux
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity

Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs

Browse Source 
Pull ubifs fixes from Al Viro:
 "A couple of ubifs readdir/lseek race fixes.  Stable fodder, really
  nasty..."

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
  UBIFS: fix a horrid bug
  UBIFS: prepare to fix a horrid bug
This commit is contained in:
Linus Torvalds 2013-06-29 10:30:31 -07:00
commit 63edbce160
1 changed files with 39 additions and 15 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

54
fs/ubifs/dir.c
View File

@ -349,31 +349,50 @@ static unsigned int vfs_dent_type(uint8_t type)
static int ubifs_readdir(struct file *file, void *dirent, filldir_t filldir)
{
int err, over = 0;
loff_t pos = file->f_pos;
struct qstr nm;
union ubifs_key key;
struct ubifs_dent_node *dent;
struct inode *dir = file_inode(file);
struct ubifs_info *c = dir->i_sb->s_fs_info;
dbg_gen("dir ino %lu, f_pos %#llx", dir->i_ino, file->f_pos);
dbg_gen("dir ino %lu, f_pos %#llx", dir->i_ino, pos);
if (file->f_pos > UBIFS_S_KEY_HASH_MASK || file->f_pos == 2)
if (pos > UBIFS_S_KEY_HASH_MASK || pos == 2)
/*
* The directory was seek'ed to a senseless position or there
* are no more entries.
*/
return 0;
if (file->f_version == 0) {
/*
* The file was seek'ed, which means that @file->private_data
* is now invalid. This may also be just the first
* 'ubifs_readdir()' invocation, in which case
* @file->private_data is NULL, and the below code is
* basically a no-op.
*/
kfree(file->private_data);
file->private_data = NULL;
}
/*
* 'generic_file_llseek()' unconditionally sets @file->f_version to
* zero, and we use this for detecting whether the file was seek'ed.
*/
file->f_version = 1;
/* File positions 0 and 1 correspond to "." and ".." */
if (file->f_pos == 0) {
if (pos == 0) {
ubifs_assert(!file->private_data);
over = filldir(dirent, ".", 1, 0, dir->i_ino, DT_DIR);
if (over)
return 0;
file->f_pos = 1;
file->f_pos = pos = 1;
}
if (file->f_pos == 1) {
if (pos == 1) {
ubifs_assert(!file->private_data);
over = filldir(dirent, "..", 2, 1,
parent_ino(file->f_path.dentry), DT_DIR);
@ -389,7 +408,7 @@ static int ubifs_readdir(struct file *file, void *dirent, filldir_t filldir)
goto out;
}
file->f_pos = key_hash_flash(c, &dent->key);
file->f_pos = pos = key_hash_flash(c, &dent->key);
file->private_data = dent;
}
@ -397,17 +416,16 @@ static int ubifs_readdir(struct file *file, void *dirent, filldir_t filldir)
if (!dent) {
/*
* The directory was seek'ed to and is now readdir'ed.
* Find the entry corresponding to @file->f_pos or the
* closest one.
* Find the entry corresponding to @pos or the closest one.
*/
dent_key_init_hash(c, &key, dir->i_ino, file->f_pos);
dent_key_init_hash(c, &key, dir->i_ino, pos);
nm.name = NULL;
dent = ubifs_tnc_next_ent(c, &key, &nm);
if (IS_ERR(dent)) {
err = PTR_ERR(dent);
goto out;
}
file->f_pos = key_hash_flash(c, &dent->key);
file->f_pos = pos = key_hash_flash(c, &dent->key);
file->private_data = dent;
}
@ -419,7 +437,7 @@ static int ubifs_readdir(struct file *file, void *dirent, filldir_t filldir)
ubifs_inode(dir)->creat_sqnum);
nm.len = le16_to_cpu(dent->nlen);
over = filldir(dirent, dent->name, nm.len, file->f_pos,
over = filldir(dirent, dent->name, nm.len, pos,
le64_to_cpu(dent->inum),
vfs_dent_type(dent->type));
if (over)
@ -435,9 +453,17 @@ static int ubifs_readdir(struct file *file, void *dirent, filldir_t filldir)
}
kfree(file->private_data);
file->f_pos = key_hash_flash(c, &dent->key);
file->f_pos = pos = key_hash_flash(c, &dent->key);
file->private_data = dent;
cond_resched();
if (file->f_version == 0)
/*
* The file was seek'ed meanwhile, lets return and start
* reading direntries from the new position on the next
* invocation.
*/
return 0;
}
out:
@ -448,15 +474,13 @@ out:
kfree(file->private_data);
file->private_data = NULL;
/* 2 is a special value indicating that there are no more direntries */
file->f_pos = 2;
return 0;
}
/* If a directory is seeked, we have to free saved readdir() state */
static loff_t ubifs_dir_llseek(struct file *file, loff_t offset, int whence)
{
kfree(file->private_data);
file->private_data = NULL;
return generic_file_llseek(file, offset, whence);
}