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

Pull overlayfs fixes from Miklos Szeredi:
 "Fix regressions:

   - missing CONFIG_EXPORTFS dependency

   - failure if upper fs doesn't support xattr

   - bad error cleanup

  This also adds the concept of "impure" directories complementing the
  "origin" marking introduced in -rc1. Together they enable getting
  consistent st_ino and d_ino for directory listings.

  And there's a bug fix and a cleanup as well"

* 'overlayfs-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/vfs:
  ovl: filter trusted xattr for non-admin
  ovl: mark upper merge dir with type origin entries "impure"
  ovl: mark upper dir with type origin entries "impure"
  ovl: remove unused arg from ovl_lookup_temp()
  ovl: handle rename when upper doesn't support xattr
  ovl: don't fail copy-up if upper doesn't support xattr
  ovl: check on mount time if upper fs supports setting xattr
  ovl: fix creds leak in copy up error path
  ovl: select EXPORTFS
hifive-unleashed-5.1
Linus Torvalds 2017-05-31 08:29:02 -07:00
parent f511c0b17b a082c6f680
commit d602fb6844
9 changed files with 178 additions and 44 deletions
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1
fs/overlayfs/Kconfig
View File

@ -1,5 +1,6 @@
config OVERLAY_FS
tristate "Overlay filesystem support"
select EXPORTFS
help
An overlay filesystem combines two filesystems - an 'upper' filesystem
and a 'lower' filesystem. When a name exists in both filesystems, the

24
fs/overlayfs/copy_up.c
View File

@ -300,7 +300,11 @@ static int ovl_set_origin(struct dentry *dentry, struct dentry *lower,
return PTR_ERR(fh);
}
err = ovl_do_setxattr(upper, OVL_XATTR_ORIGIN, fh, fh ? fh->len : 0, 0);
/*
* Do not fail when upper doesn't support xattrs.
*/
err = ovl_check_setxattr(dentry, upper, OVL_XATTR_ORIGIN, fh,
fh ? fh->len : 0, 0);
kfree(fh);
return err;
@ -342,13 +346,14 @@ static int ovl_copy_up_locked(struct dentry *workdir, struct dentry *upperdir,
if (tmpfile)
temp = ovl_do_tmpfile(upperdir, stat->mode);
else
temp = ovl_lookup_temp(workdir, dentry);
err = PTR_ERR(temp);
if (IS_ERR(temp))
goto out1;
temp = ovl_lookup_temp(workdir);
err = 0;
if (!tmpfile)
if (IS_ERR(temp)) {
err = PTR_ERR(temp);
temp = NULL;
}
if (!err && !tmpfile)
err = ovl_create_real(wdir, temp, &cattr, NULL, true);
if (new_creds) {
@ -454,6 +459,11 @@ static int ovl_copy_up_one(struct dentry *parent, struct dentry *dentry,
ovl_path_upper(parent, &parentpath);
upperdir = parentpath.dentry;
/* Mark parent "impure" because it may now contain non-pure upper */
err = ovl_set_impure(parent, upperdir);
if (err)
return err;
err = vfs_getattr(&parentpath, &pstat,
STATX_ATIME | STATX_MTIME, AT_STATX_SYNC_AS_STAT);
if (err)

61
fs/overlayfs/dir.c
View File

@ -41,7 +41,7 @@ void ovl_cleanup(struct inode *wdir, struct dentry *wdentry)
}
}
struct dentry *ovl_lookup_temp(struct dentry *workdir, struct dentry *dentry)
struct dentry *ovl_lookup_temp(struct dentry *workdir)
{
struct dentry *temp;
char name[20];
@ -68,7 +68,7 @@ static struct dentry *ovl_whiteout(struct dentry *workdir,
struct dentry *whiteout;
struct inode *wdir = workdir->d_inode;
whiteout = ovl_lookup_temp(workdir, dentry);
whiteout = ovl_lookup_temp(workdir);
if (IS_ERR(whiteout))
return whiteout;
@ -127,17 +127,28 @@ int ovl_create_real(struct inode *dir, struct dentry *newdentry,
return err;
}
static int ovl_set_opaque(struct dentry *dentry, struct dentry *upperdentry)
static int ovl_set_opaque_xerr(struct dentry *dentry, struct dentry *upper,
int xerr)
{
int err;
err = ovl_do_setxattr(upperdentry, OVL_XATTR_OPAQUE, "y", 1, 0);
err = ovl_check_setxattr(dentry, upper, OVL_XATTR_OPAQUE, "y", 1, xerr);
if (!err)
ovl_dentry_set_opaque(dentry);
return err;
}
static int ovl_set_opaque(struct dentry *dentry, struct dentry *upperdentry)
{
/*
* Fail with -EIO when trying to create opaque dir and upper doesn't
* support xattrs. ovl_rename() calls ovl_set_opaque_xerr(-EXDEV) to
* return a specific error for noxattr case.
*/
return ovl_set_opaque_xerr(dentry, upperdentry, -EIO);
}
/* Common operations required to be done after creation of file on upper */
static void ovl_instantiate(struct dentry *dentry, struct inode *inode,
struct dentry *newdentry, bool hardlink)
@ -162,6 +173,11 @@ static bool ovl_type_merge(struct dentry *dentry)
return OVL_TYPE_MERGE(ovl_path_type(dentry));
}
static bool ovl_type_origin(struct dentry *dentry)
{
return OVL_TYPE_ORIGIN(ovl_path_type(dentry));
}
static int ovl_create_upper(struct dentry *dentry, struct inode *inode,
struct cattr *attr, struct dentry *hardlink)
{
@ -250,7 +266,7 @@ static struct dentry *ovl_clear_empty(struct dentry *dentry,
if (upper->d_parent->d_inode != udir)
goto out_unlock;
opaquedir = ovl_lookup_temp(workdir, dentry);
opaquedir = ovl_lookup_temp(workdir);
err = PTR_ERR(opaquedir);
if (IS_ERR(opaquedir))
goto out_unlock;
@ -382,7 +398,7 @@ static int ovl_create_over_whiteout(struct dentry *dentry, struct inode *inode,
if (err)
goto out;
newdentry = ovl_lookup_temp(workdir, dentry);
newdentry = ovl_lookup_temp(workdir);
err = PTR_ERR(newdentry);
if (IS_ERR(newdentry))
goto out_unlock;
@ -846,18 +862,16 @@ static int ovl_set_redirect(struct dentry *dentry, bool samedir)
if (IS_ERR(redirect))
return PTR_ERR(redirect);
err = ovl_do_setxattr(ovl_dentry_upper(dentry), OVL_XATTR_REDIRECT,
redirect, strlen(redirect), 0);
err = ovl_check_setxattr(dentry, ovl_dentry_upper(dentry),
OVL_XATTR_REDIRECT,
redirect, strlen(redirect), -EXDEV);
if (!err) {
spin_lock(&dentry->d_lock);
ovl_dentry_set_redirect(dentry, redirect);
spin_unlock(&dentry->d_lock);
} else {
kfree(redirect);
if (err == -EOPNOTSUPP)
ovl_clear_redirect_dir(dentry->d_sb);
else
pr_warn_ratelimited("overlay: failed to set redirect (%i)\n", err);
pr_warn_ratelimited("overlay: failed to set redirect (%i)\n", err);
/* Fall back to userspace copy-up */
err = -EXDEV;
}
@ -943,6 +957,25 @@ static int ovl_rename(struct inode *olddir, struct dentry *old,
old_upperdir = ovl_dentry_upper(old->d_parent);
new_upperdir = ovl_dentry_upper(new->d_parent);
if (!samedir) {
/*
* When moving a merge dir or non-dir with copy up origin into
* a new parent, we are marking the new parent dir "impure".
* When ovl_iterate() iterates an "impure" upper dir, it will
* lookup the origin inodes of the entries to fill d_ino.
*/
if (ovl_type_origin(old)) {
err = ovl_set_impure(new->d_parent, new_upperdir);
if (err)
goto out_revert_creds;
}
if (!overwrite && ovl_type_origin(new)) {
err = ovl_set_impure(old->d_parent, old_upperdir);
if (err)
goto out_revert_creds;
}
}
trap = lock_rename(new_upperdir, old_upperdir);
olddentry = lookup_one_len(old->d_name.name, old_upperdir,
@ -992,7 +1025,7 @@ static int ovl_rename(struct inode *olddir, struct dentry *old,
if (ovl_type_merge_or_lower(old))
err = ovl_set_redirect(old, samedir);
else if (!old_opaque && ovl_type_merge(new->d_parent))
err = ovl_set_opaque(old, olddentry);
err = ovl_set_opaque_xerr(old, olddentry, -EXDEV);
if (err)
goto out_dput;
}
@ -1000,7 +1033,7 @@ static int ovl_rename(struct inode *olddir, struct dentry *old,
if (ovl_type_merge_or_lower(new))
err = ovl_set_redirect(new, samedir);
else if (!new_opaque && ovl_type_merge(old->d_parent))
err = ovl_set_opaque(new, newdentry);
err = ovl_set_opaque_xerr(new, newdentry, -EXDEV);
if (err)
goto out_dput;
}

12
fs/overlayfs/inode.c
View File

@ -240,6 +240,16 @@ int ovl_xattr_get(struct dentry *dentry, const char *name,
return res;
}
static bool ovl_can_list(const char *s)
{
/* List all non-trusted xatts */
if (strncmp(s, XATTR_TRUSTED_PREFIX, XATTR_TRUSTED_PREFIX_LEN) != 0)
return true;
/* Never list trusted.overlay, list other trusted for superuser only */
return !ovl_is_private_xattr(s) && capable(CAP_SYS_ADMIN);
}
ssize_t ovl_listxattr(struct dentry *dentry, char *list, size_t size)
{
struct dentry *realdentry = ovl_dentry_real(dentry);
@ -263,7 +273,7 @@ ssize_t ovl_listxattr(struct dentry *dentry, char *list, size_t size)
return -EIO;
len -= slen;
if (ovl_is_private_xattr(s)) {
if (!ovl_can_list(s)) {
res -= slen;
memmove(s, s + slen, len);
} else {

16
fs/overlayfs/namei.c
View File

@ -169,17 +169,7 @@ invalid:
static bool ovl_is_opaquedir(struct dentry *dentry)
{
int res;
char val;
if (!d_is_dir(dentry))
return false;
res = vfs_getxattr(dentry, OVL_XATTR_OPAQUE, &val, 1);
if (res == 1 && val == 'y')
return true;
return false;
return ovl_check_dir_xattr(dentry, OVL_XATTR_OPAQUE);
}
static int ovl_lookup_single(struct dentry *base, struct ovl_lookup_data *d,
@ -351,6 +341,7 @@ struct dentry *ovl_lookup(struct inode *dir, struct dentry *dentry,
unsigned int ctr = 0;
struct inode *inode = NULL;
bool upperopaque = false;
bool upperimpure = false;
char *upperredirect = NULL;
struct dentry *this;
unsigned int i;
@ -395,6 +386,8 @@ struct dentry *ovl_lookup(struct inode *dir, struct dentry *dentry,
poe = roe;
}
upperopaque = d.opaque;
if (upperdentry && d.is_dir)
upperimpure = ovl_is_impuredir(upperdentry);
}
if (!d.stop && poe->numlower) {
@ -463,6 +456,7 @@ struct dentry *ovl_lookup(struct inode *dir, struct dentry *dentry,
revert_creds(old_cred);
oe->opaque = upperopaque;
oe->impure = upperimpure;
oe->redirect = upperredirect;
oe->__upperdentry = upperdentry;
memcpy(oe->lowerstack, stack, sizeof(struct path) * ctr);

16
fs/overlayfs/overlayfs.h
View File

@ -24,6 +24,7 @@ enum ovl_path_type {
#define OVL_XATTR_OPAQUE OVL_XATTR_PREFIX "opaque"
#define OVL_XATTR_REDIRECT OVL_XATTR_PREFIX "redirect"
#define OVL_XATTR_ORIGIN OVL_XATTR_PREFIX "origin"
#define OVL_XATTR_IMPURE OVL_XATTR_PREFIX "impure"
/*
* The tuple (fh,uuid) is a universal unique identifier for a copy up origin,
@ -203,10 +204,10 @@ struct dentry *ovl_dentry_real(struct dentry *dentry);
struct ovl_dir_cache *ovl_dir_cache(struct dentry *dentry);
void ovl_set_dir_cache(struct dentry *dentry, struct ovl_dir_cache *cache);
bool ovl_dentry_is_opaque(struct dentry *dentry);
bool ovl_dentry_is_impure(struct dentry *dentry);
bool ovl_dentry_is_whiteout(struct dentry *dentry);
void ovl_dentry_set_opaque(struct dentry *dentry);
bool ovl_redirect_dir(struct super_block *sb);
void ovl_clear_redirect_dir(struct super_block *sb);
const char *ovl_dentry_get_redirect(struct dentry *dentry);
void ovl_dentry_set_redirect(struct dentry *dentry, const char *redirect);
void ovl_dentry_update(struct dentry *dentry, struct dentry *upperdentry);
@ -219,6 +220,17 @@ bool ovl_is_whiteout(struct dentry *dentry);
struct file *ovl_path_open(struct path *path, int flags);
int ovl_copy_up_start(struct dentry *dentry);
void ovl_copy_up_end(struct dentry *dentry);
bool ovl_check_dir_xattr(struct dentry *dentry, const char *name);
int ovl_check_setxattr(struct dentry *dentry, struct dentry *upperdentry,
const char *name, const void *value, size_t size,
int xerr);
int ovl_set_impure(struct dentry *dentry, struct dentry *upperdentry);
static inline bool ovl_is_impuredir(struct dentry *dentry)
{
return ovl_check_dir_xattr(dentry, OVL_XATTR_IMPURE);
}
/* namei.c */
int ovl_path_next(int idx, struct dentry *dentry, struct path *path);
@ -263,7 +275,7 @@ static inline void ovl_copyattr(struct inode *from, struct inode *to)
/* dir.c */
extern const struct inode_operations ovl_dir_inode_operations;
struct dentry *ovl_lookup_temp(struct dentry *workdir, struct dentry *dentry);
struct dentry *ovl_lookup_temp(struct dentry *workdir);
struct cattr {
dev_t rdev;
umode_t mode;

2
fs/overlayfs/ovl_entry.h
View File

@ -28,6 +28,7 @@ struct ovl_fs {
/* creds of process who forced instantiation of super block */
const struct cred *creator_cred;
bool tmpfile;
bool noxattr;
wait_queue_head_t copyup_wq;
/* sb common to all layers */
struct super_block *same_sb;
@ -42,6 +43,7 @@ struct ovl_entry {
u64 version;
const char *redirect;
bool opaque;
bool impure;
bool copying;
};
struct rcu_head rcu;

18
fs/overlayfs/super.c
View File

@ -891,6 +891,19 @@ static int ovl_fill_super(struct super_block *sb, void *data, int silent)
dput(temp);
else
pr_warn("overlayfs: upper fs does not support tmpfile.\n");
/*
* Check if upper/work fs supports trusted.overlay.*
* xattr
*/
err = ovl_do_setxattr(ufs->workdir, OVL_XATTR_OPAQUE,
"0", 1, 0);
if (err) {
ufs->noxattr = true;
pr_warn("overlayfs: upper fs does not support xattr.\n");
} else {
vfs_removexattr(ufs->workdir, OVL_XATTR_OPAQUE);
}
}
}
@ -961,7 +974,10 @@ static int ovl_fill_super(struct super_block *sb, void *data, int silent)
path_put(&workpath);
kfree(lowertmp);
oe->__upperdentry = upperpath.dentry;
if (upperpath.dentry) {
oe->__upperdentry = upperpath.dentry;
oe->impure = ovl_is_impuredir(upperpath.dentry);
}
for (i = 0; i < numlower; i++) {
oe->lowerstack[i].dentry = stack[i].dentry;
oe->lowerstack[i].mnt = ufs->lower_mnt[i];

72
fs/overlayfs/util.c
View File

@ -175,6 +175,13 @@ bool ovl_dentry_is_opaque(struct dentry *dentry)
return oe->opaque;
}
bool ovl_dentry_is_impure(struct dentry *dentry)
{
struct ovl_entry *oe = dentry->d_fsdata;
return oe->impure;
}
bool ovl_dentry_is_whiteout(struct dentry *dentry)
{
return !dentry->d_inode && ovl_dentry_is_opaque(dentry);
@ -191,14 +198,7 @@ bool ovl_redirect_dir(struct super_block *sb)
{
struct ovl_fs *ofs = sb->s_fs_info;
return ofs->config.redirect_dir;
}
void ovl_clear_redirect_dir(struct super_block *sb)
{
struct ovl_fs *ofs = sb->s_fs_info;
ofs->config.redirect_dir = false;
return ofs->config.redirect_dir && !ofs->noxattr;
}
const char *ovl_dentry_get_redirect(struct dentry *dentry)
@ -303,3 +303,59 @@ void ovl_copy_up_end(struct dentry *dentry)
wake_up_locked(&ofs->copyup_wq);
spin_unlock(&ofs->copyup_wq.lock);
}
bool ovl_check_dir_xattr(struct dentry *dentry, const char *name)
{
int res;
char val;
if (!d_is_dir(dentry))
return false;
res = vfs_getxattr(dentry, name, &val, 1);
if (res == 1 && val == 'y')
return true;
return false;
}
int ovl_check_setxattr(struct dentry *dentry, struct dentry *upperdentry,
const char *name, const void *value, size_t size,
int xerr)
{
int err;
struct ovl_fs *ofs = dentry->d_sb->s_fs_info;
if (ofs->noxattr)
return xerr;
err = ovl_do_setxattr(upperdentry, name, value, size, 0);
if (err == -EOPNOTSUPP) {
pr_warn("overlayfs: cannot set %s xattr on upper\n", name);
ofs->noxattr = true;
return xerr;
}
return err;
}
int ovl_set_impure(struct dentry *dentry, struct dentry *upperdentry)
{
int err;
struct ovl_entry *oe = dentry->d_fsdata;
if (oe->impure)
return 0;
/*
* Do not fail when upper doesn't support xattrs.
* Upper inodes won't have origin nor redirect xattr anyway.
*/
err = ovl_check_setxattr(dentry, upperdentry, OVL_XATTR_IMPURE,
"y", 1, 0);
if (!err)
oe->impure = true;
return err;
}